var http = require("http");
var url = require("url");
var fs = require("fs");
var path = require("path");

var extname = path.extname(pathname);

var http = require("http");
var url = require("url");
var fs = require("fs");
var path = require("path");
http.createServer(function(req,res) {
  //得到用户路径
  var pathname = url.parse(req.url).pathname;
  //判断此时用户输入的是文件地址还是文件夹地址
  //如果是文件夹地址，那么自动请求文件夹中的index.html
  if(pathname.indexOf(".") == -1) {
    pathname = "index.html";
  }
  //拓展名
  var extname = path.extname(pathname);

  //把文件读出来
  res.writeHead(200,{"Content-type":"text/html;charset=UTF-8"});
  fs.readFile("./static/"+pathname,function(err,data) {
    if(err) {
      //如果此文件不存在，就因该用404返回
      fs.readFile("./static/404.html",function(err,data) {
        res.writeHead(404,{"Content-type":"text/html;charset=UTF-8"});
        res.end(data);
      });
      return;
      //res.end('<center>服务器傲娇的向你抛出了一个404错误</center')
    };
    //MIME类型，就是
    //网页文件：ttext/html
    //jpg文件：image/jpg
    getMime(extname,function(mime) {
      res.writeHead(200,{"Content-type":mime});
      res.end(data);
    });

  });

}).listen(3000,"127.0.0.1");
function getMime(extname,callback) {
  fs.readFile("./static/data.json",function(err,data) {    
    if(err) {
      throw Error("找不到data,json文件");
      return;
    }
    var data = JSON.parse(data);
    var mime = data[extname]||"text/plain";
    callback(mime);
  });
  /*switch(extname) {
    case:".html":
      return "text/html";
      break;
    case ".jpg" :
      return "image/jpg";
      break; 
    case ".css" :
      return "text/css";
      break;
  }*/
  
}