Adds support base64 encoding in Netlify Functions

.changeset/hot-pumas-bathe.md

@@ -0,0 +1,5 @@
+---
+'@astrojs/netlify': patch
+---
+
+Adds support for base64 encoded responses in Netlify Functions

packages/integrations/netlify/src/netlify-functions.ts

@@ -12,6 +12,8 @@ interface Args {}
 export const createExports = (manifest: SSRManifest, args: Args) => {
 	const app = new App(manifest);
 
+	const base64Regex = /^([0-9a-zA-Z+/]{4})*(([0-9a-zA-Z+/]{2}==)|([0-9a-zA-Z+/]{3}=))?$/;
+
 	const handler: Handler = async (event) => {
 		const { httpMethod, headers, rawUrl, body: requestBody, isBase64Encoded } = event;
 		const init: RequestInit = {
@@ -35,12 +37,14 @@ export const createExports = (manifest: SSRManifest, args: Args) => {
 
 		const response: Response = await app.render(request);
 		const responseBody = await response.text();
+		const responseIsBase64 = base64Regex.test(responseBody);
 
 		const responseHeaders = Object.fromEntries(response.headers.entries());
 		const fnResponse: any = {
 			statusCode: response.status,
 			headers: responseHeaders,
 			body: responseBody,
+			isBase64Encoded: responseIsBase64,
 		};
 
 		// Special-case set-cookie which has to be set an different way :/

packages/integrations/netlify/test/functions/base64-response.test.js

@@ -0,0 +1,45 @@
+import { expect } from 'chai';
+import { load as cheerioLoad } from 'cheerio';
+import { loadFixture, testIntegration } from './test-utils.js';
+import netlifyAdapter from '../../dist/index.js';
+import { fileURLToPath } from 'url';
+
+describe('Base64 Responses', () => {
+	/** @type {import('../../../astro/test/test-utils').Fixture} */
+	let fixture;
+
+	before(async () => {
+		fixture = await loadFixture({
+			root: new URL('./fixtures/base64-response/', import.meta.url).toString(),
+			experimental: {
+				ssr: true,
+			},
+			adapter: netlifyAdapter({
+				dist: new URL('./fixtures/base64-response/dist/', import.meta.url),
+			}),
+			site: `http://example.com`,
+			integrations: [testIntegration()],
+		});
+		await fixture.build();
+	});
+
+	it('Can return base64 encoded strings', async () => {
+		const entryURL = new URL(
+			'./fixtures/base64-response/.netlify/functions-internal/entry.mjs',
+			import.meta.url
+		);
+		const { handler } = await import(entryURL);
+		const resp = await handler({
+			httpMethod: 'GET',
+			headers: {},
+			rawUrl: 'http://example.com/image',
+			body: '{}',
+			isBase64Encoded: false,
+		});
+		expect(resp.statusCode, 'successful response').to.equal(200);
+		expect(resp.isBase64Encoded, 'includes isBase64Encoded flag').to.be.true;
+
+		const buffer = Buffer.from(resp.body, 'base64');
+		expect(buffer.toString(), 'decoded base64 string matches').to.equal('base64 test string');
+	});
+});

packages/integrations/netlify/test/functions/fixtures/base64-response/src/pages/image.js

@@ -0,0 +1,8 @@
+
+export function get() {
+	const buffer = Buffer.from('base64 test string', 'utf-8')
+
+  return new Response(buffer.toString('base64'), {
+    status: 200
+  });
+}