express for node 路由route几种实现方式的思考 .
1、路由实现方式和顺序
express框架创建的模板app,js中默认代码:
- var express = require('express');
- var routes = require('./routes');
- var user = require('./routes/user');
- var http = require('http');
- var path = require('path');
- var app = express();
- // all environments
- app.set('port', process.env.PORT || 3000);
- app.set('views', __dirname + '/views');
- app.set('view engine', 'ejs');
- app.use(express.favicon());
- app.use(express.logger('dev'));
- app.use(express.bodyParser());
- app.use(express.methodOverride());
- app.use(app.router);
- app.use(express.static(path.join(__dirname, 'public')));
- // development only
- if ('development' == app.get('env')) {
- app.use(express.errorHandler());
- }
- app.get('/', routes.index);
- app.get('/users', user.list);
- http.createServer(app).listen(app.get('port'), function(){
- console.log('Express server listening on port ' + app.get('port'));
- });
其中以下两句尤其重要,对路由产生影响:
- app.use(app.router);
- app.use(express.static(path.join(__dirname, 'public')));
(1)express.static指定了静态页面的查找目录,如果定义express.static('/var/www'),当用户向node请求http://server/file.html,node将会自动查找http://server/file.html
(2)两句的前后顺序决定了当静态页面和动态路由都存在时,哪个决定node的真实路由
假设在静态目录下存在test.html,同时包含:
app.get('/test.html', function(req, res) {
res.send('Hello from route handler'); });
方式1:
- <SPAN style="FONT-FAMILY: Arial Black; FONT-SIZE: 14px">app.use(app.router);
- app.use(express.static(path.join(__dirname, 'public')));</SPAN>
则浏览器看到的结果是Hello from route handler
方式2:
- <P><SPAN style="FONT-SIZE: 14px"><SPAN style="FONT-FAMILY: Arial Black"><STRONG>app.use(express.static(path.join(__dirname, 'public')));
- </STRONG></SPAN><SPAN style="FONT-FAMILY: Arial Black"><STRONG>app.use(app.router);</STRONG></SPAN></SPAN></P>
则浏览器看到的结果是显示test.html内容
方式3:
- exports.index=function(req,res){
- res.render('index',{title:'Express'}); }
- <P><SPAN style="FONT-SIZE: 14px"><SPAN style="FONT-FAMILY: Arial Black"><STRONG>app.use(express.static(path.join(__dirname, 'public')));
- </STRONG></SPAN><SPAN style="FONT-FAMILY: Arial Black"><STRONG>//app.use(app.router); //注释掉</STRONG></SPAN></SPAN></P>
同时删除test.html文件
则浏览器看到的结果是显示Hello from route handler,说明其实写不写这句,express都是会默认执行的
express官方推荐的是方式1的写法,之所以这样做,是考虑到性能问题,不论方式2或方式3,都要首先读写磁盘查找文件,没有匹配文件后然后找路由,而方式1,如果有匹配的路由,则不必去查找磁盘,磁盘的IO操作是必然费时效率低下的
2、第二种路由写法
上述的路由方式,都是写在app.js里,当路由的内容不断增加时,可读性变差
所以有了第二种写法:
app.js
- var routes = require('./routes');
- app.get('/',routes.index);
routes/index.js
- exports.index=function(req,res){
- res.render('index',{title:'Express'}); }
3、第三种路由写法(最佳)
app.js
routes(app);//最佳
或
app.use(express.router(routes));
routes/index.js
- module.exports = function(app){
- app.get('/',function(req,res){
- res.render('index', { title: 'Express' });
- });
- app.get('/reg', function(req, res) {
- res.render('reg', {
- title: '用戶註冊',
- });
- });
- };