var http = require("http");

var url = require("url");

function start(route, handle) {

  function onRequest(request, response) {

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

 console.log("Request for " + pathname + " received."); 

 route(handle, pathname, response); 

  }

  http.createServer(onRequest).listen(8888);

  console.log("Server has started.");

}

exports.start = start;

我們將response對象作為第三個參數(shù)傳遞給route()函數(shù)，并且，我們將onRequest()處理程序中所有有關(guān)response的函數(shù)調(diào)都移除，因為我們希望這部分工作讓route()函數(shù)來完成。

接下來修改 router.js：

復(fù)制代碼代碼如下:

function route(handle, pathname, response) {

  console.log("About to route a request for " + pathname);

  if (typeof handle[pathname] === 'function') {

 handle[pathname](response);

  } 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;

同樣的模式：相對此前從請求處理程序中獲取返回值，這次取而代之的是直接傳遞response對象。如果沒有對應(yīng)的請求處理器處理，我們就直接返回“404”錯誤。

接下來修改requestHandler.js：

復(fù)制代碼代碼如下:

var exec = require("child_process").exec;

function start(response) {

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

  exec("ls -lah", function (error, stdout, stderr) {

 response.writeHead(200, {"Content-Type": "text/plain"});

 response.write(stdout);

 response.end();

  });

}

function upload(response) {

  console.log("Request handler 'upload' was called.");

  response.writeHead(200, {"Content-Type": "text/plain"});

  response.write("Hello Upload");

  response.end();

}

exports.start = start;

exports.upload = upload;

我們的處理程序函數(shù)需要接收response參數(shù)，為了對請求作出直接的響應(yīng)。 start處理程序在exec()的匿名回調(diào)函數(shù)中做請求響應(yīng)的操作，而upload處理程序仍然是簡單的回復(fù)“Hello World”，只是這次是使用response對象而已。

如果想要證明/start處理程序中耗時的操作不會阻塞對/upload請求作出立即響應(yīng)的話，可以將requestHandlers.js修改為如下形式：

復(fù)制代碼代碼如下:

var exec = require("child_process").exec;

function start(response) {

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

  exec("find /",

      { timeout: 10000, maxBuffer: 20000*1024 },

      function (error, stdout, stderr) {

  response.writeHead(200, {"Content-Type": "text/plain"});

  response.write(stdout);

  response.end();

      }

  );

}

function upload(response) {

  console.log("Request handler 'upload' was called.");

  response.writeHead(200, {"Content-Type": "text/plain"});

  response.write("Hello Upload");

  response.end();

}

exports.start = start;

exports.upload = upload;