diff --git a/.gitignore b/.gitignore
index 6311c3e..66fa4a6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,3 +8,4 @@
 MANIFEST
 docs/build/
 tests_env/
+*.zip
diff --git a/docs/source/conf.py b/docs/source/conf.py
index 43be1a0..40647a0 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -17,7 +17,10 @@
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
 #sys.path.insert(0, os.path.abspath('.'))
-sys.path.append("..")
+#sys.path.append("..")
+# Use path in the SDK. Hence need to override system package path by inserting
+# to position 0.
+sys.path.insert(0, "..")
 
 # -- General configuration -----------------------------------------------------
 
@@ -42,16 +45,16 @@
 
 # General information about the project.
 project = u'PredictionIO Python SDK'
-copyright = u'2013, TappingStone, Inc.'
+copyright = u'2014, TappingStone, Inc.'
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
 # The short X.Y version.
-version = '0.7'
+version = '0.8'
 # The full version, including alpha/beta/rc tags.
-release = '0.7.0'
+release = '0.8.0'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
diff --git a/docs/source/index.rst b/docs/source/index.rst
index dfad529..bc7a25b 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -43,6 +43,7 @@
    :maxdepth: 1
 
    predictionio
+   predictionio_legacy
 
 
 Getting Help
diff --git a/docs/source/predictionio.rst b/docs/source/predictionio.rst
index 4249a99..e7b90e7 100644
--- a/docs/source/predictionio.rst
+++ b/docs/source/predictionio.rst
@@ -3,122 +3,74 @@
 
 .. automodule:: predictionio
 
-predictionio.Client Usage Overview
---------------------------------------
+The SDK comprises of two clients: 
 
-Before making any request through the PredictionIO API, you need to create a client object for your App.
+1. EventClient, it is for importing data into the PredictionIO platform. 
+2. EngineClient, it is for querying PredictionIO Engine Instance, submit query
+   and extract prediction results.
 
-    >>> client = predictionio.Client(<your App Key>)
+Please read `PredictionIO Quick Start
+<http://docs.prediction.io/0.8.0/tutorials/engines/quickstart.html>`_ for
+detailed explanation.
 
-.. note:: The App Key can be found in the PredictionIO Admin Server web control panel.
+predictionio.EventClient Class
+------------------------------
 
-Afterwards, you can import data or retrieve recommendations for your App by calling methods of this object. For example,
+.. autoclass:: EventClient
+  :members:
 
-**User**
+  .. note::
 
-  To import a user record from you App with user id = "u100":
+    The "threads" parameter specifies the number of connection threads to
+    the PredictionIO server. Minimum is 1. The client object will spawn
+    out the specified number of threads. Each of them will establish a
+    connection with the PredictionIO server and handle requests
+    concurrently.
 
-    >>> client.create_user("u100")
+  .. note::
 
-  To import a user record with the optional predefined location attribute "pio_latlng":
+    If you ONLY use `blocking request methods`,
+    setting "threads" to 1 is enough (higher number will not improve
+    anything since every request will be blocking). However, if you want
+    to take full advantage of
+    `asynchronous request methods`, you should
+    specify a larger number for "threads" to increase the performance of
+    handling concurrent requests (although setting "threads" to 1 will still
+    work). The optimal setting depends on your system and application
+    requirement.
+   
 
-    >>> client.create_user("u100", { "pio_latlng" : [1.23, 4.56] })
+predictionio.EngineClient Class
+------------------------------
 
-  You may also define your own custom attribute "custom" = "value":
+.. autoclass:: EngineClient
+   :members:
 
-    >>> client.create_user("u100", { "pio_latlng" : [1.23, 4.56], "custom": "value" })
+predictionio.AsyncRequest Class
+------------------------------
 
-  .. note:: custom attributes and values could be any string but all attribute names with prefix ``'pio_'`` are reserved. You should not use the prefix ``'pio_'`` when define your custom attributes to avoid conflicts.
+.. autoclass:: AsyncRequest
+   :members:
 
-**Item**
-
-  To import an item record from your App with item id = "i200" and item type = "type3":
-
-    >>> client.create_item("i200", ("type3",))
-
-  To import an item record with the predefined optional attribute "pio_latlng":
-
-    >>> client.create_item("i200", ("type3",), { "pio_latlng" : [1.23, 4.56] })
-
-  You may also define your own custom attribute "custom" = "value":
-
-    >>> client.create_item("i200", ("type3",), { "pio_latlng" : [1.23, 4.56], "custom": "value" })
-
-  .. note:: custom attributes and values could be any string but all attribute names with prefix ``'pio_'`` are reserved. You should not use the prefix ``'pio_'`` when define your custom attributes to avoid conflicts.
-
-**User Action on Item**
-
-  To import a user "rate" action record from your App with user id = "u100", item id = "i200" and rating = 2:
-
-    >>> client.identify("u100")
-    >>> client.record_action_on_item("rate", "i200", { "pio_rate": 2 })
-
-  .. note:: the "pio_rate" attribute is required for "rate" action.
-
-  To import a "view" action record from your App for the same user and item:
-
-    >>> client.record_action_on_item("view", "i200" )
-
-  To import a "like" record with predefined optional timestamp attribute "pio_t":
-
-    >>> client.record_action_on_item("like", "i200", { "pio_t": 12345678 })
-
-  .. note:: predefined actions: "like", "dislike", "rate", "view", "conversion"
-
-**Item Recommendation Engine**
-
-  When there is enough data imported from your App and the prediction results are ready, you can get recommendations for a user.
-
-  To get top 5 item recommendation for the same user id from the item recommendation engine "engine-1"
-
-    >>> result = client.get_itemrec_topn("engine-1", 5)
-
-**Item Similarity Engine**
-
-  To get top 5 similar items of the item i200 from the item similarity engine "engine-2"
-
-    >>> result = client.get_itemsim_topn("engine-2", "i200", 5)
-
-  To get top 5 similar items given a list of items i200,i300,i400 from the item similarity engine "engine-2"
-
-    >>> result = client.get_itemsim_topn("engine-2", "i200,i300,i400", 5)
-
-**Item Rank Engine**
-
-  To rank a list of items i100, i101, i102, i103 for user "u100" from the item rank engine "engine-3"
-
-    >>> client.identify("u100")
-    >>> result = client.get_itemrank_ranked("engine-3", ["i100","i101","i102", "i103"])
-
-
-Please refer to the documentation of the :class:`predictionio.Client` class for more details of all available methods.
-
-
-Error Handling
---------------
-
-An exception will be raised when an error occur during the request. Please refer to the documentation of the :class:`predictionio.Client` class for details.
-In general, you may want to catch the exception and decide what to do with the error (such as logging it).
-
-For example, the method :meth:`~Client.record_action_on_item` may raise ``U2IActionNotCreatedError``.
-
-   >>> try:
-   >>>   client.record_action_on_item("view", "i200")
-   >>> except:
-   >>>   <log the error>
-
+predictionio SDK Usage Notes
+-------------------------
 
 Asynchronous Requests
----------------------
+^^^^^^^^^^^^^^^^^^^^^
 
-In addition to normal :ref:`blocking (synchronous) request methods <sync-methods-label>`, this SDK also provides :ref:`methods which can generate asynchronous requests <async-methods-label>`.
-All methods prefixed with 'a' are asynchronous (eg, :meth:`~Client.acreate_user`, :meth:`~Client.acreate_item`).
-Asynchronous requests are handled by separate threads in the background, so you can generate multiple requests at the same time without waiting for any of them to finish.
-These methods return immediately without waiting for results, allowing your code to proceed to work on something else.
-The concept is to break a normal blocking request (such as :meth:`~Client.create_user`) into two steps:
+In addition to normal `blocking (synchronous) request methods`,
+this SDK also provides `non-blocking (asynchronous) request methods`.
+All methods
+prefixed with 'a' are asynchronous (eg, :meth:`~EventClient.aset_user`,
+:meth:`~EventClient.aset_item`).  Asynchronous requests are handled by separate
+threads in the background, so you can generate multiple requests at the same
+time without waiting for any of them to finish.  These methods return
+immediately without waiting for results, allowing your code to proceed to work
+on something else.  The concept is to break a normal blocking request (such as
+:meth:`~EventClient.set_user`) into two steps:
 
-1. generate the request (e.g., calling :meth:`~Client.acreate_user`);
-2. get the request status and return data (calling :meth:`~Client.aresp`);
+1. generate the request (e.g., calling :meth:`~EngineClient.asend_query`);
+2. get the request's response by calling :meth:`~AsyncRequest.get_response`.
 
 This allows you to do other work between these two steps.
 
@@ -129,208 +81,44 @@
    If you do care about the request status or need to get the return data, then at a later time you will need to call :meth:`~Client.aresp` with the AsyncRequest object returned in step 1.
    Please refer to the documentation of :ref:`asynchronous request methods <async-methods-label>` for more details.
 
-For example, the following code first generates an asynchronous request to retrieve recommendations, then get the result at later time::
+For example, the following code first generates an asynchronous request to
+retrieve recommendations, then get the result at later time::
 
     >>> # Generates asynchronous request and return an AsyncRequest object
-    >>> request = client.aget_itemrec_topn("engine-1", 5)
+    >>> engine_client = EngineClient()
+    >>> request = engine_client.asend_query(data={"uid": "1", "n" : 3})
     >>> <...you can do other things here...>
     >>> try:
-    >>>    result = client.aresp(request) # check the request status and get the return data.
+    >>>    result = request.get_response() # check the request status and get the return data.
     >>> except:
     >>>    <log the error>
 
 
 Batch Import Data
------------------
+^^^^^^^^^^^^^^^^^^^^^
 
-When you import large amount of data at once, you may also use asynchronous request methods to generate lots of requests in the beginning and then check the status at a later time to minimize run time.
+When you import large amount of data at once, you may also use asynchronous
+request methods to generate lots of requests in the beginning and then check the
+status at a later time to minimize run time.
 
 For example, to import 100000 of user records::
 
   >>> # generate 100000 asynchronous requests and store the AsyncRequest objects
-  >>> req = {}
+  >>> event_client = EventClient(app_id=1)
   >>> for i in range(100000):
-  >>>    req[i] = client.acreate_user(user_record[i].uid)
+  >>>   event_client.aset_user(user_record[i].uid)
   >>>
   >>> <...you can do other things here...>
   >>>
-  >>> # now check the status of the previous asynchronous requests
-  >>> for i in range(100000):
-  >>>   try:
-  >>>     result = client.aresp(req[i])
-  >>>   except:
-  >>>     <log the error>
+  >>> # calling close will block until all requests are processed
+  >>> event_client.close()
 
 Alternatively, you can use blocking requests to import large amount of data, but this has significantly lower performance::
 
   >>> for i in range(100000):
   >>>   try:
-  >>>      client.create_user(user_record[i].uid)
+  >>>      client.set_user(user_record[i].uid)
   >>>   except:
   >>>      <log the error>
 
