django-facebook-login
provides an authentication backend and a GraphQL mutation
that takes a Facebook user-access-token and the user's email and then does one
of the following:
- Sign-up new user
- Connect existing Django user with their Facebook account
- Login existing, already connected Django user
In all cases, the user will be authenticated afterwards. This means, unlike most other custom authentication backends, this backend will create a new user if the given credentials (Facebook email + Facebook user access token) are not known, yet.
Make sure you read the Noteworthy Things
below before you decide to use this
library.
-
Add "facebook-login" to your INSTALLED_APPS setting like this:
INSTALLED_APPS = [ ... 'facebook-login', ]
-
Add the
FacebookAuthBackend
to yourAUTHENTICATION_BACKENDS
setting:AUTHENTICATION_BACKENDS = ( ..., "facebook_login.auth_backends.FacebookAuthBackend", )
-
Hook up the mutation in your GraphQL schema:
# in your main `schema.py`: import graphene from facebook_login import schema as fb_login class Mutation( ... fb_login.Mutation, graphene.ObjectType, ): pass class Queries(...): pass schema = graphene.Schema(query=Queries, mutation=Mutation)
-
Run
python manage.py migrate
to create theFacebookAccount
table. -
Configure the app in your
local_settings.py
:# Get these values from https://developers.facebook.com/apps/ FB_LOGIN_APP_ID = 'YOUR APP ID' FB_LOGIN_APP_SECRET = 'YOUR APP SECRET'
You still need extra code on your frontend that retrieves the user access token from Facebook. Usually you would hook up the official Facebook login button that triggers the official Facebook login popup and then write some code that sends the token that was returned by Facebook to our mutation.
During the official Facebook login popup, the user can decide to revoke access to the email address. Other libraries, like django-allauth will have some extra views where the user is then asked to enter an email anyways, after the Facebook login. We do not care about this. Instead, we will ask the user to press the login button again and this time please grant access to the email address.
Please note that we don't use JWT in our projects. We use Django's default session based authentication. Therefore, our mutation does not return anything.
Our mutation does call Django's login()
function, which will save the new
login-state into the user's session. When the mutation returns, it will instruct
the browser to save the new session key in the cookie. Our frontend will then
trigger a window.location = /new/url/
, since this is a new request (including
the new session key), the server-rendered response will realize that this is a
now logged-in user.
If you would like to disable this behavior, you may provide a custom function
for the FB_LOGIN_SUCCESS_HANDLER
setting (see below).
This app uses the following settings:
This should be your Facebook app-id.
This should be your Facebook app secret.
Default: 'v5.0'
You can set this to a higher version in order to stay compliant with the Facebook guidelines. Of course, just bumping the version number does not guarantee that this app will still work, but the APIs that we use here have been pretty stable for years, so it might just work.
Default: facebook_login.utils.success_handler_default
Set this to your own function in case you need to do additional things
when a user logs in. You can find our original implementation in utils.success_handler_default()
.
Your custom function may return a string and that string would be passed on
to the frontend by the mutation as the extra
key. You will most likely want
to return something like this: json.dumps({'token': 'ABC123...'})
.
If you do return something (i.e. a JWT token), then the mutation will return
it to the frontend as the extra
key.
Default: facebook_login.utils.error_handler_default
Set this to your own function, for example if you would like to log certain exceptions to Sentry or alert you in other ways when Facebook login attempts are crashing. By default, only the user will see error messages on the frontend but you will likely not notice that something is wrong.
Your implementation should look something like this:
from facebook_login import exceptions
def error_handler_custom(facebook_auth_mutation, request, exception):
message = ''
if isinstance(exception, exceptions.UserEmailException):
message = str(exception)
else:
message = ('Failed to login with Facebook. Our engineers have been'
' notified. Please try again, later.')
# log exception to Sentry
return facebook_auth_mutation(
status=400,
form_errors=json.dumps({
'facebook': [message]
}),
extra=None,
)
As you can see, this way you can customize the error messages that are shown to the user and you can use any logging service that you like.
Default: 'https://graph.facebook.com/v3.1'
Allows to override the base API URL, just in case. Of course, we are not sure, if a future API would be backwards compatible, so just changing this to a higher API version number might cause issues with this library.
If this happens, chances are that you are using django-allauth
. Their
authentication backend crashes when Django's authenticate()
function is
called without a username
and password
keyword-argument. As a workaround,
you can just make sure that facebook_login.auth_backends.FacebookAuthBackend
appears before other authentication backends.
- Clone this repo
mkvirtualenv --python=python3.6 django-facebook-login
pip install -r requirements.txt
pip install -r test_requirements.txt
fab test
open htmlcov/index.html
./manage.py migrate
# This creates a sqlite3 DB./manage.py createsuperuser
./manage.py runserver
Unfortunately, running the local devserver only gives you access to the Django admin. There is no demo-frontend code that would actually call this library's backend code, yet.
This library was built with love at The Artling