Support URLRouter with include

channels/routing.py

@@ -1,9 +1,10 @@
 import importlib
+import re
 
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 from django.urls.exceptions import Resolver404
-from django.urls.resolvers import RegexPattern, RoutePattern, URLResolver
+from django.urls.resolvers import RegexPattern, RoutePattern, URLResolver, URLPattern
 
 """
 All Routing instances inside this file are also valid ASGI applications - with
@@ -67,7 +68,32 @@ class URLRouter:
     _path_routing = True
 
     def __init__(self, routes):
-        self.routes = routes
+        new_routes = []
+        for route in routes:
+            if not route.callback and isinstance(route, URLResolver):
+                for url_pattern in route.url_patterns:
+                    url_pattern: URLPattern
+                    # concatenate parent's url and child's url
+                    regex = "".join(
+                        x.pattern
+                        for x in [route.pattern.regex, url_pattern.pattern.regex]
+                    )
+                    regex = re.sub(r"(/)\1+", r"\1", regex)
+                    name = (
+                        f"{route.app_name}:{url_pattern.name}"
+                        if url_pattern.name
+                        else None
+                    )
+                    pattern = RegexPattern(regex, name=name, is_endpoint=True)
+                    new_routes.append(
+                        URLPattern(
+                            pattern, url_pattern.callback, route.default_kwargs, name
+                        )
+                    )
+            else:
+                new_routes.append(route)
+
+        self.routes = new_routes
 
         for route in self.routes:
             # The inner ASGI app wants to do additional routing, route

tests/test_routing.py

@@ -1,5 +1,4 @@
 import pytest
-from django.core.exceptions import ImproperlyConfigured
 from django.urls import path, re_path
 
 from channels.routing import ChannelNameRouter, ProtocolTypeRouter, URLRouter
@@ -302,13 +301,66 @@ async def test_path_remaining():
         )
 
 
-def test_invalid_routes():
+@pytest.mark.asyncio
+async def test_url_router_nesting_by_include():
     """
-    Test URLRouter route validation
+    Tests that nested URLRouters is constructed by include function.
     """
+    import sys
     from django.urls import include
 
-    with pytest.raises(ImproperlyConfigured) as exc:
-        URLRouter([path("", include([]))])
+    test_app = MockApplication(return_value=1)
 
-    assert "include() is not supported in URLRouter." in str(exc)
+    # mocking the universe module following the directory structure;
+    # ├── universe
+    # │   └── routings.py
+    # └── routings.py (parent)
+    #
+    #
+    # in routings.py
+    # ======================
+    # ...
+    # urlpatterns = [
+    #     re_path(r"book/(?P<book>[\w\-]+)/page/(?P<page>\d+)/$", test_app),
+    #     re_path(r"test/(\d+)/$", test_app),
+    # ]
+    # ======================
+    module_routings = type(sys)("routings")
+    module_routings.urlpatterns = [
+        re_path(r"book/(?P<book>[\w\-]+)/page/(?P<page>\d+)/$", test_app),
+        re_path(r"test/(\d+)/$", test_app),
+    ]
+    module = type(sys)("universe")
+    module.routings = module_routings
+    sys.modules["universe"] = module
+    sys.modules["universe.routings"] = module.routings
+
+    # parent routings.py
+    outer_router = URLRouter(
+        [
+            path("universe/", include("universe.routings"), name="universe"),
+        ]
+    )
+    assert (
+        await outer_router(
+            {
+                "type": "http",
+                "path": "/universe/book/channels-guide/page/10/",
+            },
+            None,
+            None,
+        )
+        == 1
+    )
+
+    assert (
+        await outer_router(
+            {
+                "type": "http",
+                "path": "/universe/test/10/",
+            },
+            None,
+            None,
+        )
+        == 1
+    )