Use compiled regexes

Author: lukasbindreiter

stac_fastapi/api/stac_fastapi/api/middleware.py

@@ -1,5 +1,6 @@
 """Api middleware."""
 
+import contextlib
 import re
 import typing
 from http.client import HTTP_PORT, HTTPS_PORT
@@ -44,6 +45,10 @@ def __init__(
         )
 
 
+_PROTO_HEADER_REGEX = re.compile(r"proto=(?P<proto>http(s)?)")
+_HOST_HEADER_REGEX = re.compile(r"host=(?P<host>[\w.-]+)(:(?P<port>\d{1,5}))?")
+
+
 class ProxyHeaderMiddleware:
     """Account for forwarding headers when deriving base URL.
 
@@ -92,25 +97,20 @@ def _get_forwarded_url_parts(self, scope: Scope) -> Tuple[str]:
 
         if forwarded := self._get_header_value_by_name(scope, "forwarded"):
             for proxy in forwarded.split(","):
-                if (proto_expr := re.search(r"proto=(?P<proto>http(s)?)", proxy)) and (
-                    host_expr := re.search(
-                        r"host=(?P<host>[\w.-]+)(:(?P<port>\d{1,5}))?", proxy
-                    )
+                if (proto_expr := _PROTO_HEADER_REGEX.search(proxy)) and (
+                    host_expr := _HOST_HEADER_REGEX.search(proxy)
                 ):
-                    proto = proto_expr.groupdict()["proto"]
-                    domain = host_expr.groupdict()["host"]
-                    port_str = host_expr.groupdict().get("port", None)
+                    proto = proto_expr.group("proto")
+                    domain = host_expr.group("host")
+                    port_str = host_expr.group("port")  # None if not present in the match
 
         else:
             domain = self._get_header_value_by_name(scope, "x-forwarded-host", domain)
             proto = self._get_header_value_by_name(scope, "x-forwarded-proto", proto)
             port_str = self._get_header_value_by_name(scope, "x-forwarded-port", port)
 
-        try:
+        with contextlib.suppress(ValueError):  # ignore ports that are not valid integers
             port = int(port_str) if port_str is not None else port
-        except ValueError:
-            # ignore ports that are not valid integers
-            pass
 
         return (proto, domain, port)