background

There are times when you want to link your own service account with an external service account such as facebook or Twitter using OAuth. For Python3, you can easily add an external account linkage screen for Web services by using python-social-auth. However, if you want to do the same with a smartphone app, you need to provide a link function with API, so a memo about how to handle it.

At first, I considered using django-social-auth, but it doesn't seem to work with Python3.

Purpose

This time, we assume the user takeover function in the smartphone app. The external services I want to use are facebook and Twitter. The following two functions are implemented.

API to link an external account to an existing Django user
API to get the associated Django user information from external account information

By the way, I think that the information on the following page can be used almost as it is in the process of creating a new user based on an external account.

[Social Auth with Django REST Framework] (https://yeti.co/blog/social-auth-with-django-rest-framework/)

environment

Python 3.4.3 Django 1.8

djangorestframework 3.2.3
python-social-auth 0.2.13

Authentication flow

As the flow of authentication processing, the following usage using OAuth is assumed.

Obtain an OAuth token for authentication by using various SDKs in the smartphone app

Communication between user and external service

Send the OAuth token obtained in 1. from the smartphone app to your service

Communication between user and own service

Obtain a user ID from an external service using the OAuth token received by your own service

Communication between own service and external service

If the user ID can be obtained in 3., perform the necessary processing (linking user information, etc.) and return the processing result to the smartphone application.

Communication between own service and user

Implementation details

Install python-social-auth

`python`


$ pip install python-social-auth

Settings for python-social-auth

Rewrite information on Twitter and facebook apps as appropriate.

`settings.py`


INSTALLED_APPS = (
    ...
    'social.apps.django_app.default',
    ...
)

TEMPLATE_CONTEXT_PROCESSORS = (
    ...
    'social.apps.django_app.context_processors.backends',
    'social.apps.django_app.context_processors.login_redirect',
    ...
)

AUTHENTICATION_BACKENDS = (
   'social.backends.facebook.FacebookOAuth2',
   'social.backends.twitter.TwitterOAuth',
   'django.contrib.auth.backends.ModelBackend',
)

SOCIAL_AUTH_PIPELINE = (
    'social.pipeline.social_auth.social_details',
    'social.pipeline.social_auth.social_uid',
    'social.pipeline.social_auth.auth_allowed',
    'social.pipeline.social_auth.social_user',
    #Remove the user so that it will not be created when checking the credentials.
    #'social.pipeline.user.create_user',
    'social.pipeline.social_auth.associate_user',
    'social.pipeline.social_auth.load_extra_data',
    'social.pipeline.user.user_details',
)

SOCIAL_AUTH_TWITTER_KEY = "MY_TWITTER_APP_KEY "
SOCIAL_AUTH_TWITTER_SECRET = "MY_TWITTER_APP_SECRET"

SOCIAL_AUTH_FACEBOOK_KEY = "MY_FACEBOOK_APP_ID"
SOCIAL_AUTH_FACEBOOK_SECRET = "MY_FACEBOOK_APP_SECRET"

Creating a table for authentication information

`python`


$ ./manage.py migrate

Project-wide url settings

`myproject/urls.py`


from django.conf.urls import url

urlpatterns = [
    ...
    url('', include('social.apps.django_app.urls', namespace='social'))
    ...
]

URL setting of the app you want to use the linkage function

`myapp/urls.py`


from django.conf.urls import url
from . import views

urlpatterns = [
	# 1.API to link an external account to an existing user
    url(r'api/associate/(?P<backend>[^/]+)/$', views.associate_account, name='associate_account'),
	# 2.API to get linked user information from external account information
    url(r'api/auth/(?P<backend>[^/]+)/$', views.auth_account, name='auth_account'),
]

View of the app you want to use the linkage function

`myapp/views.py`


from django.contrib.auth import login

from rest_framework import status
from rest_framework.response import Response
from rest_framework.permissions import IsAuthenticated
from rest_framework.decorators import api_view, permission_classes

from social.backends.oauth import BaseOAuth1, BaseOAuth2
from social.apps.django_app.utils import psa

