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【javascript】初识 NodeJS(三)

上节我们将 http 服务器(server.js)和请求路由模块(route.js)整合在一起了,当然这还不够,路由,顾名思义,是指我们要针对不同的 url 有不同的处理方式。

请求处理程序模块(requestHandlers)

function start() {    console.log(‘Request handler "start" was called.‘);}function upload() {    console.log(‘Request handler "upload" was called.‘);}exports.start = start;exports.upload = upload;

下面我们需要将请求处理程序模块和路由模块相结合,修改主文件 index.js

var server = require(‘./server‘);var route = require(‘./route‘);var requestHandlers = require(‘./requestHandlers‘);var handler = {};handler[‘/‘] = requestHandlers.start;handler[‘/start‘] = requestHandlers.start;handler[‘/upload‘] = requestHandlers.upload;server.start(route.route, handler);

正如所见,将不同的 url 映射到相同的请求处理程序上是很容易的:只要在对象中添加一个键为 ‘/‘ 的属性,对应 requestHandlers.start 即可,这样我们就可以干净简洁地配置 /start 和 / 的请求都交由 start 这一处理程序处理。在完成了对象的定义后,我们把它作为额外的参数传递给服务器。

var http = require(‘http‘);var url = require(‘url‘);function start(route, handler) {    function onRequest(request, response) {        var pathname = url.parse(request.url).pathname;        console.log(‘Request ‘ + pathname + ‘ received.‘);        route(handler, pathname);        response.writeHead(200, {            ‘Content-type‘: ‘text/plain‘        });        response.write(‘Hello node.js‘);        response.end();    }    http.createServer(onRequest).listen(8888);    console.log(‘server has started.‘);}exports.start = start;

这样我们就在 start() 函数里添加了 handler 参数,并且把 handler 对象作为第一个参数传递给了 route() 回调函数。

function route(handler, pathname) {    console.log(‘Route a request for ‘ + pathname);    if (typeof handler[pathname] === ‘function‘) {        handler[pathname]();    } else {        console.log(‘No request handler found for ‘ + pathname);    }}exports.route = route;

这样,我们就把服务器、路由和请求处理程序结合在一起了。现在我们启动应用程序并在浏览器中访问 http://localhost:8888/start,以下日志可以说明系统调用了正确的请求处理程序:

server has started.Request /start received.Route a request for /startRequest handler "start" was called.Request /favicon.ico received.Route a request for /favicon.icoNo request handler found for /favicon.ico

 

【javascript】初识 NodeJS(三)