如何使用node.js中的请求以多部分formData发送对象

我正在尝试制定一个POST using request https://github.com/request/request#forms，但每当我尝试添加时，我总是收到错误to反对formData.

var fs      = require('fs');
var request = require('request');
var file    = './test/assets/test.pdf';

var opts = {
  url: 'my_service',
  method: 'POST',
  auth: { user: 'username', password: 'password' },
  json: true,
  formData: {
    front: fs.createReadStream(file),
    to: {
      name: 'joe bob',
      address_1: '123 main st',
      ...
    }
  }
};

request(opts, function(err, resp, body) {
  console.log(err, body);
});

这是错误：

/sandbox/project/node_modules/request/node_modules/combined-stream/node_modules/delayed-stream/lib/delayed_stream.js:33
  source.on('error', function() {});
         ^
TypeError: undefined is not a function
    at Function.DelayedStream.create (/Users/me/sandbox/project/node_modules/request/node_modules/combined-stream/node_modules/delayed-stream/lib/delayed_stream.js:33:10)
    at FormData.CombinedStream.append (/Users/me/sandbox/project/node_modules/request/node_modules/combined-stream/lib/combined_stream.js:43:37)
    at FormData.append (/Users/me/sandbox/lproject/node_modules/request/node_modules/form-data/lib/form_data.js:43:3)
    at appendFormValue (/Users/me/sandbox/project/node_modules/request/request.js:466:21)
    at Request.init (/Users/me/sandbox/project/node_modules/request/request.js:477:11)
    at new Request (/Users/me/sandbox/project/node_modules/request/request.js:264:8)
    at request (/Users/me/sandbox/project/node_modules/request/index.js:50:10)
    at Object.<anonymous> (/Users/me/sandbox/project/test.js:30:1)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)

如果我删除to对象，一切正常。

这是为什么——我做错了什么？

The formData属性不处理objects作为值传入。看文档 https://github.com/request/request#multipartform-data-multipart-form-uploads。一个解决方案是使用JSON.stringify

var fs      = require('fs');
var request = require('request');
var file    = './test/assets/test.pdf';

var toObj = {
  name: 'joe bob',
  address_1: '123 main st',
  ...
};
var opts = {
  url: 'my_service',
  method: 'POST',
  auth: { user: 'username', password: 'password' },
  json: true,
  formData: {
    front: fs.createReadStream(file),
    to: JSON.stringify(toObj)
  }
};

request(opts, function(err, resp, body) {
  console.log(err, body);
});

注意：它实际上是 form-data 包仅支持字符串。请求使用表单数据。这是他们的使用文档 https://github.com/form-data/form-data#usage其中提到使用“字符串、缓冲区和文件流”。