 
-|
-
-predictionio.Client Class
----------------------------------
-
-.. Autoclass:: Client
-
-  .. note::
-
-    The "threads" parameter specifies the number of connection threads to
-    the PredictionIO API server. Minimum is 1. The client object will spawn
-    out the specified number of threads. Each of them will establish a
-    connection with the PredictionIO API server and handle requests
-    concurrently.
-
-  .. note::
-
-    If you ONLY use :ref:`blocking request methods <sync-methods-label>`,
-    setting "threads" to 1 is enough (higher number will not improve
-    anything since every request will be blocking). However, if you want
-    to take full advantage of
-    :ref:`asynchronous request methods <async-methods-label>`, you should
-    specify a larger number for "threads" to increase the performance of
-    handling concurrent requests (although setting "threads" to 1 will still
-    work). The optimal setting depends on your system and application
-    requirement.
-
-  .. automethod:: close
-  .. automethod:: identify
-
-    .. versionadded:: 0.5.0
-
-  .. automethod:: pending_requests
-
-    .. versionadded:: 0.6.1
-
-  |
-
-  .. _sync-methods-label:
-
-  .. note:: The following is blocking (synchronous) request methods
-
-  .. automethod:: get_status
-  .. automethod:: create_user
-  .. automethod:: get_user
-  .. automethod:: delete_user
-
-  .. automethod:: create_item
-  .. automethod:: get_item
-  .. automethod:: delete_item
-
-  .. automethod:: record_action_on_item
-
-    .. versionadded:: 0.5.0
-
-  .. automethod:: get_itemrec_topn
-
-    .. versionadded:: 0.5.0
-
-    .. versionchanged:: 0.6.0
-      Change the order of parameters.
-
-  .. automethod:: get_itemsim_topn
-
-    .. versionadded:: 0.6.0
-
-  .. automethod:: get_itemrank_ranked
-
-    .. versionadded:: 0.7.0
-
-  .. automethod:: get_itemrec
-
-    .. deprecated:: 0.5.0
-      Use :func:`get_itemrec_topn` instead.
-
-  .. automethod:: user_conversion_item
-
-    .. deprecated:: 0.5.0
-      Use :func:`record_action_on_item` instead.
-
-  .. automethod:: user_dislike_item
-
-    .. deprecated:: 0.5.0
-      Use :func:`record_action_on_item` instead.
-
-  .. automethod:: user_like_item
-
-    .. deprecated:: 0.5.0
-      Use :func:`record_action_on_item` instead.
-
-  .. automethod:: user_rate_item
-
-    .. deprecated:: 0.5.0
-      Use :func:`record_action_on_item` instead.
-
-  .. automethod:: user_view_item
-
-    .. deprecated:: 0.5.0
-      Use :func:`record_action_on_item` instead.
-
-  |
-
-  .. _async-methods-label:
-
-  .. note:: The following is non-blocking (asynchronous) request methods
-
-  .. automethod:: acreate_user
-  .. automethod:: aget_user
-  .. automethod:: adelete_user
-
-  .. automethod:: acreate_item
-  .. automethod:: aget_item
-  .. automethod:: adelete_item
-
-  .. automethod:: arecord_action_on_item
-
-    .. versionadded:: 0.5.0
-
-  .. automethod:: aget_itemrec_topn
-
-    .. versionadded:: 0.5.0
-
-    .. versionchanged:: 0.6.0
-      Change the order of parameters.
-
-  .. automethod:: aget_itemsim_topn
-
-    .. versionadded:: 0.6.0
-
-  .. automethod:: aget_itemrank_ranked
-
-    .. versionadded:: 0.7.0
-
-  .. automethod:: aget_itemrec
-
-    .. deprecated:: 0.5.0
-      Use :func:`aget_itemrec_topn` instead.
-
-  .. automethod:: auser_conversion_item
-
-    .. deprecated:: 0.5.0
-      Use :func:`arecord_action_on_item` instead.
-
-  .. automethod:: auser_dislike_item
-
-    .. deprecated:: 0.5.0
-      Use :func:`arecord_action_on_item` instead.
-
-  .. automethod:: auser_like_item
-
-    .. deprecated:: 0.5.0
-      Use :func:`arecord_action_on_item` instead.
-
-  .. automethod:: auser_rate_item
-
-    .. deprecated:: 0.5.0
-      Use :func:`arecord_action_on_item` instead.
-
-  .. automethod:: auser_view_item
-
-    .. deprecated:: 0.5.0
-      Use :func:`arecord_action_on_item` instead.
-
-  .. automethod:: aresp
diff --git a/docs/source/predictionio_legacy.rst b/docs/source/predictionio_legacy.rst
new file mode 100644
index 0000000..42e8edb
--- /dev/null
+++ b/docs/source/predictionio_legacy.rst
@@ -0,0 +1,325 @@
+predictionio Legacy Package Documentation
+====================================
+
+.. automodule:: predictionio
+
+predictionio.Client (Deprecated) Usage Overview
+--------------------------------------
+
+.. deprecated:: 0.8.0
+
+Before making any request through the PredictionIO API, you need to create a
+client object for your App.
+
+    >>> client = predictionio.Client(<your App Key>)
+
+.. note:: The App Key can be found in the PredictionIO Admin Server web control panel.
+
+Afterwards, you can import data or retrieve recommendations for your App by
+calling methods of this object. For example,
+
+**User**
+
+  To import a user record from you App with user id = "u100":
+
+    >>> client.create_user("u100")
+
+  To import a user record with the optional predefined location attribute "pio_latlng":
+
+    >>> client.create_user("u100", { "pio_latlng" : [1.23, 4.56] })
+
+  You may also define your own custom attribute "custom" = "value":
+
+    >>> client.create_user("u100", { "pio_latlng" : [1.23, 4.56], "custom": "value" })
+
+  .. note:: custom attributes and values could be any string but all attribute names with prefix ``'pio_'`` are reserved. You should not use the prefix ``'pio_'`` when define your custom attributes to avoid conflicts.
+
+**Item**
+
+  To import an item record from your App with item id = "i200" and item type = "type3":
+
+    >>> client.create_item("i200", ("type3",))
+
+  To import an item record with the predefined optional attribute "pio_latlng":
+
+    >>> client.create_item("i200", ("type3",), { "pio_latlng" : [1.23, 4.56] })
+
+  You may also define your own custom attribute "custom" = "value":
+
+    >>> client.create_item("i200", ("type3",), { "pio_latlng" : [1.23, 4.56], "custom": "value" })
+
+  .. note:: custom attributes and values could be any string but all attribute names with prefix ``'pio_'`` are reserved. You should not use the prefix ``'pio_'`` when define your custom attributes to avoid conflicts.
+
+**User Action on Item**
+
+  To import a user "rate" action record from your App with user id = "u100", item id = "i200" and rating = 2:
+
+    >>> client.identify("u100")
+    >>> client.record_action_on_item("rate", "i200", { "pio_rate": 2 })
+
+  .. note:: the "pio_rate" attribute is required for "rate" action.
+
+  To import a "view" action record from your App for the same user and item:
+
+    >>> client.record_action_on_item("view", "i200" )
+
+  To import a "like" record with predefined optional timestamp attribute "pio_t":
+
+    >>> client.record_action_on_item("like", "i200", { "pio_t": 12345678 })
+
+  .. note:: predefined actions: "like", "dislike", "rate", "view", "conversion"
+
+**Item Recommendation Engine**
+
+  When there is enough data imported from your App and the prediction results are ready, you can get recommendations for a user.
+
+  To get top 5 item recommendation for the same user id from the item recommendation engine "engine-1"
+
+    >>> result = client.get_itemrec_topn("engine-1", 5)
+
+**Item Similarity Engine**
+
+  To get top 5 similar items of the item i200 from the item similarity engine "engine-2"
+
+    >>> result = client.get_itemsim_topn("engine-2", "i200", 5)
+
+  To get top 5 similar items given a list of items i200,i300,i400 from the item similarity engine "engine-2"
+
+    >>> result = client.get_itemsim_topn("engine-2", "i200,i300,i400", 5)
+
+**Item Rank Engine**
+
+  To rank a list of items i100, i101, i102, i103 for user "u100" from the item rank engine "engine-3"
+
+    >>> client.identify("u100")
+    >>> result = client.get_itemrank_ranked("engine-3", ["i100","i101","i102", "i103"])
+
+
+Please refer to the documentation of the :class:`predictionio.Client` class for more details of all available methods.
+
+
+Error Handling
+--------------
+
+An exception will be raised when an error occur during the request. Please refer to the documentation of the :class:`predictionio.Client` class for details.
+In general, you may want to catch the exception and decide what to do with the error (such as logging it).
+
+For example, the method :meth:`~Client.record_action_on_item` may raise ``U2IActionNotCreatedError``.
+
+   >>> try:
+   >>>   client.record_action_on_item("view", "i200")
+   >>> except:
+   >>>   <log the error>
+
+
+Asynchronous Requests
+---------------------
+
+In addition to normal :ref:`blocking (synchronous) request methods <sync-methods-label>`, this SDK also provides :ref:`methods which can generate asynchronous requests <async-methods-label>`.
+All methods prefixed with 'a' are asynchronous (eg, :meth:`~Client.acreate_user`, :meth:`~Client.acreate_item`).
+Asynchronous requests are handled by separate threads in the background, so you can generate multiple requests at the same time without waiting for any of them to finish.
+These methods return immediately without waiting for results, allowing your code to proceed to work on something else.
+The concept is to break a normal blocking request (such as :meth:`~Client.create_user`) into two steps:
+
+1. generate the request (e.g., calling :meth:`~Client.acreate_user`);
+2. get the request status and return data (calling :meth:`~Client.aresp`);
+
+This allows you to do other work between these two steps.
+
+.. note::
+   In some cases you may not care whether the request is successful for performance or application-specific reasons, then you can simply skip step 2.
+
+.. note::
+   If you do care about the request status or need to get the return data, then at a later time you will need to call :meth:`~Client.aresp` with the AsyncRequest object returned in step 1.
+   Please refer to the documentation of :ref:`asynchronous request methods <async-methods-label>` for more details.
+
+For example, the following code first generates an asynchronous request to retrieve recommendations, then get the result at later time::
+
+    >>> # Generates asynchronous request and return an AsyncRequest object
+    >>> request = client.aget_itemrec_topn("engine-1", 5)
+    >>> <...you can do other things here...>
+    >>> try:
+    >>>    result = client.aresp(request) # check the request status and get the return data.
+    >>> except:
+    >>>    <log the error>
+
+
+Batch Import Data
+-----------------
+
+When you import large amount of data at once, you may also use asynchronous request methods to generate lots of requests in the beginning and then check the status at a later time to minimize run time.
+
+For example, to import 100000 of user records::
+
+  >>> # generate 100000 asynchronous requests and store the AsyncRequest objects
+  >>> req = {}
+  >>> for i in range(100000):
+  >>>    req[i] = client.acreate_user(user_record[i].uid)
+  >>>
+  >>> <...you can do other things here...>
+  >>>
+  >>> # now check the status of the previous asynchronous requests
+  >>> for i in range(100000):
+  >>>   try:
+  >>>     result = client.aresp(req[i])
+  >>>   except:
+  >>>     <log the error>
+
+Alternatively, you can use blocking requests to import large amount of data, but this has significantly lower performance::
+
+  >>> for i in range(100000):
+  >>>   try:
+  >>>      client.create_user(user_record[i].uid)
+  >>>   except:
+  >>>      <log the error>
+
+
+
+
+predictionio.Client Class 
+---------------------------------
+
+.. autoclass:: Client
+.. deprecated:: 0.8.0
+  Use :class:`EventClient` and :class:`EngineClient` instead.
+
+
+  .. automethod:: close
+  .. automethod:: identify
+
+    .. versionadded:: 0.5.0
+
+  .. automethod:: pending_requests
+
+    .. versionadded:: 0.6.1
+
+  |
+
+  .. _sync-methods-label:
+
+  .. note:: The following is blocking (synchronous) request methods
+
+  .. automethod:: get_status
+  .. automethod:: create_user
+  .. automethod:: get_user
+  .. automethod:: delete_user
+
+  .. automethod:: create_item
+  .. automethod:: get_item
+  .. automethod:: delete_item
+
+  .. automethod:: record_action_on_item
+
+    .. versionadded:: 0.5.0
+
+  .. automethod:: get_itemrec_topn
+
+    .. versionadded:: 0.5.0
+
+    .. versionchanged:: 0.6.0
+      Change the order of parameters.
+
+  .. automethod:: get_itemsim_topn
+
+    .. versionadded:: 0.6.0
+
+  .. automethod:: get_itemrank_ranked
+
+    .. versionadded:: 0.7.0
+
+  .. automethod:: get_itemrec
+
+    .. deprecated:: 0.5.0
+      Use :func:`get_itemrec_topn` instead.
+
+  .. automethod:: user_conversion_item
+
+    .. deprecated:: 0.5.0
+      Use :func:`record_action_on_item` instead.
+
+  .. automethod:: user_dislike_item
+
+    .. deprecated:: 0.5.0
+      Use :func:`record_action_on_item` instead.
+
+  .. automethod:: user_like_item
+
+    .. deprecated:: 0.5.0
+      Use :func:`record_action_on_item` instead.
+
+  .. automethod:: user_rate_item
+
+    .. deprecated:: 0.5.0
+      Use :func:`record_action_on_item` instead.
+
+  .. automethod:: user_view_item
+
+    .. deprecated:: 0.5.0
+      Use :func:`record_action_on_item` instead.
+
+  |
+
+  .. _async-methods-label:
+
+  .. note:: The following is non-blocking (asynchronous) request methods
+
+  .. automethod:: acreate_user
+  .. automethod:: aget_user
+  .. automethod:: adelete_user
+
+  .. automethod:: acreate_item
+  .. automethod:: aget_item
+  .. automethod:: adelete_item
+
+  .. automethod:: arecord_action_on_item
+
+    .. versionadded:: 0.5.0
+
+  .. automethod:: aget_itemrec_topn
+
+    .. versionadded:: 0.5.0
+
+    .. versionchanged:: 0.6.0
+      Change the order of parameters.
+
+  .. automethod:: aget_itemsim_topn
+
+    .. versionadded:: 0.6.0
+
+  .. automethod:: aget_itemrank_ranked
+
+    .. versionadded:: 0.7.0
+
+  .. automethod:: aget_itemrec
+
+    .. deprecated:: 0.5.0
+      Use :func:`aget_itemrec_topn` instead.
+
+  .. automethod:: auser_conversion_item
+
+    .. deprecated:: 0.5.0
+      Use :func:`arecord_action_on_item` instead.
+
+  .. automethod:: auser_dislike_item
+
+    .. deprecated:: 0.5.0
+      Use :func:`arecord_action_on_item` instead.
+
+  .. automethod:: auser_like_item
+
+    .. deprecated:: 0.5.0
+      Use :func:`arecord_action_on_item` instead.
+
+  .. automethod:: auser_rate_item
+
+    .. deprecated:: 0.5.0
+      Use :func:`arecord_action_on_item` instead.
+
+  .. automethod:: auser_view_item
+
+    .. deprecated:: 0.5.0
+      Use :func:`arecord_action_on_item` instead.
+
+  .. automethod:: aresp
+
+
diff --git a/examples/demo-movielens/README.md b/examples/demo-movielens/README.md
new file mode 100644
index 0000000..bcf5aed
--- /dev/null
+++ b/examples/demo-movielens/README.md
@@ -0,0 +1,16 @@
+PredictionIO Python SDK Example - MoveLens
+==========================================
+
+Please execute all commands from repository root.
+
+Step 1. Get sample data and unzip it.
+```
+$ curl -o ml-100k.zip http://www.grouplens.org/system/files/ml-100k.zip
+$ unzip ml-100k.zip
+```
+
+Step 2. Run this app:
+```
+$ python -m examples.demo-movielens.batch_import <app_id> <server_url>
+```
+
diff --git a/examples/itemrec/movies/__init__.py b/examples/demo-movielens/__init__.py
similarity index 100%
copy from examples/itemrec/movies/__init__.py
copy to examples/demo-movielens/__init__.py
diff --git a/examples/demo-movielens/appdata.py b/examples/demo-movielens/appdata.py
new file mode 100644
index 0000000..d9637ef
--- /dev/null
+++ b/examples/demo-movielens/appdata.py
@@ -0,0 +1,183 @@
+
+import datetime
+from operator import itemgetter, attrgetter
+
+# can get sample data here:
+# wget http://www.grouplens.org/system/files/ml-100k.zip
+# app data file config
+APPDATA_DIRNAME = "ml-100k"
+USERS_FILENAME = "u.user"
+USERS_FILE_DELIMITER = "|"
+ITEMS_FILENAME = "u.item"
+ITEMS_FILE_DELIMITER = "|"
+RATE_ACTIONS_FILENAME = "u.data"
+RATE_ACTIONS_DELIMITER = "\t"
+
+
+class User:
+  def __init__(self, uid):
+    self.uid = uid
+    self.rec = [] # recommendations, list of iid
+
+  def __str__(self):
+    return "User[uid=%s,rec=%s]" % (self.uid, self.rec)
+
+class Item:
+  def __init__(self, iid, name, release_date, genres, year):
+    self.iid = iid
+    self.name = name
+    self.release_date = release_date # datetime.datetime object
+    self.genres = genres
+    self.year = year
+
+  def __str__(self):
+    return "Item[iid=%s,name=%s,release_date=%s,genres=%s]" % (self.iid, self.name, self.release_date, self.genres)
+
+class RateAction:
+  def __init__(self, uid, iid, rating, t):
+    self.uid = uid
+    self.iid = iid
+    self.rating = rating
+    self.t = t
+
+  def __str__(self):
+    return "RateAction[uid=%s,iid=%s,rating=%s,t=%s]" % (self.uid, self.iid, self.rating, self.t)
+
+
+class AppData:
+
+  def __init__(self):
+    self._users = {} # dict of User obj
+    self._items = {} # dict of Item obj
+    self._rate_actions = [] # list of RateAction obj
+
+    self._users_file = "%s/%s" % (APPDATA_DIRNAME, USERS_FILENAME)
+    self._items_file = "%s/%s" % (APPDATA_DIRNAME, ITEMS_FILENAME)
+    self._rate_actions_file = "%s/%s" % (APPDATA_DIRNAME, RATE_ACTIONS_FILENAME)
+    self.__init_users()
+    self.__init_items()
+    self.__init_rate_actions()
+
+  def __init_users(self):
+    """
+    uid|
+    """
+    print "[Info] Initializing users..."
+    f = open(self._users_file, 'r')
+    for line in f:
+      data = line.rstrip('\r\n').split(USERS_FILE_DELIMITER)
+      self.add_user(User(data[0]))
+    f.close()
+    print "[Info] %s users were initialized." % len(self._users)
+
+  def __init_items(self):
+    """
+    movie id | movie title | release date | video release date |
+        IMDb URL | unknown | Action | Adventure | Animation |
+        Children's | Comedy | Crime | Documentary | Drama | Fantasy |
+        Film-Noir | Horror | Musical | Mystery | Romance | Sci-Fi |
+        Thriller | War | Western |
+        The last 19 fields are the genres, a 1 indicates the movie
+        is of that genre, a 0 indicates it is not; movies can be in
+        several genres at once.
+
+    """
+    genre_names = [ "unknown", "Action", "Adventure", "Animation",
+      "Children's", "Comedy", "Crime", "Documentary", "Drama", "Fantasy",
+      "Film-Noir", "Horror", "Musical", "Mystery", "Romance", "Sci-Fi",
+      "Thriller", "War", "Western"]
+
+    print "[Info] Initializing items..."
+    f = open(self._items_file, 'r')
+    for line in f:
+      data = line.rstrip('\r\n').split(ITEMS_FILE_DELIMITER)
+      genres_flags = data[5:24]
+
+      genres = () # tuple of genres
+      for g,flag in zip(genre_names, genres_flags):
+        if flag == '1':
+          genres = genres + (g,)
+
+      try:
+        # eg. 01-Jan-1994
+        release_date = datetime.datetime.strptime(data[2], "%d-%b-%Y").replace(microsecond=1)
+        (day, month, year) = data[2].split('-')
+      except:
+        print "[Note] item %s %s doesn't have release date. Skip it." % (data[0], data[1])
+      else:
+        self.add_item(Item(
+          iid=data[0],
+          name=data[1],
+          release_date=release_date,
+          genres=genres,
+          year=year))
+    f.close()
+    print "[Info] %s items were initialized." % len(self._items)
+
+  def __init_rate_actions(self):
+    """
+    uid|iid|rating|timestamp
+    """
+    print "[Info] Initializing rate actions..."
+    f = open(self._rate_actions_file, 'r')
+    for line in f:
+      data = line.rstrip('\r\n').split(RATE_ACTIONS_DELIMITER)
+      t = datetime.datetime.utcfromtimestamp(int(data[3])).replace(microsecond=1)
+      self.add_rate_action(RateAction(data[0], data[1], data[2], t))
+    f.close()
+    print "[Info] %s rate actions were initialized." % len(self._rate_actions)
+
+  def add_user(self, user):
+    self._users[user.uid] = user
+
+  def add_item(self, item):
+    self._items[item.iid] = item
+
+  def add_rate_action(self, action):
+    self._rate_actions.append(action)
+
+  def get_users(self):
+    return self._users
+
+  def get_items(self):
+    return self._items
+
+  def get_rate_actions(self):
+    return self._rate_actions
+
+  def get_user(self, uid):
+    """return single user
+    """
+    if uid in self._users:
+      return self._users[uid]
+    else:
+      return None
+
+  def get_item(self, iid):
+    """return single item
+    """
+    if iid in self._items:
+      return self._items[iid]
+    else:
+      return None
+
+  def get_top_rated_items(self, uid, n):
+    """get top n rated iids by this uid
+    """
+    if uid in self._users:
