Fix external rewrite (#299)

* fix rewrites not working

* fix middleware response next 14

Author: conico974

packages/open-next/src/adapters/plugins/routing/default.replacement.ts

@@ -59,15 +59,16 @@ export const processInternalEvent: ProcessInternalEvent = async (
     internalEvent = middleware;
   }
 
-  let isExternalRewrite = false;
-  // First rewrite to be applied
-  const beforeRewrites = handleRewrites(
-    internalEvent,
-    RoutesManifest.rewrites.beforeFiles,
-  );
-  internalEvent = beforeRewrites.internalEvent;
-  isExternalRewrite = beforeRewrites.isExternalRewrite;
-
+  let isExternalRewrite = middleware.externalRewrite ?? false;
+  if (!isExternalRewrite) {
+    // First rewrite to be applied
+    const beforeRewrites = handleRewrites(
+      internalEvent,
+      RoutesManifest.rewrites.beforeFiles,
+    );
+    internalEvent = beforeRewrites.internalEvent;
+    isExternalRewrite = beforeRewrites.isExternalRewrite;
+  }
   const isStaticRoute = RoutesManifest.routes.static.some((route) =>
     new RegExp(route.regex).test(event.rawPath),
   );

packages/open-next/src/adapters/plugins/routing/util.ts

@@ -1,5 +1,6 @@
 import { SendMessageCommand, SQSClient } from "@aws-sdk/client-sqs";
 import crypto from "crypto";
+import { ServerResponse } from "http";
 
 import { BuildId, HtmlPages } from "../../config/index.js";
 import { IncomingMessage } from "../../http/request.js";
@@ -36,14 +37,28 @@ export async function proxyRequest(
   });
 
   await new Promise<void>((resolve, reject) => {
-    proxy.on("proxyRes", () => {
-      resolve();
+    proxy.on("proxyRes", (proxyRes: ServerResponse) => {
+      const body: Uint8Array[] = [];
+      proxyRes.on("data", function (chunk) {
+        body.push(chunk);
+      });
+      proxyRes.on("end", function () {
+        const newBody = Buffer.concat(body).toString();
+        debug(`Proxying response`, {
+          headers: proxyRes.getHeaders(),
+          body: newBody,
+        });
+        res.end(newBody);
+        resolve();
+      });
     });
 
     proxy.on("error", (err: any) => {
       reject(err);
     });
 
+    debug(`Proxying`, { url: req.url, headers: req.headers });
+
     proxy.web(req, res, {
       target: req.url,
       headers: req.headers,

packages/open-next/src/adapters/routing/middleware.ts

@@ -7,13 +7,15 @@ import { ServerlessResponse } from "../http/response.js";
 import {
   convertRes,
   getMiddlewareMatch,
+  isExternal,
   loadMiddlewareManifest,
 } from "./util.js";
 
 const middlewareManifest = loadMiddlewareManifest(NEXT_DIR);
 
+//NOTE: we should try to avoid importing stuff from next as much as possible
+// every release of next could break this
 const { run } = require("next/dist/server/web/sandbox");
-const { pipeReadable } = require("next/dist/server/pipe-readable");
 const { getCloneableBody } = require("next/dist/server/body-streams");
 const {
   signalFromNodeResponse,
@@ -23,13 +25,18 @@ const middleMatch = getMiddlewareMatch(middlewareManifest);
 
 type MiddlewareOutputEvent = InternalEvent & {
   responseHeaders?: Record<string, string | string[]>;
+  externalRewrite?: boolean;
 };
 
 // NOTE: As of Nextjs 13.4.13+, the middleware is handled outside the next-server.
 // OpenNext will run the middleware in a sandbox and set the appropriate req headers
 // and res.body prior to processing the next-server.
 // @returns undefined | res.end()
 
+interface MiddlewareResult {
+  response: Response;
+}
+
 //    if res.end() is return, the parent needs to return and not process next server
 export async function handleMiddleware(
   internalEvent: InternalEvent,
@@ -65,7 +72,7 @@ export async function handleMiddleware(
   initialUrl.search = new URLSearchParams(urlQuery).toString();
   const url = initialUrl.toString();
 
-  const result = await run({
+  const result: MiddlewareResult = await run({
     distDir: NEXT_DIR,
     name: middlewareInfo.name || "/",
     paths: middlewareInfo.paths || [],
@@ -129,7 +136,7 @@ export async function handleMiddleware(
       statusCode: res.statusCode,
       headers: {
         ...resHeaders,
-        Location: location,
+        Location: location ?? "",
       },
       isBase64Encoded: false,
     };
@@ -139,22 +146,34 @@ export async function handleMiddleware(
   // NOTE: the header was added to `req` from above
   const rewriteUrl = responseHeaders.get("x-middleware-rewrite");
   let rewritten = false;
+  let externalRewrite = false;
   let middlewareQueryString = internalEvent.query;
   if (rewriteUrl) {
-    const rewriteUrlObject = new URL(rewriteUrl);
-    req.url = rewriteUrlObject.pathname;
-    //reset qs
-    middlewareQueryString = {};
-    rewriteUrlObject.searchParams.forEach((v: string, k: string) => {
-      middlewareQueryString[k] = v;
-    });
-    rewritten = true;
+    if (isExternal(rewriteUrl, req.headers.host)) {
+      req.url = rewriteUrl;
+      rewritten = true;
+      externalRewrite = true;
+    } else {
+      const rewriteUrlObject = new URL(rewriteUrl);
+      req.url = rewriteUrlObject.pathname;
+      //reset qs
+      middlewareQueryString = {};
+      rewriteUrlObject.searchParams.forEach((v: string, k: string) => {
+        middlewareQueryString[k] = v;
+      });
+      rewritten = true;
+    }
   }
 
   // If the middleware returned a `NextResponse`, pipe the body to res. This will return
   // the body immediately to the client.
   if (result.response.body) {
-    await pipeReadable(result.response.body, res);
+    // transfer response body to res
+    const arrayBuffer = await result.response.arrayBuffer();
+    const buffer = Buffer.from(arrayBuffer);
+    res.end(buffer);
+
+    // await pipeReadable(result.response.body, res);
     return {
       type: internalEvent.type,
       ...convertRes(res),
@@ -174,5 +193,6 @@ export async function handleMiddleware(
     query: middlewareQueryString,
     cookies: internalEvent.cookies,
     remoteAddress: internalEvent.remoteAddress,
+    externalRewrite,
   };
 }

packages/open-next/src/adapters/routing/util.ts

@@ -5,9 +5,12 @@ import { isBinaryContentType } from "../binary";
 import { ServerlessResponse } from "../http/response";
 import { MiddlewareManifest } from "../types/next-types";
 
-export function isExternal(url?: string) {
+export function isExternal(url?: string, host?: string) {
   if (!url) return false;
   const pattern = /^https?:\/\//;
+  if (host) {
+    return pattern.test(url) && !url.includes(host);
+  }
   return pattern.test(url);
 }