feat: add support for Fetch API Response and Web ReadableStream (#374)

Author: gurgunday

README.md

@@ -106,6 +106,40 @@ app.get('/', (req, reply) => {
 await app.listen({ port: 3000 })
 ```
 
+It's also possible to pass a Fetch API `Response` object or a Web `ReadableStream`. The plugin will automatically extract the body stream from the `Response` or convert the Web stream to a Node.js `Readable` behind the scenes.
+
+```js
+import fastify from 'fastify'
+
+const app = fastify()
+await app.register(import('@fastify/compress'), { global: true })
+
+app.get('/', async (req, reply) => {
+  const resp = new Response('Hello from Fetch Response')
+  reply.compress(resp)
+})
+```
+
+```js
+app.get('/', async (req, reply) => {
+  return new Response('Hello from Fetch Response')
+})
+```
+
+```js
+app.get('/', (req, reply) => {
+  const stream = new ReadableStream({
+    start (controller) {
+      controller.enqueue(new TextEncoder().encode('Hello from Web ReadableStream'))
+      controller.close()
+    }
+  })
+
+  reply.header('content-type', 'text/plain')
+  reply.compress(stream)
+})
+```
+
 ## Compress Options
 
 ### threshold
@@ -222,15 +256,24 @@ This plugin adds a `preParsing` hook to decompress the request payload based on
 
 Currently, the following encoding tokens are supported:
 
-1. `zstd` (Node.js 22.15+/23.8+)
-2. `br`
-3. `gzip`
-4. `deflate`
+- `zstd` (Node.js 22.15+/23.8+)
+- `br`
+- `gzip`
+- `deflate`
 
 If an unsupported encoding or invalid payload is received, the plugin throws an error.
 
 If the request header is missing, the plugin yields to the next hook.
 
+### Supported payload types
+
+The plugin supports compressing the following payload types:
+
+- Strings and Buffers
+- Node.js streams
+- Response objects (from the Fetch API)
+- ReadableStream objects (from the Web Streams API)
+
 ### Global hook
 
 The global request decompression hook is enabled by default. To disable it, pass `{ global: false }`:

index.js

@@ -12,7 +12,7 @@ const { Minipass } = require('minipass')
 const pumpify = require('pumpify')
 const { Readable } = require('readable-stream')
 
-const { isStream, isGzip, isDeflate, intoAsyncIterator } = require('./lib/utils')
+const { isStream, isGzip, isDeflate, intoAsyncIterator, isWebReadableStream, isFetchResponse, webStreamToNodeReadable } = require('./lib/utils')
 
 const InvalidRequestEncodingError = createError('FST_CP_ERR_INVALID_CONTENT_ENCODING', 'Unsupported Content-Encoding: %s', 415)
 const InvalidRequestCompressedPayloadError = createError('FST_CP_ERR_INVALID_CONTENT', 'Could not decompress the request payload using the provided encoding', 400)
@@ -254,6 +254,7 @@ function buildRouteCompress (_fastify, params, routeOptions, decorateOnly) {
     if (payload == null) {
       return next()
     }
+
     const responseEncoding = reply.getHeader('Content-Encoding')
     if (responseEncoding && responseEncoding !== 'identity') {
       // response is already compressed
@@ -290,10 +291,18 @@ function buildRouteCompress (_fastify, params, routeOptions, decorateOnly) {
     }
 
     if (typeof payload.pipe !== 'function') {
-      if (Buffer.byteLength(payload) < params.threshold) {
-        return next()
+      if (isFetchResponse(payload)) {
+        payload = payload.body
+      }
+
+      if (isWebReadableStream(payload)) {
+        payload = webStreamToNodeReadable(payload)
+      } else {
+        if (Buffer.byteLength(payload) < params.threshold) {
+          return next()
+        }
+        payload = Readable.from(intoAsyncIterator(payload))
       }
-      payload = Readable.from(intoAsyncIterator(payload))
     }
 
     setVaryHeader(reply)
@@ -408,7 +417,13 @@ function compress (params) {
     }
 
     if (typeof payload.pipe !== 'function') {
-      if (!Buffer.isBuffer(payload) && typeof payload !== 'string') {
+      if (isFetchResponse(payload)) {
+        payload = payload.body
+      }
+
+      if (isWebReadableStream(payload)) {
+        payload = webStreamToNodeReadable(payload)
+      } else if (!Buffer.isBuffer(payload) && typeof payload !== 'string') {
         payload = this.serialize(payload)
       }
     }

lib/utils.js

@@ -1,5 +1,7 @@
 'use strict'
 
+const { Readable: NodeReadable } = require('node:stream')
+
 // https://datatracker.ietf.org/doc/html/rfc8878#section-3.1.1
 function isZstd (buffer) {
   return (
@@ -49,6 +51,18 @@ function isStream (stream) {
   return stream !== null && typeof stream === 'object' && typeof stream.pipe === 'function'
 }
 
+function isWebReadableStream (obj) {
+  return obj instanceof ReadableStream
+}
+
+function isFetchResponse (obj) {
+  return obj instanceof Response
+}
+
+function webStreamToNodeReadable (webStream) {
+  return NodeReadable.fromWeb(webStream)
+}
+
 /**
  * Provide a async iteratable for Readable.from
  */
@@ -90,4 +104,4 @@ async function * intoAsyncIterator (payload) {
   yield payload
 }
 
-module.exports = { isZstd, isGzip, isDeflate, isStream, intoAsyncIterator }
