Retrieve user identifier from form data

Author: OmeGak

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

@@ -30,6 +30,8 @@ class SQLAlchemyAuthProviderBase(AuthProvider):
 
     #: The :class:`~flask_wtf.Form` that is used for the login dialog
     login_form = LoginForm
+    #: The field name in the login form that contains the identifier
+    identifier_field_name = LoginForm.identifier.name
     #: The Flask-SQLAlchemy model representing a user identity
     identity_model = None
     #: The column of the identity model that contains the provider

flask_multipass/providers/static.py

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