Adding option to disable automatic decompression (#2661)

* Adding ability to disable auto decompression

* Updating decompress documentation in README

* Fixing test\unit\adapters\http.js lint errors

* Adding test for disabling auto decompression

* Removing changes that fixed lint errors in tests

* Removing formating change to unit test

Co-authored-by: Xianming Zhong <chinesedfan@qq.com>

README.md

@@ -410,7 +410,14 @@ These are the available config options for making requests. Only the `url` is re
   // `cancelToken` specifies a cancel token that can be used to cancel the request
   // (see Cancellation section below for details)
   cancelToken: new CancelToken(function (cancel) {
-  })
+  }),
+
+  // `decompress` indicates whether or not the response body should be decompressed 
+  // automatically. If set to `true` will also remove the 'content-encoding' header 
+  // from the responses objects of all decompressed responses
+  // - Node only (XHR cannot turn off decompression)
+  decompress: true // default
+
 }
 ```
 

index.d.ts

@@ -69,6 +69,7 @@ export interface AxiosRequestConfig {
   httpsAgent?: any;
   proxy?: AxiosProxyConfig | false;
   cancelToken?: CancelToken;
+  decompress?: boolean;
 }
 
 export interface AxiosResponse<T = any>  {

lib/adapters/http.js

@@ -181,20 +181,25 @@ module.exports = function httpAdapter(config) {
 
       // uncompress the response body transparently if required
       var stream = res;
+
       // return the last request in case of redirects
       var lastRequest = res.req || req;
 
-      switch (res.headers['content-encoding']) {
-      /*eslint default-case:0*/
-      case 'gzip':
-      case 'compress':
-      case 'deflate':
-        // add the unzipper to the body stream processing pipeline
-        stream = (res.statusCode === 204 || lastRequest.method === 'HEAD') ? stream : stream.pipe(zlib.createUnzip());
 
-        // remove the content-encoding in order to not confuse downstream operations
-        delete res.headers['content-encoding'];
-        break;
+      // if no content, is HEAD request or decompress disabled we should not decompress
+      if (res.statusCode !== 204 && lastRequest.method !== 'HEAD' && config.decompress !== false) {
+        switch (res.headers['content-encoding']) {
+        /*eslint default-case:0*/
+        case 'gzip':
+        case 'compress':
+        case 'deflate':
+        // add the unzipper to the body stream processing pipeline
+          stream = stream.pipe(zlib.createUnzip());
+
+          // remove the content-encoding in order to not confuse downstream operations
+          delete res.headers['content-encoding'];
+          break;
+        }
       }
 
       var response = {

test/unit/adapters/http.js

@@ -192,6 +192,27 @@ describe('supports http with nodejs', function () {
     });
   });
 
+  it('should support disabling automatic decompression of response data', function(done) {
+    var data = 'Test data';
+
+    zlib.gzip(data, function(err, zipped) {
+      server = http.createServer(function(req, res) {
+        res.setHeader('Content-Type', 'text/html;charset=utf-8');
+        res.setHeader('Content-Encoding', 'gzip');
+        res.end(zipped);
+      }).listen(4444, function() {
+        axios.get('http://localhost:4444/', {
+          decompress: false,
+          responseType: 'arraybuffer'
+
+        }).then(function(res) {
+          assert.equal(res.data.toString('base64'), zipped.toString('base64'));
+          done();
+        });
+      });
+    });
+  });
+
   it('should support UTF8', function (done) {
     var str = Array(100000).join('ж');
 
@@ -731,4 +752,3 @@ describe('supports http with nodejs', function () {
   });
 });
 
-