unhashable type when redirecting back to the website using python-social-auth in Django

Question

I'm trying to add a social media authentication to a website using Social-auth-app-django.

So I've created different apps for the most popular social media websites (Facebook, Twitter, Google+), and have set the callback url there.

But I'm coming across an error when I'm redirected back to the website from say Facebook:

    Internal Server Error: /oauth/complete/facebook/
Traceback (most recent call last):
  File "/usr/local/lib/python3.5/site-packages/django/core/handlers/exception.py", line 39, in inner
    response = get_response(request)
  File "/usr/local/lib/python3.5/site-packages/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/usr/local/lib/python3.5/site-packages/django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/usr/local/lib/python3.5/site-packages/django/views/decorators/cache.py", line 57, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "/usr/local/lib/python3.5/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
    return view_func(*args, **kwargs)
  File "/usr/local/lib/python3.5/site-packages/social_django/utils.py", line 50, in wrapper
    return func(request, backend, *args, **kwargs)
  File "/usr/local/lib/python3.5/site-packages/social_django/views.py", line 32, in complete
    redirect_name=REDIRECT_FIELD_NAME, *args, **kwargs)
  File "/usr/local/lib/python3.5/site-packages/social_core/actions.py", line 41, in do_complete
    user = backend.complete(user=user, *args, **kwargs)
  File "/usr/local/lib/python3.5/site-packages/social_core/backends/base.py", line 40, in complete
    return self.auth_complete(*args, **kwargs)
  File "/usr/local/lib/python3.5/site-packages/social_core/utils.py", line 252, in wrapper
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.5/site-packages/social_core/backends/facebook.py", line 110, in auth_complete
    return self.do_auth(access_token, response, *args, **kwargs)
  File "/usr/local/lib/python3.5/site-packages/social_core/backends/facebook.py", line 152, in do_auth
    return self.strategy.authenticate(*args, **kwargs)
  File "/usr/local/lib/python3.5/site-packages/social_django/strategy.py", line 115, in authenticate
    return authenticate(*args, **kwargs)
  File "/usr/local/lib/python3.5/site-packages/django/contrib/auth/__init__.py", line 74, in authenticate
    user = backend.authenticate(**credentials)
  File "/usr/local/lib/python3.5/site-packages/social_core/backends/base.py", line 80, in authenticate
    return self.pipeline(pipeline, *args, **kwargs)
  File "/usr/local/lib/python3.5/site-packages/social_core/backends/base.py", line 83, in pipeline
    out = self.run_pipeline(pipeline, pipeline_index, *args, **kwargs)
  File "/usr/local/lib/python3.5/site-packages/social_core/backends/base.py", line 105, in run_pipeline
    for idx, name in enumerate(pipeline[pipeline_index:]):
TypeError: unhashable type: 'slice'

---

Below is a summary of how I've configured social_django:

In settings.py:

INSTALLED_APPS = [
    'social_django',
    ...
]

AUTHENTICATION_BACKENDS = (
    'social_core.backends.google.GoogleOAuth2',
    'social_core.backends.twitter.TwitterOAuth',
    'social_core.backends.facebook.FacebookOAuth2',

    'django.contrib.auth.backends.ModelBackend',
)

SOCIAL_AUTH_FACEBOOK_KEY = 'xxx'
SOCIAL_AUTH_FACEBOOK_SECRET = 'xxx'

...

PIPELINE = {
    'PIPELINE_ENABLED': True,
    'STYLESHEETS': {...},
    'JAVASCRIPT': {...},
    'JS_COMPRESSOR': 'pipeline.compressors.NoopCompressor',
    'COMPILERS': (
        'pipeline.compilers.sass.SASSCompiler',
    )
}

Afterwards, I've obviously migrated the database to create the new tables.

Please find below the versions of Django and social_django:

• Django: 1.10.5
• social_django: 1.2.0

Regarding the pipeline used, I'm using django-pipeline but it's just for compiling SASS files to CSS.

What might cause this error?

Answer 1

Adding the pipeline below to settings.py seems to have fixed the problem (source):

SOCIAL_AUTH_PIPELINE = (
    'social_core.pipeline.social_auth.social_details',
    'social_core.pipeline.social_auth.social_uid',
    'social_core.pipeline.social_auth.social_user',
    'social_core.pipeline.user.get_username',
    'social_core.pipeline.user.create_user',
    'social_core.pipeline.social_auth.associate_user',
    'social_core.pipeline.social_auth.load_extra_data',
    'social_core.pipeline.user.user_details',
    'social_core.pipeline.social_auth.associate_by_email',
)

Answer 2

This error raises when trying to get a slice from a dict object. So, yes at the point of the last line of the traceback, pipelines is a dict object when it is supposed to be a sequence which default value is sociel_core.pipeline.DEFAULT_AUTH_PIPELINE unless your settings provides a PIPELINE object.

https://github.com/python-social-auth/social-core/blob/ccc50a5932b199a1a5209a08563c8997eb99391d/social_core/strategy.py#L99

https://github.com/python-social-auth/social-core/blob/ccc50a5932b199a1a5209a08563c8997eb99391d/social_core/pipeline/init.py#L1

Thus I suspect something probably in your settings module that messes this PIPELINE that should be a sequence (list, tuple, custom) and not a dict.

Hints: install ipython and play with python manage.py shell and inspect the followings.

>>> from social_core.strategy import BaseStrategy
>>> st = BaseStrategy()
>>> st.get_pipeline()
---> ???
>>> from django.conf import settings
>>> settings.PIPELINE
---> ???

Hope this helped