fix: strip locale from path passed to middleware (#194)

Author: ascorbic

edge-runtime/lib/next-request.ts

@@ -1,6 +1,6 @@
 import type { Context } from '@netlify/edge-functions'
 
-import { normalizeDataUrl, removeBasePath } from './util.ts'
+import { normalizeDataUrl, removeBasePath, removeLocaleFromPath } from './util.ts'
 
 interface I18NConfig {
   defaultLocale: string
@@ -37,6 +37,7 @@ const normalizeRequestURL = (originalURL: string, nextConfig?: RequestData['next
   const url = new URL(originalURL)
 
   url.pathname = removeBasePath(url.pathname, nextConfig?.basePath)
+  url.pathname = removeLocaleFromPath(url.pathname, nextConfig)
 
   // We want to run middleware for data requests and expose the URL of the
   // corresponding pages, so we have to normalize the URLs before running

edge-runtime/lib/util.ts

@@ -1,5 +1,9 @@
-// If the URL path matches a data URL, we need to normalize it.
-// https://github.com/vercel/next.js/blob/25e0988e7c9033cb1503cbe0c62ba5de2e97849c/packages/next/src/shared/lib/router/utils/get-next-pathname-info.ts#L69-L76
+import type { RequestData } from './next-request.ts'
+
+/**
+ * Normalize a data URL into a route path.
+ * @see https://github.com/vercel/next.js/blob/25e0988e7c9033cb1503cbe0c62ba5de2e97849c/packages/next/src/shared/lib/router/utils/get-next-pathname-info.ts#L69-L76
+ */
 export function normalizeDataUrl(urlPath: string) {
   if (urlPath.startsWith('/_next/data/') && urlPath.includes('.json')) {
     const paths = urlPath
@@ -20,6 +24,18 @@ export const removeBasePath = (path: string, basePath?: string) => {
   return path
 }
 
+export const removeLocaleFromPath = (path: string, nextConfig: RequestData['nextConfig']) => {
+  if (nextConfig?.i18n) {
+    for (const locale of nextConfig.i18n.locales) {
+      const regexp = new RegExp(`^/${locale}($|/)`, 'i')
+      if (path.match(regexp)) {
+        return path.replace(regexp, '/') || '/'
+      }
+    }
+  }
+  return path
+}
+
 /**
  * This is how Next handles rewritten URLs.
  */