###########
Basic setup
###########

Following the instructions on this page, your will create a provider for
allauth, which allows users to connect through a CAS server.


****************
1. Create an app
****************

``allauth`` determines available providers by scanning ``INSTALLED_APPS``.
Let's begin by creating an app for the CAS provider:

.. code-block:: bash

  $ python manage.py startapp mycas

And add it to the ``INSTALLED_APPS``:

.. code-block:: python

  INSTALLED_APPS = [
      # …
      'allauth',
      'allauth.account',
      'allauth.socialaccount',

      'allauth_cas',

      'mycas',
  ]


**********************
2. Create the provider
**********************

In ``mycas/provider.py``, create subclasses of ``ProviderAccount`` and
``CASProvider``.

The ``CASProvider`` subclass defines how to process data returned by the CAS
server.

.. code-block:: python

  from allauth.socialaccount.providers.base import ProviderAccount
  from allauth_cas.providers import CASProvider


  class MyCASAccount(ProviderAccount):
      pass


  class MyCASProvider(CASProvider):
      id = 'mycas'  # Choose an identifier for your provider
      name = 'My CAS'  # Verbose name of your provider
      account_class = MyCASAccount


  provider_classes = [MyCASProvider]

.. seealso::

  :doc:`advanced/extract_data`


*******************
3. Create the views
*******************

Subclass ``CASAdapter`` to give your configuration as a CAS client.

.. code-block:: python

  from allauth_cas.views import CASAdapter

  from .providers import MyCASProvider


  class MyCASAdapter(CASAdapter):
      provider_id = MyCASProvider.id
      url = 'https://mycas.mydomain.net'  # The CAS server url
      version = 3  # Select the CAS protocol version used by the CAS server: 1, 2, 3…

Then, you can simply create the login and callback views.

.. code-block:: python

  from allauth_cas.views import CASCallbackView, CASLoginView

  login = CASLoginView.adapter_view(MyCASAdapter)
  callback = CASLogoutView.adapter_view(MyCASAdapter)

.. seealso::

  :doc:`advanced/cas_client`


******************
4. Create the urls
******************

Finally, add the urls in ``mycas/urls.py``.

.. code-block:: python

  from allauth_cas.urls import default_urlpatterns

  from .provider import MyCASProvider

  urlpatterns = default_urlpatterns(MyCasProvider)

There is no need to do more, as ``allauth`` is responsible for including these
urls.


*******************************************
5. Allow your application at the CAS server
*******************************************

.. note::

  This step is only required if the CAS server restricts access to known
  applications.

CAS servers may restrict their usage to a list of known clients. To do so,
the service url must be known by the CAS server. For our case, the service
url is the callback url of a CAS provider.

The service url is formatted as:

.. code-block:: none

  <url of your application>/<path to allauth urls>/<provider id>/login/callback/

Assuming a site is served at ``https://mydomain.net``, that the allauth urls
are included under ``accounts/``, and the provider id is ``mycas``, the service url
is:

.. code-block:: none

  https://mydomain.net/accounts/mycas/login/callback

While in local development, it can be:

.. code-block:: none

  http://127.0.0.1:8000/accounts/mycas/login/callback

This url should be added to the authorized services within the CAS server
configuration (by yourself or someone in charge of the server).