http://chriskief.com/2012/12/22/django-register-with-oauth-facebook/

facebook.py

import urllib
import urllib2
import urlparse
import json
from django.conf import settings
from django.core.urlresolvers import reverse


def get_user_data(request):

        data = {}

        # if we don't have a token yet, get one now
        if 'facebook_access_token' not in request.session:

            # URL to where we will redirect to
            redirect_url = urllib.quote_plus(settings.SITE_URL + reverse('register_facebook'))

            # set the token URL
            url = 'https://graph.facebook.com/oauth/access_token?' \
                  + 'client_id=' + settings.FACEBOOK_APP_ID \
                  + '&redirect_uri=' + redirect_url \
                  + '&client_secret=' + settings.FACEBOOK_API_SECRET \
                  + '&code=' + request.GET['code']

            # grab the token from FB
            response = urllib2.urlopen(url).read()

            # parse the response
            # {'access_token': ['AAAGVChRC0ygBAF3...'], 'expires': ['5183529']}
            params = urlparse.parse_qs(response)

            # save the token
            request.session['facebook_access_token'] = params['access_token'][0]
            request.session['facebook_access_expires'] = params['expires'][0]

        # set the graph URL using the token we just fetched
        graph_url = 'https://graph.facebook.com/me?' \
                    + 'access_token=' + request.session['facebook_access_token']

        # get the user's data from facebook
        response = urllib2.urlopen(graph_url).read()
        user = json.loads(response)

        # get their photo
        # is_silhouette is true if the user has not uploaded a profile picture
        graph_url = 'https://graph.facebook.com/me/picture?' \
                    + 'type=large' \
                    + '&redirect=false' \
                    + '&access_token=' + request.session['facebook_access_token']

        response = urllib2.urlopen(graph_url).read()
        picture = json.loads(response)

        # get the user's info
        data['user_id'] = user['id']
        data['username'] = user['username']
        data['email'] = user['email']
        data['full_name'] = user['first_name'] + ' ' + user['last_name']
        data['first_name'] = user['first_name']
        data['last_name'] = user['last_name']
        data['timezone'] = user['timezone']

        # ensure the user has uploaded a picture
        if not picture['data']['is_silhouette']:
            data['picture'] = picture['data']['url']
        else:
            data['picture'] = ''

        return data