Fix for overriding custom error view using SAML_ACS_FAILURE_RESPONSE_FUNCTION (#247)

* Fix SAML_ACS_FAILURE_RESPONSE_FUNCTION override:

Add the `import_string` import so that you can use the above variable to
supply a different template rendering function.

* Update Custom Error Handler docs:

The custom error function that is passed in using
SAML_ACS_FAILURE_RESPONSE_FUNCTION has changed signature and the example
no longer works.

The custom function with an extra positional argument so the
documentation has been updated to include this.

Author: agxs

README.rst

@@ -388,9 +388,9 @@ This should be a view which takes a request, optional exception which occured
 and status code, and returns a response to serve the user. E.g. The default
 implementation looks like this::
 
-  def template_failure(request, exception=None, **kwargs):
+  def template_failure(request, exception=None, status=403, **kwargs):
       """ Renders a simple template with an error message. """
-      return render(request, 'djangosaml2/login_error.html', {'exception': exception}, status=kwargs.get('status', 403))
+      return render(request, 'djangosaml2/login_error.html', {'exception': exception}, status=status)
 
 
 User attributes

djangosaml2/views.py

@@ -28,6 +28,7 @@
 from django.utils.decorators import method_decorator
 from django.views.decorators.csrf import csrf_exempt
 from django.views.generic import View
+from django.utils.module_loading import import_string
 from saml2 import BINDING_HTTP_POST, BINDING_HTTP_REDIRECT
 from saml2.client_base import LogoutError
 from saml2.config import SPConfig