+module.exports = { isZstd, isGzip, isDeflate, isStream, intoAsyncIterator, isWebReadableStream, isFetchResponse, webStreamToNodeReadable }

package.json

@@ -83,7 +83,7 @@
     "url": "git+https://github.com/fastify/fastify-compress.git"
   },
   "tsd": {
-    "directory": "test/types"
+    "directory": "types"
   },
   "publishConfig": {
     "access": "public"

test/global-compress.test.js

@@ -9,6 +9,7 @@ const JSONStream = require('jsonstream')
 const Fastify = require('fastify')
 const compressPlugin = require('../index')
 const { once } = require('node:events')
+const { ReadableStream: WebReadableStream, Response } = globalThis
 
 describe('When `global` is not set, it is `true` by default :', async () => {
   test('it should compress Buffer data using brotli when `Accept-Encoding` request header is `br`', async (t) => {
@@ -265,6 +266,54 @@ describe('When `global` is not set, it is `true` by default :', async () => {
     const payload = zlib.gunzipSync(response.rawPayload)
     t.assert.equal(payload.toString('utf-8'), 'hello')
   })
+
+  test('it should compress a Fetch API Response body', async (t) => {
+    t.plan(1)
+
+    const fastify = Fastify()
+    await fastify.register(compressPlugin, { threshold: 0 })
+
+    const body = 'hello from fetch response'
+    fastify.get('/fetch-resp', (_request, reply) => {
+      const resp = new Response(body, { headers: { 'content-type': 'text/plain' } })
+      reply.send(resp)
+    })
+
+    const response = await fastify.inject({
+      url: '/fetch-resp',
+      method: 'GET',
+      headers: { 'accept-encoding': 'gzip' }
+    })
+    const payload = zlib.gunzipSync(response.rawPayload)
+    t.assert.equal(payload.toString('utf-8'), body)
+  })
+
+  test('it should compress a Web ReadableStream body', async (t) => {
+    t.plan(1)
+
+    const fastify = Fastify()
+    await fastify.register(compressPlugin, { threshold: 0 })
+
+    const body = 'hello from web stream'
+    fastify.get('/web-stream', (_request, reply) => {
+      const stream = new WebReadableStream({
+        start (controller) {
+          controller.enqueue(Buffer.from(body))
+          controller.close()
+        }
+      })
+      reply.header('content-type', 'text/plain')
+      reply.send(stream)
+    })
+
+    const response = await fastify.inject({
+      url: '/web-stream',
+      method: 'GET',
+      headers: { 'accept-encoding': 'gzip' }
+    })
+    const payload = zlib.gunzipSync(response.rawPayload)
+    t.assert.equal(payload.toString('utf-8'), body)
+  })
 })
 
 describe('It should send compressed Stream data when `global` is `true` :', async () => {

test/routes-compress.test.js

@@ -440,3 +440,33 @@ test('It should avoid to trigger `onSend` hook twice', async (t) => {
   })
   t.assert.deepEqual(JSON.parse(zlib.brotliDecompressSync(response.rawPayload)), { hi: true })
 })
+
+test('reply.compress should handle Fetch Response', async (t) => {
+  t.plan(1)
+  const fastify = Fastify()
+  await fastify.register(compressPlugin, { global: true, threshold: 0 })
+  fastify.get('/', (_req, reply) => {
+    const r = new Response('from reply.compress', { headers: { 'content-type': 'text/plain' } })
+    reply.compress(r)
+  })
+  const res = await fastify.inject({ url: '/', method: 'GET', headers: { 'accept-encoding': 'gzip' } })
+  t.assert.equal(zlib.gunzipSync(res.rawPayload).toString('utf8'), 'from reply.compress')
+})
+
+test('reply.compress should handle Web ReadableStream', async (t) => {
+  t.plan(1)
+  const fastify = Fastify()
+  await fastify.register(compressPlugin, { global: true, threshold: 0 })
+  fastify.get('/', (_req, reply) => {
+    const stream = new ReadableStream({
+      start (controller) {
+        controller.enqueue(Buffer.from('from webstream'))
+        controller.close()
+      }
+    })
+    reply.header('content-type', 'text/plain')
+    reply.compress(stream)
+  })
+  const res = await fastify.inject({ url: '/', method: 'GET', headers: { 'accept-encoding': 'gzip' } })
+  t.assert.equal(zlib.gunzipSync(res.rawPayload).toString('utf8'), 'from webstream')
+})

types/index.d.ts

@@ -26,7 +26,7 @@ declare module 'fastify' {
   }
 
   interface FastifyReply {
-    compress(input: Stream | Input): void;
+    compress(input: Stream | Input | Response | ReadableStream): void;
   }
 
   export interface RouteOptions {

types/index.test-d.ts

@@ -132,3 +132,18 @@ expectError(appThatTriggerAnError.register(fastifyCompress, {
   global: true,
   thisOptionDoesNotExist: 'trigger a typescript error'
 }))
+
+app.get('/ts-fetch-response', async (_request, reply) => {
+  const resp = new Response('ok', { headers: { 'content-type': 'text/plain' } })
+  expectType<void>(reply.compress(resp))
+})
+
+app.get('/ts-web-readable-stream', async (_request, reply) => {
+  const stream = new ReadableStream({
+    start (controller) {
+      controller.enqueue(new Uint8Array([1, 2, 3]))
+      controller.close()
+    }
+  })
+  expectType<void>(reply.compress(stream))
+})