More thorough URL checks

app/utils/url.py

@@ -24,7 +24,7 @@ class InvalidURLError(Exception):
     pass
 
 
-@functools.lru_cache
+@functools.lru_cache(maxsize=256)
 def _getaddrinfo(hostname: str, port: int) -> str:
     try:
         ip_address = str(ipaddress.ip_address(hostname))
@@ -65,7 +65,7 @@ def is_url_valid(url: str) -> bool:
     return True
 
 
-def check_url(url: str, debug: bool = False) -> None:
+def check_url(url: str) -> None:
     logger.debug(f"check_url {url=}")
     if not is_url_valid(url):
         raise InvalidURLError(f'"{url}" is invalid')

app/utils/webmentions.py

@@ -8,6 +8,7 @@ from loguru import logger
 
 from app import config
 from app.utils.datetime import now
+from app.utils.url import check_url
 from app.utils.url import is_url_valid
 from app.utils.url import make_abs
 
@@ -46,6 +47,8 @@ async def discover_webmention_endpoint(url: str) -> str | None:
     Passes all the tests at https://webmention.rocks!
 
     """
+    check_url(url)
+
     wurl = await _discover_webmention_endoint(url)
     if wurl is None:
         return None