Flask-Dance Example App: GitHub Edition

May 15, 2019 · View on GitHub
This repository provides an example of how to use Flask-Dance_ to connect to GitHub_ as an OAuth client. The example code is in github.py -- all the other files in this repository are secondary. You can run this example code locally, or deploy it to Heroku for free to see how it runs in a production-style environment.
Heroku Installation
`Heroku`_ is a great way to get up and running fast, and you don't even need
to open the terminal!

Step 1: Deploy to Heroku
------------------------
It's easy, and it's free! Just click on this button:

|heroku-deploy|

You can leave all the fields at their default values: we'll fill them in later.
The only thing that matters right now is the app name, and Heroku will
autogenerate a name for you if you leave that field blank. Using an
autogenerated name is perfectly fine, just take note of what it is.

Note that your app isn't functional yet, and if you try to visit it right now,
you'll end up at a GitHub 404 page. That's OK, we're not done yet!

Step 2: Get OAuth credentials from GitHub
-----------------------------------------
Visit https://github.com/settings/applications/new to register an
application on GitHub. In order to register the application, you'll need that
app name from Heroku. The GitHub application's authorization callback URL
must be ``https://APPNAME.herokuapp.com/login/github/authorized``. For example,
if Heroku assigned you an app name of ``peaceful-lake``, your authorization
callback URL must be
``https://peaceful-lake.herokuapp.com/login/github/authorized``.

Once you've registered your application on GitHub, GitHub will give you a
client ID and client secret, which we'll use in the next step.

Step 3: Give OAuth credentials to your app on Heroku
----------------------------------------------------
Go to Heroku and visit the settings page for your app. (You can get there from
your Heroku dashboard, or by clicking on the "Manage App" button after the
deploy step is finished.) On that page, there should be a section called
"Config Variables" where you can manage the config vars for your application.
You'll need click the "Reveal Config Vars" button to see which variables
are available, and then the "Edit" button to allow you to change these
variables.

Take the client ID you got from GitHub, and paste it into the "VALUE" field
next to the ``GITHUB_OAUTH_CLIENT_ID`` field, replacing the dummy value that
was there before. Similarly, take the client secret you got from GitHub,
and paste it into the "VALUE" field next to the ``GITHUB_OAUTH_CLIENT_SECRET``
field, replacing the dummy value that was there before.
Click the "Save" button when you're done.

Step 4: Visit your app and login with GitHub!
---------------------------------------------
Your app name from Heroku will determine the URL that your app is running on:
the URL will be ``https://APPNAME.herokuapp.com``. For example, if Heroku
assigned you an app name of ``peaceful-lake``, your app will be available at
``https://peaceful-lake.herokuapp.com``. Visit that URL, and you should
immediately be redirected to login with GitHub!

Local Installation
``````````````````
If you'd prefer to run this locally on your computer, you can do that as well.

Step 1: Get OAuth credentials from GitHub
-----------------------------------------
Visit https://github.com/settings/applications/new to register an
application on GitHub. You must set the application's authorization
callback URL to ``http://localhost:5000/login/github/authorized``.

Once you've registered your application on GitHub, GitHub will give you a
client ID and client secret, which we'll use in step 3.

Step 2: Install code and dependencies
-------------------------------------
Run the following commands on your computer::

    git clone https://github.com/singingwolfboy/flask-dance-github.git
    cd flask-dance-github
    python3 -m venv venv
    source venv/bin/activate
    pip install -r requirements.txt

These commands will clone this git repository onto your computer,
create a `virtual environment`_ for this project, activate it, and install
the dependencies listed in ``requirements.txt``.

Step 3: Set environment variables
---------------------------------
Many applications use `environment variables`_ for configuration, and
Flask-Dance is no exception. You'll need to set the following environment
variables:

* ``FLASK_APP``: set this to ``github.py``
* ``GITHUB_OAUTH_CLIENT_ID``: set this to the client ID you got
  from GitHub.
* ``GITHUB_OAUTH_CLIENT_SECRET``: set this to the client secret
  you got from GitHub.
* ``OAUTHLIB_INSECURE_TRANSPORT``: set this to ``true``. This indicates that
  you're doing local testing, and it's OK to use HTTP instead of HTTPS for
  OAuth. You should only do this for local testing.
  Do **not** set this in production! [`oauthlib docs`_]

The easiest way to set these environment variables is to define them in
an ``.env`` file. You can then install the `python-dotenv`_ package
to make Flask automatically read this file when you run the dev server.
This repository has a ``.env.example`` file that you can copy to
``.env`` to get a head start.

Step 4: Run your app and login with GitHub!
-------------------------------------------
Run your app using the ``flask`` command::

    flask run

Then, go to http://localhost:5000/ to visit your app and log in with GitHub!

If you get an error message that says "Could not locate a Flask application",
then you need to install the `python-dotenv`_ package using ``pip``::

    pip install python-dotenv

Once the package is installed, try the ``flask run`` command again!

Learn more!
```````````
`Fork this GitHub repo`_ so that you can make changes to it. Read the
documentation for `Flask`_ and `Flask-Dance`_ to learn what's possible.
Ask questions, learn as you go, build your own OAuth-enabled web application,
and don't forget to be awesome!


.. _Flask: http://flask.pocoo.org/docs/
.. _Flask-Dance: http://flask-dance.readthedocs.org/
.. _GitHub: https://github.com/
.. _Heroku: https://www.heroku.com/
.. _environment variables: https://en.wikipedia.org/wiki/Environment_variable
.. _python-dotenv: https://github.com/theskumar/python-dotenv
.. _oauthlib docs: http://oauthlib.readthedocs.org/en/latest/oauth2/security.html#envvar-OAUTHLIB_INSECURE_TRANSPORT
.. _virtual environment: https://docs.python.org/3.7/library/venv.html
.. _Fork this GitHub repo: https://help.github.com/articles/fork-a-repo/

.. |heroku-deploy| image:: https://www.herokucdn.com/deploy/button.png
   :target: https://heroku.com/deploy
   :alt: Deploy to Heroku