oauth-dropins 5.0

Drop-in OAuth Flask views for many popular sites.

oauth-dropins

Drop-in Python OAuth for popular sites!

• About
• Quick start
• Usage details
• Troubleshooting/FAQ
• Changelog
• Development
• Release instructions

About

This is a collection of drop-in Python Flask views for the initial OAuth client flows for many popular sites, including Blogger, Disqus, Dropbox, Facebook, Flickr, GitHub, Google, IndieAuth, Instagram, LinkedIn, Mastodon, Medium, Tumblr, Twitter, and WordPress.com.

oauth-dropins stores user credentials in Google Cloud Datastore. It's primarily designed for Google App Engine, but it can be used in any Python web application, regardless of host or framework.

• Available on PyPi. Install with pip install oauth-dropins.
• Getting started docs.
• Reference docs.
• Demo app at oauth-dropins.appspot.com.
• Source code on GitHub.

This software is released into the public domain. See LICENSE for details.

Quick start

Here's a full example of using the GitHub drop-in.

1. Install oauth-dropins with pip install oauth-dropins.

2. Put your GitHub OAuth application's ID and secret in two plain text files in your app's root directory, github_client_id and github_client_secret. (If you use git, you'll probably also want to add them to your .gitignore.)

3. Create a github_oauth.py file with these contents:

   from oauth_dropins import github
   from app import app  # ...or wherever your Flask app is
   
   app.add_url_rule('/start',
                    view_func=github.Start.as_view('start', '/callback'),
                    methods=['POST'])
   app.add_url_rule('/callback',
                    view_func=github.Callback.as_view('callback', '/after'))
   

Voila! Send your users to /github/start when you want them to connect their GitHub account to your app, and when they're done, they'll be redirected to /after?access_token=... in your app.

All of the sites provide the same API. To use a different one, just import the site module you want and follow the same steps. The filenames for app keys and secrets also differ by site; see each site's .py file for its filenames.

Usage details

There are three main parts to an OAuth drop-in: the initial redirect to the site itself, the redirect back to your app after the user approves or declines the request, and the datastore entity that stores the user's OAuth credentials and helps you use them. These are implemented by Start and Callback, which are Flask View classes, and auth entities, which are Google Cloud Datastore ndb models.

Start

This view class redirects you to an OAuth-enabled site so it can ask the user to grant your app permission. It has two useful methods:

• The constructor, __init__(self, to_path, scopes=None). to_path is the OAuth callback, ie URL path on your site that the site's OAuth flow should redirect back to after it's done. This is handled by a Callback view in your application, which needs to handle the to_path route.

  If you want to add OAuth scopes beyond the default one(s) needed for login, you can pass them to the scopes kwarg as a string or sequence of strings, or include them in the scopes query parameter in the POST request body. This is supported in most sites, but not all.

  Some OAuth 1 sites support alternatives to scopes. For Twitter, the Start constructor takes an additional access_type kwarg that may be read or write. It's passed through to Twitter x_auth_access_type. For Flickr, Start accepts a perms POST query parameter that may be read, write or delete; it's passed through to Flickr unchanged. (Flickr claims it's optional, but sometimes breaks if it's not provided.)

• redirect_url(state=None) returns the URL to redirect to at the site to initiate the OAuth flow. Start will redirect here automatically if it's used in a WSGI application, but you can call this manually if you want to control that redirect yourself:

class MyView(Start):
  def dispatch_request(self):
    ...
    self.redirect(self.redirect_url())

Callback

This class handles the HTTP redirect back to your app after the user has granted or declined permission. It also has two useful methods:

• The constructor, __init__(self, to_path, scopes=None). to_path is the URL path on your site that users should be redirected to after the callback view is done. It will include a state query parameter with the value provided to Start. It will also include an OAuth token in its query parameters, either access_token for OAuth 2.0 or access_token_key and access_token_secret for OAuth 1.1. It will also include an auth_entity query parameter with the string key of an auth entity that has more data (and functionality) for the authenticated user. If the user declined the OAuth authorization request, the only query parameter besides state will be declined=true.

• finish(auth_entity, state=None) is run in the initial callback request after the OAuth response has been processed. auth_entity is the newly created auth entity for this connection, or None if the user declined the OAuth authorization request.

