socketio client: How to handle socketio server down - socket.io

I've got a socketio server/client working well together, however I want to start writing events for when the server is offline on page load or during normal run.
I'm including the remote socket.io code in my header:
<script src="<?=NODE_HOST?>/socket.io/socket.io.js"></script>
<script>
var nodeHost = '<?=NODE_HOST?>';
</script>
And in my client controller I have
if(typeof io != 'undefined')
this.socket = io.connect(this.settings.server);
else
this.handleDisconnect();
The function I have to attempt to re-connect over and over if a) A socket disconnect occurs during normal operation, or b) the server is down on page load
botController.prototype.handleDisconnect = function() {
$.getScript(nodeHost+"/socket.io/socket.io.js").done(function(script, textStatus) {
bot.control.socket = io.connect(bot.control.settings.server);
}).fail(function(jqxhr, settings, exception) {
setTimeout(function() {
bot.control.handleDisconnect();
}, 5000);
});
}
Am I going about this the correct way?
The main issue I have right now (which made me create this question) is my code errors on page load when the server is down because I have functions like:
socket.on(...
When socket doesn't yet exist. I could wrap those in a function and call it when I detect the global socket object exists on successful reconnection? Would it matter if that function that contains socket.on... is called multiple times (if the server goes down more than once during operation)?

OK I managed to come up with this solution that seems to work well using yepnope which I already had using Modernizr (it handles the cross domain issue for me too).
<script src="<?=NODE_HOST?>/socket.io/socket.io.js"></script>
<script>
var nodeHost = '<?=NODE_HOST?>';
</script>
// Attempt to connect to nodejs server
botController.prototype.start = function() {
// Is our nodejs server up yet?
if(typeof io != 'undefined') {
this.socket = io.connect(this.settings.server);
this.startSocketEvents();
} else {
this.handleDisconnect();
}
}
// Our connection to the server has been lost, we need to keep
// trying to get it back until we have it!
botController.prototype.handleDisconnect = function(destroySocketObject) {
if(destroySocketObject === undefined)
destroySocketObject = true;
// Destroy any cached io object before requesting the script again
if(destroySocketObject)
io = undefined;
yepnope.injectJs(nodeHost+"/socket.io/socket.io.js",
function(result) {
// Did it actually download the script OK?
if(typeof io != 'undefined') {
bot.control.socket = io.connect(bot.control.settings.server);
bot.control.startSocketEvents();
} else {
setTimeout(function() {
bot.control.handleDisconnect(false);
}, 5000);
}
}
);
Where startSocketEvents() function contains all of my socket.on events

