angular2+nodejs做出图片上传效果

 代码如下    
varexpress = require("express");
//网络请求模块
varrequest = require("request");
//引入nodejs文件系统模块
const fs = require('fs');
//引入body-parser
//包含在请求正文中提交的键/值对数据。
//默认情况下，它是未定义的，并在使用body-parser中间件时填充。
varbodyParser = require('body-parser');
varapp = express();
//解析 application/x-www-form-urlencoded，limit:ཐmb'用于设置请求的大小
//解决nodejs Error: request entity too large问题
app.use(bodyParser.urlencoded({ limit:ཐmb',extended:true}));
//设置跨域访问
app.all('*',function(req, res, next) {
  res.header("Access-Control-Allow-Origin","*");
  res.header("Access-Control-Allow-Headers","X-Requested-With");
  res.header("Access-Control-Allow-Methods","PUT,POST,GET,DELETE,OPTIONS");
  res.header("Content-Type","application/json;charset=utf-8");
  next();
});
//上传图片
app.post('/upload',function(req,res){
  varimgData = req.body.url;
  varbase64Data = imgData.replace(/^data:image\/\w+;base64,/,"");
  vardataBuffer =newBuffer(base64Data,'base64');
  fs.writeFile("image.png", dataBuffer,function(err) {
    if(err){
      res.send(err);
    }else{
      res.send("保存成功！");
    }
  });
})
 
varserver = app.listen(4444,function() {
  console.log('监听端口 4444');
});

//上传图片
 /*
 *   let data = {
 *    size: �',
 *    type: 'image/jpeg',
 *    name: 'test.jpg',
 *    url: base64
 *   };
 *获取图片的base64码可以通过FileReader获取
 */
 uploadImage(data) {
  returnnewPromise((resolve, reject) => {
   let headers =newHeaders({
    'Content-Type':'application/x-www-form-urlencoded'
   });
   let options =newRequestOptions({
    headers: headers
   });
   this.http.post("http://localhost:4444/upload",this.toQueryString(data),options)
    .map(res => res.json())
    .subscribe(data => { resolve(data), error => { reject(error) } })
  })
 }
// JSON参数序列化
  private toQueryString(obj) {
   let result = [];
   for(let keyinobj) {
    key = encodeURIComponent(key);
    let values = obj[key];
    if(values && values.constructor == Array) {
     let queryValues = [];
     for(let i = 0, len = values.length, value; i < len; i++) {
      value = values[i];
      queryValues.push(this.toQueryPair(key, value));
     }
     result = result.concat(queryValues);
    }else{
     result.push(this.toQueryPair(key, values));
    }
  }
   returnresult.join('&');
  }
  private toQueryPair(key, value) {
   if(typeofvalue =='undefined') {
    returnkey;
   }
   returnkey +'='+ encodeURIComponent(value ===null?'': String(value));
  }