  By default, finish redirects to to_path, but you can subclass Callback and override it to run your own code instead of redirecting:

class MyCallback(github.Callback):
  def finish(self, auth_entity, state=None):
    super().finish(auth_entity, state=state)  # ignore returned redirect
    self.response.write('Hi %s, thanks for connecting your %s account.' %
        (auth_entity.user_display_name(), auth_entity.site_name()))

Auth entities

Each site defines an App Engine datastore ndb.Model class that stores each user's OAuth credentials and other useful information, like their name and profile URL. The class name is generally of the form SiteAuth, e.g. GitHubAuth. Here are the useful methods:

• site_name() returns the human-readable string name of the site, e.g. "Facebook".

• user_display_name() returns a human-readable string name for the user, e.g. "Ryan Barrett". This is usually their first name, full name, or username.

• access_token() returns the OAuth access token. For OAuth 2 sites, this is a single string. For OAuth 1.1 sites (currently just Twitter, Tumblr, and Flickr), this is a (string key, string secret) tuple.

The following methods are optional. Auth entity classes usually implement at least one of them, but not all.

• api() returns a site-specific API object. This is usually a third party library dedicated to the site, e.g. Tweepy or python-instagram. See the site class's docstring for details.

• urlopen(data=None, timeout=None) wraps urlopen() and adds the OAuth credentials to the request. Use this for making direct HTTP request to a site's REST API. Some sites may provide get() instead, which wraps requests.get().

Troubleshooting/FAQ

1. If you get this error:

   bash: ./bin/easy_install: ...bad interpreter: No such file or directory
   

You've probably hit this virtualenv bug: virtualenv doesn't support paths with spaces.

The easy fix is to recreate the virtualenv in a path without spaces. If you can't do that, then after creating the virtualenv, but before activating it, edit the activate, easy_install and pip files in local/bin/ to escape any spaces in the path.

For example, in activate, VIRTUAL_ENV=".../has space/local" becomes VIRTUAL_ENV=".../has\ space/local", and in pip and easy_install the first line changes from #!".../has space/local/bin/python" to #!".../has\ space/local/bin/python".

This should get virtualenv to install in the right place. If you do this wrong at first, you'll have installs in eg /usr/local/lib/python3.7/site-packages that you need to delete, since they'll prevent virtualenv from installing into the local site-packages.

1. If you see errors importing or using tweepy, it may be because six.py isn't installed. Try pip install six manually. tweepy does include six in its dependencies, so this shouldn't be necessary. Please let us know if it happens to you so we can debug!

2. If you get an error like this:

   Running setup.py develop for gdata
   ...
   error: option --home not recognized
   ...
   InstallationError: Command /usr/bin/python -c "import setuptools, tokenize; __file__='/home/singpolyma/src/bridgy/src/gdata/setup.py'; exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" develop --no-deps --home=/tmp/tmprBISz_ failed with error code 1 in .../src/gdata
   

...you may be hitting Pip bug 1833. Are you passing -t to pip install? Use the virtualenv instead, it's your friend. If you really want -t, try removing the -e from the lines in requirements.txt that have it.

Changelog

5.0 - 2022-03-23

Breaking changes:

• Drop Python 3.5 support. Python 3.6 is now the minimum required version.

Non-breaking changes:

• Switch from app_server to flask run for local development.
• Add webutil.util.set_user_agent to set User-Agent header to be sent with all HTTP requests.

4.0 - 2021-09-15

Breaking changes:

• Migrate from webapp2 to Flask. webapp2 had a good run, but it's no longer actively developed, and Flask is one of the most widely adopted standalone web frameworks in the Python community.

• Remove to() class methods. Instead, now pass redirect paths to Flask's as_view() function, eg:

  app = Flask()
  app.add_url_rule('/start', view_func=twitter.Callback.as_view('start', '/oauth_callback'))
  

• Remove deprecated blogger_v2 module alias.

• webutil: migrate webapp2 HTTP request handlers in the handlers module - XrdOrJrdHandler, HostMetaHandler, and HostMetaXrdsHandler - to Flask views in a new flask_util module.

Non-breaking changes:

• webutil: implement Webmention protocol in new webmention module.
• webutil: add misc Flask utilities and helpers in new flask_util module.

3.1 - 2021-04-03

• Add Python 3.8 support, drop 3.3 and 3.4. Python 3.5 is now the minimum required version.
• Add Pixelfed support, heavily based on Mastodon.
• Add Reddit support. Thanks Will Stedden!
• WordPress.com:
  • Handle errors from access token request.

