I am trying to create a nodejs app that will search in various web sites using their API. The result will be sent to the client as soon as it receive result from those API using socket.io. The front end will then add those result using jQuery.
What is the best way to implement this?
So Far I have tried:
Sample code 1
At first I created a middleware for express that add the socket to the request like -
var socketMiddleWare = function(req, res, next){
io.on('connection', function(socket){
console.log(io.engine.clientsCount + " clients connected.");
req.socket = socket;
socket.on('disconnect', function(){
console.log(io.engine.clientsCount + " clients after disconnec.");
});
});
next();
};
then added this middleware to my route -
app.use('/users', socketMiddleWare, users);
It works but the problem is it create multiple event listener each time user refresh the page.
Sample code 2
So then I tried (sample code)
io.on('connection', function(socket){
console.log("user connected");
global.socket = socket;
socket.on('disconnect', function(){
console.log("disconnect");
});
socket.on('my message', function(){
console.log("My message received");
});
});
and on my test route I did
var express = require('express');
var router = express.Router();
/* GET home page. */
router.get('/', function(req, res, next) {
if(socket){
socket.emit('response', 'nothing');
}
res.render('index', { title: 'Express' });
});
module.exports = router;
It solved the previous problem of multiple event listener on refresh But most of the time it can not emit the response. And even it emit my browser can not show the result. On client side I did something like this -
var socket = io.connect('http://localhost');
socket.on('response', function(data){
console.log(data);
document.getElementById("change").innerHTML += data;
});
I can see the response in browser console but my browser show the change for a few milliseconds before it disappear.
I think the the main problem is The page loads before establishing socket connection.
I am currently learning node.js and socket.io. So please help me.
Conclusion
I do have plan to add social network features like one to one message, live friends feed update on home page etc using socket.io in future. Please let me know if there is any good documentation or open source project that can help me implementing it.
I am searching for solution for last couple of days but with no luck so far. I am ready to learn any new methodology or fully rewrite my code.
TL;DR
When a user client search for item, push contents to the client that requested the content when new data available. Data is available after processing response from website like "The Movie Database" and "TheTVDB.com" through their API.
You can use the ID of the socket to keep track of which socket to send results to.
Client
When the user then searches for something the ID is included in the query parameters.
<body>
<form>
<!-- Disable the search bar until the socket is connected -->
<input type="search" name="q" placeholder="Search" disabled>
</form>
<div id="results"></div>
<script src="/socket.io/socket.io.js"></script>
<script>
var resultsElement = document.querySelector("#results");
var search = document.querySelector("form [type=search]");
var socket = io("http://localhost:3000");
socket.on("connect", function(){
search.disabled = false;
});
socket.on("results", function(results){
for(var i = 0;i < results.length;i++){
var result = document.createElement("div");
result.textContent = results[i];
resultsElement.appendChild(result);
}
});
document.querySelector("form").addEventListener("submit", function(event){
fetch("/search?socketID=" + encodeURIComponent(socket.id) + "&q=" + encodeURIComponent(search.value));
event.preventDefault();
});
</script>
</body>
Server
When the server receives the search request it gets the socket using the socket ID sent in the query parameters and starts sending results back to the client.
var app = require("http").createServer(handler);
var io = require("socket.io")(app);
var fs = require("fs");
var url = require("url");
app.listen(3000);
function handler(req, res) {
var query = url.parse(req.url, true).query;
if(req.url.startsWith("/search")){
var results = ["things", "stuff", "items"];
// Server-side IDs have "/#" in front of them
var socket = io.sockets.connected["/#" + query.socketID];
if(socket){
// Get and send "search results"
var interval = setInterval(function(){
var popped = results.pop();
if(popped){
socket.emit("results", [query.q + " " + popped]);
}else{
clearInterval(interval);
}
}, 1000);
}
res.writeHead(204);
res.end();
}else{
fs.readFile(__dirname + "/index.html", function(err, data) {
res.writeHead(200);
res.end(data);
});
}
}
Related
I'm new to Node.js and JavaScript. I have a specific problem but mostly need advice on the best solution.
I'm running a Node server. I want the client to be able to submit a string to the server, then the server to display a new HTML page that shows the string data.
I'm using Express and Socket.io.
In the following files, the client sees index.html, then after submitting the form it sees return.html. I print the input string to the console, and the output is as expected (whatever the user enters). But the return.html is never updated with the input string.
I also tried sending the return.html page and the change_result call in an async series, but the sendFile function never ends and the second function in the series is never called. In previous attempts it worked intermittently with a setTimeout around the emit('change_result') function.