Related

How to set up a socket connection on a strapi server

I am trying to integrate socket.io with strapi. But unfortunately I have been unable to do so without any proper tutorial or documentation covering this aspect.
I followed along with the only resource I found online which is:
https://medium.com/strapi/strapi-socket-io-a9c856e915a6
But I think the article is outdated. I can't seem to run the code mentioned in it without running into tonnes of errors.
Below is my attempt to implement it and I have been trying to connect it through a chrome websocket plugin smart websocket client But I am not getting any response when I try to run the server.
I'm totally in the dark. Any help will be appreciated
module.exports = ()=> {
// import socket io
var io = require('socket.io')(strapi.server)
console.log(strapi.server) //undefined
// listen for user connection
io.on('connect', socket => {
socket.send('Hello!');
console.log("idit")
// or with emit() and custom event names
socket.emit('greetings', 'Hey!', { 'ms': 'jane' }, Buffer.from([4, 3, 3, 1]));
// handle the event sent with socket.send()
socket.on('message', (data) => {
console.log(data);
});
// handle the event sent with socket.emit()
socket.on('salutations', (elem1, elem2, elem3) => {
console.log(elem1, elem2, elem3);
});
});
};
So I found the solution. Yay. I'll put it here just in case anybody needs it.
boostrap.js
module.exports = async () => {
process.nextTick(() =>{
var io = require('socket.io')(strapi.server);
io.on('connection', async function(socket) {
console.log(`a user connected`)
// send message on user connection
socket.emit('hello', JSON.stringify({message: await strapi.services.profile.update({"posted_by"})}));
// listen for user diconnect
socket.on('disconnect', () =>{
console.log('a user disconnected')
});
});
strapi.io = io; // register socket io inside strapi main object to use it globally anywhere
})
};
Found this at: https://github.com/strapi/strapi/issues/5869#issuecomment-619508153_
Apparently, socket.server is not available when the server starts. So you have to make use of process.nextTick that waits for the socket.server to initialize.
I'll also add a few questions that I faced when setting this up.
How do i connect from an external client like nuxt,vue or react?
You just have to connect through "http://localhost:1337" that is my usual address for strapi.
I am using nuxt as my client side and this is how set up my socketio on the client side
I first installed nuxt-socket-io through npm
Edited the nuxt.config file as per it's documention
modules:[
...
'nuxt-socket-io',
...
],
io: {
// module options
sockets: [
{
name: 'main',
url: 'http://localhost:1337',
},
],
},
And then i finally added a listener in one of my pages.
created() {
this.socket = this.$nuxtSocket({})
this.socket.on('hello', (msg, cb) => {
console.log('SOCKET HI')
console.log(msg)
})
},
And it works.
A clean way to integrate third-party services into Strapi is to use hooks. They are loaded once during the server boot. In this case, we will create a local hook.
The following example has worked with strapi#3.6.
Create a hook for socket.io at ./hooks/socket.io/index.js
module.exports = strapi => {
return {
async initialize() {
const ioServer = require('socket.io')(strapi.server, {
cors: {
origin: process.env['FRONT_APP_URL'],
methods: ['GET', 'POST'],
/* ...other cors options */
}
})
ioServer.on('connection', function(socket) {
socket.emit('hello', `Welcome ${socket.id}`)
})
/* HANDLE CLIENT SOCKET LOGIC HERE */
// store the server.io instance to global var to use elsewhere
strapi.services.ioServer = ioServer
},
}
}
Enable the new hook in order for Strapi to load it - ./config/hook.js
module.exports = {
settings: {
'socket.io': {
enabled: true,
},
},
};
That's done. You can access the websocket server inside ./config/functions/bootstrap.js or models' lifecycle hooks.
// ./api/employee/models/employee.js
module.exports = {
lifecycles: {
async afterUpdate(result, params, data) {
strapi.services.ioServer.emit('update:employee', result)
},
},
};
For those who are looking the answer using Strapi version 4
var io = require("socket.io")(strapi.server.httpServer)

a file upload progress bar with node (socket.io and formidable) and ajax

I was in the middle of teaching myself some Ajax, and this lesson required building a simple file upload form locally. I'm running XAMPP on windows 7, with a virtual host set up for http://test. The solution in the book was to use node and an almost unknown package called "multipart" which was supposed to parse the form data but was crapping out on me.
I looked for the best package for the job, and that seems to be formidable. It does the trick and my file will upload locally and I get all the details back through Ajax. BUT, it won't play nice with the simple JS code from the book which was to display the upload progress in a progress element. SO, I looked around and people suggested using socket.io to emit the progress info back to the client page.
I've managed to get formidable working locally, and I've managed to get socket.io working with some basic tutorials. Now, I can't for the life of me get them to work together. I can't even get a simple console log message to be sent back to my page from socket.io while formidable does its thing.
First, here is the file upload form by itself. The script inside the upload.html page:
document.getElementById("submit").onclick = handleButtonPress;
var httpRequest;
function handleResponse() {
if (httpRequest.readyState == 4 && httpRequest.status == 200) {
document.getElementById("results").innerHTML = httpRequest.responseText;
}
}
function handleButtonPress(e) {
e.preventDefault();
var form = document.getElementById("myform");
var formData = new FormData(form);
httpRequest = new XMLHttpRequest();
httpRequest.onreadystatechange = handleResponse;
httpRequest.open("POST", form.action);
httpRequest.send(formData);
}
And here's the corresponding node script (the important part being form.on('progress')
var http = require('http'),
util = require('util'),
formidable = require('formidable');
http.createServer(function(req, res) {
if (req.url == '/upload' && req.method.toLowerCase() == 'post') {
var form = new formidable.IncomingForm(),
files = [],
fields = [];
form.uploadDir = './files/';
form.keepExtensions = true;
form
.on('progress', function(bytesReceived, bytesExpected) {
console.log('Progress so far: '+(bytesReceived / bytesExpected * 100).toFixed(0)+"%");
})
.on('file', function(name, file) {
files.push([name, file]);
})
.on('error', function(err) {
console.log('ERROR!');
res.end();
})
.on('end', function() {
console.log('-> upload done');
res.writeHead(200, "OK", {
"Content-Type": "text/html", "Access-Control-Allow-Origin": "http://test"
});
res.end('received files: '+util.inspect(files));
});
form.parse(req);
} else {
res.writeHead(404, {'content-type': 'text/plain'});
res.end('404');
}
return;
}).listen(8080);
console.log('listening');
Ok, so that all works as expected. Now here's the simplest socket.io script which I'm hoping to infuse into the previous two to emit the progress info back to my page. Here's the client-side code:
var socket = io.connect('http://test:8080');
socket.on('news', function(data){
console.log('server sent news:', data);
});
And here's the server-side node script:
var http = require('http'),
fs = require('fs');
var server = http.createServer(function(req, res) {
fs.createReadStream('./socket.html').pipe(res);
});
var io = require('socket.io').listen(server);
io.sockets.on('connection', function(socket) {
socket.emit('news', {hello: "world"});
});
server.listen(8080);
So this works fine by itself, but my problem comes when I try to place the socket.io code inside my form.... I've tried placing it anywhere it might remotely make sense, i've tried the asynchronous mode of fs.readFile too, but it just wont send anything back to the client - meanwhile the file upload portion still works fine. Do I need to establish some sort of handshake between the two packages? Help me out here. I'm a front-end guy so I'm not too familiar with this back-end stuff. I'll put this aside for now and move onto other lessons.
Maybe you can create a room for one single client and then broadcast the percentage to this room.
I explained it here: How to connect formidable file upload to socket.io in Node.js

