fix(aws-lambda,netlify): base64 encode binary responses (#1274)

Co-authored-by: Pooya Parsa <pooya@pi0.io>

src/runtime/entries/aws-lambda.ts

@@ -10,6 +10,7 @@ import { withQuery } from "ufo";
 import { nitroApp } from "../app";
 import {
   normalizeLambdaIncomingHeaders,
+  normalizeLambdaOutgoingBody,
   normalizeLambdaOutgoingHeaders,
 } from "../utils.lambda";
 
@@ -64,13 +65,13 @@ export async function handler(
       cookies,
       statusCode: r.status,
       headers: normalizeLambdaOutgoingHeaders(r.headers, true),
-      body: r.body.toString(),
+      body: normalizeLambdaOutgoingBody(r.body, r.headers),
     };
   }
 
   return {
     statusCode: r.status,
     headers: normalizeLambdaOutgoingHeaders(r.headers),
-    body: r.body.toString(),
+    body: normalizeLambdaOutgoingBody(r.body, r.headers),
   };
 }

src/runtime/entries/netlify-lambda.ts

@@ -9,6 +9,7 @@ import { splitCookiesString } from "h3";
 import { nitroApp } from "../app";
 import {
   normalizeLambdaIncomingHeaders,
+  normalizeLambdaOutgoingBody,
   normalizeLambdaOutgoingHeaders,
 } from "../utils.lambda";
 import { normalizeCookieHeader } from "../utils";
@@ -40,7 +41,7 @@ export async function lambda(
   return {
     statusCode: r.status,
     headers: normalizeLambdaOutgoingHeaders(r.headers, true),
-    body: r.body.toString(),
+    body: normalizeLambdaOutgoingBody(r.body, r.headers),
     multiValueHeaders: {
       ...(cookies.length > 0 ? { "set-cookie": cookies } : {}),
     },

src/runtime/entries/stormkit.ts

@@ -1,6 +1,7 @@
 import type { Handler } from "aws-lambda";
 import "#internal/nitro/virtual/polyfill";
 import { nitroApp } from "../app";
+import { normalizeLambdaOutgoingBody } from "#internal/nitro/utils.lambda";
 
 interface StormkitEvent {
   url: string; // e.g. /my/path, /my/path?with=query
@@ -38,7 +39,7 @@ export const handler: Handler<StormkitEvent, StormkitResult> = async function (
   return {
     statusCode: r.status,
     headers: normalizeOutgoingHeaders(r.headers),
-    body: r.body.toString(),
+    body: normalizeLambdaOutgoingBody(r.body, r.headers),
   };
 };
 

src/runtime/utils.lambda.ts

@@ -24,3 +24,34 @@ export function normalizeLambdaOutgoingHeaders(
     entries.map(([k, v]) => [k, Array.isArray(v) ? v.join(",") : v])
   );
 }
+
+// AWS Lambda proxy integrations requires base64 encoded buffers
+// binaryMediaTypes should be */*
+// see https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-payload-encodings.html
+export function normalizeLambdaOutgoingBody(
+  body: BodyInit,
+  headers: HeadersObject
+): string {
+  if (typeof body === "string") {
+    return body;
+  }
+  if (!body) {
+    return "";
+  }
+  if (Buffer.isBuffer(body)) {
+    const contentType = (headers["content-type"] as string) || "";
+    if (isTextType(contentType)) {
+      return body.toString("utf8");
+    }
+    return body.toString("base64");
+  }
+  throw new Error(`Unsupported body type: ${typeof body}`);
+}
+
+// -- Internal --
+
+const TEXT_TYPE_RE = /^text\/|\/(json|xml)|utf-?8/;
+
+function isTextType(contentType = "") {
+  return TEXT_TYPE_RE.test(contentType);
+}

test/fixture/routes/icon.png.ts

@@ -1,12 +1,13 @@
-const LOGO_BASE64 =
-  "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";
-
-export default eventHandler((event) => {
-  const buff = base64ToArray(LOGO_BASE64);
-  event.res.end(buff);
+export default defineEventHandler((event) => {
+  setHeader(event, "Content-Type", "image/png");
+  return Buffer.from(_base64ToArray(_getLogoBase64()));
 });
 
-function base64ToArray(base64: string) {
+function _getLogoBase64() {
+  return "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";
+}
+
+function _base64ToArray(base64: string) {
   const str = atob(base64);
   const bytes = new Uint8Array(str.length);
   for (let i = 0; i < str.length; i++) {

test/tests.ts

@@ -185,6 +185,27 @@ export function testNitro(
     expect(obj.headers.location).toBe("https://nitro.unjs.io/");
   });
 
+  // aws lambda requires buffer responses to be base 64
+  const LambdaPresets = ["netlify", "aws-lambda"];
+  it.runIf(LambdaPresets.includes(ctx.preset))(
+    "buffer image responses",
+    async () => {
+      const { data } = await callHandler({ url: "/icon.png" });
+      expect(typeof data).toBe("string");
+      const buffer = Buffer.from(data, "base64");
+      // check if buffer is a png
+      function isBufferPng(buffer: Buffer) {
+        return (
+          buffer[0] === 0x89 &&
+          buffer[1] === 0x50 &&
+          buffer[2] === 0x4e &&
+          buffer[3] === 0x47
+        );
+      }
+      expect(isBufferPng(buffer)).toBe(true);
+    }
+  );
+
   it("render JSX", async () => {
     const { data } = await callHandler({ url: "/jsx" });
     expect(data).toMatch("<h1 >Hello JSX!</h1>");