var express = require('express');
var multer = require('multer');
var app = express();

var upload = multer({
  storage: multer.diskStorage({
    destination: function (req, file, cb){
      cb(null, './uploads/');
    },
    filename: function (req, file, cb){
      //file.originalname上传文件的原始文件名
      var changedName = (new Date().getTime())+'-'+file.originalname;
      cb(null, changedName);
    }
  })
});

//单个文件上传
app.post('/upload/single',upload.single('singleFile'),(req,res)=>{
  console.log(req.file);
  res.json({
    code: '0000',
    type:'single',
    originalname: req.file.originalname
  })
});

//多个文件上传
app.post('/upload/multer',upload.array('multerFile'),(req,res)=>{
  console.log(req.files);
  let fileList = [];
  req.files.map((elem)=>{
    fileList.push({
      originalname: elem.originalname
    })
  });
  res.json({
    code: '0000',
    type:'multer',
    fileList:fileList
  });
});

var upload = multer({
  //...其他代码
  fileFilter: function(req, file, cb){
    if(file.mimetype == 'image/png'){
      cb(null, true)
    } else {
      cb(null, false)
    }
  }
});

var upload = multer({
  //...其他代码
  limits:{
    //限制文件大小10kb
    fileSize: 10*1000,
    //限制文件数量
    files: 5
  }
});

//单个文件上传
let singleUpload = upload.single('singleFile');
app.post('/upload/single',(req,res)=>{
  singleUpload(req,res,(err)=>{
    if(!!err){
      console.log(err.message)
      res.json({
        code: '2000',
        type:'single',
        originalname: '',
        msg: err.message
      })
      return;
    }
    if(!!req.file){
      res.json({
        code: '0000',
        type:'single',
        originalname: req.file.originalname,
        msg: ''
      })
    } else {
      res.json({
        code: '1000',
        type:'single',
        originalname: '',
        msg: ''
      })
    }
  });
});

//多个文件上传
let multerUpload = upload.array('multerFile');
app.post('/upload/multer', (req,res)=>{
  multerUpload(req,res,(err)=>{
    if(!!err){
      res.json({
        code: '2000',
        type:'multer',
        fileList:[],
        msg: err.message
      });
    }
    let fileList = [];
    req.files.map((elem)=>{
      fileList.push({
        originalname: elem.originalname
      })
    });
    res.json({
      code: '0000',
      type:'multer',
      fileList:fileList,
      msg:''
    });
  });
});