fix: improve URL handling in getRequestURL function

Author: bjohansebas

src/utils.js

@@ -312,9 +312,18 @@ function getRequestURL(req) {
   if (typeof req.getURL === "function") {
     return req.getURL();
   }
-  // Fastify decodes URI by default, Our logic is based on encoded URI
-  else if (typeof req.originalUrl !== "undefined") {
-    return req.originalUrl;
+
+  // Fastify decodes URI by default, our logic is based on encoded URI.
+  // req.originalUrl preserves the original encoded URL; req.url may be
+  // modified by middleware (e.g. connect-history-api-fallback), in which
+  // case we re-encode it and use it instead.
+  if (typeof req.originalUrl !== "undefined") {
+    const encodedUrl =
+      typeof req.url !== "undefined" ? encodeURI(req.url) : undefined;
+
+    return encodedUrl !== req.originalUrl && encodedUrl !== undefined
+      ? encodedUrl
+      : req.originalUrl;
   }
 
   return req.url;