nodejs --- 上传文件并保存到磁盘

Posted 2020-09-27 Jason齐齐

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先复习下整个请求的过程

const express = require(‘express‘);
const static = require(‘express-static‘);
const cookieParser = require(‘cookie-parser‘);
const cookieSession = require(‘cookie-session‘);
const bodyParser = require(‘body-parser‘);
const multer = require(‘multer‘);
const ejs = require(‘ejs‘);
const jade = require(‘jade‘);

const server = express();

server.listen(8999);

// 解析cookie
server.use(cookieParser(‘dfadfasdfa‘));

// 解析session
let arr = [];
for(let i = 0; i < 100000; i++) {
    arr.push(‘key_‘ + Math.random());
}

server.use(cookieSession({name: ‘jason_name‘, keys: arr, maxAge: 20*3600*1000}));

// post数据
server.use(bodyParser.urlencoded({extended: false}));
server.use(multer({dest: ‘./www/upload‘}).any());

// 用户请求
server.use(‘/‘, (req, res, next) => {
    console.log(req.query, req.body, req.files, req.cookie, req.session);
});

server.use(static(‘./www‘));

测试下能不能上传

const express = require(‘express‘);
const bodyParser = require(‘body-parser‘);
const multer = require(‘multer‘);
// fs 可以用来添加上传文件的扩展名(重命名)
const fs = require(‘fs‘);
const pathLib = require(‘path‘);

const server = express();


// 创建一个上传文件对象
// let objMulter = multer({dest: ‘./www/upload‘});

server.use(bodyParser.urlencoded({extended: false}));
// server.use(objMulter.any());

server.post(‘/‘, (req, res) => {
    console.log(‘req.body==>‘,req.body);
    // 当请求是 enctype=application/x-www-form-urlencoded 
    // req.body==> { f1: ‘mmexport1485905379121.jpg‘ }
    // 当请求是 multertype/form-type
    // req.body==> {}
    // console.log(‘req.files==>‘, req.files);
});

server.listen(8999);

上传的表单文件

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>文件上传</title>
</head>
<body>
    <form action="http://localhost:8999" method="post" enctype="application/x-www-form-urlencoded">
    <!-- <form action="http://localhost:8999" method="post" enctype="multipart/form-data"> -->
    <!-- <form action="http://localhost:8999" method="post" enctype="text/plain"> -->
        文件： <input type="file" name="f1"> <br/>
        <input type="submit" value="上传">
    </form>   
</body>
</html>

这是因为body-parser 只能处理application/x-www-form-urlencoded

文件上传需要使用 multer 模块用来处理 multipart/form-data

const express = require(‘express‘);
const bodyParser = require(‘body-parser‘);
const multer = require(‘multer‘);
// fs 可以用来添加上传文件的扩展名(重命名)
const fs = require(‘fs‘);
const pathLib = require(‘path‘);

const server = express();


// 创建一个上传文件对象
let objMulter = multer({dest: ‘./www/upload‘});

// server.use(bodyParser.urlencoded({extended: false}));
server.use(objMulter.any());

server.post(‘/‘, (req, res) => {
    // console.log(‘req.body==>‘,req.body);
    console.log(‘req.files==>‘, req.files);
     // req.files==> [ { fieldname: ‘f1‘,
     //    originalname: ‘IMG_20170125_212945.jpg‘,
     //    encoding: ‘7bit‘,
     //    mimetype: ‘image/jpeg‘,
     //    destination: ‘./www/upload‘,
     //    filename: ‘fa0b73da8bdbcb36e9480e9869c0a2b7‘,
     //    path: ‘www\\upload\\fa0b73da8bdbcb36e9480e9869c0a2b7‘,
     //    size: 226929 } ]
     
});

server.listen(8999);

这个时候你会发现文件上传了，但是文件名没有扩展名

fs中重名的函数rename

fs.rename(‘a.txt‘, ‘b.txt‘, (err) => {

console.log(err);

});

获取扩展名的插件 path 可以小小的测试下这个node中的path插件

const path = require(‘path‘);

let str = ‘c:\\wamp\\www\\a.html‘;

let obj = path.parse(str);

console.log(obj);

// {
//   root: ‘c:\\‘,
//   dir: ‘c:\\wamp\\www‘,
//   base: ‘a.html‘,
//   ext: ‘.html‘,
//   name: ‘a‘
// }

// base 文件名部分

// ext 扩展名部分

// dir 文件路径（目录）

// name 文件名（不包含扩展名）

然后讲path插件添加进文件

const express = require(‘express‘);
const bodyParser = require(‘body-parser‘);
const multer = require(‘multer‘);
// fs 可以用来添加上传文件的扩展名(重命名)
const fs = require(‘fs‘);
const pathLib = require(‘path‘);

const server = express();


// 创建一个上传文件对象
let objMulter = multer({dest: ‘./www/upload‘});

// server.use(bodyParser.urlencoded({extended: false}));
server.use(objMulter.any());

server.post(‘/‘, (req, res) => {
    // console.log(‘req.body==>‘,req.body);
    console.log(‘req.files==>‘, req.files);
     // req.files==> [ { fieldname: ‘f1‘,
     //    originalname: ‘IMG_20170125_212945.jpg‘,
     //    encoding: ‘7bit‘,
     //    mimetype: ‘image/jpeg‘,
     //    destination: ‘./www/upload‘,
     //    filename: ‘fa0b73da8bdbcb36e9480e9869c0a2b7‘,
     //    path: ‘www\\upload\\fa0b73da8bdbcb36e9480e9869c0a2b7‘,
     //    size: 226929 } ]
    //1.获取原始的扩展名  2.重命名临时文件
    let newName = req.files[0].path + pathLib.parse(req.files[0].originalname).ext
    fs.rename(req.files[0].path, newName, (err) => {
        if(err) {
            console.log(‘重命名失败‘);
        }else {
            console.log(‘命名成功‘);
        }
    });
});

//     req.files==> [ { fieldname: ‘f1‘,
//     originalname: ‘IMG_20170125_212945.jpg‘,
//     encoding: ‘7bit‘,
//     mimetype: ‘image/jpeg‘,
//     destination: ‘./www/upload‘,
//     filename: ‘bb031c31a1016648703a0d54cc93f674‘,
//     path: ‘www\\upload\\bb031c31a1016648703a0d54cc93f674‘,
//     size: 226929 } ]
// 命名成功

server.listen(8999);