fix(http): add zlib headers if missing (#5497)

lib/adapters/http.js

@@ -19,6 +19,7 @@ import stream from 'stream';
 import AxiosHeaders from '../core/AxiosHeaders.js';
 import AxiosTransformStream from '../helpers/AxiosTransformStream.js';
 import EventEmitter from 'events';
+import ZlibHeaderTransformStream from '../helpers/ZlibHeaderTransformStream.js';
 
 const zlibOptions = {
   flush: zlib.constants.Z_SYNC_FLUSH,
@@ -425,7 +426,15 @@ export default isHttpAdapterSupported && function httpAdapter(config) {
         case 'x-gzip':
         case 'compress':
         case 'x-compress':
+          // add the unzipper to the body stream processing pipeline
+          streams.push(zlib.createUnzip(zlibOptions));
+
+          // remove the content-encoding in order to not confuse downstream operations
+          delete res.headers['content-encoding'];
+          break;
         case 'deflate':
+          streams.push(new ZlibHeaderTransformStream());
+
           // add the unzipper to the body stream processing pipeline
           streams.push(zlib.createUnzip(zlibOptions));
 

lib/helpers/ZlibHeaderTransformStream.js

@@ -0,0 +1,28 @@
+"use strict";
+
+import stream from "stream";
+
+class ZlibHeaderTransformStream extends stream.Transform {
+  __transform(chunk, encoding, callback) {
+    this.push(chunk);
+    callback();
+  }
+
+  _transform(chunk, encoding, callback) {
+    if (chunk.length !== 0) {
+      this._transform = this.__transform;
+
+      // Add Default Compression headers if no zlib headers are present
+      if (chunk[0] !== 120) { // Hex: 78
+        const header = Buffer.alloc(2);
+        header[0] = 120; // Hex: 78
+        header[1] = 156; // Hex: 9C 
+        this.push(header, encoding);
+      }
+    }
+
+    this.__transform(chunk, encoding, callback);
+  }
+}
+
+export default ZlibHeaderTransformStream;

test/unit/adapters/http.js

@@ -35,6 +35,7 @@ const pipelineAsync = util.promisify(stream.pipeline);
 const finishedAsync = util.promisify(stream.finished);
 const gzip = util.promisify(zlib.gzip);
 const deflate = util.promisify(zlib.deflate);
+const deflateRaw = util.promisify(zlib.deflateRaw);
 const brotliCompress = util.promisify(zlib.brotliCompress);
 
 function toleranceRange(positive, negative) {
@@ -493,13 +494,16 @@ describe('supports http with nodejs', function () {
     describe('algorithms', ()=> {
       const responseBody ='str';
 
-      for (const [type, zipped] of Object.entries({
+      for (const [typeName, zipped] of Object.entries({
         gzip: gzip(responseBody),
         compress: gzip(responseBody),
         deflate: deflate(responseBody),
+        'deflate-raw': deflateRaw(responseBody),
         br: brotliCompress(responseBody)
       })) {
-        describe(`${type} decompression`, async () => {
+        const type = typeName.split('-')[0];
+
+        describe(`${typeName} decompression`, async () => {
           it(`should support decompression`, async () => {
             server = await startHTTPServer(async (req, res) => {
               res.setHeader('Content-Encoding', type);