docs/manual/source/datacollection/eventapi.html.md - predictionio - Git at Google

 ---
 title: Collecting Data through REST/SDKs
 ---

 <!--
 Licensed to the Apache Software Foundation (ASF) under one or more
 contributor license agreements.  See the NOTICE file distributed with
 this work for additional information regarding copyright ownership.
 The ASF licenses this file to You under the Apache License, Version 2.0
 (the "License"); you may not use this file except in compliance with
 the License.  You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 -->

 **Event Server** is designed to collect data into Apache PredictionIO
 in an event-based style. Once the Event Server is launched, your
 application can send data to it through its **Event API** with HTTP requests or
 with `EventClient`s of PredictionIO's SDKs.

 INFO: All Apache PredictionIO-compliant engines support accessing
 the Event Store (i.e. the data store of Event Server) through [Apache
 PredictionIO's Storage
 API](http://predictionio.apache.org/api/current/index.html#org.apache.predictionio.data.storage.package).

 ## Launching the Event Server

 INFO: Before launching the Event Server, make sure that your event data store
 backend is properly configured and is running. By default, Apache PredictionIO
 uses Apache HBase, and a quick configuration can be found
 [here](/install/install-sourcecode/#hbase). Please allow a minute (usually less
 than 30 seconds) after HBase is started for its initialization to complete
 before starting the Event Server.


 Everything about Apache PredictionIO can be done through the `pio`
 command. Please add PIO binary command path to to your `PATH` first. Assuming
 PredictionIO is installed at `/home/yourname/PredictionIO/`, you can run

 ```
 $ PATH=$PATH:/home/yourname/PredictionIO/bin; export PATH
 ```

 To start the event server, run

 ```
 $ pio eventserver
 ```

 INFO: By default, the Event Server is bound to 0.0.0.0, which serves global
 traffic. To tighten security, you may use `pio eventserver --ip 127.0.0.1` to
 serve only local traffic.

 ### Check Server Status

 ```
 $ curl -i -X GET http://localhost:7070
 ```

 Sample response:

 ```
 HTTP/1.1 200 OK
 Server: akka-http/10.1.5
 Date: Wed, 10 Sep 2014 22:37:30 GMT
 Content-Type: application/json; charset=UTF-8
 Content-Length: 18

 {"status":"alive"}
 ```


 ### Generating App ID and Access Key

 First, you need to create a new app in the Event Server. You will later send data into it.

 ```
 $ pio app new MyTestApp
 ```

 > You can replace `MyTestApp` with name of your App.

 Take note of the *Access Key* and *App ID* generated. You need the *Access Key*
 to use the Event API. You should see something like the following output:

 ```
 [INFO] [App$] Created new app:
 [INFO] [App$]         Name: MyTestApp
 [INFO] [App$]           ID: 6
 [INFO] [App$]   Access Key: WPgcXKd42FPQpZHVbVeMyqF4CQJUnXQmIMTHhX3ZUrSzvy1KXJjdFUrslifa9rnB
 ```

 ### Creating Your First Event

 You may connect to the Event Server with HTTP request or by using one of many
 **Apache PredictionIO SDKs**.

 For example, the following shows how one can create an event involving a single entity.
 Replace the value of `accessKey` by the *Access Key* generated for your App.

