Make trailing slash an app-wide setting

Adds `URLS_TRAILING_SLASH` (default `False`) and `force_trailing_slash`
on `path()` so the canonical trailing-slash form is one project-wide
choice instead of a per-route decision. The slash in a route string
is stripped silently; root URLs and catchalls remain slash-neutral.

- Drop `Route` dataclass; `URLPattern`/`URLResolver` hold segments
  directly and `URLPattern.converters` is a cached property
- Methodize `_build_lookups`, `_collect_*`, `_register_namespace`,
  `_try_reverse` on `URLResolver`
- `plain urls list` renders canonical slashes from segment tuples
- Update plain-api OpenAPI generator and the internal admin/oauth/
  observer/support/loginlink/pageviews/assets routes plus example app
- Switch support embed iframe URL to the no-slash canonical form

Author: davegaeddert

example/app/contacts/urls.py

@@ -9,6 +9,6 @@ class ContactsRouter(Router):
     namespace = "contacts"
     urls = [
         path("", views.ContactView, name="form"),
-        path("success/", views.ContactSuccessView, name="success"),
-        path("archive/", views.ContactArchiveView, name="archive"),
+        path("success", views.ContactSuccessView, name="success"),
+        path("archive", views.ContactArchiveView, name="archive"),
     ]

example/app/notes/urls.py

@@ -9,8 +9,8 @@ class NotesRouter(Router):
     namespace = "notes"
     urls = [
         path("", views.NoteListView, name="list"),
-        path("new/", views.NoteCreateView, name="create"),
-        path("<int:id>/", views.NoteDetailView, name="detail"),
-        path("<int:id>/edit/", views.NoteUpdateView, name="update"),
-        path("<int:id>/delete/", views.NoteDeleteView, name="delete"),
+        path("new", views.NoteCreateView, name="create"),
+        path("<int:id>", views.NoteDetailView, name="detail"),
+        path("<int:id>/edit", views.NoteUpdateView, name="update"),
+        path("<int:id>/delete", views.NoteDeleteView, name="delete"),
     ]

example/app/tasks/urls.py

@@ -9,9 +9,9 @@ class TasksRouter(Router):
     namespace = "tasks"
     urls = [
         path("", views.TaskListView, name="list"),
-        path("seed/", views.TaskSeedView, name="seed"),
-        path("new/", views.TaskCreateView, name="create"),
-        path("<int:id>/", views.TaskDetailView, name="detail"),
-        path("<int:id>/edit/", views.TaskUpdateView, name="update"),
-        path("<int:id>/delete/", views.TaskDeleteView, name="delete"),
+        path("seed", views.TaskSeedView, name="seed"),
+        path("new", views.TaskCreateView, name="create"),
+        path("<int:id>", views.TaskDetailView, name="detail"),
+        path("<int:id>/edit", views.TaskUpdateView, name="update"),
+        path("<int:id>/delete", views.TaskDeleteView, name="delete"),
     ]

example/app/urls.py

@@ -43,23 +43,23 @@ def get(self) -> NoReturn:
 class AppRouter(Router):
     namespace = ""
     urls = [
-        include("admin/", AdminRouter),
-        include("assets/", AssetsRouter),
-        include("observer/", ObserverRouter),
-        include("pageviews/", PageviewsRouter),
-        include("notes/", NotesRouter),
-        include("contacts/", ContactsRouter),
-        include("tasks/", TasksRouter),
-        include("api/", APIRouter),
-        include("tasks-api/", TasksAPIRouter),
-        path("mcp/", NotesMCP, name="mcp"),
-        path("login/", LoginView, name="login"),
-        path("logout/", LogoutView, name="logout"),
-        path("error/", ErrorView, name="error"),
-        path("sse/", SSEDemoView, name="sse_demo"),
-        path("sse/clock/", ClockView, name="sse_clock"),
-        path("sse/ticker/", StockTickerView, name="sse_ticker"),
-        path("jobs/run/", RunExampleJobView, name="run_example_job"),
+        include("admin", AdminRouter),
+        include("assets", AssetsRouter),
+        include("observer", ObserverRouter),
+        include("pageviews", PageviewsRouter),
+        include("notes", NotesRouter),
+        include("contacts", ContactsRouter),
+        include("tasks", TasksRouter),
+        include("api", APIRouter),
+        include("tasks-api", TasksAPIRouter),
+        path("mcp", NotesMCP, name="mcp"),
+        path("login", LoginView, name="login"),
+        path("logout", LogoutView, name="logout"),
+        path("error", ErrorView, name="error"),
+        path("sse", SSEDemoView, name="sse_demo"),
+        path("sse/clock", ClockView, name="sse_clock"),
+        path("sse/ticker", StockTickerView, name="sse_ticker"),
+        path("jobs/run", RunExampleJobView, name="run_example_job"),
         path("", IndexView, name="index"),
         path("<path:_>", NotFoundView),
     ]

example/tests/test_urls.py

@@ -7,16 +7,16 @@ def test_admin_access(db):
     client = Client()
 
