我们要将response对象(从服务器的回调函数onRequest()获取)通过请求路由传递给请求处理程序。随后,处理程序就可以采用该对象上的函数来对请求作出响应。
我们先对server.js做出修改:
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;
我们将response对象作为第三个参数传递给route()函数,并且,我们将onRequest()处理程序中所有有关response的函数调都移除,因为我们希望这部分工作让route()函数来完成。
接下来修改 router.js:
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;
同样的模式:相对此前从请求处理程序中获取返回值,这次取而代之的是直接传递response对象。 如果没有对应的请求处理器处理,我们就直接返回“404”错误。
接下来修改requestHandler.js:
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;
我们的处理程序函数需要接收response参数,为了对请求作出直接的响应。 start处理程序在exec()的匿名回调函数中做请求响应的操作,而upload处理程序仍然是简单的回复“Hello World”,只是这次是使用response对象而已。
如果想要证明/start处理程序中耗时的操作不会阻塞对/upload请求作出立即响应的话,可以将requestHandlers.js修改为如下形式:
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;
这样一来,当请求http://localhost:8888/start的时候,会花10秒钟的时间才载入,而当请求http://localhost:8888/upload的时候,会立即响应,纵然这个时候/start响应还在处理中。