 <div class="tabs">
   <div data-tab="Raw HTTP" data-lang="bash">
 ```bash
 $ curl -i -X POST http://localhost:7070/events.json?accessKey=WPgcXKd42FPQpZHVbVeMyqF4CQJUnXQmIMTHhX3ZUrSzvy1KXJjdFUrslifa9rnB \
 -H "Content-Type: application/json" \
 -d '{
   "event" : "my_event",
   "entityType" : "user",
   "entityId" : "uid",
   "properties" : {
     "prop1" : 1,
     "prop2" : "value2",
     "prop3" : [1, 2, 3],
     "prop4" : true,
     "prop5" : ["a", "b", "c"],
     "prop6" : 4.56
   }
   "eventTime" : "2004-12-13T21:39:45.618-07:00"
 }'
 ```
   </div>
   <div data-tab="PHP SDK" data-lang="php">
 ```php
 <?php
   require_once("vendor/autoload.php");

   use predictionio\EventClient;

   $accessKey = 'YOUR_ACCESS_KEY';
   $client = new EventClient($accessKey);
   $response = $client->createEvent(array(
                         'event' => 'my_event',
                         'entityType' => 'user',
                         'entityId' => 'uid',
                         'properties' => array('prop1' => 1,
                                               'prop2' => 'value2',
                                               'prop3' => array(1,2,3),
                                               'prop4' => true,
                                               'prop5' => array('a','b','c'),
                                               'prop6' => 4.56
                                         ),
                         'eventTime' => '2004-12-13T21:39:45.618-07:00'
                        ));
 ?>
 ```
   </div>
   <div data-tab="Python SDK" data-lang="python">
 ```python
 from predictionio import EventClient
 from datetime import datetime
 import pytz
 client = EventClient('YOUR_ACCESS_KEY', "http://localhost:7070")

 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,
     event_time=first_event_time,
 )
 ```
   </div>
   <div data-tab="Ruby SDK" data-lang="ruby">
 ```ruby
 require 'predictionio'

 event_client = PredictionIO::EventClient.new('YOUR_ACCESS_KEY')
 event_client.create_event('my_event', 'user', 'uid',
                           'eventTime' => '2004-12-13T21:39:45.618-07:00',
                           'properties' => { 'prop1' => 1,
                                             'prop2' => 'value2',
                                             'prop3' => [1, 2, 3],
                                             'prop4' => true,
                                             'prop5' => %w(a b c),
                                             'prop6' => 4.56 })
 ```
   </div>
   <div data-tab="Java SDK" data-lang="java">
 ```java
 (coming soon)
 ```
   </div>
 </div>

 For example, the following shows how one can create an event involving two entities (with
 `targetEntity`).

 <div class="tabs">
   <div data-tab="Raw HTTP" data-lang="bash">
 ```bash
 $ curl -i -X POST http://localhost:7070/events.json?accessKey=WPgcXKd42FPQpZHVbVeMyqF4CQJUnXQmIMTHhX3ZUrSzvy1KXJjdFUrslifa9rnB \
 -H "Content-Type: application/json" \
 -d '{
   "event" : "my_event",
   "entityType" : "user",
   "entityId" : "uid",
   "targetEntityType" : "item",
   "targetEntityId" : "iid",
   "properties" : {
     "someProperty" : "value1",
     "anotherProperty" : "value2"
   },
   "eventTime" : "2004-12-13T21:39:45.618Z"
 }'
 ```
   </div>
   <div data-tab="PHP SDK" data-lang="php">
 ```php
 <?php
   require_once("vendor/autoload.php");

   use predictionio\EventClient;

   $accessKey = 'YOUR_ACCESS_KEY';
   $client = new EventClient($accessKey);
   $response = $client->createEvent(array(
                         'event' => 'my_event',
                         'entityType' => 'user',
                         'entityId' => 'uid',
                         'targetEntityType' => 'item',
                         'targetEntityId' => 'iid',
                         'properties' => array('someProperty'=>'value1',
                                               'anotherProperty'=>'value2'),
                         'eventTime' => '2004-12-13T21:39:45.618Z'
                        ));
 ?>
 ```
   </div>
   <div data-tab="Python SDK" data-lang="python">
 ```python
 # 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))
 ```
   </div>
   <div data-tab="Ruby SDK" data-lang="ruby">
 ```ruby
 require 'predictionio'

 event_client = PredictionIO::EventClient.new('YOUR_ACCESS_KEY')
 event_client.create_event('my_event', 'user', 'uid',
                           'targetEntityType' => 'item',
                           'targetEntityId' => 'iid',
                           'eventTime' => '2004-12-13T21:39:45.618Z',
                           'properties' => { 'someProperty' => 'value1',
                                             'anotherProperty' => 'value2' })
 ```
   </div>
   <div data-tab="Java SDK" data-lang="java">
 ```java
 (coming soon)
 ```
   </div>
 </div>


