fixup!

Author: bjohansebas

src/utils.js

@@ -316,14 +316,23 @@ function getRequestURL(req) {
   // 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.
+  // case we use req.url instead.
   if (typeof req.originalUrl !== "undefined") {
-    const encodedUrl =
-      typeof req.url !== "undefined" ? encodeURI(req.url) : undefined;
+    // If req.url is just the decoded form of req.originalUrl (Fastify behavior),
+    // return the original encoded URL. Otherwise middleware modified req.url.
+    try {
+      if (
+        req.url === req.originalUrl ||
+        (typeof req.url !== "undefined" &&
+          decodeURI(req.originalUrl) === req.url)
+      ) {
+        return req.originalUrl;
+      }
+    } catch {
+      // decodeURI can throw on malformed sequences, fall through
+    }
 
-    return encodedUrl !== req.originalUrl && encodedUrl !== undefined
-      ? req.url
-      : req.originalUrl;
+    return req.url;
   }
 
   return req.url;

test/utils/getRequestURL.test.js

@@ -21,15 +21,24 @@ describe("getRequestURL", () => {
       expect(getRequestURL(req)).toBe("/path%20with%20spaces");
     });
 
-    it("should return encoded req.url when middleware (e.g. connect-history-api-fallback) modified it", () => {
+    it("should return req.originalUrl for URLs with reserved characters", () => {
+      // Fastify partially decodes: %20 → space, but %26 stays as %26
+      const req = {
+        url: "/test %26 test %26 %20.txt",
+        originalUrl: "/test%20%26%20test%20%26%20%2520.txt",
+      };
+      expect(getRequestURL(req)).toBe("/test%20%26%20test%20%26%20%2520.txt");
+    });
+
+    it("should return req.url when middleware (e.g. connect-history-api-fallback) modified it", () => {
       // Middleware changed req.url to a different path
       const req = { url: "/index.html", originalUrl: "/path%20with%20spaces" };
       expect(getRequestURL(req)).toBe("/index.html");
     });
 
-    it("should encode req.url when middleware sets a path with special chars", () => {
+    it("should return req.url when middleware sets a path with special chars", () => {
       const req = { url: "/new path", originalUrl: "/old%20path" };
-      expect(getRequestURL(req)).toBe("/new%20path");
+      expect(getRequestURL(req)).toBe("/new path");
     });
 
     it("should preserve query string from modified req.url", () => {
@@ -39,5 +48,22 @@ describe("getRequestURL", () => {
       };
       expect(getRequestURL(req)).toBe("/index.html?redirect=/other");
     });
+
+    it("should return req.originalUrl when req.url equals req.originalUrl (Express)", () => {
+      const req = {
+        url: "/path%20foo",
+        originalUrl: "/path%20foo",
+      };
+      expect(getRequestURL(req)).toBe("/path%20foo");
+    });
+
+    it("should handle malformed percent-encoding in originalUrl gracefully", () => {
+      // decodeURI would throw on malformed sequences
+      const req = {
+        url: "/foo",
+        originalUrl: "/%GG%bad",
+      };
+      expect(getRequestURL(req)).toBe("/foo");
+    });
   });
 });