StartURL KeyError

[GoogleCodeExporter]

Regarding SSO/SAML, I've noticed that sometimes we get an error from saml2idp 
trying to access a key in a dict that isn't really there... this looks like 
something you could maybe try to fix? One example of this is

  MultiValueDictKeyError: "Key 'SAMLRequest' not found in <QueryDict: {u'XY': [u'123'], u'startURL': [u'/abc']}>"

      File "/srv/.../lib/django/core/handlers/base.py", line 115, in get_response
    response = callback(request, *callback_args, **callback_kwargs)
  File "/srv/.../lib/django/views/decorators/csrf.py", line 77, in wrapped_view
    return view_func(*args, **kwargs)
  File "/srv/.../src/ubuntu_sso_saml/views.py", line 14, in saml_begin
    return login_begin(request)
  File "/srv/.../lib/django/views/decorators/csrf.py", line 77, in wrapped_view
    return view_func(*args, **kwargs)
  File "/srv/.../lib/saml2idp/views.py", line 49, in login_begin
    request.session['SAMLRequest'] = source['SAMLRequest']
  File "/srv/.../lib/django/utils/datastructures.py", line 295, in __getitem__
    raise MultiValueDictKeyError("Key %r not found in %r" % (key, self))

Original issue reported on code.google.com by [email protected] on 26 Nov 2013 at 2:35