 Sample response:

 ```
 HTTP/1.1 201 Created
 Server: akka-http/10.1.5
 Date: Wed, 10 Sep 2014 22:51:33 GMT
 Content-Type: application/json; charset=UTF-8
 Content-Length: 41

 {"eventId":"AAAABAAAAQDP3-jSlTMGVu0waj8"}
 ```


 ## Using Event API

 ### Event Creation API

 URL: `http://localhost:7070/events.json?accessKey=yourAccessKeyString`

 Query parameters:

 Field | Type | Description
 :---- | :----| :-----
 `accessKey` | String | The Access Key for your App

 The event creation support many commonly used data. POST request body:

 Field | Type | Description
 :---- | :----| :-----
 `event` | String | Name of the event.
         | | (Examples: "sign-up", "rate", "view", "buy").
         | | **Note**: All event names start with "$" and "pio_" are reserved
         | | and shouldn't be used as your custom event name (eg. "$set").
 `entityType` | String | The 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.
              | | **Note**: All entityType names start with "$" and "pio_" are
              | | reserved and shouldn't be used.
 `entityId` | String | The entity ID. `entityType-entityId` becomes the unique
            | | identifier of the entity. For example, you may have entityType
            | | named `user`, and different entity IDs, say `1` and `2`. In this
            | | case, `user-1` and `user-2` uniquely identifies | these two
            | | entities.
 `targetEntityType` | String | (Optional) The target entity type.
                    | | **Note**: All entityType names start with "$" and "pio_"
                    | | are reserved and shouldn't be used.
 `targetEntityId` | String | (Optional) The target entity ID.
 `properties` | JSON | (Optional) See **Note About Properties** below
              | | **Note**: All property names start with "$" and "pio_"
              | | are reserved and shouldn't be used as keys inside `properties`.
 `eventTime` | String | (Optional) The time of the event. Although Event Server's
             | | current system time and UTC timezone will be used if this is
             | | unspecified, it is highly recommended that this time should be
             | | generated by the client application in order to accurately
             | | record the time of the event.
             | |  Must be in ISO 8601 format (e.g.
             | | `2004-12-13T21:39:45.618Z`, or `2014-09-09T16:17:42.937-08:00`).

 ## Note About Properties

 Note that `properties` can be:

 1. Associated with an *generic event*: The `properties` field provide additional information about this event
 2. Associated with an *entity*: The `properties` field is used to record the changes of an entity's properties with special events `$set`, `$unset` and `$delete`.

 Please see the [Events Modeling](/datacollection/eventmodel/) for detailed explanation.


 ## Debugging Recipes

 WARNING: The following API are mainly for development or debugging purpose
 only. They should not be supported by SDK nor used by real application under
 normal circumstances and they are subject to changes.

 INFO: Instead of using `curl`, you can also install JSON browser plugins such as **JSONView** to pretty-print the JSON on your browser. With the browser plugin you can make the `GET` queries below by passing in the URL. Plugins like **Postman - REST Client** provide a more advanced interface for making queries.

 The `accessKey` query parameter is mandatory.

 Replace `<your_accessKey>` and `<your_eventId>` by a real one in the following:

 ### Get an Event

 ```
 $ curl -i -X GET http://localhost:7070/events/<your_eventId>.json?accessKey=<your_accessKey>
 ```

 ### Delete an Event

 ```
 $ curl -i -X DELETE http://localhost:7070/events/<your_eventId>.json?accessKey=<your_accessKey>
 ```

 ### Get Events of an App

 ```
 $ curl -i -X GET http://localhost:7070/events.json?accessKey=<your_accessKey>
 ```

 INFO: By default, it returns at most 20 events. Use the `limit` parameter to specify how many events returned (see below). Use cautiously!