3.0 - 2020-03-14

Breaking changes:

• Python 2 is no longer supported! Including the App Engine Standard Python 2 runtime. On the plus side, the Python 3 runtimes, both Standard and Flexible, are now supported.
• Replace handlers.memcache_response(), which used Python 2 App Engine's memcache service, with cache_response(), which uses local runtime memory.
• Remove the handlers.TemplateHandler.USE_APPENGINE_WEBAPP toggle to use Python 2 App Engine's google.appengine.ext.webapp2.template instead of Jinja.
• Blogger:
  • Login is now based on Google Sign-In. The api_from_creds(), creds(), and http() methods have been removed. Use the remaining api() method to get a BloggerClient, or access_token() to make API calls manually.
• Google:
  • Replace GoogleAuth with the new GoogleUser NDB model class, which doesn't depend on the deprecated oauth2client.
  • Drop http() method (which returned an httplib2.Http).
• Mastodon:
  • StartHandler: drop APP_NAME/APP_URL class attributes and app_name/app_url kwargs in the to() method and replace them with new app_name()/app_url() methods that subclasses should override, since they often depend on WSGI environment variables like HTTP_HOST and SERVER_NAME that are available during requests but not at runtime startup.
• webutil:
  • Drop handlers.memcache_response() since the Python 3 runtime doesn't include memcache.
  • Drop handlers.TemplateHandler support for webapp2.template via USE_APPENGINE_WEBAPP, since the Python 3 runtime doesn't include webapp2 built in.
  • Remove cache and fail_cache_time_secs kwargs from util.follow_redirects(). Caching is now built in. You can bypass the cache with follow_redirects.__wrapped__(). Details.

Non-breaking changes:

• Add Meetup support. (Thanks Jamie Tanna!)
• Blogger, Google:
  • The state query parameter now works!
• Add new outer_classes kwarg to button_html() for the outer <div>, eg as Bootstrap columns.
• Add new image_file kwarg to StartHandler.button_html()

2.2 - 2019-11-01

• Add LinkedIn and Mastodon!
• Add Python 3.7 support, and improve overall Python 3 compatibility.
• Add new button_html() method to all StartHandler classes. Generates the same button HTML and styling as on oauth-dropins.appspot.com.
• Blogger: rename module from blogger_v2 to blogger. The blogger_v2 module name is still available as an alias, implemented via symlink, but is now deprecated.
• Dropbox: fix crash with unicode header value.
• Google: fix crash when user object doesn't have name field.
• Facebook: upgrade Graph API version from 2.10 to 4.0.
• Update a number of dependencies.
• Switch from Python's built in json module to ujson (built into App Engine) to speed up JSON parsing and encoding.

2.0 - 2019-02-25

• Breaking change: switch from Google+ Sign-In (which shuts down in March) to Google Sign-In. Notably, this removes the googleplus module and adds a new google_signin module, renames the GooglePlusAuth class to GoogleAuth, and removes its api() method. Otherwise, the implementation is mostly the same.
• webutil.logs: return HTTP 400 if start_time is before 2008-04-01 (App Engine's rough launch window).

1.14 - 2018-11-12

• Fix dev_appserver in Cloud SDK 219 / app-engine-python 1.9.76 and onward. Background.
• Upgrade google-api-python-client from 1.6.3 to 1.7.4 to stop using the global HTTP Batch endpoint.
• Other minor internal updates.

1.13 - 2018-08-08

• IndieAuth: support JSON code verification responses as well as form-encoded (snarfed/bridgy#809).

1.12 - 2018-03-24

• More Python 3 updates and bug fixes in webutil.util.

1.11 - 2018-03-08

• Add GitHub!
• Facebook:
  • Pass state to the initial OAuth endpoint directly, instead of encoding it into the redirect URL, so the redirect can match the Strict Mode whitelist.
• Add Python 3 support to webutil.util!
• Add humanize dependency for webutil.logs.

1.10 - 2017-12-10

Mostly just internal changes to webutil to support granary v1.10.

1.9 - 2017-10-24

Mostly just internal changes to webutil to support granary v1.9.

• Flickr:
  • Handle punctuation in error messages.

1.8 - 2017-08-29

• Facebook:
  • Upgrade Graph API from v2.6 to v2.10.
• Flickr:
  • Fix broken FlickrAuth.urlopen() method.
• Medium:
  • Bug fix for Medium OAuth callback error handling.
• IndieAuth:
  • Store authorization endpoint in state instead of rediscovering it from me parameter, which is going away.

