WebSocket + node. js: Create an instant messaging Web chat server, websocketnode. js

WebSocket + node. js: Create an instant messaging Web chat server, websocketnode. js

In this example, node. js creates an instant messaging Web chat server for your reference. The details are as follows:

1. Use nodejs-websocket
Nodejs-websocket is a backend library that implements the websocket protocol based on node. js,
Connection: https://github.com/sitegui/nodejs-websocket.
(1) Installation
Install: npm install nodejs-websocket in the project directory
(2) create a server

// Introduce nodejs-websocketvar ws = require ("nodejs-websocket"); // call the createServer method to create a server. the conn in the callback function is the connection instance var server = ws. create (function (conn) {console. log ("New connection"); // listens for text events. A text event is triggered whenever the server receives text data. The callback function parameter is the passed string conn. on ("text", function (str) {console. log ("disconnected ed" + str) ;}); // listens for the close event, triggering conn each time the connection is closed. on ("close", function (code, reason) {console. log ("Connection closed ");})}). listen (0, 8888 );

 2. The client uses websocket
On the client, you must first instantiate a websocket object: ws = new WebSocket ("ws: // localhost: 5000"). The parameter input format is ws: // + url, this is the same as the http prefix http. Next, we can use some built-in websocket methods for event listening and data presentation.
Here we will introduce all listener events: onopen is triggered when the server and the client establish a connection; onmessage is triggered when the client receives the data sent by the server; onclose is triggered when the connection between the client and the server is closed; onerror is triggered when a connection error occurs.

3. Use websocket + nodejs to implement online chat rooms
(1) html and css Code omitted
(2) Client js:

OConnect. onclick = function () {ws = new WebSocket ('ws: // localhost: 5000 '); ws. onopen = function () {oUl. innerHTML + = "<li> Client Connected </li>";} ws. onmessage = function (evt) {oUl. innerHTML + = "<li>" + evt. data + "</li>";} ws. onclose = function () {oUl. innerHTML + = "<li> client disconnected </li>" ;}; ws. onerror = function (evt) {oUl. innerHTML + = "<li>" + evt. data + "</li>" ;};}; oSend. onclick = function () {if (ws) {ws. send (oInput. value) ;}} (3) server-side js :/* Websocket supports two types of data transmission: text and binary, binary data is sent and read in stream mode */var app = require ('HTTP '). createServer (handler); // to simplify the code, place the server creation code in the handler function var ws = require ('nodejs-websocket '); var fs = require ('fs'); app. listen (8888); function handler (req, res) {// _ dirname returns the current directory of the file. Call the readFile method to read the file fs. readFile (_ dirname + '/index.html', function (err, data) {if (err) {res. writehead( 500); return res. end ('error');} res. writehead( 200); res. end (data) ;}) ;}// the above steps are successfully rendered on port 8888. The corresponding html interface // conn is the corresponding connection instance var server = ws. createServer (function (conn) {console. log ('new citciton'); // listens for text events. conn is triggered whenever the text is received. on ("text", function (str) {broadcast (server, str) ;}); // triggered when the connection is closed at any end. The connection closed conn is output on the console. on ("close", function (code, reason) {console. log ('Connection closed ');})}). listen (5000); // note that the listen listener is the port of the server you just opened. The client sends the message to function broadcast (server, msg) {// server. connections is an array containing all connected client servers. connections. forEach (function (conn) {// connection. the sendText method can send specified content to the client and input a string // here to traverse each client and send the content conn for it. sendText (msg) ;}} the above is the article

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