     # Login required
-    assert client.get("/admin/").status_code == 302
+    assert client.get("/admin").status_code == 302
 
     user = User.query.create(email="admin@example.com", password="strongpass1")
     client.force_login(user)
 
     # Not admin yet
-    assert client.get("/admin/").status_code == 404
+    assert client.get("/admin").status_code == 404
 
     user.is_admin = True
     user.save()
 
     # Now admin
-    assert client.get("/admin/").status_code in {200, 302}
+    assert client.get("/admin").status_code in {200, 302}

plain-admin/plain/admin/impersonate/urls.py

@@ -6,6 +6,6 @@
 class ImpersonateRouter(Router):
     namespace = "impersonate"
     urls = [
-        path("stop/", ImpersonateStopView, name="stop"),
-        path("start/<id>/", ImpersonateStartView, name="start"),
+        path("stop", ImpersonateStopView, name="stop"),
+        path("start/<id>", ImpersonateStartView, name="start"),
     ]

plain-admin/plain/admin/urls.py

@@ -21,16 +21,16 @@
 class AdminRouter(Router):
     namespace = "admin"
     urls = [
-        path("search/", AdminSearchView, name="search"),
-        path("ui/", UIView, name="ui"),
-        path("settings/", SettingsView, name="settings"),
-        path("settings/<name>/", SettingDetailView, name="setting_detail"),
-        path("preflight/", PreflightView, name="preflight"),
-        path("logout/", LogoutView, name="logout"),
-        path("_/pin/", PinNavView, name="pin"),
-        path("_/unpin/", UnpinNavView, name="unpin"),
-        path("_/reorder/", ReorderPinnedView, name="reorder"),
-        include("impersonate/", ImpersonateRouter),
+        path("search", AdminSearchView, name="search"),
+        path("ui", UIView, name="ui"),
+        path("settings", SettingsView, name="settings"),
+        path("settings/<name>", SettingDetailView, name="setting_detail"),
+        path("preflight", PreflightView, name="preflight"),
+        path("logout", LogoutView, name="logout"),
+        path("_/pin", PinNavView, name="pin"),
+        path("_/unpin", UnpinNavView, name="unpin"),
+        path("_/reorder", ReorderPinnedView, name="reorder"),
+        include("impersonate", ImpersonateRouter),
         include("", registry.get_urls()),
         path("", AdminIndexView, name="index"),
     ]

plain-admin/tests/app/urls.py

@@ -17,8 +17,8 @@ def get(self):
 class AppRouter(Router):
     namespace = ""
     urls = [
-        include("admin/", AdminRouter),
-        include("assets/", AssetsRouter),
-        path("login/", LoginView, name="login"),
-        path("logout/", LogoutView, name="logout"),
+        include("admin", AdminRouter),
+        include("assets", AssetsRouter),
+        path("login", LoginView, name="login"),
+        path("logout", LogoutView, name="logout"),
     ]

plain-admin/tests/public/test_admin.py

@@ -9,21 +9,21 @@ def test_admin_login_required(db):
     client = Client()
 
     # Login required
-    assert client.get("/admin/").status_code == 302
+    assert client.get("/admin").status_code == 302
 
     user = User.query.create(username="test")
     client.force_login(user)
 
     # Not admin yet
-    assert client.get("/admin/").status_code == 404
+    assert client.get("/admin").status_code == 404
 
     user.is_admin = True
     user.save()
 
     # Now admin (currently redirects to the first view)
-    resp = client.get("/admin/")
+    resp = client.get("/admin")
     assert resp.status_code == 302
-    assert resp.url == "/admin/p/session/"
+    assert resp.url == "/admin/p/session"
 
 
 def test_has_permission_on_view(db):
@@ -80,7 +80,7 @@ def test_ui_view_renders(db):
     client = Client()
     client.force_login(user)
 
-    resp = client.get("/admin/ui/")
+    resp = client.get("/admin/ui")
     assert resp.status_code == 200
     body = resp.content.decode()
     # Sanity-check a few markers from each major section

plain-api/plain/api/openapi/generator.py

@@ -124,8 +124,10 @@ def get_paths(
 
     def path_from_url_pattern(self, url_pattern: URLPattern, root_path: str) -> str:
         path = root_path + url_pattern.raw_route
+        if url_pattern.trailing_slash and url_pattern.raw_route:
+            path += "/"
 
-        for name, converter in url_pattern.route.converters.items():
+        for name, converter in url_pattern.converters.items():
             # Handle both `<type:name>` and the `<name>` shorthand for the default `str` converter.
             path = path.replace(f"<{converter.keyword}:{name}>", f"{{{name}}}")
             path = path.replace(f"<{name}>", f"{{{name}}}")
@@ -266,7 +268,7 @@ def parameters_from_url_patterns(
         parameters = []
 
         for url_pattern in url_patterns:
-            for name, converter in url_pattern.route.converters.items():
+            for name, converter in url_pattern.converters.items():
                 parameters.append(
                     {
                         "name": name,