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;