handle facebook oauth authentication with python sdk


I took the occasion of leaving Facebook to write a Python program to inform my Facebook friends on how to contact me after my farewell. Therefore, I learnt something new. I would like to share with you how to manage Facebook OAuth steps using Python SDK, because I could not find a suitable well-written example on the Internet.

Let’s take a look at my access.py file. I stripped down some details in this post:

import facebook
import urllib
import warnings
import webbrowser
import dbmanager
import urlparse
import settings
import os

class FBOAuth(object):
    Handles the OAuth phases of Facebook and returns an authenticated GrapApi object, to be used for
    using the Facebook API.
    # the following values are taken from settings.py file but could be hardcoded here
    CLIENT_ID     = settings.CLIENT_ID

    SECRET_CODE = None

    def __init__(self):
        self.database = dbmanager.DBManager()
        FBOAuth.SECRET_CODE = self.get_secret_code()
        FBOAuth.ACCESS_TOKEN = self.get_access_token()

    def authorize(self):
        warnings.filterwarnings('ignore', category=DeprecationWarning)
        savout = os.dup(1)
        os.open(os.devnull, os.O_RDWR)
                                 'scope':'read_stream, publish_stream'}))
            os.dup2(savout, 1)

        FBOAuth.SECRET_CODE = raw_input("Secret Code: ")

        return FBOAuth.SECRET_CODE

    def access_token(self):

        if not FBOAuth.SECRET_CODE:
            FBOAuth.SECRET_CODE = self.authorize()

        args = {'redirect_uri': FBOAuth.REDIRECT_URI,
                'client_id' : FBOAuth.CLIENT_ID,
        access_token = urllib.urlopen(FBOAuth.FACEBOOK_GRAPH_URL + "/oauth/access_token?" + urllib.urlencode(args)).read()
        access_token = urlparse.parse_qs(access_token)
        FBOAuth.ACCESS_TOKEN = access_token['access_token'][0]
        return FBOAuth.ACCESS_TOKEN

    def get_graph_api(self):

        if not FBOAuth.ACCESS_TOKEN:

        return facebook.GraphAPI(FBOAuth.ACCESS_TOKEN)

    def invalidate_login(self):
    # The following four methods are using database.py for making SECRET_CODE and ACCESS_TOKEN persistent
    def get_secret_code(self):
        return self.database.get('SECRET_CODE') or None

    def save_secret_code(self, secret_code):
        self.database.save('SECRET_CODE', secret_code)

    def get_access_token(self):
        return self.database.get('ACCESS_TOKEN') or None

    def save_access_token(self, access_token):
        self.database.save('ACCESS_TOKEN', access_token)

Let’s understand it. This class is responsible for handling the OAuth phases of authentications for FB, and is able to create and return an instance of


ready to be used, because it’s authenticated by the user. The class variables just hold the API keys, the URI that Facebook needs to know for displaying the secret code to the user, the secret code inputted by the user after the permissions for the applications are gathered, and the final access token.

The constructor


tries to get already stored secret codes and access tokens from my tiny database. I am omitting the details on how I implemented the tiny database but you can see this by looking at the source code of FacebookGreeter.

The following is a picture summarizing Facebook OAuth 2 authentication steps. It is taken from the developers page.



method is responsible for getting User authorization to use the application and for gathering the secret code for getting access then. It opens a web browser and accesses


, passing as parameters how to identify the application, the permissions requested to the user, and which callback URI must be called by Facebook in order to receive the secret code that the user must input. The lines of code related to


are needed in order to redirect standard output because of this issue. The secret code is then returned by this method.



method is for getting the final access token from Facebook. As you note, it calls the previous method if the secret code has not been gathered yet. A call to


is performed, including the same information plus the user provided secret code. Facebook will then return the so much desired access token and its expiration. In this tiny program I do not take care of the expiration because it was not needed for me. You should do.

Finally, the


method checks if an access token is present, otherwise it calls the previous method. You can notice the beauty of this reaction chain that ensures the present of the required data at each entry point. It returns an instance of


that is authorized by the access token. This object is then used to query Facebook Graph Api (e.g.,



I hope that this post clarifies how to login/authorize a Python Facebook application using OAuth 2.0 protocol.

I do not use a commenting system anymore, but I would be glad to read your comments and feedback. Feel free to contact me.