+      actions = filter(lambda u: u.uid==uid, self._rate_actions)
+      top = sorted(actions, key=attrgetter('rating'), reverse=True)
+      topn_iids = map(lambda a: a.iid, top[:n])
+      return topn_iids
+    else:
+      return None
+
+  def get_top_rate_actions(self, uid, n):
+    """get top n rated actions by this uid
+    """
+    if uid in self._users:
+      actions = filter(lambda u: u.uid==uid, self._rate_actions)
+      top = sorted(actions, key=attrgetter('rating'), reverse=True)
+      return top[:n]
+    else:
+      return None
diff --git a/examples/demo-movielens/batch_import.py b/examples/demo-movielens/batch_import.py
new file mode 100644
index 0000000..fa2e1c0
--- /dev/null
+++ b/examples/demo-movielens/batch_import.py
@@ -0,0 +1,91 @@
+
+from appdata import AppData
+import predictionio
+import sys
+import pytz
+
+def batch_import_task(app_id, app_data, client, all_info=False):
+
+  print "[Info] Importing users to PredictionIO..."
+  count = 0
+  for k, v in app_data.get_users().iteritems():
+    count += 1
+    if all_info:
+      print "[Info] Importing %s..." % v
+    else:
+      if (count % 32 == 0):
+        sys.stdout.write('\r[Info] %s' % count)
+        sys.stdout.flush()
+
+    client.aset_user(uid=v.uid)
+
+  sys.stdout.write('\r[Info] %s users were imported.\n' % count)
+  sys.stdout.flush()
+
+  print "[Info] Importing items to PredictionIO..."
+  count = 0
+  for k, v in app_data.get_items().iteritems():
+    count += 1
+    if all_info:
+      print "[Info] Importing %s..." % v
+    else:
+      if (count % 32 == 0):
+        sys.stdout.write('\r[Info] %s' % count)
+        sys.stdout.flush()
+
+    itypes = ("movie",) + v.genres
+    client.aset_item(iid=v.iid,
+      properties={ 
+        "pio_itypes" : list(itypes),
+        "pio_starttime" : v.release_date.isoformat() + 'Z',
+        "name" : v.name,
+        "year" : v.year } )
+
+  sys.stdout.write('\r[Info] %s items were imported.\n' % count)
+  sys.stdout.flush()
+
+  print "[Info] Importing rate actions to PredictionIO..."
+  count = 0
+  for v in app_data.get_rate_actions():
+    count += 1
+    if all_info:
+      print "[Info] Importing %s..." % v
+    else:
+      if (count % 32 == 0):
+        sys.stdout.write('\r[Info] %s' % count)
+        sys.stdout.flush()
+
+    properties = { "pio_rating" : int(v.rating) }
+    req = client.acreate_event(
+        event="rate",
+        entity_type="pio_user",
+        entity_id=v.uid,
+        target_entity_type="pio_item",
+        target_entity_id=v.iid,
+        properties=properties,
+        event_time=v.t.replace(tzinfo=pytz.utc),
+        )
+
+  sys.stdout.write('\r[Info] %s rate actions were imported.\n' % count)
+  sys.stdout.flush()
+
+
+if __name__ == '__main__':
+  if len(sys.argv) < 3:
+    sys.exit("Usage: python -m examples.demo-movielens.batch_import "
+        "<app_id> <url>")
+
+  app_id = int(sys.argv[1])
+
+  client = predictionio.EventClient(
+      app_id=app_id,
+      url=sys.argv[2],
+      threads=5,
+      qsize=500)
+
+  # Test connection
+  print "Status:", client.get_status()
+  
+  app_data = AppData()
+  batch_import_task(app_id, app_data, client)
+  client.close()
diff --git a/examples/event_sample.py b/examples/event_sample.py
new file mode 100644
index 0000000..2ba2069
--- /dev/null
+++ b/examples/event_sample.py
@@ -0,0 +1,134 @@
+from predictionio import EventClient
+from predictionio import NotFoundError
+from datetime import datetime
+import pytz
+import sys
+
+client = EventClient(app_id=4, url="http://localhost:7070")
+
+# Check status
+print("Check status")
+print(client.get_status())
+
+# First event
+first_event_properties = {
+    "prop1" : 1,
+    "prop2" : "value2",
+    "prop3" : [1, 2, 3],
+    "prop4" : True,
+    "prop5" : ["a", "b", "c"],
+    "prop6" : 4.56 ,
+    }
+first_event_time = datetime(
+    2004, 12, 13, 21, 39, 45, 618000, pytz.timezone('US/Mountain'))
+first_event_response = client.create_event(
+    event="my_event",
+    entity_type="user",
+    entity_id="uid",
+    properties=first_event_properties,
+    first_event_time=first_event_time,
+    )
+print("First Event response")
+print(first_event_response)
+print
+
+# Second event
+second_event_properties = {
+    "someProperty" : "value1",
+    "anotherProperty" : "value2",
+    }
+second_event_response = client.create_event(
+    event="my_event",
+    entity_type="user",
+    entity_id="uid",
+    target_entity_type="item",
+    target_entity_id="iid",
+    properties=second_event_properties,
+    event_time=datetime(2014, 12, 13, 21, 38, 45, 618000, pytz.utc))
+print("Second Event response")
+print(second_event_response)
+print
+
+
+# Get the first event from Event Server
+first_event_id = first_event_response.json_body["eventId"]
+print("Get Event")
+event = client.get_event(first_event_id)
+print(event)
+print
+
+# Delete the first event from Event Server
+print("Delete Event")
+delete_response = client.delete_event(first_event_id)
+print(delete_response)
+print
+
+# Delete the first event from Event Server again should yield exception.
+print("Delete Event Again")
+try:
+  delete_response = client.delete_event(first_event_id)
+except NotFoundError, ex:
+  print("The expected error: {0}".format(ex))
+print
+
+# "user"-helper methods
+
+# Set user properties implicitly create a user
+# This call creates a user "foo", and set the properties of "foo".
+print("Create user foo")
+foo_properties = {"city": "sunnyvale", "car": "honda fit"}
+print(client.set_user("foo", properties=foo_properties))
+
+# This call overrides the existing properties for user "foo", setting "car" to
+# a new "honda odyssey" and create a new property "food" to "seafood".
+print("Set new properties")
+foo_properties = {"car": "honda odyssey", "food": "seafood"}
+print(client.set_user("foo", properties=foo_properties))
+
+# This call removes the specified properties. It ignores the value of the dict.
+# After this call, the "city" will become an unset field.
+print("Unset properties")
+foo_properties = {"city": "x"}
+print(client.unset_user("foo", properties=foo_properties))
+
+# This call deletes a user
+print("Delete user")
+print(client.delete_user("foo"))
+
+# The SDK also support specifying the eventTime. It is useful for importing 
+# events happened in the past.
+foo_time = datetime(2014, 8, 31, 4, 56, tzinfo=pytz.timezone('US/Pacific'))
+print("Create user at " + str(foo_time))
+print(client.set_user("Jarvis", {}, foo_time))
+
+# "item"-helper methods
+
+# Set item properties implicitly create a item
+# This call creates a item "bar", and set the properties of "bar".
+print("Create item bar")
+bar_properties = {"city": "santa clara", "weight": 6.9}
+print(client.set_item("bar", properties=bar_properties))
+
+# Similar to user-methods, we can do the same thing with item
+print("Set new properties")
+bar_properties = {"weight": 6.2}
+print(client.set_item("bar", properties=bar_properties))
+
+# This call removes the specified properties. It ignores the value of the dict.
+# After this call, the "city" will become an unset field.
+print("Unset properties")
+bar_properties = {"city": None}
+print(client.unset_item("bar", properties=bar_properties))
+
+# This call deletes a item
+print("Delete item")
+print(client.delete_item("bar"))
+
+
+# "record" action helper functions
+
+# This call creates a event between a user and an item. In particular, this set
+# the price of the action
+print("Record user action")
+action_properties = {"price": 10.0}
+print(client.record_user_action_on_item("buy", "foo", "bar", action_properties))
diff --git a/examples/import_yahoo.py b/examples/import_yahoo.py
new file mode 100644
index 0000000..69421d4
--- /dev/null
+++ b/examples/import_yahoo.py
@@ -0,0 +1,208 @@
+"""
+Import historical stock data from yahoo finance.
+"""
+
+import argparse
+from datetime import datetime
+import predictionio
+import pytz
+import time
+from pandas.io import data as pdata
+import numpy
+
+EPOCH = datetime(1970, 1, 1, tzinfo=pytz.utc)
+
+SP500_LIST = [
+    "A", "AA", "AAPL", "ABBV", "ABC", "ABT", "ACE", "ACN", "ACT", "ADBE", "ADI",
+    "ADM", "ADP", "ADS", "ADSK", "ADT", "AEE", "AEP", "AES", "AET", "AFL",
+    "AGN", "AIG", "AIV", "AIZ", "AKAM", "ALL", "ALLE", "ALTR", "ALXN", "AMAT",
+    "AME", "AMGN", "AMP", "AMT", "AMZN", "AN", "AON", "APA", "APC", "APD",
+    "APH", "ARG", "ATI", "AVB", "AVP", "AVY", "AXP", "AZO", "BA", "BAC", "BAX",
+    "BBBY", "BBT", "BBY", "BCR", "BDX", "BEAM", "BEN", "BF-B", "BHI", "BIIB",
+    "BK", "BLK", "BLL", "BMS", "BMY", "BRCM", "BRK-B", "BSX", "BTU", "BWA",
+    "BXP", "C", "CA", "CAG", "CAH", "CAM", "CAT", "CB", "CBG", "CBS", "CCE",
+    "CCI", "CCL", "CELG", "CERN", "CF", "CFN", "CHK", "CHRW", "CI", "CINF",
+    "CL", "CLX", "CMA", "CMCSA", "CME", "CMG", "CMI", "CMS", "CNP", "CNX",
+    "COF", "COG", "COH", "COL", "COP", "COST", "COV", "CPB", "CRM", "CSC",
+    "CSCO", "CSX", "CTAS", "CTL", "CTSH", "CTXS", "CVC", "CVS", "CVX", "D",
+    "DAL", "DD", "DE", "DFS", "DG", "DGX", "DHI", "DHR", "DIS", "DISCA", "DLPH",
+    "DLTR", "DNB", "DNR", "DO", "DOV", "DOW", "DPS", "DRI", "DTE", "DTV", "DUK",
+    "DVA", "DVN", "EA", "EBAY", "ECL", "ED", "EFX", "EIX", "EL", "EMC", "EMN",
+    "EMR", "EOG", "EQR", "EQT", "ESRX", "ESS", "ESV", "ETFC", "ETN", "ETR",
+    "EW", "EXC", "EXPD", "EXPE", "F", "FAST", "FB", "FCX", "FDO", "FDX", "FE",
+    "FFIV", "FIS", "FISV", "FITB", "FLIR", "FLR", "FLS", "FMC", "FOSL", "FOXA",
+    "FRX", "FSLR", "FTI", "FTR", "GAS", "GCI", "GD", "GE", "GGP", "GHC", "GILD",
+    "GIS", "GLW", "GM", "GMCR", "GME", "GNW", "GOOG", "GOOGL", "GPC", "GPS",
+    "GRMN", "GS", "GT", "GWW", "HAL", "HAR", "HAS", "HBAN", "HCBK", "HCN",
+    "HCP", "HD", "HES", "HIG", "HOG", "HON", "HOT", "HP", "HPQ", "HRB", "HRL",
+    "HRS", "HSP", "HST", "HSY", "HUM", "IBM", "ICE", "IFF", "IGT", "INTC",
+    "INTU", "IP", "IPG", "IR", "IRM", "ISRG", "ITW", "IVZ", "JBL", "JCI", "JEC",
+    "JNJ", "JNPR", "JOY", "JPM", "JWN", "K", "KEY", "KIM", "KLAC", "KMB", "KMI",
+    "KMX", "KO", "KORS", "KR", "KRFT", "KSS", "KSU", "L", "LB", "LEG", "LEN",
+    "LH", "LLL", "LLTC", "LLY", "LM", "LMT", "LNC", "LO", "LOW", "LRCX", "LSI",
+    "LUK", "LUV", "LYB", "M", "MA", "MAC", "MAR", "MAS", "MAT", "MCD", "MCHP",
+    "MCK", "MCO", "MDLZ", "MDT", "MET", "MHFI", "MHK", "MJN", "MKC", "MMC",
+    "MMM", "MNST", "MO", "MON", "MOS", "MPC", "MRK", "MRO", "MS", "MSFT", "MSI",
+    "MTB", "MU", "MUR", "MWV", "MYL", "NBL", "NBR", "NDAQ", "NE", "NEE", "NEM",
+    "NFLX", "NFX", "NI", "NKE", "NLSN", "NOC", "NOV", "NRG", "NSC", "NTAP",
+    "NTRS", "NU", "NUE", "NVDA", "NWL", "NWSA", "OI", "OKE", "OMC", "ORCL",
+    "ORLY", "OXY", "PAYX", "PBCT", "PBI", "PCAR", "PCG", "PCL", "PCLN", "PCP",
+    "PDCO", "PEG", "PEP", "PETM", "PFE", "PFG", "PG", "PGR", "PH", "PHM", "PKI",
+    "PLD", "PLL", "PM", "PNC", "PNR", "PNW", "POM", "PPG", "PPL", "PRGO", "PRU",
+    "PSA", "PSX", "PVH", "PWR", "PX", "PXD", "QCOM", "QEP", "R", "RAI", "RDC",
+    "REGN", "RF", "RHI", "RHT", "RIG", "RL", "ROK", "ROP", "ROST", "RRC", "RSG",
+    "RTN", "SBUX", "SCG", "SCHW", "SE", "SEE", "SHW", "SIAL", "SJM", "SLB",
+    "SLM", "SNA", "SNDK", "SNI", "SO", "SPG", "SPLS", "SRCL", "SRE", "STI",
+    "STJ", "STT", "STX", "STZ", "SWK", "SWN", "SWY", "SYK", "SYMC", "SYY", "T",
+    "TAP", "TDC", "TE", "TEG", "TEL", "TGT", "THC", "TIF", "TJX", "TMK", "TMO",
+    "TRIP", "TROW", "TRV", "TSCO", "TSN", "TSO", "TSS", "TWC", "TWX", "TXN",
+    "TXT", "TYC", "UNH", "UNM", "UNP", "UPS", "URBN", "USB", "UTX", "V", "VAR",
+    "VFC", "VIAB", "VLO", "VMC", "VNO", "VRSN", "VRTX", "VTR", "VZ", "WAG",
+    "WAT", "WDC", "WEC", "WFC", "WFM", "WHR", "WIN", "WLP", "WM", "WMB", "WMT",
+    "WU", "WY", "WYN", "WYNN", "X", "XEL", "XL", "XLNX", "XOM", "XRAY", "XRX",
+    "XYL", "YHOO", "YUM", "ZION", "ZMH", "ZTS"]
+
+ETF_LIST = ["QQQ", "SPY", "XLY", "XLP", "XLE", "XLF", "XLV", 
+    "XLI", "XLB", "XLK", "XLU"]
+
+
+def since_epoch(dt):
+  return (dt - EPOCH).total_seconds()
+
+
+def import_data(client, app_id, ticker, start_time, end_time, event_time):
+  print "Importing:", ticker, start_time, end_time
+
+  try:
+    df = pdata.DataReader(ticker, 'yahoo', start_time, end_time)
+    print "Extracted:", df.index[0], df.index[-1]
+  except IOError, ex:
+    print ex
+    print "Data not exist. Returning"
+    return
+
+  # assume we only extract US data
+  eastern = pytz.timezone('US/Eastern')
+
+  columns = [
+      ('Open', 'open'),
+      ('High', 'high'),
+      ('Low', 'low'),
+      ('Close', 'close'),
+      ('Volume', 'volume'),
+      ('Adj Close', 'adjclose')]
+
+  yahoo_data = dict()
+  yahoo_data['ticker'] = ticker
+  yahoo_data['t'] = [
+      # hour=16 to indicate market close time
+      since_epoch(eastern.localize(date_.to_pydatetime().replace(hour=16)))
+      for date_ in df.index]
+
+  for column in columns:
+    yahoo_data[column[1]] = map(numpy.asscalar, df[column[0]].values)
+
+  properties = {'yahoo': yahoo_data}
+
+  response = client.create_event(
+      event='$set',
+      entity_type='yahoo',
+      entity_id=ticker,
+      properties=properties,
+      event_time=event_time.replace(tzinfo=pytz.utc))
+      
+  print(response)
+
+
+def import_all(app_id):
+  """This method import all SP500 stocks and some SPDR ETFs."""
+  time_slices = [
+      (datetime(1999, 1, 1), datetime(2004, 1, 1), datetime(2004, 1, 2)),
+      (datetime(2003, 12, 1), datetime(2009, 1, 1), datetime(2009, 1, 2)),
+      (datetime(2008, 12, 1), datetime(2014, 9, 1), datetime(2014, 9, 2)),
+      ]
+
+  url = 'http://localhost:7070'
+  client = predictionio.EventClient(app_id=app_id, threads=1, url=url)
+
+  tickers = SP500_LIST + ETF_LIST 
+
+  for ticker in tickers:
+    for time_slice in time_slices:
+      import_data(client, app_id, ticker, 
+          time_slice[0], time_slice[1], time_slice[2])
+
+
+def import_data_with_gaps(app_id):
+  """This method import data with time gaps. 
+  
+  Data imported by this method is used by stock engine, it demonsrates how it
+  can handle time series data with gaps.
+  """ 
+
+  # time_slices is discontinuted
+  # startTime, endTime, eventDate
+  time_slices = [
+      (datetime(2013, 12, 1), datetime(2014, 2, 1), datetime(2014, 2, 2)),
+      (datetime(2014, 1, 1), datetime(2014, 1, 20), datetime(2014, 2, 10)),
+      (datetime(2014, 1, 10), datetime(2014, 2, 20), datetime(2014, 2, 28)),
+      (datetime(2014, 2, 10), datetime(2014, 3, 31), datetime(2014, 4, 2)),
+      (datetime(2014, 5, 1), datetime(2014, 6, 15), datetime(2014, 6, 20)),
+      (datetime(2014, 6, 1), datetime(2014, 7, 1), datetime(2014, 7, 15)),
+      ]
+
+  tickers = ['SPY', 'AAPL', 'IBM', 'MSFT']
+ 
+  url = 'http://localhost:7070'
+  client = predictionio.EventClient(app_id=app_id, threads=1, url=url)
+
+  for ticker in tickers:
+    for time_slice in time_slices:
+      import_data(client, app_id, ticker, 
+          time_slice[0], time_slice[1], time_slice[2])
+
+  # below are data with holes
+  time_slices = [
+      (datetime(2014, 1, 1), datetime(2014, 1, 20), datetime(2014, 2, 10)),
+      (datetime(2014, 2, 10), datetime(2014, 3, 31), datetime(2014, 4, 2)),
+      (datetime(2014, 6, 1), datetime(2014, 7, 1), datetime(2014, 7, 15)),
+      ]
+
+  tickers = ['AMZN']
+  for ticker in tickers:
+    for time_slice in time_slices:
+      import_data(client, app_id, ticker, 
+          time_slice[0], time_slice[1], time_slice[2])
+
+  time_slices = [
+      (datetime(2014, 1, 10), datetime(2014, 2, 20), datetime(2014, 2, 28)),
+      (datetime(2014, 2, 10), datetime(2014, 3, 31), datetime(2014, 4, 2)),
+      ]
+  tickers = ['FB']
+  for ticker in tickers:
+    for time_slice in time_slices:
+      import_data(client, app_id, ticker, 
+          time_slice[0], time_slice[1], time_slice[2])
+
+
+def import_one(app_id):
+  """Import TSLA.
+  
+  Import data with from 2014-01-01 until 2014-03-01. event_time specifies when
+  this data is extracted. 
+  """
+  start_time = datetime(2014, 1, 1)
+  end_time = datetime(2014, 3, 1)
+  event_time = datetime(2014, 9, 1)
+  ticker = 'TSLA'
+ 
+  url = 'http://localhost:7070'
+  client = predictionio.EventClient(app_id=app_id, threads=1, url=url)
+
+  import_data(client, app_id, ticker, start_time, end_time, event_time)
+
+
+if __name__ == '__main__':
+  #import_all(app_id=2)
+  import_data_with_gaps(app_id=1)
+  #import_one(app_id=1)
diff --git a/examples/itemrank_quick_query.py b/examples/itemrank_quick_query.py
new file mode 100644
index 0000000..3c43713
--- /dev/null
+++ b/examples/itemrank_quick_query.py
@@ -0,0 +1,23 @@
+"""
+itemrank quickstart query
+"""
+
+import predictionio
+
+client = predictionio.EngineClient("http://localhost:8000")
+
+# Rank item 1 to 5 for each user
+item_ids = [str(i) for i in range(1, 6)]
+user_ids = [str(x) for x in range(1, 6)] + ["NOT_EXIST_USER"]
+for user_id in user_ids:
+  print "Rank item 1 to 5 for user", user_id
+  try:
+    response = client.send_query({
+      "uid": user_id,
+      "iids": item_ids
+    })
+    print response
+  except predictionio.PredictionIOAPIError as e:
+    print 'Caught exception:', e
+
+client.close()
diff --git a/examples/itemrank_quick_start.py b/examples/itemrank_quick_start.py
new file mode 100644
index 0000000..b76abc1
--- /dev/null
+++ b/examples/itemrank_quick_start.py
@@ -0,0 +1,42 @@
+"""
+itemrank quickstart import data
+"""
+
+import predictionio
+
+import random
+
+def import_itemrank(app_id):
+
+  random.seed()
+  
+  client = predictionio.EventClient(app_id=app_id)
+
+  print client.get_status()
+  
+  # generate 10 users, with user ids 1,2,....,10
+  user_ids = [str(i) for i in range(1, 11)]
+  for user_id in user_ids:
+    print "Set user", user_id
+    client.set_user(user_id)
+  
+  # generate 50 items, with item ids 1,2,....,50
+  # assign type id 1 to all of them
+  item_ids = [str(i) for i in range(1, 51)]
+  for item_id in item_ids:
+    print "Set item", item_id
+    client.set_item(item_id, {
+      "pio_itypes" : ['1']
+    })
+  
+  # each user randomly views 10 items
+  for user_id in user_ids:
+    for viewed_item in random.sample(item_ids, 10):
+      print "User", user_id ,"views item", viewed_item
+      client.record_user_action_on_item("view", user_id, viewed_item)
+  
+  client.close()
+
+
+if __name__ == '__main__':
+  import_itemrank(7)
diff --git a/examples/itemrec/__init__.py b/examples/obsolete/__init__.py
similarity index 100%
copy from examples/itemrec/__init__.py
copy to examples/obsolete/__init__.py
diff --git a/examples/itemrec/__init__.py b/examples/obsolete/itemrec/__init__.py
similarity index 100%
rename from examples/itemrec/__init__.py
rename to examples/obsolete/itemrec/__init__.py
diff --git a/examples/itemrec/movies/.gitignore b/examples/obsolete/itemrec/movies/.gitignore
similarity index 100%
rename from examples/itemrec/movies/.gitignore
rename to examples/obsolete/itemrec/movies/.gitignore
diff --git a/examples/itemrec/movies/README.md b/examples/obsolete/itemrec/movies/README.md
similarity index 100%
rename from examples/itemrec/movies/README.md
rename to examples/obsolete/itemrec/movies/README.md
diff --git a/examples/itemrec/movies/__init__.py b/examples/obsolete/itemrec/movies/__init__.py
similarity index 100%
rename from examples/itemrec/movies/__init__.py
rename to examples/obsolete/itemrec/movies/__init__.py
diff --git a/examples/itemrec/movies/app_config.py b/examples/obsolete/itemrec/movies/app_config.py
similarity index 100%
rename from examples/itemrec/movies/app_config.py
rename to examples/obsolete/itemrec/movies/app_config.py
diff --git a/examples/itemrec/movies/appdata.py b/examples/obsolete/itemrec/movies/appdata.py
similarity index 100%
rename from examples/itemrec/movies/appdata.py
rename to examples/obsolete/itemrec/movies/appdata.py
diff --git a/examples/itemrec/movies/batch_import.py b/examples/obsolete/itemrec/movies/batch_import.py
similarity index 100%
rename from examples/itemrec/movies/batch_import.py
rename to examples/obsolete/itemrec/movies/batch_import.py
diff --git a/examples/itemrec/movies/movie_rec_app.py b/examples/obsolete/itemrec/movies/movie_rec_app.py
similarity index 100%
rename from examples/itemrec/movies/movie_rec_app.py
rename to examples/obsolete/itemrec/movies/movie_rec_app.py
diff --git a/predictionio/__init__.py b/predictionio/__init__.py
index 30e39e6..d7c369f 100644
--- a/predictionio/__init__.py
+++ b/predictionio/__init__.py
@@ -9,8 +9,10 @@
 __copyright__ = "Copyright 2014, TappingStone, Inc."
 __license__ = "Apache License, Version 2.0"
 