Why doesn't the call to change_result do anything? I used the same technique to update the headings of the original index.html in previous versions. Should I be routing to localhost.../return.html and sending the post data there, or something like that?
server.js
var express = require('express');
var app = express();
var server = require('http').createServer(app);
var io = require('socket.io')(server);
var bodyParser = require('body-parser') //for POST request
app.use( bodyParser.json() ); // to support JSON-encoded bodies
app.use(bodyParser.urlencoded({ // to support URL-encoded bodies
extended: true
}));
server.listen(8080, function() {
console.log("Server running on port 8080.");
});
var dir = __dirname;
app.get('/', function(req, res) {
res.sendFile(dir + '/index.html');
});
app.post('/', function(req, res) {
var query1=req.body.input1
console.log("Server: In post request.")
console.log(query1);
res.sendFile(dir + '/return.html');
io.emit('change_result', {
result: query1
});
});
index.html
<!DOCTYPE html>
<html>
<body id="body">
<form method="post" action="http://localhost:8080">
String: <input type="text" name="input1" id="input1" />
<input type="submit" id="button1" value="Submit" />
</form>
</body>
</html>
return.html
<!DOCTYPE html>
<html>
<body id="body">
<p id="heading1">Result: </p>
<script>
document.addEventListener('DOMContentLoaded', function() {
var socket = io();
socket.on('change_result', function(data) {
document.getElementById('heading1').innerHTML = "Result: \""+data.result"\"";
});
});
</script>
</body>
</html>
I'm not knee-deep inside socket.io, but IMO the problem is, that the server has no way to know if any listeners are ready.
I think you should emit a 'ready' event, once the return.html is loaded, then listen to 'change_result'. Also separate the socket communication from the POST response on the server. Like so.
server.js
var query;
app.get('/', function(req, res) {
res.sendFile(dir + '/index.html');
});
app.post('/', function(req, res) {
query = req.body.input1;
console.log("Server: In post request.");
console.log(query);
res.sendFile(dir + '/return.html');
});
io.on('connection', function(socket) {
socket.on('ready', function() {
socket.emit('change_result', {result: query});
});
});
return.html
<script>
document.addEventListener('DOMContentLoaded', function() {
var socket = io();
socket.emit('ready', function(data) {});
socket.on('change_result', function(data) {
document.getElementById('heading1').innerHTML = "Result: \""+data.result + "\"";
});
});
</script>
While trying to setup a simple NodeJS server and Socket.io client to test something with WebSockets, I've stumbled into something stupid. I'm pretty sure it's something stupid I've done because I've worked with NodeJS/Socket.io before and never had this problem.
With the code below, I'm able to receive the 'tick' event from the server on the client, but the server seems unable to receive the 'ping' event from the client. 'tick' was used to make sure server->client worked, and 'ping' to test client->server.
Using latest Socket.io (1.4.6) and express (4.14.0)
server.js:
var express = require('express');
var app = require('express')();
var server = require('http').createServer(app);
var sio = require('socket.io')(server);
var path = require('path');
app.use(express.static(path.join(__dirname, 'public_html')));
// Socket.io
sio.on('connection', (socket) => {
// Store socket ID
var socketID = socket.conn.id;
// Log connection
console.log('Connection:', socketID);
// Ping event
socket.on('ping', (message) => {
console.log('Ping:', socketID, '-', (message || '(no message>'));
});
// Tick event
var tick = function(){
var now = new Date().getTime().toString();
socket.emit('tick', now);
}
setInterval(tick, 5000);
// Disconnect event
socket.on('disconnect', () => {
console.log('Disconnected:', socketID);
});
});
server.listen(4100, () => {
console.log('Listening on :4100');
});
index.html:
<!DOCTYPE html>
<html>
<head>
<title>Websockets Benchmark</title>
</head>
<body>
<script src="/socket.io/socket.io.js"></script>
<script>
// Socket.io
var sio = io();
// Connection event
sio.on('connect', () => {
console.log('Connected');
sio.emit('ping', 'on connect');
});
// Tick event
sio.on('tick', (time) => {
console.log('Tick', time);
});
// Error event
sio.on('error', (e) => {
console.error(e);
});
</script>
</body>
hope i understood your question...
i did some work with chat by using socket.io so maybe it will help you.
