ENH: Save BigQuery account credentials in a hidden user folder

docs/source/changelog.rst

@@ -6,7 +6,7 @@ Changelog
 
 - :func:`read_gbq` now raises ``QueryTimeout`` if the request exceeds the ``query.timeoutMs`` value specified in the BigQuery configuration. (:issue:`76`)
 - Environment variable ``PANDAS_GBQ_CREDENTIALS_FILE`` can now be used to override the default location where the BigQuery user account credentials are stored. (:issue:`86`)
-
+- BigQuery user account credentials are now stored in an application-specific hidden user folder on the operating system. (:issue:`41`)
 
 0.2.0 / 2017-07-24
 ------------------

docs/source/intro.rst

@@ -37,7 +37,9 @@ is possible with either user or service account credentials.
 Authentication via user account credentials is as simple as following the prompts in a browser window
 which will automatically open for you. You authenticate to the specified
 ``BigQuery`` account using the product name ``pandas GBQ``.
-The remote authentication is supported via specifying ``auth_local_webserver`` in ``read_gbq``.
+The remote authentication is supported via the ``auth_local_webserver`` in ``read_gbq``. By default,
+account credentials are stored in an application-specific hidden user folder on the operating system. You
+can override the default credentials location via the ``PANDAS_GBQ_CREDENTIALS_FILE`` environment variable.
 Additional information on the authentication mechanism can be found
 `here <https://developers.google.com/identity/protocols/OAuth2#clientside/>`__.
 

pandas_gbq/gbq.py

@@ -208,6 +208,7 @@ def __init__(self, project_id, reauth=False, verbose=False,
         self.private_key = private_key
         self.auth_local_webserver = auth_local_webserver
         self.dialect = dialect
+        self.credentials_path = _get_credentials_file()
         self.credentials = self.get_credentials()
         self.service = self.get_service()
 
@@ -279,8 +280,21 @@ def load_user_account_credentials(self):
         from google_auth_httplib2 import Request
         from google.oauth2.credentials import Credentials
 
+        # Use the default credentials location under ~/.config and the
+        # equivalent directory on windows if the user has not specified a
+        # credentials path.
+        if not self.credentials_path:
+            self.credentials_path = self.get_default_credentials_path()
+
+            # Previously, pandas-gbq saved user account credentials in the
+            # current working directory. If the bigquery_credentials.dat file
+            # exists in the current working directory, move the credentials to
+            # the new default location.
+            if os.path.isfile('bigquery_credentials.dat'):
+                os.rename('bigquery_credentials.dat', self.credentials_path)
+
         try:
-            with open(_get_credentials_file()) as credentials_file:
+            with open(self.credentials_path) as credentials_file:
                 credentials_json = json.load(credentials_file)
         except (IOError, ValueError):
             return None
@@ -301,14 +315,41 @@ def load_user_account_credentials(self):
 
         return _try_credentials(self.project_id, credentials)
 
+    def get_default_credentials_path(self):
+        """
+        Gets the default path to the BigQuery credentials
+
+        .. versionadded 0.3.0
+
+        Returns
+        -------
+        Path to the BigQuery credentials
+        """
+
+        import os
+
+        if os.name == 'nt':
+            config_path = os.environ['APPDATA']
+        else:
+            config_path = os.path.join(os.path.expanduser('~'), '.config')
+
+        config_path = os.path.join(config_path, 'pandas_gbq')
+
+        # Create a pandas_gbq directory in an application-specific hidden
+        # user folder on the operating system.
+        if not os.path.exists(config_path):
+            os.makedirs(config_path)
+
+        return os.path.join(config_path, 'bigquery_credentials.dat')
+
     def save_user_account_credentials(self, credentials):
         """
         Saves user account credentials to a local file.
 
         .. versionadded 0.2.0
         """
         try:
-            with open(_get_credentials_file(), 'w') as credentials_file:
+            with open(self.credentials_path, 'w') as credentials_file:
                 credentials_json = {
                     'refresh_token': credentials.refresh_token,
                     'id_token': credentials.id_token,
@@ -793,7 +834,7 @@ def delete_and_recreate_table(self, dataset_id, table_id, table_schema):
 
 def _get_credentials_file():
     return os.environ.get(
-        'PANDAS_GBQ_CREDENTIALS_FILE', 'bigquery_credentials.dat')
+        'PANDAS_GBQ_CREDENTIALS_FILE')
 
 
 def _parse_data(schema, rows):

pandas_gbq/tests/test_gbq.py

@@ -1388,6 +1388,7 @@ def setup_method(self, method):
         # put here any instruction you want to be run *BEFORE* *EVERY* test
         # is executed.
 
+        gbq.GbqConnector(_get_project_id(), auth_local_webserver=True)
         self.dataset_prefix = _get_dataset_prefix_random()
         clean_gbq_environment(self.dataset_prefix)
         self.destination_table = "{0}{1}.{2}".format(self.dataset_prefix, "2",