Index resources in the UrlDispatcher to avoid linear search for most cases

aiohttp/web_urldispatcher.py

@@ -979,8 +979,24 @@ def __init__(self) -> None:
         super().__init__()
         self._resources: List[AbstractResource] = []
         self._named_resources: Dict[str, AbstractResource] = {}
+        self._resource_index: dict[str, list[AbstractResource]] = {}
 
     async def resolve(self, request: Request) -> UrlMappingMatchInfo:
+        url_parts = request.rel_url.raw_parts
+        resource_index = self._resource_index
+
+        # Walk the url parts looking for candidates
+        for i in range(len(url_parts), 0, -1):
+            url_part = "/" + "/".join(url_parts[1:i])
+            if (resource_candidates := resource_index.get(url_part)) is not None:
+                for candidate in resource_candidates:
+                    if (
+                        match_dict := (await candidate.resolve(request))[0]
+                    ) is not None:
+                        return match_dict
+
+        # We didn't find any candidates, so will fallback to a linear search
+
         method = request.method
         allowed_methods: Set[str] = set()
 
@@ -1049,6 +1065,12 @@ def register_resource(self, resource: AbstractResource) -> None:
                 )
             self._named_resources[name] = resource
         self._resources.append(resource)
+        canonical = resource.canonical
+        if "{" in canonical:  # strip at the first { to allow for variables
+            canonical = canonical.partition("{")[0].rstrip("/")
+        # There may be multiple resources for a canonical path
+        # so we use a list to avoid falling back to a full linear search
+        self._resource_index.setdefault(canonical, []).append(resource)
 
     def add_resource(self, path: str, *, name: Optional[str] = None) -> Resource:
         if path and not path.startswith("/"):