socket.io join/leave

I'm on the socket.io wiki looking into using rooms but join and leave are not working, i'm wondering if they may have changed up a few things but not had the chance to update the wiki?
socket.join("room-"+data.meid);
socket.leave("room-"+meid);
cause im getting console errors:
Uncaught TypeError: Object #<SocketNamespace> has no method 'leave'
Uncaught TypeError: Object #<SocketNamespace> has no method 'join'
It looks like you had the socket.join on the client side. Its a server side function.
Put this on the server:
io.sockets.on('connection', function (socket) {
socket.on('subscribe', function(data) { socket.join(data.room); })
socket.on('unsubscribe', function(data) { socket.leave(data.room); })
});
setInterval(function(){
io.sockets.in('global').emit('roomChanged', { chicken: 'tasty' });
}, 1000);
And this on the client:
var socket = io.connect();
socket.emit("subscribe", { room: "global" });
socket.on("roomChanged", function(data) {
console.log("roomChanged", data);
});
You're probably not declaring 'socket' correctly either that of you haven't installed Socket-io correctly. Try the following...
var io = require("socket.io");
var socket = io.listen(80);
socket.join('room');
socket.leave('room');
There's a useful executable example here.

How to send data from server to client via http?

I want to send the filepath of a file on my server to the client in order to play it using a media player. How can I retrieve that string on the client side in order to concatenate it in the src attribute of a <video element without using sockets?
Server snippet:
res.set('content-type', 'text/plain');
res.send('/files/download.mp4');
This is how you make a request to the server without any frameworks. "/path_to_page" is the route you set to the page that is supposed to process the request.
var xhr = new XMLHttpRequest();
xhr.open('GET', '/path_to_page', true);
xhr.onload = function(e) {
if (this.status == 200) {
console.log(this.responseText); // output will be "/files/download.mp4"
}
};
xhr.send();
}
You might also want to send some params.
var formdata = new FormData();
formdata.append("param_name", "value");
So you might for instance want to send the filename or such.
You just need to change 2 lines from the first code snippet. One would be
xhr.open('POST', '/path_to_page', true); // set to post to send the params
xhr.send(formdata); // send the params
To get the params on the server, if you are using express, they are in req.body.param_name
Which framework are you using??
You can declare base path of your project directory in ajax and the followed by your file.
jQuery.ajax({
type: "GET",
url: "/files/download.mp4",
});
Since you are using express (on node), you could use socket.io:
Server:
var io = require('socket.io').listen(80),
fs = require('fs');
io.sockets.on('connection', function (socket) {
socket.on('download', function(req) {
fs.readFile(req.path, function (err, data) {
if (err) throw err;
socket.emit('video', { video: data });
});
});
});
Client:
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io.connect('http://localhost');
...
// request a download
socket.emit('download', { path: '/files/download.mp4' });
// receive a download
socket.on('video', function (data) {
// do sth with data.video;
});
...
</script>
Edit: didnt notice you didnt want to use sockets. Still it is a viable solution.