 In addition, the following *optional* parameters are supported:

 - `startTime`: time in ISO8601 format. Return events with `eventTime >= startTime`.
 - `untilTime`: time in ISO8601 format. Return events with `eventTime < untilTime`.
 - `entityType`: String. The entityType. Return events for this `entityType` only.
 - `entityId`: String. The entityId. Return events for this `entityId` only.
 - `event`: String. The event name. Return events with this name only.
 - `targetEntityType`: String. The targetEntityType. Return events for this `targetEntityType` only.
 - `targetEntityId`: String. The targetEntityId. Return events for this `targetEntityId` only.
 - `limit`: Integer. The number of record events returned. Default is 20. -1 to
   get all.
 - `reversed`: Boolean. **Must be used with both `entityType` and `entityId` specified**, returns events in reversed chronological order. Default is false.

 WARNING: If you are using <code>curl</code> with the <code>&</code> symbol, you should quote the entire URL by using single or double quotes.

 WARNING: Depending on the size of data, you may encounter timeout when querying with some of the above filters. Event server uses `entityType` and `entityId` as the key so any query without both `entityType` and `entityId` specified might result in a timeout.

 For example, get all events of an app with `eventTime >= startTime`

 ```
 $ curl -i -X GET "http://localhost:7070/events.json?accessKey=<your_accessKey>&startTime=<time in ISO8601 format>"
 ```

 For example, get all events of an app with `eventTime < untilTime`:

 ```
 $ curl -i -X GET "http://localhost:7070/events.json?accessKey=<your_accessKey>&untilTime=<time in ISO8601 format>"
 ```

 For example, get all events of an app with `eventTime >= startTime` and `eventTime < untilTime`:

 ```
 $ curl -i -X GET "http://localhost:7070/events.json?accessKey=<your_accessKey>&startTime=<time in ISO8601 format>&untilTime=<time in ISO8601 format>"
 ```

 For example, get all events of a specific entity with `eventTime < untilTime`:

 ```
 $ curl -i -X GET "http://localhost:7070/events.json?accessKey=<your_accessKey>&entityType=<your_entityType>&entityId=<your_entityId>&untilTime=<time in ISO801 format>"
 ```

 ### Delete All Events of an App

 Please use the following CLI command:

 ```
 $ pio app data-delete <your_app_name>
 ```

 INFO: See [here](/cli/#event-server-commands) to know details of command-line interface for the event server.
	---
	title: Collecting Data through REST/SDKs
	---

	<!--
	Licensed to the Apache Software Foundation (ASF) under one or more
	contributor license agreements. See the NOTICE file distributed with
	this work for additional information regarding copyright ownership.
	The ASF licenses this file to You under the Apache License, Version 2.0
	(the "License"); you may not use this file except in compliance with
	the License. You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
	-->

	Event Server is designed to collect data into Apache PredictionIO
	in an event-based style. Once the Event Server is launched, your
	application can send data to it through its Event API with HTTP requests or
	with `EventClient`s of PredictionIO's SDKs.

	INFO: All Apache PredictionIO-compliant engines support accessing
	the Event Store (i.e. the data store of Event Server) through [Apache
	PredictionIO's Storage
	API](http://predictionio.apache.org/api/current/index.html#org.apache.predictionio.data.storage.package).

	## Launching the Event Server

	INFO: Before launching the Event Server, make sure that your event data store
	backend is properly configured and is running. By default, Apache PredictionIO
	uses Apache HBase, and a quick configuration can be found
	[here](/install/install-sourcecode/#hbase). Please allow a minute (usually less
	than 30 seconds) after HBase is started for its initialization to complete
	before starting the Event Server.


	Everything about Apache PredictionIO can be done through the `pio`
	command. Please add PIO binary command path to to your `PATH` first. Assuming
	PredictionIO is installed at `/home/yourname/PredictionIO/`, you can run

	```
	$ PATH=$PATH:/home/yourname/PredictionIO/bin; export PATH
	```

	To start the event server, run

	```
	$ pio eventserver
	```

	INFO: By default, the Event Server is bound to 0.0.0.0, which serves global
	traffic. To tighten security, you may use `pio eventserver --ip 127.0.0.1` to
	serve only local traffic.