-__version__ = "0.7.0"
+__version__ = "0.8.0"
 
+# import deprecated libraries.
+from predictionio.obsolete import Client
 
 # import packages
 import re
@@ -23,138 +25,59 @@
 import json
 import urllib
 
+from datetime import datetime
+import pytz
+
 from predictionio.connection import Connection
 from predictionio.connection import AsyncRequest
+from predictionio.connection import AsyncResponse
 from predictionio.connection import PredictionIOAPIError
 
-"""Error exception defined for this API
 
-Should be handled by the user
-"""
-
-
-class ServerStatusError(PredictionIOAPIError):
-
-  "Error happened when tried to get status of the API server"
+class NotCreatedError(PredictionIOAPIError):
   pass
 
 
-class UserNotCreatedError(PredictionIOAPIError):
-
-  "Error happened when tried to create user"
+class NotFoundError(PredictionIOAPIError):
   pass
 
 
-class UserNotFoundError(PredictionIOAPIError):
-
-  "Error happened when tried to get user"
-  pass
-
-
-class UserNotDeletedError(PredictionIOAPIError):
-
-  "Error happened when tried to delete user"
-  pass
-
-
-class ItemNotCreatedError(PredictionIOAPIError):
-
-  "Error happened when tried to create item"
-  pass
-
-
-class ItemNotFoundError(PredictionIOAPIError):
-
-  "Error happened when tried to get item"
-  pass
-
-
-class ItemNotDeletedError(PredictionIOAPIError):
-
-  "Error happened when tried to delete item"
-  pass
-
-
-class U2IActionNotCreatedError(PredictionIOAPIError):
-
-  "Error happened when tried to create user-to-item action"
-  pass
-
-
-class ItemRecNotFoundError(PredictionIOAPIError):
-
-  "Error happened when tried to get item recommendation"
-  pass
-
-
-class ItemSimNotFoundError(PredictionIOAPIError):
-
-  "Error happened when tried to get similar items"
-  pass
-
-class ItemRankNotFoundError(PredictionIOAPIError):
-
-  "Error happened when treid to rank item"
-  pass
-
-class InvalidArgumentError(PredictionIOAPIError):
-
-  "Arguments are not valid"
-  pass
-
-# map to API
-LIKE_API = "like"
-DISLIKE_API = "dislike"
-VIEW_API = "view"
-CONVERSION_API = "conversion"
-RATE_API = "rate"
-
-
-class Client(object):
-
-  """PredictionIO client object.
-
-  This is an object representing a PredictionIO's client. This object
-  provides methods for making PredictionIO API requests.
-
-  :param appkey: the App Key provided by PredictionIO.
-  :param threads: number of threads to handle PredictionIO API requests.
-          Must be >= 1.
-  :param apiurl: the PredictionIO API URL path.
-  :param apiversion: the PredictionIO API version. (optional)
-       (eg. "", or "/v1")
-  :param qsize: the max size of the request queue (optional).
-      The asynchronous request becomes blocking once this size has been
-      reached, until the queued requests are handled.
-      Default value is 0, which means infinite queue size.
-  :param timeout: timeout for HTTP connection attempts and requests in
-    seconds (optional).
-    Default value is 5.
-
+def event_time_validation(t):
+  """ Validate event_time according to EventAPI Specification.
   """
 
-  def __init__(self, appkey, threads=1, apiurl="http://localhost:8000",
-         apiversion="", qsize=0, timeout=5):
+  if t is None:
+    return datetime.now(pytz.utc)
+
+  if type(t) != datetime:
+    raise AttributeError("event_time must be datetime.datetime")
+
+  if t.tzinfo is None:
+    raise AttributeError("event_time must have tzinfo")
+
+  return t
+
+
+class BaseClient(object):
+  def __init__(self, url, threads=1, qsize=0, timeout=5):
     """Constructor of Client object.
 
     """
-    self.appkey = appkey
     self.threads = threads
-    self.apiurl = apiurl
-    self.apiversion = apiversion
+    self.url = url
     self.qsize = qsize
     self.timeout = timeout
 
     # check connection type
     https_pattern = r'^https://(.*)'
     http_pattern = r'^http://(.*)'
-    m = re.match(https_pattern, apiurl)
+    m = re.match(https_pattern, url)
     self.https = True
     if m is None:  # not matching https
-      m = re.match(http_pattern, apiurl)
+      m = re.match(http_pattern, url)
       self.https = False
       if m is None:  # not matching http either
-        raise InvalidArgumentError("apiurl is not valid: %s" % apiurl)
+        raise InvalidArgumentError("url is not valid: %s" % url)
     self.host = m.group(1)
 
     self._uid = None  # identified uid
@@ -179,13 +102,6 @@
     """
     return self._connection.pending_requests()
 
-  def identify(self, uid):
-    """Identify the uid
-
-    :param uid: user id. type str.
-    """
-    self._uid = uid
-
   def get_status(self):
     """Get the status of the PredictionIO API Server
 
@@ -197,1018 +113,337 @@
     """
     path = "/"
     request = AsyncRequest("GET", path)
-    request.set_rfunc(self._aget_status_resp)
+    request.set_rfunc(self._aget_resp)
     self._connection.make_request(request)
-    result = self.aresp(request)
+    result = request.get_response()
     return result
 
-  def _aget_status_resp(self, response):
-    """Handle the AsyncResponse of get status request"""
+  def _acreate_resp(self, response):
     if response.error is not None:
-      raise ServerStatusError("Exception happened: %s for request %s" %
+      raise NotCreatedError("Exception happened: %s for request %s" %
+                    (response.error, response.request))
+    elif response.status != httplib.CREATED:
+      raise NotCreatedError("request: %s status: %s body: %s" %
+                    (response.request, response.status,
+                     response.body))
+
+    return response
+
+  def _aget_resp(self, response):
+    if response.error is not None:
+      raise NotFoundError("Exception happened: %s for request %s" %
                   (response.error, response.request))
     elif response.status != httplib.OK:
-      raise ServerStatusError("request: %s status: %s body: %s" %
+      raise NotFoundError("request: %s status: %s body: %s" %
                   (response.request, response.status,
                    response.body))
 
-    # data = json.loads(response.body) # convert json string to dict
+    return response.json_body
+
+  def _adelete_resp(self, response):
+    if response.error is not None:
+      raise NotFoundError("Exception happened: %s for request %s" %
+                  (response.error, response.request))
+    elif response.status != httplib.OK:
+      raise NotFoundError("request: %s status: %s body: %s" %
+                  (response.request, response.status,
+                   response.body))
+
     return response.body
 
-  def acreate_user(self, uid, params={}):
-    """Asynchronously create a user.
 
-    :param uid: user id. type str.
-    :param params: optional attributes. type dictionary.
-        For example,
-        { 'custom': 'value', 'pio_inactive' : True,
-        'pio_latlng': [4.5,67.8] }
+class EventClient(BaseClient):
+  """Client for importing data into PredictionIO Event Server.
+
+  :param app_id: the id used to identify application data.
+  :param url: the url of PredictionIO Event Server.
+  :param threads: number of threads to handle PredictionIO API requests.
+          Must be >= 1.
+  :param qsize: the max size of the request queue (optional).
+      The asynchronous request becomes blocking once this size has been
+      reached, until the queued requests are handled.
+      Default value is 0, which means infinite queue size.
+  :param timeout: timeout for HTTP connection attempts and requests in
+    seconds (optional).
+    Default value is 5.
+
+  """
+
+  def __init__(self, app_id, url="http://localhost:7070",
+      threads=1, qsize=0, timeout=5):
+    super(EventClient, self).__init__(url, threads, qsize, timeout)
+    self.app_id = app_id
+
+  def acreate_event(self, event, entity_type, entity_id,
+      target_entity_type=None, target_entity_id=None, properties=None,
+      event_time=None):
+    """Asynchronously create an event.
+
+    :param event: event name. type str.
+    :param entity_type: entity type. It is the namespace of the entityId and
+      analogous to the table name of a relational database. The entityId must be
+      unique within same entityType. type str.
+    :param entity_id: entity id. *entity_type-entity_id* becomes the unique
+      identifier of the entity. For example, you may have entityType named user,
+      and different entity IDs, say 1 and 2. In this case, user-1 and user-2
+      uniquely identifies entities. type str
+    :param target_entity_type: target entity type. type str.
+    :param target_entity_id: target entity id. type str.
+    :param properties: a custom dict associated with an event. type dict.
+    :param event_time: the time of the event. type datetime, must contain
+      timezone info. 
 
     :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-
+      AsyncRequest object. You can call the get_response() method using this
+      object to get the final resuls or status of this asynchronous request.
     """
+    data = {
+        "appId": self.app_id,
+        "event": event,
+        "entityType": entity_type,
+        "entityId": entity_id,
+        }
 
-    if "pio_latlng" in params:
-      params["pio_latlng"] = ",".join(map(str, params["pio_latlng"]))
-    if "pio_inactive" in params:
-      params["pio_inactive"] = str(params["pio_inactive"]).lower()
+    if target_entity_type is not None:
+      data["targetEntityType"] = target_entity_type
 
-    path = "%s/users.json" % self.apiversion
-    request = AsyncRequest(
-      "POST", path, pio_appkey=self.appkey, pio_uid=uid, **params)
-    request.set_rfunc(self._acreate_user_resp)
-    self._connection.make_request(request)
+    if target_entity_id is not None:
+      data["targetEntityId"] = target_entity_id
 
-    return request
+    if properties is not None:
+      data["properties"] = properties
 
-  def _acreate_user_resp(self, response):
-    """Private function to handle the AsyncResponse of the acreate_user
-    request.
-
-    :param response: AsyncResponse object.
-
-    :returns:
-      None.
-
-    :raises:
-      UserNotCreatedError.
-
-    """
-    if response.error is not None:
-      raise UserNotCreatedError("Exception happened: %s for request %s" %
-                    (response.error, response.request))
-    elif response.status != httplib.CREATED:
-      raise UserNotCreatedError("request: %s status: %s body: %s" %
-                    (response.request, response.status,
-                     response.body))
-
-    return None
-
-  def aget_user(self, uid):
-    """Asynchronously get user.
-
-    :param uid: user id. type str.
-
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-
-    enc_uid = urllib.quote(uid, "")  # replace special char with %xx
-    path = "%s/users/%s.json" % (self.apiversion, enc_uid)
-    request = AsyncRequest("GET", path, pio_appkey=self.appkey)
-    request.set_rfunc(self._aget_user_resp)
-    self._connection.make_request(request)
-
-    return request
-
-  def _aget_user_resp(self, response):
-    """Private function to handle the AsyncResponse of the aget_user
-    request .
-
-    :param response: AsyncResponse object.
-
-    :returns:
-      User data in Dictionary format.
-
-    :rasies:
-      UserNotFoundError.
-
-    """
-    if response.error is not None:
-      raise UserNotFoundError("Exception happened: %s for request %s" %
-                  (response.error, response.request))
-    elif response.status != httplib.OK:
-      raise UserNotFoundError("request: %s status: %s body: %s" %
-                  (response.request, response.status,
-                   response.body))
-
-    data = json.loads(response.body)  # convert json string to dict
-    return data
-
-  def adelete_user(self, uid):
-    """Asynchronously delete user.
-
-    :param uid: user id. type str.
-
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-
-    enc_uid = urllib.quote(uid, "")  # replace special char with %xx
-    path = "%s/users/%s.json" % (self.apiversion, enc_uid)
-    request = AsyncRequest("DELETE", path, pio_appkey=self.appkey)
-    request.set_rfunc(self._adelete_user_resp)
-    self._connection.make_request(request)
-
-    return request
-
-  def _adelete_user_resp(self, response):
-    """Private function to handle the AsyncResponse of the adelete_user
-    request.
-
-    :param response: AsyncResponse object.
-
-    :returns:
-      None.
-
-    :raises:
-      UserNotDeletedError.
-
-    """
-    if response.error is not None:
-      raise UserNotDeletedError("Exception happened: %s for request %s" %
-                    (response.error, response.request))
-    elif response.status != httplib.OK:
-      raise UserNotDeletedError("request: %s status: %s body: %s" %
-                    (response.request, response.status,
-                     response.body))
-    return None
-
-  def acreate_item(self, iid, itypes, params={}):
-    """Asynchronously create item.
-
-    :param iid: item id. type str.
-    :param itypes: item types. Tuple of Str.
-        For example, if this item belongs to item types "t1", "t2",
-        "t3", "t4",then itypes=("t1", "t2", "t3", "t4").
-        NOTE: if this item belongs to only one itype, use tuple of one
-        element, eg. itypes=("t1",)
-    :param params: optional attributes. type dictionary.
-        For example,
-        { 'custom': 'value', 'pio_inactive' : True,
-        'pio_latlng': [4.5,67.8] }
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-    itypes_str = ",".join(itypes)  # join items with ","
-
-    if "pio_latlng" in params:
-      params["pio_latlng"] = ",".join(map(str, params["pio_latlng"]))
-    if "pio_inactive" in params:
-      params["pio_inactive"] = str(params["pio_inactive"]).lower()
-
-    path = "%s/items.json" % self.apiversion
-    request = AsyncRequest("POST", path, pio_appkey=self.appkey,
-                 pio_iid=iid, pio_itypes=itypes_str, **params)
-    request.set_rfunc(self._acreate_item_resp)
+    et = event_time_validation(event_time)
+    # EventServer uses milliseconds, but python datetime class uses micro. Hence
+    # need to skip the last three digits.
+    et_str = et.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-3] + et.strftime("%z")
+    data["eventTime"] = et_str
+    
+    path = "/events.json"
+    request = AsyncRequest("POST", path, **data)
+    request.set_rfunc(self._acreate_resp)
     self._connection.make_request(request)
     return request
 
