fix: support deflate raw responses

Author: Uzlopak

lib/fetch/index.js

@@ -57,7 +57,7 @@ const {
 } = require('./constants')
 const { kHeadersList, kConstruct } = require('../core/symbols')
 const EE = require('events')
-const { Readable, pipeline } = require('stream')
+const { Readable, pipeline, Transform } = require('stream')
 const { addAbortListener, isErrored, isReadable, nodeMajor, nodeMinor, bufferToLowerCasedHeaderName } = require('../core/util')
 const { dataURLProcessor, serializeAMimeType, parseMIMEType } = require('./dataURL')
 const { getGlobalDispatcher } = require('../global')
@@ -1096,7 +1096,7 @@ function fetchFinale (fetchParams, response) {
     // 3. Set up transformStream with transformAlgorithm set to identityTransformAlgorithm and flushAlgorithm
     //    set to processResponseEndOfBody.
     const transformStream = new TransformStream({
-      start () {},
+      start () { },
       transform (chunk, controller) {
         controller.enqueue(chunk)
       },
@@ -2186,7 +2186,35 @@ async function httpNetworkFetch (
                   finishFlush: zlib.constants.Z_SYNC_FLUSH
                 }))
               } else if (coding === 'deflate') {
-                decoders.push(zlib.createInflate())
+                // Instantiate a Stream, which pipes the response to zlib.createInflate()
+                // or zlib.createInflateRaw() depending on the first byte of the Buffer.
+                // If the lower byte of the first byte is 0x08, then the stream is
+                // interpreted as a zlib stream, otherwise it's interpreted as a
+                // raw deflate stream.
+                const deflateDecoder = new Transform({
+                  transform (chunk, encoding, callback) {
+                    if (!this._inflateStream) {
+                      this._inflateStream = (chunk[0] & 0x0F) === 0x08
+                        ? zlib.createInflate()
+                        : zlib.createInflateRaw()
+
+                      this._inflateStream.on('data', this.push.bind(this))
+                      this._inflateStream.on('end', callback)
+                      this._inflateStream.on('error', callback)
+                    }
+
+                    this._inflateStream.write(chunk, encoding, callback)
+                  },
+                  final (callback) {
+                    if (this._inflateStream) {
+                      this._inflateStream.end()
+                      this._inflateStream = null
+                    }
+                    callback()
+                  }
+                })
+
+                decoders.push(deflateDecoder)
               } else if (coding === 'br') {
                 decoders.push(zlib.createBrotliDecompress())
               } else {
@@ -2202,7 +2230,7 @@ async function httpNetworkFetch (
             headersList,
             body: decoders.length
               ? pipeline(this.body, ...decoders, () => { })
-              : this.body.on('error', () => {})
+              : this.body.on('error', () => { })
           })
 
           return true

test/node-fetch/main.js

@@ -659,7 +659,7 @@ describe('node-fetch', () => {
     })
   })
 
-  xit('should decompress deflate raw response from old apache server', () => {
+  it('should decompress deflate raw response from old apache server', () => {
     const url = `${base}deflate-raw`
     return fetch(url).then(res => {
       expect(res.headers.get('content-type')).to.equal('text/plain')