	### Check Server Status

	```
	$ curl -i -X GET http://localhost:7070
	```

	Sample response:

	```
	HTTP/1.1 200 OK
	Server: akka-http/10.1.5
	Date: Wed, 10 Sep 2014 22:37:30 GMT
	Content-Type: application/json; charset=UTF-8
	Content-Length: 18

	{"status":"alive"}
	```


	### Generating App ID and Access Key

	First, you need to create a new app in the Event Server. You will later send data into it.

	```
	$ pio app new MyTestApp
	```

	> You can replace `MyTestApp` with name of your App.

	Take note of the Access Key and App ID generated. You need the Access Key
	to use the Event API. You should see something like the following output:

	```
	[INFO] [App$] Created new app:
	[INFO] [App$] Name: MyTestApp
	[INFO] [App$] ID: 6
	[INFO] [App$] Access Key: WPgcXKd42FPQpZHVbVeMyqF4CQJUnXQmIMTHhX3ZUrSzvy1KXJjdFUrslifa9rnB
	```

	### Creating Your First Event

	You may connect to the Event Server with HTTP request or by using one of many
	Apache PredictionIO SDKs.

	For example, the following shows how one can create an event involving a single entity.
	Replace the value of `accessKey` by the Access Key generated for your App.

	<div class="tabs">
	<div data-tab="Raw HTTP" data-lang="bash">
	```bash
	$ curl -i -X POST http://localhost:7070/events.json?accessKey=WPgcXKd42FPQpZHVbVeMyqF4CQJUnXQmIMTHhX3ZUrSzvy1KXJjdFUrslifa9rnB \
	-H "Content-Type: application/json" \
	-d '{
	"event" : "my_event",
	"entityType" : "user",
	"entityId" : "uid",
	"properties" : {
	"prop1" : 1,
	"prop2" : "value2",
	"prop3" : [1, 2, 3],
	"prop4" : true,
	"prop5" : ["a", "b", "c"],
	"prop6" : 4.56
	}
	"eventTime" : "2004-12-13T21:39:45.618-07:00"
	}'
	```
	</div>
	<div data-tab="PHP SDK" data-lang="php">
	```php
	<?php
	require_once("vendor/autoload.php");

	use predictionio\EventClient;

	$accessKey = 'YOUR_ACCESS_KEY';
	$client = new EventClient($accessKey);
	$response = $client->createEvent(array(
	'event' => 'my_event',
	'entityType' => 'user',
	'entityId' => 'uid',
	'properties' => array('prop1' => 1,
	'prop2' => 'value2',
	'prop3' => array(1,2,3),
	'prop4' => true,
	'prop5' => array('a','b','c'),
	'prop6' => 4.56
	),
	'eventTime' => '2004-12-13T21:39:45.618-07:00'
	));
	?>
	```
	</div>
	<div data-tab="Python SDK" data-lang="python">
	```python
	from predictionio import EventClient
	from datetime import datetime
	import pytz
	client = EventClient('YOUR_ACCESS_KEY', "http://localhost:7070")

	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,
	event_time=first_event_time,
	)
	```
	</div>
	<div data-tab="Ruby SDK" data-lang="ruby">
	```ruby
	require 'predictionio'

	event_client = PredictionIO::EventClient.new('YOUR_ACCESS_KEY')
	event_client.create_event('my_event', 'user', 'uid',
	'eventTime' => '2004-12-13T21:39:45.618-07:00',
	'properties' => { 'prop1' => 1,
	'prop2' => 'value2',
	'prop3' => [1, 2, 3],
	'prop4' => true,
	'prop5' => %w(a b c),
	'prop6' => 4.56 })
	```
	</div>
	<div data-tab="Java SDK" data-lang="java">
	```java
	(coming soon)
	```
	</div>
	</div>

	For example, the following shows how one can create an event involving two entities (with
	`targetEntity`).

