Nodejs implements a simple chat room function sharing _ node. js

This article mainly introduces a simple chat room function implemented by nodejs. This article uses express and socket. i/O libraries can be implemented in combination. For more information about how to implement a simple chat room today, nodejs is used in the background, and socket is used for communication between the client and the server. io, which is a mature websocket framework.

Initial work

1. install express. Use this to host socket. io and static pages. Run the npm install express -- save and -- save command to add the package to the package. json file.
2. install socket. io and run npm install socket. io -- save.

Write server code

First, we host the website through express and attach it to the socket. io instance, because the first connection to socket. io requires the http protocol

The Code is as follows:

Var express = require ('express '),
Io = require ('socket. io ');

Var app = express ();

App. use (express. static (_ dirname ));

Var server = app. listen (8888 );

Var ws = io. listen (server );

Add a server connection event. After the client connection is successful, an announcement will be issued to all online users. When a user sends a message, a broadcast will be sent to other users.

The Code is as follows:

Ws. on ('connection', function (client ){
Console. log ('\ 033 [96 msomeone is connect \ 033 [39 m \ n ');
Client. on ('join', function (msg ){
// Check whether there are duplicates
If (checkNickname (msg )){
Client. emit ('nickname', 'duplicate nicknames! ');
} Else {
Client. nickname = msg;
Ws. sockets. emit ('announcement ', 'system', msg +' joined the chat room! ');
}
});
// Listen for messages sent
Client. on ('send. message', function (msg ){
Client. broadcast. emit ('send. message', client. nickname, msg );
});
// Notify other users when the connection is disconnected
Client. on ('disconnect', function (){
If (client. nickname ){
Client. broadcast. emit ('send. message', 'system', client. nickname + 'leave the chat room! ');
}
})

})

Because the client is identified by a nickname, the server needs a function to detect duplicate nicknames.

The Code is as follows:

// Check whether the nickname is repeated
Var checkNickname = function (name ){
For (var k in ws. sockets. sockets ){
If (ws. sockets. sockets. hasOwnProperty (k )){
If (ws. sockets. sockets [k] & ws. sockets. sockets [k]. nickname = name ){
Return true;
}
}
}
Return false;
}

Write client code

Because the server uses a third-party websokcet framework, the front-end page must reference socket separately. io client code, the source file can be from socket. find in the io module. In windows, the path is node_modules \ socket. io \ node_modules \ socket. io-client \ dist. The developer and compressed versions are available here. By default, the developer version can be referenced.

The front-end mainly processes the input nickname check and message processing. The complete code is as follows:

The Code is as follows:

Socket. io chat room example

Clear Screen
Send