var

    fs = require('fs'),

    url = require('url'),

    path = require('path'),

    http = require('http');

// 从命令行参数获取root目录，默认是当前目录:

var root = path.resolve(process.argv[2] || '.');

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

// 创建服务器:

var server = http.createServer(function (request, response) {

    // 获得URL的path，类似 '/css/bootstrap.css':

    var pathname = url.parse(request.url).pathname;

    // 获得对应的本地文件路径，类似 '/srv/www/css/bootstrap.css':

    var filepath = path.join(root, pathname);

    var defaultPage = ['/default.html','/index.html'];

    var filePathWithDefault = false;

    // 获取文件状态:

    fs.stat(filepath, function (err, stats) {

        if (!err && stats.isFile()) {

            // 没有出错并且文件存在:

            console.log('200 ' + request.url);

            // 发送200响应:

            response.writeHead(200);

            // 将文件流导向response:

            fs.createReadStream(filepath).pipe(response);

        }

        else if (!err && stats.isDirectory()) {

            for(let i=0; i<defaultPage.length; i++) {

                var filePathto = path.join(root, defaultPage[i]);

                try {

                    fs.statSync(filePathto);

                    console.log('200 ' + request.url);

                    // 发送200响应:

                    response.writeHead(200);

                    fs.createReadStream(filePathto).pipe(response);

                    filePathWithDefault = true;

                } catch(e) {

                    filePathWithDefault = false;

                }

                if (filePathWithDefault) break;

            }

            if (!filePathWithDefault) {

                console.log('404' + request.url);

                response.writeHead(404);

                response.end('404 Not Found');

            }

        }

        else {

            // 出错了或者文件不存在:

            console.log('404 ' + request.url);

            // 发送404响应:

            response.writeHead(404);

            response.end('404 Not Found');

        }

    });

});

server.listen(8080);

console.log('Server is running at http://127.0.0.1:8080/');