如何使用 node.js 中的请求以多部分形式数据发送对象

Question

我正在尝试使用 request 来构建 POST，但每当我尝试将 to 对象添加到 formData 时，我总是遇到错误。

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);
});

这里是错误：

/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？

Answer 1

我在使用请求模块时遇到了类似的问题，在我向 'formData' 添加新行之前一切正常。唯一对我有用的是创建一个字符串 JSON ，它将构成请求之外的 POST 主体，并使用 'body' 而不是 'formData'.

var postBody = "post body content";

request({
  method: "POST",
  uri: "my_service",
  auth: { user: 'username', password: 'password' },
  body: '{' + postBody + '}',
  ...
}).on("error", function(error){
  ...
};

Answer 2

formData 属性不处理作为值传入的对象。参见 the documentation。一种解决方案是使用 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：实际上是只支持字符串的form-data包。请求使用表单数据。这是他们的 usage doc，其中提到使用 "a string, a buffer and a file stream."

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