-  def _acreate_item_resp(self, response):
-    """Private function to handle the AsyncResponse of the acreate_item
-    request
+  def create_event(self, event, entity_type, entity_id,
+      target_entity_type=None, target_entity_id=None, properties=None,
+      event_time=None):
+    """Synchronously (blocking) create an event."""
+    return self.acreate_event(event, entity_type, entity_id,
+        target_entity_type, target_entity_id, properties, 
+        event_time).get_response()
 
-    :param response: AsyncResponse object.
+  def aget_event(self, event_id):
+    """Asynchronouly get an event from Event Server.
+
+    :param event_id: event id returned by the EventServer when creating the
+      event.
 
     :returns:
-      None
-    :raises:
-      ItemNotCreatedError
-
+      AsyncRequest object. 
     """
-    if response.error is not None:
-      raise ItemNotCreatedError("Exception happened: %s for request %s" %
-                    (response.error, response.request))
-    elif response.status != httplib.CREATED:
-      raise ItemNotCreatedError("request: %s status: %s body: %s" %
-                    (response.request, response.status,
-                     response.body))
-    return None
-
-  def aget_item(self, iid):
-    """Asynchronously get item
-
-    :param iid: item id. type str.
-
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-    enc_iid = urllib.quote(iid, "")
-    path = "%s/items/%s.json" % (self.apiversion, enc_iid)
-    request = AsyncRequest("GET", path, pio_appkey=self.appkey)
-    request.set_rfunc(self._aget_item_resp)
+    enc_event_id = urllib.quote(event_id, "") # replace special char with %xx
+    path = "/events/%s.json" % enc_event_id
+    request = AsyncRequest("GET", path)
+    request.set_rfunc(self._aget_resp)
     self._connection.make_request(request)
     return request
 
-  def _aget_item_resp(self, response):
-    """Private function to handle the AsyncResponse of the aget_item
-    request
+  def get_event(self, event_id):
+    """Synchronouly get an event from Event Server."""
+    return self.aget_event(event_id).get_response()
 
-    :param response: AsyncResponse object.
+  def adelete_event(self, event_id):
+    """Asynchronouly delete an event from Event Server.
+
+    :param event_id: event id returned by the EventServer when creating the
+      event.
 
     :returns:
-      item data in dictionary format.
-
-    :raises:
-      ItemNotFoundError.
-
+      AsyncRequest object. 
     """
-    if response.error is not None:
-      raise ItemNotFoundError("Exception happened: %s for request %s" %
-                  (response.error, response.request))
-    elif response.status != httplib.OK:
-      raise ItemNotFoundError("request: %s status: %s body: %s" %
-                  (response.request, response.status,
-                   response.body))
-
-    data = json.loads(response.body)  # convert json string to dict
-    if "pio_itypes" in data:
-      # convert from list to tuple
-      data["pio_itypes"] = tuple(data["pio_itypes"])
-
-    return data
-
-  def adelete_item(self, iid):
-    """Asynchronously delete item
-
-    :param iid: item id. type str.
-
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-
-    enc_iid = urllib.quote(iid, "")
-    path = "%s/items/%s.json" % (self.apiversion, enc_iid)
-    request = AsyncRequest("DELETE", path, pio_appkey=self.appkey)
-    request.set_rfunc(self._adelete_item_resp)
+    enc_event_id = urllib.quote(event_id, "") # replace special char with %xx
+    path = "/events/%s.json" % enc_event_id
+    request = AsyncRequest("DELETE", path)
+    request.set_rfunc(self._adelete_resp)
     self._connection.make_request(request)
     return request
 
-  def _adelete_item_resp(self, response):
-    """Private function to handle the AsyncResponse of the adelete_item
-    request
+  def delete_event(self, event_id):
+    """Synchronouly delete an event from Event Server."""
+    return self.adelete_event(event_id).get_response()
 
-    :param response: AsyncResponse object
+  ## Below are helper functions
+
+  def aset_user(self, uid, properties={}, event_time=None):
+    """Set properties of a user.
+   
+    Wrapper of acreate_event function, setting event to "$set" and entity_type
+    to "pio_user".
+    """
+    return self.acreate_event(
+      event="$set",
+      entity_type="pio_user",
+      entity_id=uid,
+      properties=properties,
+      event_time=event_time,
+    )
+
+  def set_user(self, uid, properties={}, event_time=None):
+    """Set properties of a user"""
+    return self.aset_user(uid, properties, event_time).get_response()
+
+  def aunset_user(self, uid, properties, event_time=None):
+    """Unset properties of an user.
+   
+    Wrapper of acreate_event function, setting event to "$unset" and entity_type
+    to "pio_user".
+    """
+    # check properties={}, it cannot be empty
+    return self.acreate_event(
+        event="$unset",
+        entity_type="pio_user",
+        entity_id=uid,
+        properties=properties,
+        event_time=event_time,
+        )
+
+  def unset_user(self, uid, properties, event_time=None):
+    """Set properties of a user"""
+    return self.aunset_user(uid, properties, event_time).get_response()
+
+  def adelete_user(self, uid, event_time=None):
+    """Delete a user.
+   
+    Wrapper of acreate_event function, setting event to "$delete" and entity_type
+    to "pio_user".
+    """
+    return self.acreate_event(
+        event="$delete",
+        entity_type="pio_user",
+        entity_id=uid,
+        event_time=event_time)
+
+  def delete_user(self, uid, event_time=None):
+    """Delete a user."""
+    return self.adelete_user(uid, event_time).get_response()
+
+  def aset_item(self, iid, properties={}, event_time=None):
+    """Set properties of an item.
+   
+    Wrapper of acreate_event function, setting event to "$set" and entity_type
+    to "pio_item".
+    """
+    return self.acreate_event(
+        event="$set",
+        entity_type="pio_item",
+        entity_id=iid,
+        properties=properties,
+        event_time=event_time)
+
+  def set_item(self, iid, properties={}, event_time=None):
+    """Set properties of an item."""
+    return self.aset_item(iid, properties, event_time).get_response()
+
+  def aunset_item(self, iid, properties={}, event_time=None):
+    """Unset properties of an item.
+   
+    Wrapper of acreate_event function, setting event to "$unset" and entity_type
+    to "pio_item".
+    """
+    return self.acreate_event(
+        event="$unset",
+        entity_type="pio_item",
+        entity_id=iid,
+        properties=properties,
+        event_time=event_time)
+
+  def unset_item(self, iid, properties={}, event_time=None):
+    """Unset properties of an item."""
+    return self.aunset_item(iid, properties, event_time).get_response()
+
+  def adelete_item(self, iid, event_time=None):
+    """Delete an item.
+   
+    Wrapper of acreate_event function, setting event to "$delete" and entity_type
+    to "pio_item".
+    """
+    return self.acreate_event(
+        event="$delete",
+        entity_type="pio_item",
+        entity_id=iid,
+        event_time=event_time)
+
+  def delete_item(self, iid, event_time=None):
+    """Delete an item."""
+    return self.adelete_item(iid, event_time).get_response()
+
+  def arecord_user_action_on_item(self, action, uid, iid, properties={},
+      event_time=None):
+    """Create a user-to-item action.
+
+    Wrapper of acreate_event function, setting entity_type to "pio_user" and
+    target_entity_type to "pio_item".
+    """
+    return self.acreate_event(
+        event=action,
+        entity_type="pio_user",
+        entity_id=uid,
+        target_entity_type="pio_item",
+        target_entity_id=iid,
+        properties=properties,
+        event_time=event_time)
+
+  def record_user_action_on_item(self, action, uid, iid, properties={},
+      event_time=None):
+    """Create a user-to-item action."""
+    return self.arecord_user_action_on_item(
+      action, uid, iid, properties, event_time).get_response()
+
+
+class EngineClient(BaseClient):
+  """Client for extracting prediction results from an PredictionIO Engine
+  Instance.
+  
+  :param url: the url of the PredictionIO Engine Instance.
+  :param threads: number of threads to handle PredictionIO API requests.
+          Must be >= 1.
+  :param qsize: the max size of the request queue (optional).
+      The asynchronous request becomes blocking once this size has been
+      reached, until the queued requests are handled.
+      Default value is 0, which means infinite queue size.
+  :param timeout: timeout for HTTP connection attempts and requests in
+    seconds (optional).
+    Default value is 5.
+  
+  """
+  def __init__(self, url="http://localhost:8000", threads=1,
+      qsize=0, timeout=5):
+    super(EngineClient, self).__init__(url, threads, qsize, timeout)
+
+  def asend_query(self, data):
+    """Asynchronously send a request to the engine instance with data as the
+    query.
+
+    :param data: the query: It is coverted to an json object using json.dumps
+      method. type dict. 
 
     :returns:
-      None
-
-    :raises:
-      ItemNotDeletedError
+      AsyncRequest object. You can call the get_response() method using this
+      object to get the final resuls or status of this asynchronous request.
     """
-    if response.error is not None:
-      raise ItemNotDeletedError("Exception happened: %s for request %s" %
-                    (response.error, response.request))
-    elif response.status != httplib.OK:
-      raise ItemNotDeletedError("request: %s status: %s body: %s" %
-                    (response.request, response.status,
-                     response.body))
-    return None
-
-  def _aget_user_itemrec_topn(self, engine, uid, n, params={}):
-    """Private function to asynchronously get recommendations for user
-
-    :param engine: name of the prediction engine. type str.
-    :param uid: user id. type str.
-    :param n: number of recommendation. type int.
-    :param params: optional parameters. type dictionary
-        For example, { 'pio_itypes' : ("t1","t2") }
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-    if "pio_itypes" in params:
-      params["pio_itypes"] = ",".join(params["pio_itypes"])
-    if "pio_latlng" in params:
-      params["pio_latlng"] = ",".join(map(str, params["pio_latlng"]))
-    if "pio_attributes" in params:
-      params["pio_attributes"] = ",".join(params["pio_attributes"])
-
-    path = "%s/engines/itemrec/%s/topn.json" % (self.apiversion, engine)
-    request = AsyncRequest("GET", path, pio_appkey=self.appkey,
-                 pio_uid=uid, pio_n=n, **params)
-    request.set_rfunc(self._aget_user_itemrec_topn_resp)
+    path = "/queries.json"
+    request = AsyncRequest("POST", path, **data)
+    request.set_rfunc(self._aget_resp)
     self._connection.make_request(request)
     return request
 
-  def _aget_user_itemrec_topn_resp(self, response):
-    """Private function to handle the AsyncResponse of the aget_itemrec
-    request
+  def send_query(self, data):
+    """Synchronously send a request.
+    
+    :param data: the query: It is coverted to an json object using json.dumps
+      method. type dict. 
 
