Add convenience for annotated handlers (#2225)

sanic/router.py

@@ -1,5 +1,9 @@
+from __future__ import annotations
+
 from functools import lru_cache
+from inspect import signature
 from typing import Any, Dict, Iterable, List, Optional, Tuple, Union
+from uuid import UUID
 
 from sanic_routing import BaseRouter  # type: ignore
 from sanic_routing.exceptions import NoMethod  # type: ignore
@@ -106,6 +110,8 @@ class Router(BaseRouter):
             version = str(version).strip("/").lstrip("v")
             uri = "/".join([f"{version_prefix}{version}", uri.lstrip("/")])
 
+        uri = self._normalize(uri, handler)
+
         params = dict(
             path=uri,
             handler=handler,
@@ -187,3 +193,24 @@ class Router(BaseRouter):
                 raise SanicException(
                     f"Invalid route: {route}. Parameter names cannot use '__'."
                 )
+
+    def _normalize(self, uri: str, handler: RouteHandler) -> str:
+        if "<" not in uri:
+            return uri
+
+        sig = signature(handler)
+        mapping = {
+            param.name: param.annotation.__name__.lower()
+            for param in sig.parameters.values()
+            if param.annotation in (str, int, float, UUID)
+        }
+
+        reconstruction = []
+        for part in uri.split("/"):
+            if part.startswith("<") and ":" not in part:
+                name = part[1:-1]
+                annotation = mapping.get(name)
+                if annotation:
+                    part = f"<{name}:{annotation}>"
+            reconstruction.append(part)
+        return "/".join(reconstruction)

tests/test_handler_annotations.py

@@ -0,0 +1,39 @@
+from uuid import UUID
+
+import pytest
+
+from sanic import json
+
+
+@pytest.mark.parametrize(
+    "idx,path,expectation",
+    (
+        (0, "/abc", "str"),
+        (1, "/123", "int"),
+        (2, "/123.5", "float"),
+        (3, "/8af729fe-2b94-4a95-a168-c07068568429", "UUID"),
+    ),
+)
+def test_annotated_handlers(app, idx, path, expectation):
+    def build_response(num, foo):
+        return json({"num": num, "type": type(foo).__name__})
+
+    @app.get("/<foo>")
+    def handler0(_, foo: str):
+        return build_response(0, foo)
+
+    @app.get("/<foo>")
+    def handler1(_, foo: int):
+        return build_response(1, foo)
+
+    @app.get("/<foo>")
+    def handler2(_, foo: float):
+        return build_response(2, foo)
+
+    @app.get("/<foo>")
+    def handler3(_, foo: UUID):
+        return build_response(3, foo)
+
+    _, response = app.test_client.get(path)
+    assert response.json["num"] == idx
+    assert response.json["type"] == expectation