here it is:
<div class="searchBox" style="height: 600px ; width: 500px">
<div style=";width:400px;border-right:1px solid black;;overflow:scroll-y;">
<b style="color: black ;text-decoration: underline">USERS:</b>
<div id="users" style="color: black"></div>
</div>
<div style=";width:300px;height:250px;overflow:scroll-y;padding:10px;">
<b style="color: black ; text-decoration: underline">CONVERSATION:</b>
<div id="conversation" style="color: black"></div>
<input id="data" style="width:200px;" />
<button id="datasend" style="color: #0f0f0f;">send</button>
</div>
and the js:
var socket = io.connect('http://localhost:8080');
// on connection to server, ask for user's name with an anonymous callback
socket.on('connect', function(){
// call the server-side function 'adduser' and send one parameter (value of prompt)
socket.emit('adduser', prompt("What's your name?"));
});
// listener, whenever the server emits 'updatechat', this updates the chat body
socket.on('updatechat', function (username, data) {
$('#conversation').append('<b>'+username + ':</b> ' + data + '<br>');
});
// listener, whenever the server emits 'updateusers', this updates the username list
socket.on('updateusers', function(data) {
$('#users').empty();
$.each(data, function(key, value) {
$('#users').append('<div>' + key + '</div>');
});
});
// on load of page
$(function(){
// when the client clicks SEND
$('#datasend').click( function() {
var message = $('#data').val();
$('#data').val('');
// tell server to execute 'sendchat' and send along one parameter
socket.emit('sendchat', message);
});
// when the client hits ENTER on their keyboard
$('#data').keypress(function(e) {
if(e.which == 13) {
$(this).blur();
$('#datasend').focus().click();
}
});
});
server:
var app = require('./app');
var http = require('http');
var server = http.createServer(app);
var io = require('socket.io').listen(server);
server.listen(8080, function() {
console.log("Gym Project is listening to: http://127.0.0.1:8080");
});
// routing
app.get('/', function (req, res) {
res.sendfile(__dirname + '/index.html');
});
// usernames which are currently connected to the chat
var usernames = {};
io.sockets.on('connection', function (socket) {
// when the client emits 'sendchat', this listens and executes
socket.on('sendchat', function (data) {
// we tell the client to execute 'updatechat' with 2 parameters
io.sockets.emit('updatechat', socket.username, data);
});
// when the client emits 'adduser', this listens and executes
socket.on('adduser', function(username){
// we store the username in the socket session for this client
socket.username = username;
// add the client's username to the global list
usernames[username] = username;
// echo to client they've connected
socket.emit('updatechat', 'SERVER', 'you have connected');
// echo globally (all clients) that a person has connected
socket.broadcast.emit('updatechat', 'SERVER', username + ' has connected');
// update the list of users in chat, client-side
io.sockets.emit('updateusers', usernames);
});
// when the user disconnects.. perform this
socket.on('disconnect', function(){
// remove the username from global usernames list
delete usernames[socket.username];
// update list of users in chat, client-side
io.sockets.emit('updateusers', usernames);
// echo globally that this client has left
socket.broadcast.emit('updatechat', 'SERVER', socket.username + ' has disconnected');
});
});
this is a very simple chat with some clients...
may it helps :)
Can't tell if the ping event is taken by Socket.io, or the following line caused an issue:
console.log('Ping:', socketID, '-', (message || '(no message)'));
Either way, by changing the event name to ev:ping (which is easier to understand anyway), and simplifying that line it's fixed! :)
This question has already been answered, but I can't understand it at all. You can find it at this link.
socket.on calls its callback too many times
I have the same problem as this fellow. I'm attempting to make a chat program with socket.io, but when more than one user joins, each message outputs the number of times of how many users have been connected.
For example, when one user is connected, and he submits a message. It outputs once. When two users are connected, each of their messages output twice.
When three users are connected, each of their messages output three times.
Here is my client side code:
$('document').ready(function() {
var server = io.connect('http://localhost:8888');
$('.chat').keydown(function(event){
var save = this;
if(event.which == 13){
server.emit('message', $(save).val());
$(save).val('');
return false;
}
});
server.on('incoming', function(message){
$('#textfield').append("<p>" + message + "</p>");
});
});
Here is my server side code:
var socket_io = require('socket.io').listen(8888).sockets;
socket_io.on('connection', function(socket){
socket.on('message', function(message){
socket_io.emit('incoming', message)
});
});
Thank you!
