support expose decorator in ModelView(#881)

Co-authored-by: jdraaijer <jelmerdraaijer@z-cert.nl>

Author: foarsitter

docs/writing_custom_views.md

@@ -32,6 +32,26 @@ admin = Admin(templates_dir="my_templates", ...)
 
 Now visiting `/admin/report` you can render your `report.html` file.
 
+It is also possible to use the expose decorator to add extra endpoints to a ModelView. 
+The `path` is in this case prepended with the view's identity, in this case `/admin/user/profile/{pk}`.
+
+!!! example
+
+    ```python
+    from sqladmin import ModelView, expose
+
+    class UserView(ModelView):
+
+        @expose("/profile/{pk}", methods=["GET"])
+        async def profile(self, request):
+            user: User = await self.get_object_for_edit(request)
+            return await self.templates.TemplateResponse(
+                request, "user.html", {"user": user}
+            )
+
+    admin.add_view(UserView)
+    ```
+
 ### Database access
 
 The example above was very basic and you probably want to access database and SQLAlchemy models in your custom view. You can use `sessionmaker` the same way SQLAdmin is using it to do so:

sqladmin/application.py

@@ -197,16 +197,22 @@ def _handle_expose_decorated_func(
         view_instance: BaseView | ModelView,
     ) -> None:
         if hasattr(func, "_exposed"):
+            if view.is_model:
+                path = f"/{view_instance.identity}" + getattr(func, "_path")
+                name = f"view-{view_instance.identity}-{func.__name__}"
+            else:
+                view.identity = getattr(func, "_identity")
+                path = getattr(func, "_path")
+                name = getattr(func, "_identity")
+
             self.admin.add_route(
                 route=func,
-                path=getattr(func, "_path"),
+                path=path,
                 methods=getattr(func, "_methods"),
-                name=getattr(func, "_identity"),
+                name=name,
                 include_in_schema=getattr(func, "_include_in_schema"),
             )
 
-            view.identity = getattr(func, "_identity")
-
     def add_model_view(self, view: type[ModelView]) -> None:
         """Add ModelView to the Admin.
 
@@ -233,6 +239,11 @@ class UserAdmin(ModelView, model=User):
         self._find_decorated_funcs(
             view, view_instance, self._handle_action_decorated_func
         )
+
+        self._find_decorated_funcs(
+            view, view_instance, self._handle_expose_decorated_func
+        )
+
         self._views.append(view_instance)
         self._build_menu(view_instance)
 

tests/test_models.py

@@ -2,15 +2,17 @@
 from typing import Generator
 
 import pytest
+from jinja2 import TemplateNotFound
 from markupsafe import Markup
 from sqlalchemy import Boolean, Column, Enum, ForeignKey, Integer, String, select
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.orm import contains_eager, declarative_base, relationship, sessionmaker
 from sqlalchemy.sql.expression import Select
 from starlette.applications import Starlette
 from starlette.requests import Request
+from starlette.testclient import TestClient
 
-from sqladmin import Admin, ModelView
+from sqladmin import Admin, ModelView, expose
 from sqladmin.exceptions import InvalidModelError
 from sqladmin.helpers import get_column_python_type
 from tests.common import sync_engine as engine
@@ -77,6 +79,12 @@ def prepare_database() -> Generator[None, None, None]:
     Base.metadata.drop_all(engine)
 
 
+@pytest.fixture
+def client() -> Generator[TestClient, None, None]:
+    with TestClient(app=app, base_url="http://testserver") as c:
+        yield c
+
+
 def test_metadata_setup() -> None:
     class UserAdmin(ModelView, model=User):
         pass
@@ -478,3 +486,18 @@ class AddressAdmin(ModelView, model=Address):
     stmt = AddressAdmin().search_query(select(Address), "example")
     assert "lower(CAST(users.name AS VARCHAR))" in str(stmt)
     assert "lower(CAST(profiles.role AS VARCHAR))" in str(stmt)
+
+
+def test_expose_decorator(client: TestClient) -> None:
+    class UserAdmin(ModelView, model=User):
+        @expose("/profile/{pk}")
+        async def profile(self, request: Request):
+            user: User = await self.get_object_for_edit(request)
+            return await self.templates.TemplateResponse(
+                request, "user.html", {"user": user}
+            )
+
+    admin.add_view(UserAdmin)
+
+    with pytest.raises(TemplateNotFound, match="user.html"):
+        client.get("/admin/user/profile/1")