nodejs express route 的用法

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nodejs express route 的用法

1. 首先是最基本的用法。

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var app=require( 'express' ).createServer();                                                     app.get( "/" , function (req,res){                                                          res.send( "hello world" );                                                     });                                                     app.listen(3000);

当用户访问 127.0.0.1:3000的时候，页面会输出hello world

2. 加个路径试试。

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var app=require( "express" ).createServer();                                                                                                                                                   app.get( "/toolmao" , function (req,res){                                                     res.send( "welcome to toolmao" );                                                });                                                                                                                                                   app.listen(3000);

当用户访问 127.0.0.1:3000/toolmao的时候，就会输出welcome to toolmao

3. 更为复杂一点的，能够把路径做为参数。

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var app=require( "express" ).createServer();                                                                                                                                       app.get( '/user/:id' , function (req, res){                                                 res.send( 'user ' + req.params.id);                                            });                                                                                                                                       app.listen(3000);

当用户访问 127.0.0.1:3000/user/gainover 的时候，就会输出 user gainover

4. 3中的代码，也能够写为正则表达式的形式。

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var app=require( "express" ).createServer();                                                                                                                           app.get(/\/user\/([^\/]+)\/?/, function (req, res){                                             res.send(req.params);                                        });                                                                                                                           app.listen(3000);

这里能够根据你的须要进行正则的自定义。正则中的匹配结果，存储在req.params参数中。

一个更复杂的正则的例子，以下：含有2个匹配。

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app.get(/^\/users?(?:\/(\d+)(?:\.\.(\d+))?)?/, function (req, res){                                        res.send(req.params);                                   });

请求时，输出以下：

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$ curl http: //dev:3000/user                                 [ null , null ]                                 $ curl http: //dev:3000/users                                 [ null , null ]                                 $ curl http: //dev:3000/users/1                                 [ "1" , null ]                                 $ curl http: //dev:3000/users/1..15                                 [ "1" , "15" ]

5. 若是咱们想指定参数为id，同时又想用正则进行限制，能够写为：

/user/:id([0-9]+)

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Route的依次执行

1. 当一个请求，可以匹配到多个route时，咱们能够调用内置的next函数，来依次进行处理。

例如：

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app.get( '/users/:id?' , function (req, res, next){                             var id = req.params.id;                             if (id) {                                 // do something                             } else {                                 next();                             }                        });                                                                           app.get( '/users' , function (req, res){                             // do something else                        });

当用户请求，/users/gainover时，能够进行某种处理，而当用户请求为/users/, id 不存在，则会调用next()函数，进而调用 app.get("/users/", ....);

2. 一个route里能够有多个处理函数。例如：

app.get('/users/:id/edit/',function1,function2,...);

一个实际的例子可能以下：

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function loadUser(req, res, next) {               // You would fetch your user from the db               var user = users[req.params.id];               if (user) {                 req.user = user;                 next();               } else {                 next( new Error( 'Failed to load user ' + req.params.id));               }            }            function andRestrictToSelf(req, res, next) {               req.authenticatedUser.id == req.user.id                 ? next()                 : next( new Error( 'Unauthorized' ));            }                                       app.get( '/user/:id/edit' , loadUser, andRestrictToSelf, function (req, res){               res.send( 'Editing user ' + req.user.name);            });

当用户访问：/user/gainover/edit时，首先会调用第一个处理函数loadUser，判断用户是否存在于users中，若是不存在，经过next(new Error(msg)); 的方式抛出异常，不然，执行next()，而next此时实际就是指向 andRestrictToSelf 函数，而后判断当前登陆的id和被编辑的id是否等同，若是等同，则继续next()，从而执行 res.send( ...);

 

nodejs  express  route

原文地址:http://node-js.diandian.com/post/2012-07-03/40029072624