-    :param response: AsyncResponse object
-
-    :returns:
-      data in dictionary format.
-
-    :raises:
-      ItemRecNotFoundError.
+    :returns: the prediction.
     """
-    if response.error is not None:
-      raise ItemRecNotFoundError(
-        "Exception happened: %s for request %s" %
-        (response.error, response.request))
-    elif response.status != httplib.OK:
-      raise ItemRecNotFoundError("request: %s status: %s body: %s" %
-                    (response.request, response.status,
-                     response.body))
-
-    data = json.loads(response.body)  # convert json string to dict
-    return data
-
-  def aget_itemrec_topn(self, engine, n, params={}):
-    """Asynchronously get recommendations for the identified user
-
-    :param engine: name of the prediction engine. type str.
-    :param n: number of recommendation. type int.
-    :param params: optional parameters. type dictionary
-        For example, { 'pio_itypes' : ("t1",) }
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-
-    if self._uid is None:
-      raise InvalidArgumentError(
-        "uid is not identified. Please call identify(uid) first.")
-
-    request = self._aget_user_itemrec_topn(engine, self._uid, n, params)
-    return request
-
-  def aget_itemrec(self, uid, n, engine, **params):
-    """Deprecated. Asynchronously get recommendations
-
-    :param uid: user id. type str.
-    :param n: number of recommendation. type int.
-    :param engine: name of the prediction engine. type str.
-    :param params: keyword arguments for optional attributes.
-        For example, pio_latlng="123.4, 56.7"
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-    request = self._aget_user_itemrec_topn(engine, uid, n, params)
-    return request
-
-  def _aget_itemsim_topn(self, engine, iid, n, params={}):
-    """Private function to asynchronously get top n similar items of the
-    item
-
-    :param engine: name of the prediction engine. type str.
-    :param iid: item id. type str.
-    :param n: number of similar items. type int.
-    :param params: optional parameters. type dictionary
-        For example, { 'pio_itypes' : ("t1","t2") }
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-    if "pio_itypes" in params:
-      params["pio_itypes"] = ",".join(params["pio_itypes"])
-    if "pio_latlng" in params:
-      params["pio_latlng"] = ",".join(map(str, params["pio_latlng"]))
-    if "pio_attributes" in params:
-      params["pio_attributes"] = ",".join(params["pio_attributes"])
-
-    path = "%s/engines/itemsim/%s/topn.json" % (self.apiversion, engine)
-    request = AsyncRequest("GET", path, pio_appkey=self.appkey,
-                 pio_iid=iid, pio_n=n, **params)
-    request.set_rfunc(self._aget_itemsim_topn_resp)
-    self._connection.make_request(request)
-    return request
-
-  def _aget_itemsim_topn_resp(self, response):
-    """Private function to handle the AsyncResponse of the aget_itemsim
-    request
-
-    :param response: AsyncResponse object
-
-    :returns:
-      data in dictionary format.
-
-    :raises:
-      ItemSimNotFoundError.
-    """
-    if response.error is not None:
-      raise ItemSimNotFoundError(
-        "Exception happened: %s for request %s" %
-        (response.error, response.request))
-    elif response.status != httplib.OK:
-      raise ItemSimNotFoundError("request: %s status: %s body: %s" %
-                    (response.request, response.status,
-                     response.body))
-
-    data = json.loads(response.body)  # convert json string to dict
-    return data
-
-  def aget_itemsim_topn(self, engine, iid, n, params={}):
-    """Asynchronously get top n similar items of the item
-
-    :param engine: name of the prediction engine. type str.
-    :param iid: item id. type str.
-    :param n: number of similar items. type int.
-    :param params: optional parameters. type dictionary
-        For example, { 'pio_itypes' : ("t1",) }
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-
-    request = self._aget_itemsim_topn(engine, iid, n, params)
-    return request
-
-  def _aget_user_itemrank_ranked(self, engine, uid, iids, params={}):
-    """Private function to asynchronously get ranked item for user
-
-    :param engine: name of the prediction engine. type str.
-    :param uid: user id. type str.
-    :param iids: items to be ranked. type list of item ids.
-      For example, ["i0", "i1", "i2"]
-    :param params: optional parameters. type dictionary
-      For example. { 'pio_attributes' : "name" }
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-    if "pio_attributes" in params:
-      params["pio_attributes"] = ",".join(params["pio_attributes"])
-
-    pio_iids = ",".join(iids)
-
-    path = "%s/engines/itemrank/%s/ranked.json" % \
-      (self.apiversion, engine)
-    request = AsyncRequest("GET", path, pio_appkey=self.appkey,
-                           pio_uid=uid, pio_iids=pio_iids, **params)
-    request.set_rfunc(self._aget_user_itemrank_ranked_resp)
-    self._connection.make_request(request)
-    return request
-
-  def _aget_user_itemrank_ranked_resp(self, response):
-    """Private function to handle the AsyncResponse of the aget_itemreoder
-      request
-
-    :param response: AsyncResponse object
-
-    :returns:
-      data in dictionary format.
-
-    :raises:
-      ItemRankNotFoundError.
-    """
-    if response.error is not None:
-      raise ItemRankNotFoundError(
-        "Exception happened: %s for request %s" %
-        (response.error, response.request))
-    elif response.status != httplib.OK:
-      raise ItemRankNotFoundError("request: %s status: %s body: %s" %
-                                  (response.request, response.status,
-                                   response.body))
-
-    data = json.loads(response.body)  # convert json string to dict
-    return data
-
-  def aget_itemrank_ranked(self, engine, iids, params={}):
-    """Asynchronously get ranked item for user
-
-    :param engine: name of the prediction engine. type str.
-    :param iids: items to be ranked. type list of item ids.
-      For example, ["i0", "i1", "i2"]
-    :param params: optional parameters. type dictionary
-      For example. { 'pio_attributes' : "name" }
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-
-    if self._uid is None:
-      raise InvalidArgumentError(
-        "uid is not identified. Please call identify(uid) first.")
-
-    request = self._aget_user_itemrank_ranked(engine,
-      self._uid, iids, params)
-    return request
-
-  def _auser_action_on_item(self, action, uid, iid, params):
-    """Private function to asynchronously create an user action on an item
-
-    :param action: action type. type str. ("like", "dislike", "conversion",
-                         "rate", "view")
-    :param uid: user id. type str or int.
-    :param iid: item id. type str or int.
-    :param params: optional attributes. type dictionary.
-        For example, { 'pio_rate' : 4, 'pio_latlng' : [1.23,4.56] }
-        NOTE: For "rate" action, pio_rate attribute is required.
-            integer value of 1-5 (1 is least preferred and 5 is most
-            preferred)
-
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-    if "pio_latlng" in params:
-      params["pio_latlng"] = ",".join(map(str, params["pio_latlng"]))
-
-    path = "%s/actions/u2i.json" % (self.apiversion)
-    request = AsyncRequest("POST", path, pio_appkey=self.appkey,
-                 pio_action=action, pio_uid=uid, pio_iid=iid,
-                 **params)
-    request.set_rfunc(self._auser_action_on_item_resp)
-    self._connection.make_request(request)
-    return request
-
-  def _auser_action_on_item_resp(self, response):
-    """Private function to handle the AsyncResponse of the
-    _auser_action_on_item request
-
-    :param response: AsyncResponse object
-
-    :returns:
-      None
-
-    :raises:
-      U2IActionNotCreatedError
-    """
-    if response.error is not None:
-      raise U2IActionNotCreatedError(
-        "Exception happened: %s for request %s" %
-        (response.error, response.request))
-    elif response.status != httplib.CREATED:
-      raise U2IActionNotCreatedError("request: %s status: %s body: %s" %
-                       (response.request, response.status,
-                      response.body))
-    return None
-
-  def arecord_action_on_item(self, action, iid, params={}):
-    """Asynchronously create action on item
-
-    :param action: action name. type String. For example, "rate", "like",
-             etc
-    :param iid: item id. type str or int.
-    :param params: optional attributes. type dictionary.
-        For example, { 'pio_rate' : 4, 'pio_latlng': [4.5,67.8] }
-        NOTE: For "rate" action, pio_rate attribute is required.
-        integer value of 1-5 (1 is least preferred and 5 is most
-        preferred)
-
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-
-    :raises:
-      U2IActionNotCreatedError
-    """
-
-    if self._uid is None:
-      raise InvalidArgumentError(
-        "uid is not identified. Please call identify(uid) first.")
-
-    request = self._auser_action_on_item(action, self._uid, iid, params)
-    return request
-
-  def auser_conversion_item(self, uid, iid, **params):
-    """Deprecated. Asynchronously create an user conversion action on an
-    item
-
-    :param uid: user id. type str.
-    :param iid: item id. type str.
-    :param params: keyword arguments for optional attributes.
-        For example, pio_latlng=[123.4, 56.7]
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-    request = self._auser_action_on_item(CONVERSION_API, uid, iid, params)
-    return request
-
-  def auser_dislike_item(self, uid, iid, **params):
-    """Deprecated. Asynchronously create an user dislike action on an item
-
-    :param uid: user id. type str.
-    :param iid: item id. type str.
-    :param params: keyword arguments for optional attributes.
-        For example, pio_latlng=[123.4, 56.7]
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-    request = self._auser_action_on_item(DISLIKE_API, uid, iid, params)
-    return request
-
-  def auser_like_item(self, uid, iid, **params):
-    """Deprecated. Asynchronously create an user like action on an item
-
-    :param uid: user id. type str.
-    :param iid: item id. type str.
-    :param params: keyword arguments for optional attributes.
-        For example, pio_latlng=[123.4, 56.7]
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-    request = self._auser_action_on_item(LIKE_API, uid, iid, params)
-    return request
-
-  def auser_rate_item(self, uid, iid, rate, **params):
-    """Deprecated. Asynchronously create an user rate action on an item
-
-    :param uid: user id. type str.
-    :param iid: item id. type str.
-    :param rate: rating. integer value of 1-5 (1 is least preferred and 5
-           is most preferred)
-    :param params: keyword arguments for optional attributes.
-        For example, pio_latlng=[123.4, 56.7]
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-
-    params['pio_rate'] = rate
-    request = self._auser_action_on_item(RATE_API, uid, iid, params)
-    return request
-
-  def auser_view_item(self, uid, iid, **params):
-    """Deprecated. Asynchronously create an user view action on an item
-
-    :param uid: user id. type str.
-    :param iid: item id. type str.
-    :param params: keyword arguments for optional attributes.
-        For example, pio_latlng=[123.4, 56.7]
-    :returns:
-      AsyncRequest object. You should call the aresp() method using this
-      AsyncRequest object as argument to get the final result or status
-      of this asynchronous request.
-    """
-    request = self._auser_action_on_item(VIEW_API, uid, iid, params)
-    return request
-
-  def aresp(self, request):
-    """Get the result of the asynchronous request
-
-    :param request: AsyncRequest object. This object must be returned by
-            the asynchronous request function
-            For example, to get the result of a aget_user()
-            request, call this aresp() with the argument of
-            AsyncRequest object returned by aget_user().
-
-    :returns:
-      The result of this AsyncRequest. The return type is the same as
-      the return type of corresponding blocking request.
-
-      For example,
-
-      Calling aresp() with acreate_user() AsyncRequest returns the same
-      type as create_user(), which is None.
-
-      Calling aresp() with aget_user() AsyncRequest returns the same
-      type as get_user(), which is dictionary data.
-
-    :raises:
-      Exception may be raised if there is error happened. The type of
-      exception is the same as exception type of the correspdoning
-      blocking request.
-
-      For example,
-
-      Calling aresp() with acreate_user() AsyncRequest may raise
-      UserNotCreatedError exception.
-
-      Calling aresp() with aget_user() AsyncRequest may raise
-      UserNotFoundError exception.
-
-    """
-    response = request.get_response()
-    result = request.rfunc(response)
-    return result
-
-  def create_user(self, uid, params={}):
-    """Blocking request to create user
-
-    :param uid: user id. type str.
-    :param params: optional attributes. type dictionary.
-      For example, { 'custom': 'value', 'pio_inactive' : True,
-      'pio_latlng': [4.5,67.8] }
-
-    :returns:
-      None.
-
-    :raises:
-      UserNotCreatedError.
-
-    """
-    request = self.acreate_user(uid, params)
-    result = self.aresp(request)
-    return result
-
-  def get_user(self, uid):
-    """Blocking request to get user
-
-    :param uid: user id. type str or int.
-
-    :returns:
-      User data in Dictionary format.
-
-    :rasies:
-      UserNotFoundError.
-
-    """
-    request = self.aget_user(uid)
-    result = self.aresp(request)
-    return result
-
-  def delete_user(self, uid):
-    """Blocking request to delete the user
-
-    :param uid: user id. type str.
-
-    :returns:
-      None.
-
-    :raises:
-      UserNotDeletedError.
-
-    """
-    request = self.adelete_user(uid)
-    result = self.aresp(request)
-    return result
-
-  def create_item(self, iid, itypes, params={}):
-    """Blocking request to create item
-
-    :param iid: item id. type str.
-    :param itypes: item types. Tuple of Str.
-        For example, if this item belongs to item types "t1", "t2",
-        "t3", "t4", then itypes=("t1", "t2", "t3", "t4").
-        NOTE: if this item belongs to only one itype, use tuple of one
-        element, eg. itypes=("t1",)
-    :param params: optional attributes. type dictionary.
-        For example,
-        { 'custom': 'value', 'pio_inactive' : True,
-        'pio_latlng': [4.5,67.8] }
-
-    :returns:
-      None
-
-    :raises:
-      ItemNotCreatedError
-
-    """
-    request = self.acreate_item(iid, itypes, params)
-    result = self.aresp(request)
-    return result
-
-  def get_item(self, iid):
-    """Blocking request to get item
-
-    :param iid: item id. type str.
-
-    :returns:
-      item data in dictionary format.
-
-    :raises:
-      ItemNotFoundError.
-
-    """
-    request = self.aget_item(iid)
-    result = self.aresp(request)
-    return result
-
-  def delete_item(self, iid):
-    """Blocking request to delete item
-
-    :param iid: item id. type str.
-
-    :returns:
-      None
-
-    :raises:
-      ItemNotDeletedError
-
-    """
-    request = self.adelete_item(iid)
-    result = self.aresp(request)
-    return result
-
-  def get_itemrec_topn(self, engine, n, params={}):
-    """Blocking request to get recommendations for the identified user
-
-    :param engine: name of the prediction engine. type str.
-    :param n: number of recommendation. type int.
-    :param params: optional parameters. type dictionary
-        For example, { 'pio_itypes' : ("t1", "t2") }
-    :returns:
-      data in dictionary format.
-
-    :raises:
-      ItemRecNotFoundError.
-    """
-    request = self.aget_itemrec_topn(engine, n, params)
-    result = self.aresp(request)
-    return result
-
-  def get_itemrec(self, uid, n, engine, **params):
-    """Deprecated. Blocking request to get recommendations
-
-    :param uid: user id. type str or int.
-    :param n: number of recommendation. type int.
-    :param engine: name of the prediction engine. type str.
-    :param params: keyword arguments for optional attributes.
-        For example, pio_latlng=[123.4, 56.7]
-
-    :returns:
-      data in dictionary format.
-
-    :raises:
-      ItemRecNotFoundError.
-
-    """
-    request = self.aget_itemrec(uid, n, engine, **params)
-    result = self.aresp(request)
-    return result
-
-  def get_itemsim_topn(self, engine, iid, n, params={}):
-    """Blocking request to get top n similar items of the item
-
-    :param engine: name of the prediction engine. type str.
-    :param iid: item id. type str.
-    :param n: number of similar items. type int.
-    :param params: optional parameters. type dictionary
-        For example, { 'pio_itypes' : ("t1",) }
-    :returns:
-      data in dictionary format.
-
-    :raises:
-      ItemSimNotFoundError.
-    """
-
-    request = self.aget_itemsim_topn(engine, iid, n, params)
-    result = self.aresp(request)
-    return result
-
-  def get_itemrank_ranked(self, engine, iids, params={}):
-    """Blocking request to get ranked item for user
-
-    :param engine: name of the prediction engine. type str.
-    :param iids: items to be ranked. type list of item ids.
-        For example, ["i0", "i1", "i2"]
-    :param params: optional parameters. type dictionary
-        For example. { 'pio_attributes' : "name" }
-    :returns:
-      data in dictionary format.
-
-    :raises:
-      ItemRankNotFoundError.
-    """
-    request = self.aget_itemrank_ranked(engine, iids, params)
-    result = self.aresp(request)
-    return result
-
-  def record_action_on_item(self, action, iid, params={}):
-    """Blocking request to create action on an item
-
-    :param action: action name. type String. For example, "rate", "like",
-             etc
-    :param iid: item id. type str.
-    :param params: optional attributes. type dictionary.
-        For example, { 'pio_rate' : 4, 'pio_latlng' : [1.23,4.56] }
-        NOTE: For "rate" action, pio_rate attribute is required.
-        integer value of 1-5 (1 is least preferred and 5 is most
-        preferred)
-
-    :returns:
-      None
-
-    :raises:
-      U2IActionNotCreatedError
-    """
-    request = self.arecord_action_on_item(action, iid, params)
-    result = self.aresp(request)
-    return result
-
-  def user_conversion_item(self, uid, iid, **params):
-    """Deprecated. Blocking request to create user conversion action on an
-     item
-
-    :param uid: user id. type str.
-    :param iid: item id. type str.
-    :param params: keyword arguments for optional attributes.
-        For example, pio_latlng=[123.4, 56.7]
-
-    :returns:
-      None
-
-    :raises:
-      U2IActionNotCreatedError
-    """
-    request = self.auser_conversion_item(uid, iid, **params)
-    result = self.aresp(request)
-    return result
-
-  def user_dislike_item(self, uid, iid, **params):
-    """Deprecated. Blocking request to create user dislike action on an
-     item
-
-    :param uid: user id. type str.
-    :param iid: item id. type str.
-    :param params: keyword arguments for optional attributes.
-        For example, pio_latlng=[123.4, 56.7]
-
-    :returns:
-      None
-
-    :raises:
-      U2IActionNotCreatedError
-    """
-    request = self.auser_dislike_item(uid, iid, **params)
-    result = self.aresp(request)
-    return result
-
-  def user_like_item(self, uid, iid, **params):
-    """Deprecated. Blocking request to create user like action on an item
-
-    :param uid: user id. type str.
-    :param iid: item id. type str.
-    :param params: keyword arguments for optional attributes.
-        For example, pio_latlng=[123.4, 56.7]
-
-    :returns:
-      None
-
-    :raises:
-      U2IActionNotCreatedError
-    """
-    request = self.auser_like_item(uid, iid, **params)
-    result = self.aresp(request)
-    return result
-
-  def user_rate_item(self, uid, iid, rate, **params):
-    """Deprecated. Blocking request to create user rate action on an item
-
-    :param uid: user id. type str.
-    :param iid: item id. type str.
-    :param rate: rating. integer value of 1-5 (1 is least preferred and 5
-           is most preferred)
-    :param params: keyword arguments for optional attributes.
-        For example, pio_latlng=[123.4, 56.7]
-
-    :returns:
-      None
-
-    :raises:
-      U2IActionNotCreatedError
-    """
-    request = self.auser_rate_item(uid, iid, rate, **params)
-    result = self.aresp(request)
-    return result
-
-  def user_view_item(self, uid, iid, **params):
-    """Deprecated. Blocking request to create user view action on an item
-
-    :param uid: user id. type str.
-    :param iid: item id. type str.
-    :param params: keyword arguments for optional attributes.
-        For example, pio_latlng=[123.4, 56.7]
-
-    :returns:
-      None
-
-    :raises:
-      U2IActionNotCreatedError
-    """
-    request = self.auser_view_item(uid, iid, **params)
-    result = self.aresp(request)
-    return result
+    return self.asend_query(data).get_response()
diff --git a/predictionio/connection.py b/predictionio/connection.py
index e124c5b..9609047 100644
--- a/predictionio/connection.py
+++ b/predictionio/connection.py
@@ -20,6 +20,7 @@
   from urllib.parse import urlencode
 
 import datetime
+import json
 import logging
 
 # use generators for python2 and python3
@@ -100,44 +101,43 @@
     self.response_q.put(response)
 
   def get_response(self):
-    """get the response
+    """Get the response. Blocking.
 