	<div class="tabs">
	<div data-tab="Raw HTTP" data-lang="bash">
	```bash
	$ curl -i -X POST http://localhost:7070/events.json?accessKey=WPgcXKd42FPQpZHVbVeMyqF4CQJUnXQmIMTHhX3ZUrSzvy1KXJjdFUrslifa9rnB \
	-H "Content-Type: application/json" \
	-d '{
	"event" : "my_event",
	"entityType" : "user",
	"entityId" : "uid",
	"targetEntityType" : "item",
	"targetEntityId" : "iid",
	"properties" : {
	"someProperty" : "value1",
	"anotherProperty" : "value2"
	},
	"eventTime" : "2004-12-13T21:39:45.618Z"
	}'
	```
	</div>
	<div data-tab="PHP SDK" data-lang="php">
	```php
	<?php
	require_once("vendor/autoload.php");

	use predictionio\EventClient;

	$accessKey = 'YOUR_ACCESS_KEY';
	$client = new EventClient($accessKey);
	$response = $client->createEvent(array(
	'event' => 'my_event',
	'entityType' => 'user',
	'entityId' => 'uid',
	'targetEntityType' => 'item',
	'targetEntityId' => 'iid',
	'properties' => array('someProperty'=>'value1',
	'anotherProperty'=>'value2'),
	'eventTime' => '2004-12-13T21:39:45.618Z'
	));
	?>
	```
	</div>
	<div data-tab="Python SDK" data-lang="python">
	```python
	# 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))
	```
	</div>
	<div data-tab="Ruby SDK" data-lang="ruby">
	```ruby
	require 'predictionio'

	event_client = PredictionIO::EventClient.new('YOUR_ACCESS_KEY')
	event_client.create_event('my_event', 'user', 'uid',
	'targetEntityType' => 'item',
	'targetEntityId' => 'iid',
	'eventTime' => '2004-12-13T21:39:45.618Z',
	'properties' => { 'someProperty' => 'value1',
	'anotherProperty' => 'value2' })
	```
	</div>
	<div data-tab="Java SDK" data-lang="java">
	```java
	(coming soon)
	```
	</div>
	</div>


	Sample response:

	```
	HTTP/1.1 201 Created
	Server: akka-http/10.1.5
	Date: Wed, 10 Sep 2014 22:51:33 GMT
	Content-Type: application/json; charset=UTF-8
	Content-Length: 41

	{"eventId":"AAAABAAAAQDP3-jSlTMGVu0waj8"}
	```


	## Using Event API

	### Event Creation API

	URL: `http://localhost:7070/events.json?accessKey=yourAccessKeyString`

	Query parameters:

	Field \| Type \| Description
	:---- \| :----\| :-----
	`accessKey` \| String \| The Access Key for your App

	The event creation support many commonly used data. POST request body:

	Field \| Type \| Description
	:---- \| :----\| :-----
	`event` \| String \| Name of the event.
	\| \| (Examples: "sign-up", "rate", "view", "buy").
	\| \| Note: All event names start with "$" and "pio_" are reserved
	\| \| and shouldn't be used as your custom event name (eg. "$set").
	`entityType` \| String \| The 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.
	\| \| Note: All entityType names start with "$" and "pio_" are
	\| \| reserved and shouldn't be used.
	`entityId` \| String \| The entity ID. `entityType-entityId` becomes the unique
	\| \| identifier of the entity. For example, you may have entityType
	\| \| named `user`, and different entity IDs, say `1` and `2`. In this
	\| \| case, `user-1` and `user-2` uniquely identifies \| these two
	\| \| entities.
	`targetEntityType` \| String \| (Optional) The target entity type.
	\| \| Note: All entityType names start with "$" and "pio_"
	\| \| are reserved and shouldn't be used.
	`targetEntityId` \| String \| (Optional) The target entity ID.
	`properties` \| JSON \| (Optional) See Note About Properties below
	\| \| Note: All property names start with "$" and "pio_"
	\| \| are reserved and shouldn't be used as keys inside `properties`.
	`eventTime` \| String \| (Optional) The time of the event. Although Event Server's
	\| \| current system time and UTC timezone will be used if this is
	\| \| unspecified, it is highly recommended that this time should be
	\| \| generated by the client application in order to accurately
	\| \| record the time of the event.
	\| \| Must be in ISO 8601 format (e.g.
	\| \| `2004-12-13T21:39:45.618Z`, or `2014-09-09T16:17:42.937-08:00`).

