Retrieve user identifier from form data

flask_multipass/auth.py

@@ -30,6 +30,10 @@ class AuthProvider(metaclass=SupportsMeta):
     #: form in your application, specify a :class:`~flask_wtf.Form`
     #: here (usually containing a username/email and a password field).
     login_form = None
+    #: The field name in the login form that contains the identifier.
+    #: Useful to reliably retrieve identifier data in applications that use
+    #: multiple auth providers.
+    identifier_field_name = None
 
     def __init__(self, multipass, name, settings):
         self.multipass = multipass
@@ -113,5 +117,11 @@ def process_logout(self, return_url):
         """
         return None
 
+    def get_identifier(self, data):
+        """Get the user identifier from form data."""
+        if self.identifier_field_name is None:
+            raise NotImplementedError('No identifier field name set')
+        return data.get(self.identifier_field_name)
+
     def __repr__(self):
         return f'<{type(self).__name__}({self.name})>'

flask_multipass/providers/sqlalchemy.py

@@ -40,6 +40,8 @@ class SQLAlchemyAuthProviderBase(AuthProvider):
     #: i.e. the username. This needs to be a SQLAlchemy column object,
     #: e.g. ``Identity.identifier``
     identifier_column = None
+    #: The field name in the ``login_form`` that contains the identifier
+    identifier_field_name = 'identifier'
 
     def check_password(self, identity, password):
         """Checks the entered password.

flask_multipass/providers/static.py

@@ -33,6 +33,7 @@ class StaticAuthProvider(AuthProvider):
     """
 
     login_form = StaticLoginForm
+    identifier_field_name = 'username'
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)

tests/test_util.py

@@ -145,8 +145,10 @@ class NoProvider:
     class InvalidProvider(AuthProvider, IdentityProvider):
         pass
 
-    pytest.raises(TypeError, get_provider_base, NoProvider)
-    pytest.raises(TypeError, get_provider_base, InvalidProvider)
+    with pytest.raises(TypeError):
+        get_provider_base(NoProvider)
+    with pytest.raises(TypeError):
+        get_provider_base(InvalidProvider)
 
 
 def test_login_view(mocker):
@@ -267,7 +269,8 @@ def test_validate_provider_map(valid, auth_providers, identity_providers, provid
     if valid:
         validate_provider_map(state)
     else:
-        pytest.raises(ValueError, validate_provider_map, state)
+        with pytest.raises(ValueError):
+            validate_provider_map(state)
 
 
 def test_classproperty():