1.7 - 2017-02-27

• Updates to bundled webutil library, notably WideUnicode class.

1.6 - 2016-11-21

• Add auto-generated docs with Sphinx. Published at oauth-dropins.readthedocs.io.
• Fix Dropbox bug with fetching access token.

1.5 - 2016-08-25

• Add Medium.

1.4 - 2016-06-27

• Upgrade Facebook API from v2.2 to v2.6.

1.3 - 2016-04-07

• Add IndieAuth.
• More consistent logging of HTTP requests.
• Set up Coveralls.

1.2 - 2016-01-11

• Flickr:
  • Add upload method.
  • Improve error handling and logging.
• Bug fixes and cleanup for constructing scope strings.
• Add developer setup and troubleshooting docs.
• Set up CircleCI.

1.1 - 2015-09-06

• Flickr: split out flickr_auth.py file.
• Add a number of utility functions to webutil.

1.0 - 2015-06-27

• Initial PyPi release.

Development

First, fork and clone this repo. Then, you'll need the Google Cloud SDK with the gcloud-appengine-python and gcloud-appengine-python-extras components. Once you have them, set up your environment by running these commands in the repo root directory:

gcloud config set project oauth-dropins
git submodule init
git submodule update
python3 -m venv local
source local/bin/activate
pip install -r requirements.txt

Run the demo app locally with flask run:

gcloud beta emulators datastore start --no-store-on-disk --consistency=1.0 --host-port=localhost:8089 < /dev/null >& /dev/null &
GAE_ENV=localdev FLASK_ENV=development flask run -p 8080

To deploy to production:

gcloud -q beta app deploy --no-cache oauth-dropins *.yaml

The docs are built with Sphinx, including apidoc, autodoc, and napoleon. Configuration is in docs/conf.py To build them, first install Sphinx with pip install sphinx. (You may want to do this outside your virtualenv; if so, you'll need to reconfigure it to see system packages with python3 -m venv --system-site-packages local.) Then, run docs/build.sh.

Release instructions

Here's how to package, test, and ship a new release. (Note that this is largely duplicated in granary's readme too.)

1. Run the unit tests.

   source local/bin/activate.csh
   gcloud beta emulators datastore start --no-store-on-disk --consistency=1.0 --host-port=localhost:8089 < /dev/null >& /dev/null &
   sleep 2s
   DATASTORE_EMULATOR_HOST=localhost:8081 DATASTORE_DATASET=oauth-dropins \
     python3 -m unittest discover
   kill %1
   deactivate
   

2. Bump the version number in setup.py and docs/conf.py. git grep the old version number to make sure it only appears in the changelog. Change the current changelog entry in README.md for this new version from unreleased to the current date.
3. Build the docs. If you added any new modules, add them to the appropriate file(s) in docs/source/. Then run ./docs/build.sh.
4. git commit -am 'release vX.Y'
5. Upload to test.pypi.org for testing.

   python3 setup.py clean build sdist
   setenv ver X.Y
   source local/bin/activate.csh
   twine upload -r pypitest dist/oauth-dropins-$ver.tar.gz
   

6. Install from test.pypi.org.

   cd /tmp
   python3 -m venv local
   source local/bin/activate.csh
   pip3 install --upgrade pip
   # mf2py 1.1.2 on test.pypi.org is broken :(
   pip3 install mf2py
   pip3 install -i https://test.pypi.org/simple --extra-index-url https://pypi.org/simple oauth-dropins
   deactivate
   

7. Smoke test that the code trivially loads and runs.

   source local/bin/activate.csh
   python3
   # run test code below
   deactivate
   

   Test code to paste into the interpreter:

   from oauth_dropins.webutil import util
   util.__file__
   util.UrlCanonicalizer()('http://asdf.com')
   # should print 'https://asdf.com/'
   exit()
   

8. Tag the release in git. In the tag message editor, delete the generated comments at bottom, leave the first line blank (to omit the release "title" in github), put ### Notable changes on the second line, then copy and paste this version's changelog contents below it.

   git tag -a v$ver --cleanup=verbatim
   git push
   git push --tags
   

9. Click here to draft a new release on GitHub. Enter vX.Y in the Tag version box. Leave Release title empty. Copy ### Notable changes and the changelog contents into the description text box.
10. Upload to pypi.org!

    twine upload dist/oauth-dropins-$ver.tar.gz
    

Related work

• Loginpass/Authlib
• Authomatic
• Python Social Auth
• Authl