1. 路由的原理：

当服务端接收到HTTP请求时，可以通过onRequest() 获取到url， pathname，query，及paramParams参数

为了解析这些数据需要使用url和querystring模块

当在服务端的onRequest()方法中解析出pathname后，将pathname传入路由模块，路由模块将进行分发处理；即需要在解析出pathname后及创建Response对象之前将pathname传给路由模块进行分发处理

伪代码是这样的：

# 请求处理函数
function onRequest(url){
    解析url得到pathname
    pathname = querystring.parse(url)

      #调用路由函数
    route(pathname)
    返回
    createResponse()
}

# 启动服务器等待客户端请求
server.start(onRequest())

Node.js的路由实现如下：

sever.js

var http = require("http");
var url = require("url");
 
function start(route) {
  function onRequest(request, response) {
    var pathname = url.parse(request.url).pathname;
    console.log("Request for " + pathname + " received.");
 
    route(pathname);
 
    response.writeHead(200, {"Content-Type": "text/plain"});
    response.write("Hello World");
    response.end();
  }
 
  http.createServer(onRequest).listen(8888);
  console.log("Server has started.");
}
 
exports.start = start;

router.js

function route(pathname) {
  console.log("About to route a request for " + pathname);
}
 
exports.route = route;

index.js

var server = require("./server");
var router = require("./router");
 
server.start(router.route);

链接: https://fly63.com/article/detial/2358