Allow additional models customisation in Auth.use_database (#466)

* fix: exposed models in emmett/tools/auth/__init__.py and made membership, group and permission model customizable.

* Update emmett/tools/auth/ext.py

stricter issubclass check

Co-authored-by: Giovanni Barillari <g@baro.dev>

* Update apis.py

fix: changed order of membership, group and permission to group, membership and permission

* Update auth.md

added changes to documentation

---------

Co-authored-by: Giovanni Barillari <g@baro.dev>

docs/auth.md

@@ -58,6 +58,41 @@ You can obviously change the routing URL prefix (default set to *auth*) as any o
 auth_routes = auth.module(__name__, url_prefix='account')
 ```
 
+Adding Custom Fields to Auth Models
+------------------
+
+*changed in version 2.5.3*
+
+By extending the default auth models provided by your authentication framework, you can easily add custom fields all of the auth models. 
+
+To add custom fields to the auth models, you can add this piece of code:
+```
+from emmett import App
+from emmett.orm import Database, Field
+from emmett.tools.auth import Auth, AuthUser, AuthMembership, AuthGroup, AuthPermission
+from emmett.sessions import SessionManager
+
+app = App(__name__)
+app.config.db.uri = "sqlite://storage.sqlite"
+app.config.auth.hmac_key = "mysupersecretkey"
+app.config.auth.single_template = True
+
+class User(AuthUser):
+    pass
+
+class Membership(AuthMembership):
+    pass
+
+class Group(AuthGroup):
+    extra_field = field.string()
+
+class Permission(AuthPermission):
+    pass
+
+db = Database(app)
+auth = Auth(app, db, user_model=User, membership_model=Membership, group_model=Group, permission_model=Permission)
+```
+
 Auth module configuration
 -------------------------
 

emmett/tools/auth/__init__.py

@@ -1,2 +1,2 @@
 from .apis import Auth
-from .models import AuthUser
+from .models import AuthUser, AuthMembership, AuthGroup, AuthPermission

emmett/tools/auth/apis.py

@@ -27,10 +27,10 @@
 
 
 class Auth:
-    def __init__(self, app, db, user_model=None):
+    def __init__(self, app, db, user_model=None, group_model=None, membership_model=None, permission_model=None):
         self.ext = app.use_extension(AuthExtension)
         self.ext.bind_auth(self)
-        self.ext.use_database(db, user_model)
+        self.ext.use_database(db, user_model, membership_model, group_model, permission_model)
         self.ext.init_forms()
         self.pipe = AuthPipe(self)
 

emmett/tools/auth/ext.py

@@ -189,13 +189,25 @@ def _inject_pipe(self):
         if self.config.inject_pipe:
             self.app.pipeline.append(self.auth.pipe)
 
-    def use_database(self, db, user_model=None):
+    def _set_model_config(self, config_name, model):
+        if not model:
+            return
+        _model_bases = {
+            'user': AuthModel,
+            'group': AuthGroup,
+            'membership': AuthMembership,
+            'permission': AuthPermission
+        }
+        if not issubclass(model, _model_bases[config_name]):
+            raise RuntimeError(f'{model.__name__} is an invalid {config_name} auth model')
+        self.config.models[config_name] = model
+
+    def use_database(self, db, user_model=None, membership_model=None, group_model=None, permission_model=None):
         self.db = db
-        if user_model:
-            if not issubclass(user_model, AuthModel):
-                raise RuntimeError(
-                    '%s is an invalid user model' % user_model.__name__)
-            self.config.models['user'] = user_model
+        self._set_model_config("user", user_model)
+        self._set_model_config("membership", membership_model)
+        self._set_model_config("group", group_model)
+        self._set_model_config("permission", permission_model)
         self.define_models()
 
     def __set_models_labels(self):