Wechat.prototype.uploadMaterial = function(type,filepath){

  var that=this;

  var form={

    media: fs.createReadStream(filepath)

  }

  return new Promise(function(resolve,reject){//

    that.fetchAccesstionToken()

    .then(function(data){//102 行

  var url=api.upload+'access_token='+data.access_token+'&type='+type;//

    request({method:'POST',url:url,formData:form,json:true})

     .then(function(response){

      var data=response.body;

     if(data){

      resolve(data)

     }else{

      throw  new Error("Upload fails mertial")

     }

    })

     .catch(function(err){

      reject(err);

     })

    })

  })

}