Node.js formidable 上传文件的实现-优快云博客

本教程介绍如何使用Node.js实现文件上传与处理，包括安装Node.js、配置防火墙、使用第三方库formidable简化文件处理过程，并通过示例展示如何在服务器端接收、保存并展示上传的文件。

本案例来自Node.js入门书籍：

http://www.nodebeginner.org/index-zh-cn.html

示例中只能上传并展示png图片，当然其他文件都是可行的，自己微调一下即可。

安装node.js：

# curl -sL https://rpm.nodesource.com/setup | bash -

# yum install -y nodejs

防火墙打开8888端口；

Node.js自身处理上传文件会非常繁琐，可使用第三方的node-formidable来轻松处理：

npm install formidable

以下是代码：

Server端：

#server.js
var http = require("http");
var url = require("url");

var order = 1; //请求次数

function start(route, handle) {
    function onRequest(request, response) {
        var postData = "";
        var pathname = url.parse(request.url).pathname; //请求位置
        console.log("Request for " + pathname + " received.");

        route(handle, pathname, response, request); //路由此次请求

        console.log("Reauest received ~ +" + order); //请求次数
        order++;
    }

    http.createServer(onRequest).listen(8888); //监听8888端口

    console.log("Server has started");

}

exports.start = start;

路由：

#router.js

function route(handle, pathname, response, request) {
    console.log("About to route a request for " + pathname);

    if (typeof(handle[pathname]) === 'function') {
        handle[pathname](response, request); //执行请求处理方法
    } else {
        console.log("No request handler found for " + pathname);
        response.writeHead(404, {
            "Content-Type": "text/plain"
        });
        response.write("404 Not found");
        response.end();
    }
}

exports.route = route;

Handler：

#requestHandlers.js
var querystring = require("querystring");
var formidable = require("formidable");
var fs = require("fs");


function start(response) {
    console.log("Request handler 'start' was called.");

    var body = '<html>' +
        '<head>' +
        '<meta http-equiv="Content-Type" content="text/html; ' +
        'charset=UTF-8" />' +
        '</head>' +
        '<body>' +
        '<form action="/upload" enctype="multipart/form-data" ' +
        'method="post">' +
        '<input type="file" name="upload">' +
        '<input type="submit" value="Upload file" />' +
        '</form>' +
        '</body>' +
        '</html>';

    response.writeHead(200, {
        "Content-Type": "text/html"
    });
    response.write(body);
    response.end();
}

function upload(response, request) {
    console.log("Request handler 'upload' was called.");

    var form = new formidable.IncomingForm();
    console.log("about to parse");
    form.parse(request, function(error, fields, files) {
        console.log("parsing done");
        fs.renameSync(files.upload.path, "/tmp/test.png"); //更名
        response.writeHead(200, {
            "Content-Type": "text/html"
        });
        response.write("received image:<br/>");
        response.write("<img src='/show' />"); //调用show方法展示图片
        response.end();
    });
}

function show(response) {
    var imagePath = "/tmp/test.png";
    console.log("Request handler 'show' was called.");
    fs.readFile(imagePath, "binary", function(error, file) {
        if (error) {
            response.writeHead(500, {
                "Content-Type": "text/plain"
            });
            response.write(error + "\n");
            response.end();
        } else {
            response.writeHead(200, {
                "Content-Type": "image/png"
            });
            response.write(file, "binary");
            response.end();
        }
    });
}

exports.start = start;
exports.upload = upload;
exports.show = show;

入口文件：

#index.js

var server = require("./server"); //服务端
var router = require("./router"); //路由

var requestHandlers = require("./requestHandlers"); //请求处理器

var handle = {};

handle["/"] = handle["/start"] = requestHandlers.start;
handle["/upload"] = requestHandlers.upload;
handle["/show"] = requestHandlers.show;

server.start(router.route, handle); //初始函数 - 参数为路由方法及相应的处理方法