+    :returns: self.rfunc's return type.
     """
     if self._response is None:
-      self._response = self.response_q.get(True)  # NOTE: blocking
+      tmp_response = self.response_q.get(True)  # NOTE: blocking
+      if self.rfunc is None:
+        self._response = tmp_response
+      else:
+        self._response = self.rfunc(tmp_response)
 
     return self._response
 
 
 class AsyncResponse(object):
+  """Store the response of asynchronous request
 
-  """AsyncResponse object.
-
-  Store the response of asynchronous request
-
-  when get the response, user should check if error is None (which means no
-  Exception happens)
-  if error is None, then should check if the status is expected
-
-  Attributes:
-    error: exception object if any happens
-    version: int
-    status: int
-    reason: str
-    headers: dict
-    body: str (NOTE: not necessarily can be converted to JSON,
-        eg, for GET request to /v1/status)
-    request: the corresponding AsyncRequest object
+  When get the response, user should check if error is None (which means no
+  Exception happens).
+  If error is None, then should check if the status is expected.
   """
 
   def __init__(self):
+    #: exception object if any happens
     self.error = None
+
     self.version = None
     self.status = None
     self.reason = None
+    #: Response header. str
     self.headers = None
+    #: Response body. str
     self.body = None
-    self.request = None  # point back to the request object
+    #: Jsonified response body. Remains None if conversion is unsuccessful.
+    self.json_body = None
+    #: Point back to the AsyncRequest object
+    self.request = None  
 
   def __str__(self):
     return "e:%s v:%s s:%s r:%s h:%s b:%s" % (self.error, self.version,
@@ -150,6 +150,11 @@
     self.reason = reason
     self.headers = headers
     self.body = body
+    # Try to extract the json.
+    try:
+      self.json_body = json.loads(body)
+    except ValueError, ex:
+      self.json_body = None
 
