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用同步的方法处理web服务都会阻塞应用，要用连续的异步回调

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#1 Created at ... [Delete] [Delete and Lock User] 
var fs = require('fs'),
    url = require('url'),
    path = require('path'),
    http = require('http');
var root = path.resolve('.');

console.log('root dir: ' + root);

var server = http.createServer((req, rep) => {
    var pathname = url.parse(req.url).pathname;
    var filepath = path.join(root, pathname);
    console.log('filepath: ' + filepath);
    fs.stat(filepath, (err, stat) => {
        if (!err && stat.isFile()) {

            console.log('200 ' + req.url);
            rep.writeHead(200);
            fs.createReadStream(filepath).pipe(rep);

        } else if (!err && stat.isDirectory()) {

            fs.stat(path.join(filepath, 'index.html'), (err2, stat2) => {
                if (!err2) {
                    console.log('200 ' + req.url);
                    rep.writeHead(200);
                    fs.createReadStream(path.join(filepath, 'index.html')).pipe(rep);
                } else {
                    fs.stat(path.join(filepath, 'default.html'), (err3, stat2) => {
                        if (!err3) {
                            console.log('200 ' + req.url);
                            rep.writeHead(200);
                            fs.createReadStream(path.join(filepath, 'default.html')).pipe(rep);
                        } else {
                            console.log('404 ' + req.url);
                            rep.writeHead(404);
                            rep.end('404 Not Found');
                        }
                    });
                }
            });
            
        } else {
            console.log('404 ' + req.url);
            rep.writeHead(404);
            rep.end('404 Not Found');
        }
    })
})

server.listen(8888);

起伏

#2 Created at ... [Delete] [Delete and Lock User]

递归版本异步回调，支持配置白名单列表

var fs = require('fs'),
    url = require('url'),
    path = require('path'),
    http = require('http');
var root = path.resolve('.');

var default_index = ['index.html', 'default.html'];
console.log('root dir: ' + root);

// 递归回调函数
function checkFileEx(t_list,filepath,req,rep) {
    // 不在白名单返回404
    if (!t_list) {
        console.log('404 ' + req.url);
        rep.writeHead(404);
        rep.end('404 Not Found');
    }
    var f_name = t_list.pop()
    fs.stat(path.join(filepath, f_name), (err2, stat2) => {
        if (!err2) {
            console.log('200 ' + req.url);
            rep.writeHead(200);
            fs.createReadStream(path.join(filepath, f_name)).pipe(rep);
        } else { 
            // 开始递归
            checkFileEx(t_list,filepath,req,rep)
        }
    });
}
var server = http.createServer((req, rep) => {
    var pathname = url.parse(req.url).pathname;
    var filepath = path.join(root, pathname);
    console.log('filepath: ' + filepath);
    fs.stat(filepath, (err, stat) => {
        if (!err && stat.isFile()) {

            console.log('200 ' + req.url);
            rep.writeHead(200);
            fs.createReadStream(filepath).pipe(rep);

        } else if (!err && stat.isDirectory()) {
            // 复制白名单
            var bi_bk = default_index.slice();
            // 递归回调
            checkFileEx(bi_bk,filepath,req,rep);

        } else {
            console.log('404 ' + req.url);
            rep.writeHead(404);
            rep.end('404 Not Found');
        }
    })
})

server.listen(8888);
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