Dropbox: add configurable timeout and improve docs (#747)

* Dropbox: add configurable timeout and improve docs

* Fix Flake8

docs/backends/dropbox.rst

@@ -1,14 +1,13 @@
-DropBox
+Dropbox
 =======
 
-A custom storage system for Django using Dropbox Storage backend.
+A Django files storage using Dropbox as a backend via the official
+`Dropbox SDK for Python`_. Currently only v2 of the API is supported.
 
-Before you start configuration, you will need to install `Dropbox SDK for Python`_.
+Before you start configuration, you will need to install the SDK
+which can be done for you automatically by doing::
 
-
-Install the package::
-
-  pip install dropbox
+   pip install django-storages[dropbox]
 
 Settings
 --------
@@ -18,10 +17,14 @@ To use DropBoxStorage set::
     DEFAULT_FILE_STORAGE = 'storages.backends.dropbox.DropBoxStorage'
 
 ``DROPBOX_OAUTH2_TOKEN``
-    Your DropBox token, if you haven't follow this `guide step`_.
+    Your Dropbox token. You can obtain one by following the instructions in the `tutorial`_.
 
-``DROPBOX_ROOT_PATH``
+``DROPBOX_ROOT_PATH`` (optional)
     Allow to jail your storage to a defined directory.
 
-.. _`guide step`: https://www.dropbox.com/developers/documentation/python#tutorial
+``DROPBOX_TIMEOUT`` (optional)
+      Timeout in seconds for making requests to the API. If ``None``, the client will wait forever.
+      The default is ``100`` seconds which is the current default in the official SDK.
+
+.. _`tutorial`: https://www.dropbox.com/developers/documentation/python#tutorial
 .. _`Dropbox SDK for Python`: https://www.dropbox.com/developers/documentation/python#tutorial

storages/backends/dropbox.py

@@ -25,6 +25,8 @@
 
 from storages.utils import setting
 
+_DEFAULT_TIMEOUT = 100
+
 
 class DropBoxStorageException(Exception):
     pass
@@ -67,13 +69,15 @@ class DropBoxStorage(Storage):
 
     CHUNK_SIZE = 4 * 1024 * 1024
 
-    def __init__(self, oauth2_access_token=None, root_path=None):
+    def __init__(self, oauth2_access_token=None, root_path=None, timeout=None):
         oauth2_access_token = oauth2_access_token or setting('DROPBOX_OAUTH2_TOKEN')
-        self.root_path = root_path or setting('DROPBOX_ROOT_PATH', '/')
         if oauth2_access_token is None:
-            raise ImproperlyConfigured("You must configure a token auth at"
+            raise ImproperlyConfigured("You must configure an auth token at"
                                        "'settings.DROPBOX_OAUTH2_TOKEN'.")
-        self.client = Dropbox(oauth2_access_token)
+
+        self.root_path = root_path or setting('DROPBOX_ROOT_PATH', '/')
+        timeout = timeout or setting('DROPBOX_TIMEOUT', _DEFAULT_TIMEOUT)
+        self.client = Dropbox(oauth2_access_token, timeout=timeout)
 
     def _full_path(self, name):
         if name == '/':