1、request 支持流模式，管道流pipe，抓取图片并保存就很方便了
request('https://s.gravatar.com/avatar/184a1f14c759795b94ae1d01b23cc9c7') .pipe(fs.createWriteStream('./doodle.jpg'))
2、浏览器中自带支持FormData数据类型，
var formData = new FormData()
node环境可以用依赖第三方“form-data”，创建 "multipart/form-data" streams，用来做 submit forms 和资源上传 upload file
var FormData = require('form-data'); var fs = require('fs'); var form = new FormData(); form.append('my_field', 'my value'); form.append('my_buffer', new Buffer(10)); form.append('my_file', fs.createReadStream('/foo/bar.jpg'));
3、uri与url都支持
request({ method: 'POST', url: uploadUrl,//uri url 都支持 formData })