How to retrieve Facebook extra info from Django

When we use python-social-auth sometimes there is a need to obtain
some extra information from the Facebook about a registered user. Let's look at
how to retrieve a list of friends and their location.

To specify to which fields we need to have access, we need to add them to SOCIAL_AUTH_FACEBOOK_SCOPE list in settings.py file:

SOCIAL_AUTH_FACEBOOK_SCOPE = [
    'email',
    'user_friends',
    'friends_location',
]

So when a user will try to log in to our website using his Facebook account,
he
will be asked
if our application can access his personal data:

In our case the app will ask him for his email, list of his friends and their location.

If the user agrees,
python-social-auth will create an instance of SocialUser clas with the following attributes:

As we can see, accessing
extra_data JSON, we can get a Facebook
token
will allow us to get the extra information we need via Facebook API.
Firstly, we get an
SocialUser object:

<pre lang="python">social_user = request.user.social_auth.filter(<br/> provider='facebook',<br/>).first()<br/></pre>

Since we got it, we can sent a GET request to Facebook API, passing
the user's
uid, access token and a list of fields we want to obtain:

if social_user:
    url = u'<a href="https://graph.facebook.com/{0}/'">https://graph.facebook.com/{0}/'</a> \
          u'friends?fields=id,name,location,picture' \
          u'&access;_token={1}'.format(
              social_user.uid,
              social_user.extra_data['access_token'],
          )
    request = urllib2.Request(url)

The API returns us a JSON with the data we requested:

{
   "data":[
      {
         "id":"uid",
         "name":"John Doe",
         "location":{
            "id":"id",
            "name":"Bogotá, Colombia"
         },
         "picture":{
            "data":{
               "url":"avatar url",
               "is_silhouette":false
            }
         }
      }
   ]
}

So now we can load it co a Python dictionary:

    friends = json.loads(urllib2.urlopen(request).read()).get('data')
    for friend in friends:
        location = friend.get('location')
        # do something