Add url_for method to Router for named route URL generation

CHANGELOG.md

@@ -5,14 +5,29 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [2.6.1] - 2026-??-??
+## [2.6.1] - 2026-02-22 :cat:
 
 - Fix missing escaping in `multipart/form-data` filenames and content-disposition headers.
 - Fix [#193](https://github.com/Neoteroi/BlackSheep/issues/193), adding support for [`a2wsgi`](https://github.com/abersheeran/a2wsgi).
 - `raw_path` is optional in ASGI specification. If not present, now the `instantiate_request` method automatically obtains it from `path` and sets it in the scope.
 - Static files are now served with `Content-Length` header instead of `Transfer-Encoding: chunked` when file size is known. This improves compatibility with `WSGI` servers via `a2wsgi`.
 - Automatically run the `Application` start logic if the `__call__` method is called with **http** or **websocket** messages. This is useful when `lifespan` events are not supported, like when using `WSGI`.
 - Fix the issue [#396](https://github.com/Neoteroi/BlackSheep/issues/396). Requests for mounted apps are redirected to a directory (ending with '/') only if the request includes a `Sec-Fetch-Mode: navigate`, which is used by modern browsers to inform the server the request is for navigation. This way, mounted apps serving HTML documents containing relative links work properly (their path must end with `/`). Reported by @satori1995.
+- Fix the issue [#256](https://github.com/Neoteroi/BlackSheep/issues/256): add support
+  for configuring names for routes, and for obtaining URLs by route name. Example:
+
+  ```python
+    from blacksheep.routing import URLResolver
+
+
+    @app.router.get("/cats/{cat_id}", name="cat-detail")
+    async def get_cat_detail(cat_id: int) -> Response:
+        return Response(200)
+
+    @app.router.get("/redirect")
+    async def redirect_handler(url_resolver: URLResolver) -> Response:
+        return redirect(url_resolver.url_for("cat-detail", cat_id="42"))
+  ```
 
 ## [2.6.0] - 2026-02-15 :cupid:
 

blacksheep/__init__.py

@@ -66,6 +66,7 @@
 from .server.responses import unauthorized as unauthorized
 from .server.routing import Route as Route
 from .server.routing import RouteException as RouteException
+from .server.routing import RouteNotFound as RouteNotFound
 from .server.routing import Router as Router
 from .server.routing import RoutesRegistry as RoutesRegistry
 from .server.routing import connect as connect

blacksheep/server/application.py

@@ -751,6 +751,7 @@ async def start(self):
         if not self.router.fallback:
             self.router.fallback = default_fallback
 
+        self.register_default_di_types()
         self.router.apply_routes()
 
         if self.on_start:
@@ -773,6 +774,14 @@ async def stop(self):
         self.started = False
         self._started_complete.clear()
 
+    def register_default_di_types(self):
+        """
+        Registers default DI types in the Application DI controller.
+        By default, only the Application object is registered in the DI controller.
+        """
+        if Application not in self._services:
+            self._services.register(Application, instance=self)
+
     async def _handle_lifespan(self, receive, send) -> None:
         message = await receive()
         assert message["type"] == "lifespan.startup"
@@ -912,7 +921,9 @@ def handle_mount_path(self, scope, route_match):
         # Update root_path per the ASGI spec: the child app must know its mount
         # prefix so it can generate correct absolute URLs (analogous to WSGI
         # SCRIPT_NAME).  root_path = parent root_path + the stripped mount prefix.
-        mount_prefix = scope["path"][: -len(tail)] if tail != "/" else scope["path"].rstrip("/")
+        mount_prefix = (
+            scope["path"][: -len(tail)] if tail != "/" else scope["path"].rstrip("/")
+        )
         scope["root_path"] = scope.get("root_path", "") + mount_prefix
 
         scope["path"] = tail
@@ -952,8 +963,7 @@ async def _handle_redirect_to_mount_root(self, scope, send):
         )
         await send_asgi_response(response, send)
 
-    def _get_request_scope(self, scope):
-        ...
+    def _get_request_scope(self, scope): ...
 
     async def __call__(self, scope, receive, send):
         if scope["type"] == "lifespan":

blacksheep/server/bindings/__init__.py

@@ -8,7 +8,6 @@
     https://www.neoteroi.dev/blacksheep/binders/
 """
 
-import warnings
 from abc import abstractmethod
 from collections.abc import Iterable as IterableAbc
 from functools import partial
@@ -27,10 +26,11 @@
 from guardpost import Identity
 from rodi import CannotResolveTypeException, ContainerProtocol
 
-from blacksheep import Request
 from blacksheep.contents import FormPart
 from blacksheep.exceptions import BadRequest
+from blacksheep.messages import Request
 from blacksheep.server.bindings.converters import class_converters, converters
+from blacksheep.server.routing import Router, URLResolver
 from blacksheep.server.websocket import WebSocket
 from blacksheep.url import URL
 
@@ -870,3 +870,28 @@ class FilesBinder(Binder):
 
     async def get_value(self, request: Request) -> list[FormPart]:
         return await request.files()
+
+
+class URLResolverBinder(Binder):
+    """
+    Binder that injects a URLResolver into request handlers.
+    The URLResolver is constructed per-request from the singleton Router and the
+    current Request, so it correctly reflects the request's base_path for
+    generating URLs relative to the mount root.
+    """
+
+    type_alias = URLResolver
+
+    def __init__(self, router: Router, implicit: bool = True):
+        super().__init__(URLResolver, implicit=implicit)
+        self._router = router
+
+    @classmethod
+    def from_alias(cls, services: ContainerProtocol) -> "URLResolverBinder":
+        from blacksheep.server import Application
+
+        app: Application = services.resolve(Application)
+        return cls(app.router)
+
+    async def get_value(self, request: Request) -> URLResolver:
+        return URLResolver(self._router, request)

blacksheep/server/files/dynamic.py

@@ -252,7 +252,7 @@ def serve_files_dynamic(
     *,
     discovery: bool,
     cache_time: int,
-    extensions: Set[str | None],
+    extensions: Set[str] | None,
     root_path: str,
     index_document: str | None,
     fallback_document: str | None,