Decode compressed JS HTTP/2 responses

Author: matthewlouisbrockman

packages/js-sdk/src/envd/http2.ts

@@ -183,7 +183,7 @@ class NodeHttp2Fetch {
           return
         }
 
-        const responseBody = new ReadableStream<Uint8Array>({
+        let responseBody = new ReadableStream<Uint8Array>({
           start(controller) {
             bodyController = controller
             stream.on('data', (chunk: Buffer) => {
@@ -208,6 +208,7 @@ class NodeHttp2Fetch {
             stream.close(cancelCode)
           },
         })
+        responseBody = decodeResponseBody(responseBody, responseHeaders)
 
         resolve(
           new Response(responseBody, { status, headers: responseHeaders })
@@ -271,6 +272,21 @@ class NodeHttp2Fetch {
   }
 }
 
+function decodeResponseBody(
+  body: ReadableStream<Uint8Array>,
+  headers: Headers
+) {
+  const encoding = headers.get('content-encoding')?.toLowerCase()
+  if (encoding !== 'gzip' && encoding !== 'deflate') {
+    return body
+  }
+
+  headers.delete('content-encoding')
+  headers.delete('content-length')
+
+  return body.pipeThrough(new DecompressionStream(encoding))
+}
+
 function isRedirect(status: number) {
   return (
     status === 301 ||

packages/js-sdk/tests/envd/http2.test.ts

@@ -1,5 +1,6 @@
 import http2 from 'node:http2'
 import { AddressInfo } from 'node:net'
+import { gzipSync } from 'node:zlib'
 import { afterEach, beforeEach, expect, test, vi } from 'vitest'
 
 import { createEnvdFetchForRuntime } from '../../src/envd/http2'
@@ -141,6 +142,18 @@ test('body cancel is safe', async () => {
   await expect(res.body!.cancel()).resolves.toBeUndefined()
 })
 
+test('decodes gzip responses', async () => {
+  const origin = await startServer((stream) => {
+    stream.respond({ ':status': 200, 'content-encoding': 'gzip' })
+    stream.end(gzipSync('compressed'))
+  })
+
+  const res = await createEnvdFetchForRuntime('node')(`${origin}/gzip`)
+
+  expect(res.headers.has('content-encoding')).toBe(false)
+  await expect(res.text()).resolves.toBe('compressed')
+})
+
 test('pauses streaming response bodies when the reader is behind', async () => {
   const calls = { pause: 0, resume: 0 }
   const connect = http2.connect