flask-dance: multiple auth-providers - flask

Question

I have successfully followed the examples in the documentation of Flask-Dance to add Oauth from GitHub, and manage the users with SQLAlchemy. However, I am unable to add more providers. I tried to simply add another blueprint for Twitter and registering it, but I get various errors when trying to login with Twitter. Also, I end up with lots of duplicated code, so this is not a good approach.
Is there a better way to add another provider?
import sys
from flask import Flask, redirect, url_for, flash, render_template
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy.orm.exc import NoResultFound
from flask_dance.contrib.github import make_github_blueprint, github
from flask_dance.consumer.backend.sqla import OAuthConsumerMixin, SQLAlchemyBackend
from flask_dance.consumer import oauth_authorized, oauth_error
from flask_login import (
LoginManager, UserMixin, current_user,
login_required, login_user, logout_user
)
# setup Flask application
app = Flask(__name__)
app.secret_key = "supersekrit"
blueprint = make_github_blueprint(
client_id="my-key-here",
client_secret="my-secret-here",
)
app.register_blueprint(blueprint, url_prefix="/login")
# setup database models
app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///multi.db"
db = SQLAlchemy()
class User(db.Model, UserMixin):
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.String(256), unique=True)
# ... other columns as needed
class OAuth(db.Model, OAuthConsumerMixin):
user_id = db.Column(db.Integer, db.ForeignKey(User.id))
user = db.relationship(User)
# setup login manager
login_manager = LoginManager()
login_manager.login_view = 'github.login'
#login_manager.user_loader
def load_user(user_id):
return User.query.get(int(user_id))
# setup SQLAlchemy backend
blueprint.backend = SQLAlchemyBackend(OAuth, db.session, user=current_user)
# create/login local user on successful OAuth login
#oauth_authorized.connect_via(blueprint)
def github_logged_in(blueprint, token):
if not token:
flash("Failed to log in with {name}".format(name=blueprint.name))
return
# figure out who the user is
resp = blueprint.session.get("/user")
if resp.ok:
username = resp.json()["login"]
query = User.query.filter_by(username=username)
try:
user = query.one()
except NoResultFound:
# create a user
user = User(username=username)
db.session.add(user)
db.session.commit()
login_user(user)
flash("Successfully signed in with GitHub")
else:
msg = "Failed to fetch user info from {name}".format(name=blueprint.name)
flash(msg, category="error")
# notify on OAuth provider error
#oauth_error.connect_via(blueprint)
def github_error(blueprint, error, error_description=None, error_uri=None):
msg = (
"OAuth error from {name}! "
"error={error} description={description} uri={uri}"
).format(
name=blueprint.name,
error=error,
description=error_description,
uri=error_uri,
)
flash(msg, category="error")
#app.route("/logout")
#login_required
def logout():
logout_user()
flash("You have logged out")
return redirect(url_for("index"))
#app.route("/")
def index():
return render_template("home.html")
# hook up extensions to app
db.init_app(app)
login_manager.init_app(app)
if __name__ == "__main__":
if "--setup" in sys.argv:
with app.app_context():
db.create_all()
db.session.commit()
print("Database tables created")
else:
app.run(debug=True)

Answer 1

Here is a sample project that uses multiple providers simultaneously: flask-dance-multi-provider. You can read through the code to see how it works. Does that help?