	## Note About Properties

	Note that `properties` can be:

	1. Associated with an generic event: The `properties` field provide additional information about this event
	2. Associated with an entity: The `properties` field is used to record the changes of an entity's properties with special events `$set`, `$unset` and `$delete`.

	Please see the [Events Modeling](/datacollection/eventmodel/) for detailed explanation.


	## Debugging Recipes

	WARNING: The following API are mainly for development or debugging purpose
	only. They should not be supported by SDK nor used by real application under
	normal circumstances and they are subject to changes.

	INFO: Instead of using `curl`, you can also install JSON browser plugins such as JSONView to pretty-print the JSON on your browser. With the browser plugin you can make the `GET` queries below by passing in the URL. Plugins like Postman - REST Client provide a more advanced interface for making queries.

	The `accessKey` query parameter is mandatory.

	Replace `<your_accessKey>` and `<your_eventId>` by a real one in the following:

	### Get an Event

	```
	$ curl -i -X GET http://localhost:7070/events/<your_eventId>.json?accessKey=<your_accessKey>
	```

	### Delete an Event

	```
	$ curl -i -X DELETE http://localhost:7070/events/<your_eventId>.json?accessKey=<your_accessKey>
	```

	### Get Events of an App

	```
	$ curl -i -X GET http://localhost:7070/events.json?accessKey=<your_accessKey>
	```

	INFO: By default, it returns at most 20 events. Use the `limit` parameter to specify how many events returned (see below). Use cautiously!

	In addition, the following optional parameters are supported:

	- `startTime`: time in ISO8601 format. Return events with `eventTime >= startTime`.
	- `untilTime`: time in ISO8601 format. Return events with `eventTime < untilTime`.
	- `entityType`: String. The entityType. Return events for this `entityType` only.
	- `entityId`: String. The entityId. Return events for this `entityId` only.
	- `event`: String. The event name. Return events with this name only.
	- `targetEntityType`: String. The targetEntityType. Return events for this `targetEntityType` only.
	- `targetEntityId`: String. The targetEntityId. Return events for this `targetEntityId` only.
	- `limit`: Integer. The number of record events returned. Default is 20. -1 to
	get all.
	- `reversed`: Boolean. Must be used with both `entityType` and `entityId` specified, returns events in reversed chronological order. Default is false.

	WARNING: If you are using <code>curl</code> with the <code>&</code> symbol, you should quote the entire URL by using single or double quotes.

	WARNING: Depending on the size of data, you may encounter timeout when querying with some of the above filters. Event server uses `entityType` and `entityId` as the key so any query without both `entityType` and `entityId` specified might result in a timeout.

	For example, get all events of an app with `eventTime >= startTime`

	```
	$ curl -i -X GET "http://localhost:7070/events.json?accessKey=<your_accessKey>&startTime=<time in ISO8601 format>"
	```

	For example, get all events of an app with `eventTime < untilTime`:

	```
	$ curl -i -X GET "http://localhost:7070/events.json?accessKey=<your_accessKey>&untilTime=<time in ISO8601 format>"
	```

	For example, get all events of an app with `eventTime >= startTime` and `eventTime < untilTime`:

	```
	$ curl -i -X GET "http://localhost:7070/events.json?accessKey=<your_accessKey>&startTime=<time in ISO8601 format>&untilTime=<time in ISO8601 format>"
	```

	For example, get all events of a specific entity with `eventTime < untilTime`:

	```
	$ curl -i -X GET "http://localhost:7070/events.json?accessKey=<your_accessKey>&entityType=<your_entityType>&entityId=<your_entityId>&untilTime=<time in ISO801 format>"
	```

	### Delete All Events of an App

	Please use the following CLI command:

	```
	$ pio app data-delete <your_app_name>
	```

	INFO: See [here](/cli/#event-server-commands) to know details of command-line interface for the event server.