NodeJS study notes - Connect middleware application example

NodeJS study notes - Connect middleware application example_node.js

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Release： 2016-05-16 16:17:42

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1, opening analysis

Hello everyone, Mr. Big Bear is here again. I didn’t write a blog yesterday because of some personal matters. Today I have another article. This article is mainly about writing a small notepad application. The previous article,

I have also introduced the use of "Connect" middleware and the usage of "Mongodb". Today I will combine these two middlewares and write a practical example. I will continue to improve and reconstruct them and have reached

Full learning purpose. Okay, let’s stop talking nonsense and go directly to the topic.

2. Demand analysis

(1), user registration and login functions (no complex interaction scenarios involved, the user will determine whether it already exists during registration).

(2), the user logs in successfully and enters the background of the note management system (add, delete, modify and check functions of the note module).

(3), users can have simple permission division (administrator, registered user).

(4), the interface is relatively simple and focuses on learning.

3. Start designing the application (Part 1)

(1), create a user login page, the code is as follows:

Copy code The code is as follows:

        Bigbear记事本应用登录

　　效果图：

（2），建立用户注册页面，代码如下：

复制代码代码如下:

         Bigbear记事本应用注册

　　效果图：

（3），建立“Mongodb”连接代码，如下：

复制代码代码如下:

 var mongodb = require("mongodb") ;

 var server = new mongodb.Server("localhost",27017,{

     auto_reconnect : true

 }) ;

 var conn = new mongodb.Db("bb",server,{

     safe : true

 }) ;

 conn.open(function(error,db){

     if(error) throw error ;

     console.info("mongodb connected !") ;

 }) ;

 exports = module.exports = conn ;

（4），建立模型实体类“User”，如下：

复制代码代码如下:

 var conn = require("../conn") ;

 function User(user){

     this.name = user["name"] ;

     this.password = user["password"] ;

 } ;

 User.prototype.save = function(callback){

     var that = this ;

     conn.collection("users",{

         safe : true

     },function(error,collection){

         if(error) return conn.close() ;

         collection.findOne({   // 判断此用户是否存在

             name : that.name

         },function(error,user){

             if(error) return conn.close() ;

             if(!user){

                 collection.insert({

                     name : that.name   "" ,

                     password : that.password   ""

                 },{

                     safe : true

                 },function(error,user){

                     if(error) return conn.close() ;

                     callback && callback(user) ;

                     conn.close() ;

                 }) ;        

             }

             else{

                 callback("User has registed !") ;

             }

         }) ; 

     }) ;

 } ;

 User.login = function(name,password,callback){

     conn.collection("users",{

         safe : true

     },function(error,collection){

         if(error) return conn.close() ;

         collection.findOne({

             name : name ,

             password : password

         },function(error,user){

             if(error) return conn.close() ;

             callback && callback(user) ;

             conn.close() ;

         }) ; 

     }) ;

 } ;

 exports = module.exports = User ;

　　效果图：

（5），建立应用程序“app”,如下：

复制代码代码如下:

 // app.js

 var connect = require("./lib/connect") ;

 var user = require("./models/user") ;

 var app = connect.createServer() ;

 app .use(connect.logger("dev"))

 .use(connect.query())

 .use(connect.bodyParser())

 .use(connect.cookieParser())

 .use(connect.static(__dirname   "/views"))

 .use(connect.static(__dirname   "/public"))

 .use("/login",function(request,response,next){

     var name = request.body["name"] ;

     var password = request.body["password"] ;

     user.login(name,password,function(user){

         if(user){

             response.end("Welcome to:"   user["name"]   " ^_^ ... ...") ;    

         }

         else{

             response.end("User:"   name   " Not Register !")    ;

         }

     }) ;

 })

 .use("/reg",function(request,response,next){

     var name = request.body["name"] ;

     var password = request.body["password"] ;

     new user({

         name : name ,

         password : password

     }).save(function(user){

         if(user && user["name"]){

         　　response.end("User:"   name   "Register Done !")    ;    

         }

         else{

         　　response.end("User: "   name   "has registed !") ;  

         }

     }) ;

 })

 .listen(8888,function(){

     console.log("Web Server Running On Port ---> 8888 .") ;

 }) ;