Login to Flask App with Twitter

from flask import Flask, request, redirect, url_for, session, g, flash, \
render_template
from flask_oauth import OAuth
 
from sqlalchemy import create_engine, Column, Integer, String
from sqlalchemy.orm import scoped_session, sessionmaker
from sqlalchemy.ext.declarative import declarative_base
 
# configuration
SECRET_KEY = 'development key'
DEBUG = True
 
# setup flask
app = Flask(__name__)
app.debug = DEBUG
app.secret_key = SECRET_KEY
oauth = OAuth()
 
# Use Twitter as example remote application
twitter = oauth.remote_app('twitter',
# unless absolute urls are used to make requests, this will be added
# before all URLs.  This is also true for request_token_url and others.
base_url='https://api.twitter.com/1/',
# where flask should look for new request tokens
request_token_url='https://api.twitter.com/oauth/request_token',
# where flask should exchange the token with the remote application
access_token_url='https://api.twitter.com/oauth/access_token',
# twitter knows two authorizatiom URLs.  /authorize and /authenticate.
# they mostly work the same, but for sign on /authenticate is
# expected because this will give the user a slightly different
# user interface on the twitter side.
authorize_url='https://api.twitter.com/oauth/authenticate',
# the consumer keys from the twitter application registry.
consumer_key='ADD TWITTER CONSUMER KEY',
consumer_secret='ADD TWITTER CONSUMER SECRET'
)
 
@twitter.tokengetter
def get_twitter_token(token=None):
return session.get('twitter_token')
 
@app.route('/')
def index():
access_token = session.get('access_token')
if access_token is None:
return redirect(url_for('login'))
 
access_token = access_token[0]
 
return render_template('index.html')
 
@app.route('/login')
def login():
return twitter.authorize(callback=url_for('oauth_authorized',
next=request.args.get('next') or request.referrer or None))
 
@app.route('/logout')
def logout():
session.pop('screen_name', None)
flash('You were signed out')
return redirect(request.referrer or url_for('index'))
 
@app.route('/oauth-authorized')
@twitter.authorized_handler
def oauth_authorized(resp):
next_url = request.args.get('next') or url_for('index')
if resp is None:
flash(u'You denied the request to sign in.')
return redirect(next_url)
 
access_token = resp['oauth_token']
session['access_token'] = access_token
session['screen_name'] = resp['screen_name']
 
session['twitter_token'] = (
resp['oauth_token'],
resp['oauth_token_secret']
)
 
return redirect(url_for('index'))
 
if __name__ == '__main__':
app.run()

{% block body %}
<h2>Flask Login App</h2>
{% if session['screen_name'] %}
Hello {{ session['screen_name'] }}!
{% else %}
 
Sign in with twitter.
 
<a href="{{ url_for('login') }}"><img src="{{
        url_for('static', filename='sign-in.png') }}" alt="sign in"></a>
{% endif %}
{% endblock %}

python app.py