Fix Host based routing to check path too

starlette/routing.py

@@ -489,9 +489,12 @@ def matches(self, scope: Scope) -> typing.Tuple[Match, Scope]:
         if scope["type"] in ("http", "websocket"):
             headers = Headers(scope=scope)
             host = headers.get("host", "").split(":")[0]
-            match = self.host_regex.match(host)
-            if match:
-                matched_params = match.groupdict()
+            host_match = self.host_regex.match(host)
+            path_match = self.routes == [] or any(
+                [route.matches(scope)[0] == Match.FULL for route in self.routes]
+            )
+            if host_match and path_match:
+                matched_params = host_match.groupdict()
                 for key, value in matched_params.items():
                     matched_params[key] = self.param_convertors[key].convert(value)
                 path_params = dict(scope.get("path_params", {}))

tests/test_routing.py

@@ -1159,3 +1159,36 @@ async def startup() -> None:
             ...  # pragma: nocover
 
         router.on_event("startup")(startup)
+
+
+def host_endpoint(request):
+    name = request.path_params["name"]
+    return JSONResponse({"name": name})
+
+
+host_based_router = Router(
+    routes=[
+        Host(
+            "example.org",
+            app=Router([Route("/foo/{name}", host_endpoint, name="foo")]),
+        ),
+        Host(
+            "example.org",
+            app=Router([Route("/bar/{name}", host_endpoint, name="bar")]),
+        ),
+    ],
+)
+
+
+def test_host_based_routing(test_client_factory):
+    client = test_client_factory(host_based_router, base_url="https://example.org/")
+
+    response = client.get("/foo/foo")
+    assert response.status_code == 200
+    assert response.json() == {"name": "foo"}
+
+    client = test_client_factory(host_based_router, base_url="https://example.org/")
+
+    response = client.get("/bar/bar")
+    assert response.status_code == 200
+    assert response.json() == {"name": "bar"}