fix isBase64encoded for external rewrites (#698)

* fix isBase64encoded for external rewrites

* changeset

* add e2e test

* review

.changeset/little-badgers-sparkle.md

@@ -0,0 +1,5 @@
+---
+"@opennextjs/aws": patch
+---
+
+Fix external rewrites for binary data

examples/pages-router/next.config.ts

@@ -38,6 +38,10 @@ const nextConfig: NextConfig = {
         },
       ],
     },
+    {
+      source: "/external-on-image",
+      destination: "https://opennext.js.org/share.png",
+    },
   ],
   redirects: async () => [
     {

packages/open-next/src/overrides/proxyExternalRequest/node.ts

@@ -47,19 +47,19 @@ const nodeProxy: ProxyExternalRequest = {
           rejectUnauthorized: false,
         },
         (_res) => {
+          const resHeaders = _res.headers;
           const nodeReadableStream =
-            _res.headers["content-encoding"] === "br"
+            resHeaders["content-encoding"] === "br"
               ? _res.pipe(require("node:zlib").createBrotliDecompress())
-              : _res.headers["content-encoding"] === "gzip"
+              : resHeaders["content-encoding"] === "gzip"
                 ? _res.pipe(require("node:zlib").createGunzip())
                 : _res;
-
           const isBase64Encoded =
-            isBinaryContentType(headers["content-type"]) ||
-            !!headers["content-encoding"];
+            isBinaryContentType(resHeaders["content-type"]) ||
+            !!resHeaders["content-encoding"];
           const result: InternalResult = {
             type: "core",
-            headers: filterHeadersForProxy(_res.headers),
+            headers: filterHeadersForProxy(resHeaders),
             statusCode: _res.statusCode ?? 200,
             // TODO: check base64 encoding
             isBase64Encoded,

packages/tests-e2e/tests/appRouter/og.test.ts

@@ -1,14 +1,10 @@
-import { createHash } from "node:crypto";
 import { expect, test } from "@playwright/test";
+import { validateMd5 } from "../utils";
 
 // This is the md5sums of the expected PNGs generated with `md5sum <file>`
 const OG_MD5 = "6e5e794ac0c27598a331690f96f05d00";
 const API_OG_MD5 = "cac95fc3e2d4d52870c0536bb18ba85b";
 
-function validateMd5(data: Buffer, expectedHash: string) {
-  return createHash("md5").update(data).digest("hex") === expectedHash;
-}
-
 test("Open-graph image to be in metatags and present", async ({
   page,
   request,

packages/tests-e2e/tests/pagesRouter/rewrite.test.ts

@@ -1,4 +1,7 @@
 import { expect, test } from "@playwright/test";
+import { validateMd5 } from "../utils";
+
+const EXT_PNG_MD5 = "405f45cc3397b09717a13ebd6f1e027b";
 
 test("Single Rewrite", async ({ page }) => {
   await page.goto("/rewrite");
@@ -13,3 +16,10 @@ test("Rewrite with query", async ({ page }) => {
   const el = page.getByText("SSR");
   await expect(el).toBeVisible();
 });
+
+test("Rewrite to external image", async ({ request }) => {
+  const response = await request.get("/external-on-image");
+  expect(response.status()).toBe(200);
+  expect(response.headers()["content-type"]).toBe("image/png");
+  expect(validateMd5(await response.body(), EXT_PNG_MD5)).toBe(true);
+});

packages/tests-e2e/tests/utils.ts

@@ -0,0 +1,5 @@
+import { createHash } from "node:crypto";
+
+export function validateMd5(data: Buffer, expectedHash: string) {
+  return createHash("md5").update(data).digest("hex") === expectedHash;
+}