Socket.io as server, 'standard' javascript as client?

So i've built a simple websocket client implementation using Haxe NME (HTML5 target ofc).
It connects to
ws://echo.websocket.org (sorry no link, SO sees this as an invalid domain)
which works perfectly!
(i'm using xirsys_stdjs haxelib to use the HTML5 websocket stuff.)
I want to have a local (on my own machine) running websocket server.
I'm using Socket.io at the moment, because i cannot find an easier / simpler solution to go with.
I'm currently trying to use socket.io as socket server, but a 'standard' javascript socket implementation as client (Haxe HTML5), without using the socket.io library clientside.
Does anyone know if this should be possible? because i cannot get it working.
Here's my socket.io code:
var app = require('http').createServer(handler)
, io = require('socket.io').listen(app)
, fs = require('fs')
app.listen(1337);
function handler (req, res) {
fs.readFile(__dirname + '/client.html',
function (err, data) {
if (err) {
res.writeHead(500);
return res.end('Error loading index.html');
}
res.writeHead(200);
res.end(data);
});
}
// WEBSOCKET IMPLEMENTATION
io.sockets.on('connection', function (socket) {
console.log("webSocket connected...");
socket.on('message', function () {
console.log("server recieved something");
// TODO: find out how to access data recieved.
// probably 'msg' parameter, omitted in example?
});
socket.on('disconnect', function () {
console.log("webSocket disconnected.");
});
});
And here's my Haxe (client) code:
static var webSocketEndPoint:String = "ws://echo.websocket.org";
//static var webSocketEndPoint:String = "ws://localhost:1337";
...
private function initializeWebSocket ():Void {
if (untyped __js__('"MozWebSocket" in window') ) {
websocket = new MozWebSocket(webSocketEndPoint);
trace("websocket endpoint: " + webSocketEndPoint);
} else {
websocket = new WebSocket(webSocketEndPoint);
}
// add websocket JS events
websocket.onopen = function (event:Dynamic):Void {
jeash.Lib.trace("websocket opened...");
websocket.send("hello HaXe WebSocket!");
}
websocket.onerror = function (event:Dynamic):Void {
jeash.Lib.trace("websocket erred... " + event.data);
}
websocket.onmessage = function (event:Dynamic):Void {
jeash.Lib.trace("recieved message: " + event.data);
switchDataRecieved(event.data);
}
websocket.onclose = function (event:Dynamic):Void {
jeash.Lib.trace("websocket closed.");
}
}
In case the Haxe code is unclear: it's using 2 extern classes for the webSocket implementation: MozWebSocket and WebSocket. These are just typed 'interfaces' for the corresponding JavaScript classes.
websocket.io! from the same guys. sample shows exact same thing that you are asking about... and something that I spent past 20 hours searching for (and finally found!)
https://github.com/LearnBoost/websocket.io
Update: Jan 2014
The websocket.io repository has not seen any activity for about 2 years. It could be because it is stable, or it could be because it is abandoned.
The same people have another repository called engine.io. In the readme they say that this is isomorphic with websocket.io... It seems that engine.io is where all the action is these days.
https://github.com/LearnBoost/engine.io
While searching for the same thing I just found https://github.com/einaros/ws/ and its server example worked for me with my pre-existing plain javascript client.
http://socket.io/#how-to-use
At the mentioned link, down towards the bottom of the page,
the socket.io documentation demonstrates as it's last
example, how to use their module as a plain
old xbrowser webSocket server.
SERVER
var io = require('socket.io').listen(80);
io.sockets.on('connection', function (socket)
{
socket.on('message', function () { });
socket.on('disconnect', function () { });
});
BROWSER
<script>
var socket= io.connect('http://localhost/');
socket.on('connect', function ()
{
socket.send('hi');
socket.on('message', function (msg)
{ // my msg
});
});
</script>
Hope that's what your looking for
--Doc

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