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Create a Flask App using Flask-Dance

This is the heart of the method.

The best thing to do here is just to walk you through the script.

Import statements:

import os, json
from os.path import join, isfile, isdir
from werkzeug.contrib.fixers import ProxyFix
from flask import Flask, redirect, url_for, send_from_directory
from flask_dance.contrib.github import make_github_blueprint, github

Note that flask-dance adds an OAuth login/callback route to your Flask app by creating a /login blueprint, meaning all the OAuth stuff is just magically available via /login.

Set paths for static content:

PROJECT_ROOT = os.path.dirname(os.path.realpath(__file__))
STATIC_PATH = 'content'

Create and configure app. This requires confidential information for the Github application you created, specifically the client ID and client secret. These are at the very top of the page when you visit your app's settings page.

To find this, after you log in, click your profile photo in the upper right > Settings > Developer Settings > OAuth Apps > click the name for your OAuth app.

app = Flask(__name__)

# this worked locally, but not on heroku
app.wsgi_app = ProxyFix(app.wsgi_app)

app.secret_key = os.environ.get("FLASK_SECRET_KEY", "9502861d41e8729c5cae3225920b1b46")

app.config["GITHUB_OAUTH_CLIENT_ID"] = os.environ.get("GITHUB_OAUTH_CLIENT_ID")

Now the magic happens: we use flask-dance to create a blueprint that has methods and settings all ready to go for us to do the OAuth dance.

make_github_blueprint() is part of the contrib module of flask-dance. There are several similar methods to generate blueprints for authenticating with other APIs.

github_bp = make_github_blueprint(
                        client_id = os.environ.get('GITHUB_OAUTH_CLIENT_ID'),
                        client_secret = os.environ.get('GITHUB_OAUTH_CLIENT_SECRET'),

app.register_blueprint(github_bp, url_prefix="/login")

contents404 = "<html><body><h1>Status: Error 404 Page Not Found</h1></body></html>"
contents403 = "<html><body><h1>Status: Error 403 Access Denied</h1></body></html>"
contents200 = "<html><body><h1>Status: OK 200</h1></body></html>"

Deal with the / route first:

  • Check if authorized, if not, redirect them to the login URL (magical URLs taken care of magically by our make_github_blueprint function above)
  • If user is authorized (i.e., if they have gone through the OAuth process and given their passsword to Github and been redirected to your app with an OAuth token), then the next step is to find out some information about them.
  • Use the github object to call the Github API directly.
  • Decide what to do from there.
def index():
    if not github.authorized:
        return redirect(url_for("github.login"))

    resp = github.get("/user/orgs")
    if resp.ok:

        all_orgs = resp.json()
        for org in all_orgs:
            if org['login']=='rainbow-mind-machine':

The next line is important to how the server works: if all of the criteria above have been met, we return a static file:

                return send_from_directory(STATIC_PATH, 'index.html')

This is normally "bad practice," and numerous type A people on the internet will tell you Flask should not be used for serving static files, and that you should use nginx etc., but these fail to igonore the following:

  • Heroku does not let you run or configure nginx
  • For crying out loud this example is about attack rabbits stop taking everything so seriously

Now that we've got that out of the way...

Here's how we serve up static files. This is a total hack, but it works. It takes any arbitrary path supplied by the user, and attempts to find a corresponding file to serve up on disk.

If the user passes a file, then that file is served up.

If the user passes a directory, then index.html is served up.

If the user asks for a non-existent file, a 404 error is shown.

If the user is not allowed to view the content, they will face the bowel-emptying terrors of the 403 error.

def catch_all(path):

    if not github.authorized:
        return redirect(url_for("github.login"))

    username = github.get("/user").json()['login']

    rsp = app.config["RESULT_STATIC_PATH"]
    resp = github.get("/user/orgs")
    if resp.ok:

        all_orgs = resp.json()
        for org in all_orgs:
            if org['login']=='dcppc':

                    return send_from_directory(rsp, 'index.html')

                    return send_from_directory(join(rsp,path),'index.html')

                    return send_from_directory(rsp, path)

                    return contents404

    return contents403

Last, set a default 404 handler, and run the app:

def oops(e):
    return contents404

if __name__ == "__main__":