:mod:`airflow.contrib.hooks.salesforce_hook`
============================================

.. py:module:: airflow.contrib.hooks.salesforce_hook

.. autoapi-nested-parse::

   This module contains a Salesforce Hook
   which allows you to connect to your Salesforce instance,
   retrieve data from it, and write that data to a file
   for other uses.

   NOTE:   this hook also relies on the simple_salesforce package:
           https://github.com/simple-salesforce/simple-salesforce


Module Contents
---------------

.. py:class:: SalesforceHook(conn_id, *args, **kwargs)

   Bases: :class:`airflow.hooks.base_hook.BaseHook`

   
   .. method:: sign_in(self)

      Sign into Salesforce.

      If we have already signed it, this will just return the original object


   .. method:: make_query(self, query)

      Make a query to Salesforce.  Returns result in dictionary

      :param query:    The query to make to Salesforce


   .. method:: describe_object(self, obj)

      Get the description of an object from Salesforce.

      This description is the object's schema
      and some extra metadata that Salesforce stores for each object

      :param obj:     Name of the Salesforce object
                      that we are getting a description of.


   .. method:: get_available_fields(self, obj)

      Get a list of all available fields for an object.

      This only returns the names of the fields.


   .. staticmethod:: _build_field_list(fields)


   .. method:: get_object_from_salesforce(self, obj, fields)

      Get all instances of the `object` from Salesforce.
      For each model, only get the fields specified in fields.

      All we really do underneath the hood is run:
          SELECT <fields> FROM <obj>;


   .. classmethod:: _to_timestamp(cls, col)

      Convert a column of a dataframe to UNIX timestamps if applicable

      :param col:     A Series object representing a column of a dataframe.


   .. method:: write_object_to_file(self, query_results, filename, fmt='csv', coerce_to_timestamp=False, record_time_added=False)

      Write query results to file.

      Acceptable formats are:
          - csv:
              comma-separated-values file.  This is the default format.
          - json:
              JSON array.  Each element in the array is a different row.
          - ndjson:
              JSON array but each element is new-line delimited
              instead of comma delimited like in `json`

      This requires a significant amount of cleanup.
      Pandas doesn't handle output to CSV and json in a uniform way.
      This is especially painful for datetime types.
      Pandas wants to write them as strings in CSV,
      but as millisecond Unix timestamps.

      By default, this function will try and leave all values as
      they are represented in Salesforce.
      You use the `coerce_to_timestamp` flag to force all datetimes
      to become Unix timestamps (UTC).
      This is can be greatly beneficial as it will make all of your
      datetime fields look the same,
      and makes it easier to work with in other database environments

      :param query_results:       the results from a SQL query
      :param filename:            the name of the file where the data
                                  should be dumped to
      :param fmt:                 the format you want the output in.
                                  *Default:* csv.
      :param coerce_to_timestamp: True if you want all datetime fields to be
                                  converted into Unix timestamps.
                                  False if you want them to be left in the
                                  same format as they were in Salesforce.
                                  Leaving the value as False will result
                                  in datetimes being strings.
                                  *Defaults to False*
      :param record_time_added:   *(optional)* True if you want to add a
                                  Unix timestamp field to the resulting data
                                  that marks when the data
                                  was fetched from Salesforce.
                                  *Default: False*.