使用python将Facebook登录集成到Google App Engine中

Question

I created google app engine app.

In that i used google direct login as well as login with openid.

openid i integrate using do_openid_login.py as google document suggested. Now i want integrate facebook login too.

So how could i integrate facebook login?

Answer 1

There is unofficial SDK for Facebook ( https://github.com/pythonforfacebook/facebook-sdk ). It includes great thing for AppEngine where user logins via html/js button and you get data about the user on server-side from FB cookie. In sample code on GitHub you have great, easy to implement code.

You get user from fb cookie by using:

fb_user = facebook.get_user_from_cookie(request.cookies, FACEBOOK_APP_ID, FACEBOOK_APP_SECRET)

where request.cookies is dictionary containing cookies from request (like in GAE's webapp2)

When you have fb_user you can start retrieving data about him/her:

graph = facebook.GraphAPI(fb_user["access_token"])
profile = graph.get_object("me")
user_email = profile["email"]

facebook.GraphAPI uses user's access token to authorize your requests from facebook. Then you select object "me" which is user using your app. Later you can use any data that you have permission to use based on scope of sign-in button via which your user logged in.

If you're using webapp2 additionaly you can create your custom Handler class to save user data that you want to use in current session

from webapp2_extras import sessions # import session
config = {}
config['webapp2_extras.sessions'] = dict(secret_key='')

# remember to pass config to webapp2.WSGIApplication:
app = webapp2.WSGIApplication(
    [('/', HomeHandler), ('/logout', LogoutHandler)], #handlers
    debug=True, # debug state
    config=config # CONFIG!
)

class MyHandler(webapp2.RequestHandler):
   # ...
   @property
   def current_user(self):
       # check if user logged in during this session
       if self.session.get("user"):
            # user is logged in
            return self.session.get("user")
       else:
            # either user just logged in or just saw the first page
            # we'll see here
            fb_user = facebook.get_user_from_cookie(self.request.cookies, FACEBOOK_APP_ID, FACEBOOK_APP_SECRET)
            if fb_user:
                # okay so user logged in.
                # now, check to see if existing user

                graph = facebook.GraphAPI(fb_user["access_token"])
                profile = graph.get_object("me")

                # DB # user = User.get_by_key_name(PREFIX+fb_user["uid"])
                # NDB # user = ndb.Key("User",PREFIX+str(profile["id"])).get()
                # you can add prefix if you're using multiple social networks (g+, twitter)
                if not user:
                    # not an existing user so get user info
                    # DB # user = User(key_name = PREFIX+str(profile["id"]), OTHER DATA)
                    # NDB # user = User(id = PREFIX+str(profile["id"]), OTHER DATA)
                    user.put()
                elif user.SOMETHING_THAT_MIGHT_CHANGE != fb_user["SOMETHING_THAT_MIGHT_CHANGE"]:
                    # update values that changed since las check to database
                    user.SOMETHING_THAT_MIGHT_CHANGE = fb_user["SOMETHING_THAT_MIGHT_CHANGE"]
                    user.put()
                # User is now logged in
                # Save often used values to session so you don't have to query database all the time
                self.session["user"] = dict(
                    id = "f"+str(profile["id"]),
                    email = profile["email"],
                    access_token = fb_user["access_token"]
                )
            return self.session.get("user")
    return None

    def dispatch(self):
        self.session_store = sessions.get_store(request=self.request)
        try:
            webapp2.RequestHandler.dispatch(self)
        finally:
            self.session_store.save_sessions(self.response)

    @webapp2.cached_property
    def session(self):
        return self.session_store.get_session()

Now you can use your handlers and access current user:

class MainPageHandler(Handler):
    def get(self):
        current_user = self.current_user
        graph = facebook.GraphAPI(self.current_user['access_token'])

Remember that this are just the basics, you can learn more at https://github.com/pythonforfacebook/facebook-sdk