Fixed user retrieval and creation issues (#4)

Author: ahmedjawed01

django_saml2_auth/views.py

@@ -146,8 +146,8 @@ def denied(r):
     return render(r, 'django_saml2_auth/denied.html')
 
 
-def _create_new_user(email, firstname, lastname):
-    user = User.objects.create_user(email)
+def _create_new_user(username, email, firstname, lastname):
+    user = User.objects.create_user(username, email)
     user.first_name = firstname
     user.last_name = lastname
     groups = [Group.objects.get(name=x) for x in settings.SAML2_AUTH.get(
@@ -210,13 +210,12 @@ def acs(r):
                 **{User.USERNAME_FIELD: user_name})
         else:
             target_user = User.objects.get(
-                {User.USERNAME_FIELD__iexact: user_name})
+                {"{}__iexact".format(User.USERNAME_FIELD): user_name})
     except User.DoesNotExist:
         new_user_should_be_created = settings.SAML2_AUTH.get(
             'CREATE_USER', True)
         if new_user_should_be_created:
-            target_user = _create_new_user(
-                user_email, user_first_name, user_last_name)
+            target_user = _create_new_user(user_name, user_email, user_first_name, user_last_name)
 
             if settings.SAML2_AUTH.get('TRIGGER', {}).get('CREATE_USER', None):
                 run_hook(settings.SAML2_AUTH['TRIGGER']
@@ -261,7 +260,7 @@ def acs(r):
             **{User.USERNAME_FIELD: user_name})
     else:
         target_user = User.objects.get(
-            {User.USERNAME_FIELD__iexact: user_name})
+            {"{}__iexact".format(User.USERNAME_FIELD): user_name})
 
     if settings.SAML2_AUTH.get('USE_JWT') is True and target_user.is_active:
         # We use JWT auth send token to frontend