You can use socket.broadcast.emit() to send to everyone except that socket:
var io = require('socket.io')(8888);
io.on('connection', function(socket) {
socket.on('message', function(message) {
socket.broadcast.emit('incoming', message);
});
});
UPDATE: The following example works just fine for me:
server.js:
var app = require('http').createServer(handler);
var io = require('socket.io')(app);
var fs = require('fs');
app.listen(80);
function handler (req, res) {
fs.readFile(__dirname + '/index.html',
function (err, data) {
if (err) {
res.writeHead(500);
return res.end('Error loading index.html');
}
res.writeHead(200);
res.end(data);
});
}
io.on('connection', function(socket) {
socket.on('message', function(message) {
socket.broadcast.emit('incoming', message);
});
});
index.html:
<html>
<head>
<script src="//code.jquery.com/jquery-1.11.3.min.js"></script>
<script src="/socket.io/socket.io.js"></script>
<script>
$('document').ready(function() {
var server = io.connect('http://localhost');
$('.chat').keydown(function(event) {
if (event.which == 13) {
var $save = $(this);
server.emit('message', $save.val());
$save.val('');
return false;
}
});
server.on('incoming', function(message){
$('#textfield').append("<p>" + message + "</p>");
});
});
</script>
</head>
<body>
<input type="text" class="chat">
<div id="textfield"></div>
</body>
</html>
When pressing enter, the message in the input box is only displayed once to all other connected socket.io users.
Okay, I've finally figured out the problem.
I'm using Express 4.0. That means, I'm using routes to run the server, and I had the socket io code running inside the route. Each time a user connects, it has to go through the route first, and it's all binding onto the same socket_io.
Thanks to everybody who helped!
I also faced it, like multiple socket calls in network tab and i just add this "transports" key object to socket instance, both on client and backend.
socket = io("http://localhost:3002", {
transports: ['websocket']
})
React, Node, AWS EB
I'm totally new to node.js and I want to implement push notification system on a MySql database. I have a notification table in my database. In this table I have store recipient_id that specify the recipient of the notification. Now I want when a new notification with recipient_id is equal to current logged in user's id notify that user. Something like Stackoverflow If you are in the for example java tagged questions, every time a new question with java tag create, a notification appear on top of the page : 1 question with new activity.
Sorry for my poor English. Please help me to implement this system, because I'm new to it.
I have made a simple app like your requirement.
You can get help from following lines of code.You need to understand the basics of code. after that you will easily achieve your target. most of things from your requirement covered in this demo app.
Its not a exact but you will meet your target through this.
In this example a status post by any user will emit to all other users also at same time. we can manipulate it to achieve "1 new status".
make a table in database where your entries to be saved
CREATE TABLE status
(
`status_id` INT NOT NULL AUTO_INCREMENT,
`s_text` TEXT,
`t_status` TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY ( `status_id` )
);
//server.js
var app = require("express")();
var mysql = require("mysql");
var http = require('http').Server(app);
var io = require("socket.io")(http);
/* Creating POOL MySQL connection.*/
var pool = mysql.createPool({
connectionLimit: 100,
host: 'localhost',
user: 'root',
password: '',
database: 'fbstatus',
debug: false
});
app.get("/", function(req, res) {
res.sendFile(__dirname + '/index.html');
});
io.on('connection', function(socket) {
console.log("A user is connected");
socket.on('status added', function(status) {
add_status(status, function(res) {
if (res) {
io.emit('new status', status);
} else {
io.emit('error');
}
});
});
});
var add_status = function(status, callback) {
pool.getConnection(function(err, connection) {
if (err) {
connection.release();
callback(false);
return;
}
connection.query("INSERT INTO `status` (`s_text`) VALUES ('" + status + "')", function(err, rows) {
connection.release();
if (!err) {
callback(true);
}
});
connection.on('error', function(err) {
callback(false);
return;
});
});
}
http.listen(3000, function() {
console.log("Listening on 3000");
});
//index.html
<html>
<head>
<title>Socket.io</title>
<script src="/socket.io/socket.io.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.2/css/bootstrap.min.css">
<script src = "http://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/js/bootstrap.min.js"></script>
<script>
$(document).ready(function(){
var socket = io();
$("#add_status").click(function(){
socket.emit('status added',$("#comment").val());
});
socket.on('new status',function(msg){
var count = $('#count_status').text();
var valCount = parseInt(count);
if(valCount>=1) {
valCount = valCount+1;
} else {
valCount = 1;
}
var showMsg = '<div id="count_status"> '+valCount+' </div> new status';
$("#show_comments").html(showMsg);
});
});
</script>
</head>
<body>
<div id="comment_box" style = "padding:5%;">
<textarea id="comment" rows="5" cols="70"></textarea><br /><br />
<input type="button" id="add_status" value="Add">
</div>
<div id= "show_comments" class = "jumbotron"></div>
</body>
</html>
Run the app with following command
node Server.js
Now run http://localhost:3000/ in browser and to see the result open a new window in which you post a status and see your new status notification in both the window.
Thanks
Edited: This a great startup tutorial. a few thing needs modification.
connection.release() code ends up unreadable and not working. you should comets or remove it.