# 1.API to link an external account to an existing user

@api_view(('POST',))
@permission_classes((IsAuthenticated,))
@psa('social:complete')
def associate_account(request, backend):
    backend = request.backend
    token = _make_token(request, backend)
    #User is returned only when authentication with OAuth is successful
    user = backend.do_auth(token, user=request.user)
    if user:
        login(request, user)
        return Response({'success': True})
    else:
        return Response({"errors": "Error with social authentication"},
                            status=status.HTTP_400_BAD_REQUEST)

# 2.API to get linked user information from external account information

@api_view(('POST',))
@psa('social:complete')
def auth_account(request, backend):
    backend = request.backend
    token = _make_token(request, backend)
    #User is returned only when authentication with OAuth is successful and there is a user associated with that information
    user = backend.do_auth(token)
    if user:
        return Response({'id': user.id, 'username': user.username})
    else:
        return Response({"errors": "User Not Found"},
                            status=status.HTTP_404_NOT_FOUND)

#The shape of the token used is different between OAuth1 and OAuth2

def _make_token(request, backend):
    if isinstance(backend, BaseOAuth1):
        token = {
            'oauth_token': request.data.get('access_token'),
            'oauth_token_secret': request.data.get('access_token_secret'),
        }
    elif isinstance(backend, BaseOAuth2):
        token = request.data.get('access_token')
    return token

Operation check

Cooperation with Twitter

Preparation

Prepare an access_token and access_token_secret (in some way) for the user linked with your own Twitter app.
Log in to the management screen of your own service with a browser.

How to check the external service linkage function

Access the URL (ex. Http://myserver/myapp/api/associate/twitter/) with associate_account set with a browser.

As shown in the screen above, enter access_token and access_token_secret in json format in content and press [POST].

{
   "access_token": "my_access_token",
   "access_token_secret": "my_access_token_secret"
}

If {" success ": true} is returned, authentication is successful.

How to check the external service authentication function

Access the URL (ex. Http://myserver/myapp/api/auth/twitter/) for which auth_account is set with a browser, and perform the same procedure as in the previous section.

Success if the ID of the user who linked earlier is returned.

For Facebook

You can check it with almost the same procedure as Twitter, but the following two points are different.

In the above confirmation procedure, change the place where it is twitter to facebook.
The only json information to send is ʻaccess_token. (OAuth2 does not have ʻaccess_token_secret)

Impressions

python-social-auth Convenient! I was able to write the code required for authentication in just a few lines!

However, this implementation seems to have finally been realized by gathering various scattered English information, and I got the impression that Python has little information in Japanese.

reference

I want to log in on Twitter and Facebook with Python 3.4 and Django 1.6.5-Today's Hack http://narusemotoki.tumblr.com/post/90525892180/python-34%E3%81%A8django-165%E3%81%A7twitter%E3%82%84facebook%E3%81%A7%E3%81%AE%E3%83%AD%E3%82%B0%E3%82%A4%E3%83%B3%E3%82%92%E3%81%97%E3%81%9F%E3%81%84

omab/python-social-auth https://github.com/omab/python-social-auth

Django Framework — Python Social Auth documentation https://python-social-auth.readthedocs.org/en/latest/configuration/django.html

Pipeline — Python Social Auth documentation https://python-social-auth.readthedocs.org/en/latest/pipeline.html#authentication-pipeline

Use Cases — Python Social Auth documentation http://psa.matiasaguirre.net/docs/use_cases.html#signup-by-oauth-access-token

Twitter OAuth using access_token · Issue #272 · omab/python-social-auth https://github.com/omab/python-social-auth/issues/272

Social Auth with Django REST Framework - Yeti https://yeti.co/blog/social-auth-with-django-rest-framework/

Create a social integration API for smartphone apps with Django

background

Purpose

environment

Authentication flow

Implementation details

python

settings.py

python

myproject/urls.py

myapp/urls.py

myapp/views.py

Operation check

Cooperation with Twitter

Preparation

How to check the external service linkage function

How to check the external service authentication function

For Facebook

Impressions

reference

`python`

`settings.py`

`python`

`myproject/urls.py`

`myapp/urls.py`

`myapp/views.py`