   def set_error(self, error):
     self.error = error
@@ -194,9 +199,12 @@
       mod_headers["Connection"] = "keep-alive"
       enc_body = None
       if body:  # if body is not empty
-        enc_body = urlencode(body)
+        #enc_body = urlencode(body)
+        #mod_headers[
+        #  "Content-type"] = "application/x-www-form-urlencoded"
+        enc_body = json.dumps(body)
         mod_headers[
-          "Content-type"] = "application/x-www-form-urlencoded"
+          "Content-type"] = "application/json"
         #mod_headers["Accept"] = "text/plain"
     except Exception as e:
       response.set_error(e)
diff --git a/predictionio/obsolete.py b/predictionio/obsolete.py
new file mode 100644
index 0000000..dc19a09
--- /dev/null
+++ b/predictionio/obsolete.py
@@ -0,0 +1,1205 @@
+# import packages
+import re
+try:
+  import httplib
+except ImportError:
+  # pylint: disable=F0401
+  # http is a Python3 module, replacing httplib
+  from http import client as httplib
+import json
+import urllib
+import warnings
+
+from predictionio.connection import Connection
+from predictionio.connection import AsyncRequest
+from predictionio.connection import PredictionIOAPIError
+
+"""Error exception defined for this API
+
+Should be handled by the user
+"""
+
+
+class ServerStatusError(PredictionIOAPIError):
+
+  "Error happened when tried to get status of the API server"
+  pass
+
+
+class UserNotCreatedError(PredictionIOAPIError):
+
+  "Error happened when tried to create user"
+  pass
+
+
+class UserNotFoundError(PredictionIOAPIError):
+
+  "Error happened when tried to get user"
+  pass
+
+
+class UserNotDeletedError(PredictionIOAPIError):
+
+  "Error happened when tried to delete user"
+  pass
+
+
+class ItemNotCreatedError(PredictionIOAPIError):
+
+  "Error happened when tried to create item"
+  pass
+
+
+class ItemNotFoundError(PredictionIOAPIError):
+
+  "Error happened when tried to get item"
+  pass
+
+
+class ItemNotDeletedError(PredictionIOAPIError):
+
+  "Error happened when tried to delete item"
+  pass
+
+
+class U2IActionNotCreatedError(PredictionIOAPIError):
+
+  "Error happened when tried to create user-to-item action"
+  pass
+
+
+class ItemRecNotFoundError(PredictionIOAPIError):
+
+  "Error happened when tried to get item recommendation"
+  pass
+
+
+class ItemSimNotFoundError(PredictionIOAPIError):
+
+  "Error happened when tried to get similar items"
+  pass
+
+class ItemRankNotFoundError(PredictionIOAPIError):
+
+  "Error happened when treid to rank item"
+  pass
+
+class InvalidArgumentError(PredictionIOAPIError):
+
+  "Arguments are not valid"
+  pass
+
+# map to API
+LIKE_API = "like"
+DISLIKE_API = "dislike"
+VIEW_API = "view"
+CONVERSION_API = "conversion"
+RATE_API = "rate"
+
+
+class Client(object):
+
+  """PredictionIO client object.
+
+  This is an object representing a PredictionIO's client. This object
+  provides methods for making PredictionIO API requests.
+
+  :param appkey: the App Key provided by PredictionIO.
+  :param threads: number of threads to handle PredictionIO API requests.
+          Must be >= 1.
+  :param apiurl: the PredictionIO API URL path.
+  :param apiversion: the PredictionIO API version. (optional)
+       (eg. "", or "/v1")
+  :param qsize: the max size of the request queue (optional).
+      The asynchronous request becomes blocking once this size has been
+      reached, until the queued requests are handled.
+      Default value is 0, which means infinite queue size.
+  :param timeout: timeout for HTTP connection attempts and requests in
+    seconds (optional).
+    Default value is 5.
+
+  """
+
+  def __init__(self, appkey, threads=1, apiurl="http://localhost:8000",
+         apiversion="", qsize=0, timeout=5):
+    """Constructor of Client object.
+
+    """
+    warnings.warn("predictionio.Client is deprecated. " + 
+      "Please consider upgrading to our latest version.")
+
+    self.appkey = appkey
+    self.threads = threads
+    self.apiurl = apiurl
+    self.apiversion = apiversion
+    self.qsize = qsize
+    self.timeout = timeout
+
+    # check connection type
+    https_pattern = r'^https://(.*)'
+    http_pattern = r'^http://(.*)'
+    m = re.match(https_pattern, apiurl)
+    self.https = True
+    if m is None:  # not matching https
+      m = re.match(http_pattern, apiurl)
+      self.https = False
+      if m is None:  # not matching http either
+        raise InvalidArgumentError("apiurl is not valid: %s" % apiurl)
+    self.host = m.group(1)
+
+    self._uid = None  # identified uid
+    self._connection = Connection(host=self.host, threads=self.threads,
+                    qsize=self.qsize, https=self.https,
+                    timeout=self.timeout)
+
+  def close(self):
+    """Close this client and the connection.
+
+    Call this method when you want to completely terminate the connection
+    with PredictionIO.
+    It will wait for all pending requests to finish.
+    """
+    self._connection.close()
+
+  def pending_requests(self):
+    """Return the number of pending requests.
+
+    :returns:
+      The number of pending requests of this client.
+    """
+    return self._connection.pending_requests()
+
+  def identify(self, uid):
+    """Identify the uid
+
+    :param uid: user id. type str.
+    """
+    self._uid = uid
+
+  def get_status(self):
+    """Get the status of the PredictionIO API Server
+
+    :returns:
+      status message.
+
+    :raises:
+      ServerStatusError.
+    """
+    path = "/"
+    request = AsyncRequest("GET", path)
+    request.set_rfunc(self._aget_status_resp)
+    self._connection.make_request(request)
+    result = self.aresp(request)
+    return result
+
+  def _aget_status_resp(self, response):
+    """Handle the AsyncResponse of get status request"""
+    if response.error is not None:
+      raise ServerStatusError("Exception happened: %s for request %s" %
+                  (response.error, response.request))
+    elif response.status != httplib.OK:
+      raise ServerStatusError("request: %s status: %s body: %s" %
+                  (response.request, response.status,
+                   response.body))
+
+    # data = json.loads(response.body) # convert json string to dict
+    return response.body
+
+  def acreate_user(self, uid, params={}):
+    """Asynchronously create a user.
+
+    :param uid: user id. type str.
+    :param params: optional attributes. type dictionary.
+        For example,
+        { 'custom': 'value', 'pio_inactive' : True,
+        'pio_latlng': [4.5,67.8] }
+
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+
+    """
+
+    if "pio_latlng" in params:
+      params["pio_latlng"] = ",".join(map(str, params["pio_latlng"]))
+    if "pio_inactive" in params:
+      params["pio_inactive"] = str(params["pio_inactive"]).lower()
+
+    path = "%s/users.json" % self.apiversion
+    request = AsyncRequest(
+      "POST", path, pio_appkey=self.appkey, pio_uid=uid, **params)
+    request.set_rfunc(self._acreate_user_resp)
+    self._connection.make_request(request)
+
+    return request
+
+  def _acreate_user_resp(self, response):
+    """Private function to handle the AsyncResponse of the acreate_user
+    request.
+
+    :param response: AsyncResponse object.
+
+    :returns:
+      None.
+
+    :raises:
+      UserNotCreatedError.
+
+    """
+    if response.error is not None:
+      raise UserNotCreatedError("Exception happened: %s for request %s" %
+                    (response.error, response.request))
+    elif response.status != httplib.CREATED:
+      raise UserNotCreatedError("request: %s status: %s body: %s" %
+                    (response.request, response.status,
+                     response.body))
+
+    return None
+
+  def aget_user(self, uid):
+    """Asynchronously get user.
+
+    :param uid: user id. type str.
+
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+
+    enc_uid = urllib.quote(uid, "")  # replace special char with %xx
+    path = "%s/users/%s.json" % (self.apiversion, enc_uid)
+    request = AsyncRequest("GET", path, pio_appkey=self.appkey)
+    request.set_rfunc(self._aget_user_resp)
+    self._connection.make_request(request)
+
+    return request
+
+  def _aget_user_resp(self, response):
+    """Private function to handle the AsyncResponse of the aget_user
+    request .
+
+    :param response: AsyncResponse object.
+
+    :returns:
+      User data in Dictionary format.
+
+    :rasies:
+      UserNotFoundError.
+
+    """
+    if response.error is not None:
+      raise UserNotFoundError("Exception happened: %s for request %s" %
+                  (response.error, response.request))
+    elif response.status != httplib.OK:
+      raise UserNotFoundError("request: %s status: %s body: %s" %
+                  (response.request, response.status,
+                   response.body))
+
+    data = json.loads(response.body)  # convert json string to dict
+    return data
+
+  def adelete_user(self, uid):
+    """Asynchronously delete user.
+
+    :param uid: user id. type str.
+
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+
+    enc_uid = urllib.quote(uid, "")  # replace special char with %xx
+    path = "%s/users/%s.json" % (self.apiversion, enc_uid)
+    request = AsyncRequest("DELETE", path, pio_appkey=self.appkey)
+    request.set_rfunc(self._adelete_user_resp)
+    self._connection.make_request(request)
+
+    return request
+
+  def _adelete_user_resp(self, response):
+    """Private function to handle the AsyncResponse of the adelete_user
+    request.
+
+    :param response: AsyncResponse object.
+
+    :returns:
+      None.
+
+    :raises:
+      UserNotDeletedError.
+
+    """
+    if response.error is not None:
+      raise UserNotDeletedError("Exception happened: %s for request %s" %
+                    (response.error, response.request))
+    elif response.status != httplib.OK:
+      raise UserNotDeletedError("request: %s status: %s body: %s" %
+                    (response.request, response.status,
+                     response.body))
+    return None
+
+  def acreate_item(self, iid, itypes, params={}):
+    """Asynchronously create item.
+
+    :param iid: item id. type str.
+    :param itypes: item types. Tuple of Str.
+        For example, if this item belongs to item types "t1", "t2",
+        "t3", "t4",then itypes=("t1", "t2", "t3", "t4").
+        NOTE: if this item belongs to only one itype, use tuple of one
+        element, eg. itypes=("t1",)
+    :param params: optional attributes. type dictionary.
+        For example,
+        { 'custom': 'value', 'pio_inactive' : True,
+        'pio_latlng': [4.5,67.8] }
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+    itypes_str = ",".join(itypes)  # join items with ","
+
+    if "pio_latlng" in params:
+      params["pio_latlng"] = ",".join(map(str, params["pio_latlng"]))
+    if "pio_inactive" in params:
+      params["pio_inactive"] = str(params["pio_inactive"]).lower()
+
+    path = "%s/items.json" % self.apiversion
+    request = AsyncRequest("POST", path, pio_appkey=self.appkey,
+                 pio_iid=iid, pio_itypes=itypes_str, **params)
+    request.set_rfunc(self._acreate_item_resp)
+    self._connection.make_request(request)
+    return request
+
+  def _acreate_item_resp(self, response):
+    """Private function to handle the AsyncResponse of the acreate_item
+    request
+
+    :param response: AsyncResponse object.
+
+    :returns:
+      None
+    :raises:
+      ItemNotCreatedError
+
+    """
+    if response.error is not None:
+      raise ItemNotCreatedError("Exception happened: %s for request %s" %
+                    (response.error, response.request))
+    elif response.status != httplib.CREATED:
+      raise ItemNotCreatedError("request: %s status: %s body: %s" %
+                    (response.request, response.status,
+                     response.body))
+    return None
+
+  def aget_item(self, iid):
+    """Asynchronously get item
+
+    :param iid: item id. type str.
+
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+    enc_iid = urllib.quote(iid, "")
+    path = "%s/items/%s.json" % (self.apiversion, enc_iid)
+    request = AsyncRequest("GET", path, pio_appkey=self.appkey)
+    request.set_rfunc(self._aget_item_resp)
+    self._connection.make_request(request)
+    return request
+
+  def _aget_item_resp(self, response):
+    """Private function to handle the AsyncResponse of the aget_item
+    request
+
+    :param response: AsyncResponse object.
+
+    :returns:
+      item data in dictionary format.
+
+    :raises:
+      ItemNotFoundError.
+
+    """
+    if response.error is not None:
+      raise ItemNotFoundError("Exception happened: %s for request %s" %
+                  (response.error, response.request))
+    elif response.status != httplib.OK:
+      raise ItemNotFoundError("request: %s status: %s body: %s" %
+                  (response.request, response.status,
+                   response.body))
+
+    data = json.loads(response.body)  # convert json string to dict
+    if "pio_itypes" in data:
+      # convert from list to tuple
+      data["pio_itypes"] = tuple(data["pio_itypes"])
+
+    return data
+
+  def adelete_item(self, iid):
+    """Asynchronously delete item
+
+    :param iid: item id. type str.
+
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+
+    enc_iid = urllib.quote(iid, "")
+    path = "%s/items/%s.json" % (self.apiversion, enc_iid)
+    request = AsyncRequest("DELETE", path, pio_appkey=self.appkey)
+    request.set_rfunc(self._adelete_item_resp)
+    self._connection.make_request(request)
+    return request
+
+  def _adelete_item_resp(self, response):
+    """Private function to handle the AsyncResponse of the adelete_item
+    request
+
+    :param response: AsyncResponse object
+
+    :returns:
+      None
+
+    :raises:
+      ItemNotDeletedError
+    """
+    if response.error is not None:
+      raise ItemNotDeletedError("Exception happened: %s for request %s" %
+                    (response.error, response.request))
+    elif response.status != httplib.OK:
+      raise ItemNotDeletedError("request: %s status: %s body: %s" %
+                    (response.request, response.status,
+                     response.body))
+    return None
+
+  def _aget_user_itemrec_topn(self, engine, uid, n, params={}):
+    """Private function to asynchronously get recommendations for user
+
+    :param engine: name of the prediction engine. type str.
+    :param uid: user id. type str.
+    :param n: number of recommendation. type int.
+    :param params: optional parameters. type dictionary
+        For example, { 'pio_itypes' : ("t1","t2") }
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+    if "pio_itypes" in params:
+      params["pio_itypes"] = ",".join(params["pio_itypes"])
+    if "pio_latlng" in params:
+      params["pio_latlng"] = ",".join(map(str, params["pio_latlng"]))
+    if "pio_attributes" in params:
+      params["pio_attributes"] = ",".join(params["pio_attributes"])
+
+    path = "%s/engines/itemrec/%s/topn.json" % (self.apiversion, engine)
+    request = AsyncRequest("GET", path, pio_appkey=self.appkey,
+                 pio_uid=uid, pio_n=n, **params)
+    request.set_rfunc(self._aget_user_itemrec_topn_resp)
+    self._connection.make_request(request)
+    return request
+
+  def _aget_user_itemrec_topn_resp(self, response):
+    """Private function to handle the AsyncResponse of the aget_itemrec
+    request
+
+    :param response: AsyncResponse object
+
+    :returns:
+      data in dictionary format.
+
+    :raises:
+      ItemRecNotFoundError.
+    """
+    if response.error is not None:
+      raise ItemRecNotFoundError(
+        "Exception happened: %s for request %s" %
+        (response.error, response.request))
+    elif response.status != httplib.OK:
+      raise ItemRecNotFoundError("request: %s status: %s body: %s" %
+                    (response.request, response.status,
+                     response.body))
+
+    data = json.loads(response.body)  # convert json string to dict
+    return data
+
+  def aget_itemrec_topn(self, engine, n, params={}):
+    """Asynchronously get recommendations for the identified user
+
+    :param engine: name of the prediction engine. type str.
+    :param n: number of recommendation. type int.
+    :param params: optional parameters. type dictionary
+        For example, { 'pio_itypes' : ("t1",) }
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+
+    if self._uid is None:
+      raise InvalidArgumentError(
+        "uid is not identified. Please call identify(uid) first.")
+
+    request = self._aget_user_itemrec_topn(engine, self._uid, n, params)
+    return request
+
+  def aget_itemrec(self, uid, n, engine, **params):
+    """Deprecated. Asynchronously get recommendations
+
+    :param uid: user id. type str.
+    :param n: number of recommendation. type int.
+    :param engine: name of the prediction engine. type str.
+    :param params: keyword arguments for optional attributes.
+        For example, pio_latlng="123.4, 56.7"
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+    request = self._aget_user_itemrec_topn(engine, uid, n, params)
+    return request
+
+  def _aget_itemsim_topn(self, engine, iid, n, params={}):
+    """Private function to asynchronously get top n similar items of the
+    item
+
+    :param engine: name of the prediction engine. type str.
+    :param iid: item id. type str.
+    :param n: number of similar items. type int.
+    :param params: optional parameters. type dictionary
+        For example, { 'pio_itypes' : ("t1","t2") }
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+    if "pio_itypes" in params:
+      params["pio_itypes"] = ",".join(params["pio_itypes"])
+    if "pio_latlng" in params:
+      params["pio_latlng"] = ",".join(map(str, params["pio_latlng"]))
+    if "pio_attributes" in params:
+      params["pio_attributes"] = ",".join(params["pio_attributes"])
+
+    path = "%s/engines/itemsim/%s/topn.json" % (self.apiversion, engine)
+    request = AsyncRequest("GET", path, pio_appkey=self.appkey,
+                 pio_iid=iid, pio_n=n, **params)
+    request.set_rfunc(self._aget_itemsim_topn_resp)
+    self._connection.make_request(request)
+    return request
+
+  def _aget_itemsim_topn_resp(self, response):
+    """Private function to handle the AsyncResponse of the aget_itemsim
+    request
+
+    :param response: AsyncResponse object
+
+    :returns:
+      data in dictionary format.
+
+    :raises:
+      ItemSimNotFoundError.
+    """
+    if response.error is not None:
+      raise ItemSimNotFoundError(
+        "Exception happened: %s for request %s" %
+        (response.error, response.request))
+    elif response.status != httplib.OK:
+      raise ItemSimNotFoundError("request: %s status: %s body: %s" %
+                    (response.request, response.status,
+                     response.body))
+
+    data = json.loads(response.body)  # convert json string to dict
+    return data
+
+  def aget_itemsim_topn(self, engine, iid, n, params={}):
+    """Asynchronously get top n similar items of the item
+
+    :param engine: name of the prediction engine. type str.
+    :param iid: item id. type str.
+    :param n: number of similar items. type int.
+    :param params: optional parameters. type dictionary
+        For example, { 'pio_itypes' : ("t1",) }
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+
+    request = self._aget_itemsim_topn(engine, iid, n, params)
+    return request
+
+  def _aget_user_itemrank_ranked(self, engine, uid, iids, params={}):
+    """Private function to asynchronously get ranked item for user
+
+    :param engine: name of the prediction engine. type str.
+    :param uid: user id. type str.
+    :param iids: items to be ranked. type list of item ids.
+      For example, ["i0", "i1", "i2"]
+    :param params: optional parameters. type dictionary
+      For example. { 'pio_attributes' : "name" }
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+    if "pio_attributes" in params:
+      params["pio_attributes"] = ",".join(params["pio_attributes"])
+
+    pio_iids = ",".join(iids)
+
+    path = "%s/engines/itemrank/%s/ranked.json" % \
+      (self.apiversion, engine)
+    request = AsyncRequest("GET", path, pio_appkey=self.appkey,
+                           pio_uid=uid, pio_iids=pio_iids, **params)
+    request.set_rfunc(self._aget_user_itemrank_ranked_resp)
+    self._connection.make_request(request)
+    return request
+
+  def _aget_user_itemrank_ranked_resp(self, response):
+    """Private function to handle the AsyncResponse of the aget_itemreoder
+      request
+
+    :param response: AsyncResponse object
+
+    :returns:
+      data in dictionary format.
+
+    :raises:
+      ItemRankNotFoundError.
+    """
+    if response.error is not None:
+      raise ItemRankNotFoundError(
+        "Exception happened: %s for request %s" %
+        (response.error, response.request))
+    elif response.status != httplib.OK:
+      raise ItemRankNotFoundError("request: %s status: %s body: %s" %
+                                  (response.request, response.status,
+                                   response.body))
+
+    data = json.loads(response.body)  # convert json string to dict
+    return data
+
+  def aget_itemrank_ranked(self, engine, iids, params={}):
+    """Asynchronously get ranked item for user
+
+    :param engine: name of the prediction engine. type str.
+    :param iids: items to be ranked. type list of item ids.
+      For example, ["i0", "i1", "i2"]
+    :param params: optional parameters. type dictionary
+      For example. { 'pio_attributes' : "name" }
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+
+    if self._uid is None:
+      raise InvalidArgumentError(
+        "uid is not identified. Please call identify(uid) first.")
+
+    request = self._aget_user_itemrank_ranked(engine,
+      self._uid, iids, params)
+    return request
+
+  def _auser_action_on_item(self, action, uid, iid, params):
+    """Private function to asynchronously create an user action on an item
+
+    :param action: action type. type str. ("like", "dislike", "conversion",
+                         "rate", "view")
+    :param uid: user id. type str or int.
+    :param iid: item id. type str or int.
+    :param params: optional attributes. type dictionary.
+        For example, { 'pio_rate' : 4, 'pio_latlng' : [1.23,4.56] }
+        NOTE: For "rate" action, pio_rate attribute is required.
+            integer value of 1-5 (1 is least preferred and 5 is most
+            preferred)
+
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+    if "pio_latlng" in params:
+      params["pio_latlng"] = ",".join(map(str, params["pio_latlng"]))
+
+    path = "%s/actions/u2i.json" % (self.apiversion)
+    request = AsyncRequest("POST", path, pio_appkey=self.appkey,
+                 pio_action=action, pio_uid=uid, pio_iid=iid,
+                 **params)
+    request.set_rfunc(self._auser_action_on_item_resp)
+    self._connection.make_request(request)
+    return request
+
+  def _auser_action_on_item_resp(self, response):
+    """Private function to handle the AsyncResponse of the
+    _auser_action_on_item request
+
+    :param response: AsyncResponse object
+
+    :returns:
+      None
+
+    :raises:
+      U2IActionNotCreatedError
+    """
+    if response.error is not None:
+      raise U2IActionNotCreatedError(
+        "Exception happened: %s for request %s" %
+        (response.error, response.request))
+    elif response.status != httplib.CREATED:
+      raise U2IActionNotCreatedError("request: %s status: %s body: %s" %
+                       (response.request, response.status,
+                      response.body))
+    return None
+
+  def arecord_action_on_item(self, action, iid, params={}):
+    """Asynchronously create action on item
+
+    :param action: action name. type String. For example, "rate", "like",
+             etc
+    :param iid: item id. type str or int.
+    :param params: optional attributes. type dictionary.
+        For example, { 'pio_rate' : 4, 'pio_latlng': [4.5,67.8] }
+        NOTE: For "rate" action, pio_rate attribute is required.
+        integer value of 1-5 (1 is least preferred and 5 is most
+        preferred)
+
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+
+    :raises:
+      U2IActionNotCreatedError
+    """
+
+    if self._uid is None:
+      raise InvalidArgumentError(
+        "uid is not identified. Please call identify(uid) first.")
+
+    request = self._auser_action_on_item(action, self._uid, iid, params)
+    return request
+
+  def auser_conversion_item(self, uid, iid, **params):
+    """Deprecated. Asynchronously create an user conversion action on an
+    item
+
+    :param uid: user id. type str.
+    :param iid: item id. type str.
+    :param params: keyword arguments for optional attributes.
+        For example, pio_latlng=[123.4, 56.7]
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+    request = self._auser_action_on_item(CONVERSION_API, uid, iid, params)
+    return request
+
+  def auser_dislike_item(self, uid, iid, **params):
+    """Deprecated. Asynchronously create an user dislike action on an item
+
+    :param uid: user id. type str.
+    :param iid: item id. type str.
+    :param params: keyword arguments for optional attributes.
+        For example, pio_latlng=[123.4, 56.7]
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+    request = self._auser_action_on_item(DISLIKE_API, uid, iid, params)
+    return request
+
+  def auser_like_item(self, uid, iid, **params):
+    """Deprecated. Asynchronously create an user like action on an item
+
+    :param uid: user id. type str.
+    :param iid: item id. type str.
+    :param params: keyword arguments for optional attributes.
+        For example, pio_latlng=[123.4, 56.7]
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+    request = self._auser_action_on_item(LIKE_API, uid, iid, params)
+    return request
+
+  def auser_rate_item(self, uid, iid, rate, **params):
+    """Deprecated. Asynchronously create an user rate action on an item
+
+    :param uid: user id. type str.
+    :param iid: item id. type str.
+    :param rate: rating. integer value of 1-5 (1 is least preferred and 5
+           is most preferred)
+    :param params: keyword arguments for optional attributes.
+        For example, pio_latlng=[123.4, 56.7]
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+
+    params['pio_rate'] = rate
+    request = self._auser_action_on_item(RATE_API, uid, iid, params)
+    return request
+
+  def auser_view_item(self, uid, iid, **params):
+    """Deprecated. Asynchronously create an user view action on an item
+
+    :param uid: user id. type str.
+    :param iid: item id. type str.
+    :param params: keyword arguments for optional attributes.
+        For example, pio_latlng=[123.4, 56.7]
+    :returns:
+      AsyncRequest object. You should call the aresp() method using this
+      AsyncRequest object as argument to get the final result or status
+      of this asynchronous request.
+    """
+    request = self._auser_action_on_item(VIEW_API, uid, iid, params)
+    return request
+
+  def aresp(self, request):
+    """Get the result of the asynchronous request
+
+    :param request: AsyncRequest object. This object must be returned by
+            the asynchronous request function
+            For example, to get the result of a aget_user()
+            request, call this aresp() with the argument of
+            AsyncRequest object returned by aget_user().
+
+    :returns:
+      The result of this AsyncRequest. The return type is the same as
+      the return type of corresponding blocking request.
+
+      For example,
+
+      Calling aresp() with acreate_user() AsyncRequest returns the same
+      type as create_user(), which is None.
+
+      Calling aresp() with aget_user() AsyncRequest returns the same
+      type as get_user(), which is dictionary data.
+
+    :raises:
+      Exception may be raised if there is error happened. The type of
+      exception is the same as exception type of the correspdoning
+      blocking request.
+
+      For example,
+
+      Calling aresp() with acreate_user() AsyncRequest may raise
+      UserNotCreatedError exception.
+
+      Calling aresp() with aget_user() AsyncRequest may raise
+      UserNotFoundError exception.
+
+    """
+    response = request.get_response()
+    result = request.rfunc(response)
+    return result
+
+  def create_user(self, uid, params={}):
+    """Blocking request to create user
+
+    :param uid: user id. type str.
+    :param params: optional attributes. type dictionary.
+      For example, { 'custom': 'value', 'pio_inactive' : True,
+      'pio_latlng': [4.5,67.8] }
+
+    :returns:
+      None.
+
+    :raises:
+      UserNotCreatedError.
+
+    """
+    request = self.acreate_user(uid, params)
+    result = self.aresp(request)
+    return result
+
+  def get_user(self, uid):
+    """Blocking request to get user
+
+    :param uid: user id. type str or int.
+
+    :returns:
+      User data in Dictionary format.
+
+    :rasies:
+      UserNotFoundError.
+
+    """
+    request = self.aget_user(uid)
+    result = self.aresp(request)
+    return result
+
+  def delete_user(self, uid):
+    """Blocking request to delete the user
+
+    :param uid: user id. type str.
+
+    :returns:
+      None.
+
+    :raises:
+      UserNotDeletedError.
+
+    """
+    request = self.adelete_user(uid)
+    result = self.aresp(request)
+    return result
+
+  def create_item(self, iid, itypes, params={}):
+    """Blocking request to create item
+
+    :param iid: item id. type str.
+    :param itypes: item types. Tuple of Str.
+        For example, if this item belongs to item types "t1", "t2",
+        "t3", "t4", then itypes=("t1", "t2", "t3", "t4").
+        NOTE: if this item belongs to only one itype, use tuple of one
+        element, eg. itypes=("t1",)
+    :param params: optional attributes. type dictionary.
+        For example,
+        { 'custom': 'value', 'pio_inactive' : True,
+        'pio_latlng': [4.5,67.8] }
+
+    :returns:
+      None
+
+    :raises:
+      ItemNotCreatedError
+
+    """
+    request = self.acreate_item(iid, itypes, params)
+    result = self.aresp(request)
+    return result
+
+  def get_item(self, iid):
+    """Blocking request to get item
+
+    :param iid: item id. type str.
+
+    :returns:
+      item data in dictionary format.
+
+    :raises:
+      ItemNotFoundError.
+
+    """
+    request = self.aget_item(iid)
+    result = self.aresp(request)
+    return result
+
+  def delete_item(self, iid):
+    """Blocking request to delete item
+
+    :param iid: item id. type str.
+
+    :returns:
+      None
+
+    :raises:
+      ItemNotDeletedError
+
+    """
+    request = self.adelete_item(iid)
+    result = self.aresp(request)
+    return result
+
+  def get_itemrec_topn(self, engine, n, params={}):
+    """Blocking request to get recommendations for the identified user
+
+    :param engine: name of the prediction engine. type str.
+    :param n: number of recommendation. type int.
+    :param params: optional parameters. type dictionary
+        For example, { 'pio_itypes' : ("t1", "t2") }
+    :returns:
+      data in dictionary format.
+
+    :raises:
+      ItemRecNotFoundError.
+    """
+    request = self.aget_itemrec_topn(engine, n, params)
+    result = self.aresp(request)
+    return result
+
+  def get_itemrec(self, uid, n, engine, **params):
+    """Deprecated. Blocking request to get recommendations
+
+    :param uid: user id. type str or int.
+    :param n: number of recommendation. type int.
+    :param engine: name of the prediction engine. type str.
+    :param params: keyword arguments for optional attributes.
+        For example, pio_latlng=[123.4, 56.7]
+
+    :returns:
+      data in dictionary format.
+
+    :raises:
+      ItemRecNotFoundError.
+
+    """
+    request = self.aget_itemrec(uid, n, engine, **params)
+    result = self.aresp(request)
+    return result
+
+  def get_itemsim_topn(self, engine, iid, n, params={}):
+    """Blocking request to get top n similar items of the item
+
+    :param engine: name of the prediction engine. type str.
+    :param iid: item id. type str.
+    :param n: number of similar items. type int.
+    :param params: optional parameters. type dictionary
+        For example, { 'pio_itypes' : ("t1",) }
+    :returns:
+      data in dictionary format.
+
+    :raises:
+      ItemSimNotFoundError.
+    """
+
+    request = self.aget_itemsim_topn(engine, iid, n, params)
+    result = self.aresp(request)
+    return result
+
+  def get_itemrank_ranked(self, engine, iids, params={}):
+    """Blocking request to get ranked item for user
+
+    :param engine: name of the prediction engine. type str.
+    :param iids: items to be ranked. type list of item ids.
+        For example, ["i0", "i1", "i2"]
+    :param params: optional parameters. type dictionary
+        For example. { 'pio_attributes' : "name" }
+    :returns:
+      data in dictionary format.
+
+    :raises:
+      ItemRankNotFoundError.
+    """
+    request = self.aget_itemrank_ranked(engine, iids, params)
+    result = self.aresp(request)
+    return result
+
+  def record_action_on_item(self, action, iid, params={}):
+    """Blocking request to create action on an item
+
+    :param action: action name. type String. For example, "rate", "like",
+             etc
+    :param iid: item id. type str.
+    :param params: optional attributes. type dictionary.
+        For example, { 'pio_rate' : 4, 'pio_latlng' : [1.23,4.56] }
+        NOTE: For "rate" action, pio_rate attribute is required.
+        integer value of 1-5 (1 is least preferred and 5 is most
+        preferred)
+
+    :returns:
+      None
+
+    :raises:
+      U2IActionNotCreatedError
+    """
+    request = self.arecord_action_on_item(action, iid, params)
+    result = self.aresp(request)
+    return result
+
+  def user_conversion_item(self, uid, iid, **params):
+    """Deprecated. Blocking request to create user conversion action on an
+     item
+
+    :param uid: user id. type str.
+    :param iid: item id. type str.
+    :param params: keyword arguments for optional attributes.
+        For example, pio_latlng=[123.4, 56.7]
+
+    :returns:
+      None
+
+    :raises:
+      U2IActionNotCreatedError
+    """
+    request = self.auser_conversion_item(uid, iid, **params)
+    result = self.aresp(request)
+    return result
+
+  def user_dislike_item(self, uid, iid, **params):
+    """Deprecated. Blocking request to create user dislike action on an
+     item
+
+    :param uid: user id. type str.
+    :param iid: item id. type str.
+    :param params: keyword arguments for optional attributes.
+        For example, pio_latlng=[123.4, 56.7]
+
+    :returns:
+      None
+
+    :raises:
+      U2IActionNotCreatedError
+    """
+    request = self.auser_dislike_item(uid, iid, **params)
+    result = self.aresp(request)
+    return result
+
+  def user_like_item(self, uid, iid, **params):
+    """Deprecated. Blocking request to create user like action on an item
+
+    :param uid: user id. type str.
+    :param iid: item id. type str.
+    :param params: keyword arguments for optional attributes.
+        For example, pio_latlng=[123.4, 56.7]
+
+    :returns:
+      None
+
+    :raises:
+      U2IActionNotCreatedError
+    """
+    request = self.auser_like_item(uid, iid, **params)
+    result = self.aresp(request)
+    return result
+
+  def user_rate_item(self, uid, iid, rate, **params):
+    """Deprecated. Blocking request to create user rate action on an item
+
+    :param uid: user id. type str.
+    :param iid: item id. type str.
+    :param rate: rating. integer value of 1-5 (1 is least preferred and 5
+           is most preferred)
+    :param params: keyword arguments for optional attributes.
+        For example, pio_latlng=[123.4, 56.7]
+
+    :returns:
+      None
+
+    :raises:
+      U2IActionNotCreatedError
+    """
+    request = self.auser_rate_item(uid, iid, rate, **params)
+    result = self.aresp(request)
+    return result
+
+  def user_view_item(self, uid, iid, **params):
+    """Deprecated. Blocking request to create user view action on an item
+
+    :param uid: user id. type str.
+    :param iid: item id. type str.
+    :param params: keyword arguments for optional attributes.
+        For example, pio_latlng=[123.4, 56.7]
+
+    :returns:
+      None
+
+    :raises:
+      U2IActionNotCreatedError
+    """
+    request = self.auser_view_item(uid, iid, **params)
+    result = self.aresp(request)
+    return result
+