feat: redirect requests with repeated slashes

Author: theredandtheblue

packages/open-next/src/core/routing/matcher.ts

@@ -10,6 +10,7 @@ import type {
 } from "types/next-types";
 import type { InternalEvent, InternalResult } from "types/open-next";
 import { emptyReadableStream, toReadableStream } from "utils/stream";
+import { normalizePath } from "utils/normalize-path"
 
 import { debug } from "../../adapters/logger";
 import { handleLocaleRedirect, localizePath } from "./i18n";
@@ -262,6 +263,28 @@ export function handleRewrites<T extends RewriteDefinition>(
   };
 }
 
+function handleRepeatedSlashRedirect(
+  event: InternalEvent,
+): false | InternalResult {
+  // Redirect `https://example.com//foo` to `https://example.com/foo`.
+  const url = new URL(event.url);
+  if (url.pathname.match(/(\\|\/\/)/)) {
+    return {
+      type: event.type,
+      statusCode: 308,
+      headers: {
+        Location: `${url.protocol}//${url.host}${normalizePath(url.pathname)}${
+          url.search
+        }`,
+      },
+      body: emptyReadableStream(),
+      isBase64Encoded: false,
+    };
+  }
+
+  return false;
+}
+
 function handleTrailingSlashRedirect(
   event: InternalEvent,
 ): false | InternalResult {
@@ -326,6 +349,9 @@ export function handleRedirects(
   event: InternalEvent,
   redirects: RedirectDefinition[],
 ): InternalResult | undefined {
+  const repeatedSlashRedirect = handleRepeatedSlashRedirect(event);
+  if (repeatedSlashRedirect) return repeatedSlashRedirect;
+
   const trailingSlashRedirect = handleTrailingSlashRedirect(event);
   if (trailingSlashRedirect) return trailingSlashRedirect;
 

packages/open-next/src/utils/normalize-path.ts

@@ -1,7 +1,7 @@
 import path from "node:path";
 
 export function normalizePath(path: string) {
-  return path.replace(/\\/g, "/");
+  return path.replace(/\\/g, "/").replace(/\/\/+/g, "/");
 }
 
 export function getMonorepoRelativePath(relativePath = "../.."): string {

packages/tests-unit/tests/core/routing/matcher.test.ts

@@ -271,6 +271,17 @@ describe("getNextConfigHeaders", () => {
 });
 
 describe("handleRedirects", () => {
+  it("should redirect repeated slashes", () => {
+    const event = createEvent({
+      url: "https://on/api-route//foo",
+    });
+
+    const result = handleRedirects(event, []);
+
+    expect(result.statusCode).toEqual(308);
+    expect(result.headers.Location).toEqual("https://on/api-route/foo");
+  });
+
   it("should redirect trailing slash by default", () => {
     const event = createEvent({
       url: "https://on/api-route/",