2.The actual output in my case:
You can do it 2 ways:
Query the server every n seconds for any new messages. Pass a timestamp of the last time you checked as a parameter and if any notification since the last check, return as json and display them in the client. This is called a pull strategy.
Or you can use websockets which maintains a permanent connection between your client and server, and then you can send notifications to the client from your server code in real-time. See socket.io tutorials. This is called a push strategy.
I'm working on an applicatioin that I want to use with websocket interaction. I've used a node.js and socket.io based server and simple chat page as a starter for my page. I'm making modifications and figuring out the interactions between the server and html page.
The person who wrote the basic chat page used inline javascript on the html page as the client side of the chat, so I've broken that out into its own javascript file, no big deal there.
The issue is that I want to use the html and associated javascript file from the local machine, to connect to the node.js server I'm creating on the web-server. His setup was accessing the html page on the web-server in the same folder as the server.js file that acted as the web-socket server.
I'm trying to figure out how to get the client side javascript file to start doing it's thing when the page is opened (i'm guessing an on load event is needed), and how to set it up to call to the webserver javascript file.
I'm going to post his code here, it's not mine, I just used his tutorial to make the chat.html and server.js. Basically copy and paste.
Any help or guidance is greatly appreciated as always.
-----------------chat.html--------------------------
<!doctype html>
<html>
<head>
<meta charset="UTF-8">
<title>WebSocket Chat</title>
<script src="/socket.io/socket.io.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script>
<script>
var URL = window.location.protocol + "//" + window.location.host;
console.log("Connecting to " + URL);
var socket = io.connect(URL);
// on connection to server, ask for user's name with an anonymous callback
socket.on('connect', function() {
// call the server-side function 'adduser' and send one parameter (value of prompt)
socket.emit('adduser', prompt("What's your name?"));
});
// listener, whenever the server emits 'updatechat', this updates the chat body
socket.on('updatechat', function(username, data) {
$('#conversation').append('<b>' + username + ':</b> ' + data + '<br>');
});
// listener, whenever the server emits 'updateusers', this updates the username list
socket.on('updateusers', function(data) {
$('#users').empty();
$.each(data, function(key, value) {
$('#users').append('<div>' + key + '</div>');
});
});
// on load of page
$(function() {
// when the client clicks SEND
$('#datasend').click(function() {
var message = $('#data').val();
$('#data').val('');
// tell server to execute 'sendchat' and send along one parameter
socket.emit('sendchat', message);
});
// when the client hits ENTER on their keyboard
$('#data').keypress(function(e) {
if (e.which == 13) {
$(this).blur();
$('#datasend').focus().click();
}
});
});
</script>
</head>
<body>
<h1>WebSocket Chat</h1>
<div style="float:left;width:100px;border-right:1px solid black;height:300px;padding:10px;overflow:scroll-y;">
<b>USERS</b>
<div id="users"></div>
</div>
<div style="float:left;width:300px;height:250px;overflow:scroll-y;padding:10px;">
<div id="conversation"></div>
<input id="data" style="width:200px;" />
<input type="button" id="datasend" value="send" />
</div>
</body>
</html>
---------------------server.js-----------------------------
var port = 5000;
var app = require('express')();
var server = require('http').createServer(app);
var io = require('socket.io').listen(server);
console.log("Listening on port " + port);
server.listen(port);
// routing
app.get('/', function (req, res) {
res.sendfile(__dirname + '/chat.html');
});
// usernames which are currently connected to the chat
var usernames = {};
io.sockets.on('connection', function (socket) {
// when the client emits 'sendchat', this listens and executes
socket.on('sendchat', function (data) {
// we tell the client to execute 'updatechat' with 2 parameter
io.sockets.emit('updatechat', socket.username, data);
});
// when the client emits 'adduser', this listens and executes
socket.on('adduser', function(username){
// we store the username in the socket session for this client
socket.username = username;
// add the client's username to the global list
usernames[username] = username;
// echo to client they've connected
socket.emit('updatechat', 'SERVER', 'you have connected');
// echo globally (all clients) that a person has connected
socket.broadcast.emit('updatechat', 'SERVER', username + ' has connected');
// update the list of users in chat, client-side
io.sockets.emit('updateusers', usernames);
});
// when the user disconnects.. perform this
socket.on('disconnect', function(){
// remove the username from global usernames list
delete usernames[socket.username];
// update list of users in chat, client-side
io.sockets.emit('updateusers', usernames);
// echo globally that this client has left
socket.broadcast.emit('updatechat', 'SERVER', socket.username + ' has disconnected');
});
});