koa文件上传中间件——koa-multer

koa-multer用法基本和multer一致，npm里koa-multer的用法介绍比较简单，可以参考multer的用法

 

使用

const Koa = require('koa');
const Router = require('koa-router');
const multer = require('koa-multer');
const path = require('path');

const server = new Koa();

let storage = multer.diskStorage({
    destination: path.resolve('upload'),
    filename: (ctx, file, cb)=>{
        cb(null, file.originalname);
    }
});
let fileFilter = (ctx, file ,cb)=>{
//过滤上传的后缀为txt的文件
    if (file.originalname.split('.').splice(-1) == 'txt'){
        cb(null, false); 
    }else {
        cb(null, true); 
    }
}
let upload = multer({ storage: storage, fileFilter: fileFilter });

let router = new Router();
router.post('/upload', upload.single('file'), async ctx => {
    if (ctx.req.file){
        ctx.body = 'upload success';
    } else {
        ctx.body = 'upload error';
    }
});
server.use(router.routes());

server.listen(8080, ()=>{
    console.log('usage: curl http://localhost:8080/upload -F "[email protected]"');
});

测试：

curl http://localhost:8080/upload -F "[email protected]"
>> upload success
curl http://localhost:8080/upload -F "[email protected]"
>> upload error

 

说明

文件信息

Key	Description Note
fieldname	Field name specified in the form
originalname	Name of the file on the user’s computer
encoding	Encoding type of the file
mimetype	Mime type of the file
size	Size of the file in bytes
destination	The folder to which the file has been saved DiskStorage
filename	The name of the file within the destination DiskStorage
path	The full path to the uploaded file DiskStorage
buffer	A Buffer of the entire file MemoryStorage

multer(opts)

opts参数

Key	Description
dest or storage	Where to store the files
fileFilter	Function to control which files are accepted
limits	Limits of the uploaded data
preservePath	Keep the full path of files instead of just the base name