fix: do not stringify form data (#475)

* fix: do not stringify form data

Co-authored-by: yoshi-automation <yoshi-automation@google.com>
Co-authored-by: Benjamin E. Coe <bencoe@google.com>

Author: 3 people

package.json

@@ -57,6 +57,7 @@
     "cors": "^2.8.5",
     "execa": "^5.0.0",
     "express": "^4.16.4",
+    "form-data": "^4.0.0",
     "gts": "^3.0.0",
     "is-docker": "^2.0.0",
     "karma": "^6.0.0",

src/gaxios.ts

@@ -236,6 +236,10 @@ export class Gaxios {
 
     opts.headers = opts.headers || {};
     if (opts.data) {
+      const isFormData =
+        typeof FormData === 'undefined'
+          ? false
+          : opts?.data instanceof FormData;
       if (isStream.readable(opts.data)) {
         opts.body = opts.data;
       } else if (hasBuffer() && Buffer.isBuffer(opts.data)) {
@@ -247,16 +251,19 @@ export class Gaxios {
       } else if (typeof opts.data === 'object') {
         // If www-form-urlencoded content type has been set, but data is
         // provided as an object, serialize the content using querystring:
-        if (
-          getHeader(opts, 'content-type') ===
-          'application/x-www-form-urlencoded'
-        ) {
-          opts.body = opts.paramsSerializer(opts.data);
-        } else {
-          if (!hasHeader(opts, 'Content-Type')) {
-            opts.headers['Content-Type'] = 'application/json';
+        if (!isFormData) {
+          if (
+            getHeader(opts, 'content-type') ===
+            'application/x-www-form-urlencoded'
+          ) {
+            opts.body = opts.paramsSerializer(opts.data);
+          } else {
+            // } else if (!(opts.data instanceof FormData)) {
+            if (!hasHeader(opts, 'Content-Type')) {
+              opts.headers['Content-Type'] = 'application/json';
+            }
+            opts.body = JSON.stringify(opts.data);
           }
-          opts.body = JSON.stringify(opts.data);
         }
       } else {
         opts.body = opts.data;

test/test.getch.ts

@@ -30,6 +30,7 @@ import {
 import qs from 'querystring';
 import fs from 'fs';
 import {Blob} from 'node-fetch';
+global.FormData = require('form-data');
 
 nock.disableNetConnect();
 
@@ -381,6 +382,22 @@ describe('🥁 configuration options', () => {
     assert.deepStrictEqual(res.config.data, body);
   });
 
+  it('should not stringify the data if it is appended by a form', async () => {
+    const formData = new FormData();
+    formData.append('test', '123');
+    // I don't think matching formdata is supported in nock, so skipping: https://github.com/nock/nock/issues/887
+    const scope = nock(url).post('/').reply(200);
+    const res = await request({
+      url,
+      method: 'POST',
+      data: formData,
+    });
+    scope.done();
+    assert.deepStrictEqual(res.config.data, formData);
+    assert.ok(res.config.data instanceof FormData);
+    assert.deepEqual(res.config.body, undefined);
+  });
+
   it('should allow explicitly setting the fetch implementation to node-fetch', async () => {
     const scope = nock(url).get('/').reply(200);
     const res = await request({url, fetchImplementation: fetch});