Develop Reference

Checking IP and port using jQuery

I have an intranet app that periodically checks status of a set of printers by sending it a "Host Status" command. If status returned is "No Response" I display the printer with a red background that user can click and get some additional info. This additional info is the part I need help with.
When clicked, I send a ping command using printer's IP. If I get a "timeout" I have the answer: printer is offline. But I might get a response which means printer is online; "No Response" could be a port issue. However, it seems I can't ping IP:Port since ping uses ICMP and has no concept of port.
How can I check for this in JS/jQuery?
This is what I am using to test for ping response (and IP:Port which I think is useless):
function ping(ip, callback) {
if (!this.inUse) {
this.status = 'unchecked';
this.inUse = true;
this.callback = callback;
this.ip = ip;
var _that = this;
this.img = new Image();
this.img.onload = function () {
_that.inUse = false;
_that.callback('responded');
};
this.img.onerror = function (e) {
if (_that.inUse) {
_that.inUse = false;
_that.callback('responded', e);
}
};
this.start = new Date().getTime();
this.img.src = "http://" + ip + "/?cachebreaker=" + new Date().getTime();
this.timer = setTimeout(function () {
if (_that.inUse) {
_that.inUse = false;
_that.callback('timeout');
}
}, 1500);
}
}
Somewhere in script checking status:
$(document).on('click', '.extLink', function () {
var ip = $(this).data("ip");
...
new ping(ip, function (status, e) {
if (status == 'responded') {
$('<p>Printer is reachable. Ping was successful.<br />Checking port 9100.</p>').appendTo('#divInfo');
new ping(ip + ":9100", function (status, e) { // not sure about this
if (status == 'timeout') {
$('<p>Port 9100 is blocked.</p>').appendTo('#divInfo');
}
});
}
else if (status == 'timeout') {
$('<p>Printer is not reachable. Ping failed.</p>').appendTo('#divInfo');
}
});
...
});

WebRTC NodeJS to js

I have a problem I have these files in js that I need to create a webrtc. The problem is that hosting doesn't support nodejs. i was wondering if it was possible to change them in js to make it work. Can I copy the request files that I do to require ("node-static") and put them in the hosting?
Help me I don't know how to proceed. Thanks so much
server.js
var static = require('node-static');
var https = require('https');
var util = require('util');
var file = new(static.Server)();
var app = https.createServer(function (req, res) {
file.serve(req, res);
}).listen(443);
var io = require('socket.io').listen(app);
io.sockets.on('connection', function (socket){
// convenience function to log server messages on the client
function log(){
var array = [">>> Message from server: "];
for (var i = 0; i < arguments.length; i++) {
array.push(arguments[i]);
}
socket.emit('log', array);
}
// when receive sdp, broadcast sdp to other user
socket.on('sdp', function(data){
console.log('Received SDP from ' + socket.id);
socket.to(data.room).emit('sdp received', data.sdp);
});
// when receive ice candidate, broadcast sdp to other user
socket.on('ice candidate', function(data){
console.log('Received ICE candidate from ' + socket.id + ' ' + data.candidate);
socket.to(data.room).emit('ice candidate received', data.candidate);
});
socket.on('message', function (message) {
log('Got message:', message);
// for a real app, would be room only (not broadcast)
socket.broadcast.emit('message', message);
});
socket.on('create or join', function (room) {
// join room
var existingRoom = io.sockets.adapter.rooms[room];
var clients = [];
if(existingRoom){
clients = Object.keys(existingRoom);
}
if(clients.length == 0){
socket.join(room);
io.to(room).emit('empty', room);
}
else if(clients.length == 1){
socket.join(room);
socket.to(room).emit('joined', room, clients.length + 1);
}
// only allow 2 users max per room
else{
socket.emit('full', room);
}
});
socket.on('error', function(error){
console.error(error);
})
});
main.js
"use strict"
//my signalling server
var serverIP = "https://www.website.com/";
// RTCPeerConnection Options
var server = {
// Uses Google's STUN server
iceServers: [{
"urls" :
navigator.mozGetUserMedia ? "stun:stun.services.mozilla.com" :
navigator.webkitGetUserMedia ? "stun:stun.l.google.com:19302" :
"stun:23.21.150.121"
}
]
};
var localPeerConnection, signallingServer;
var localStream, localIsCaller;
function disconnect() {
var localVideo = document.getElementById('from-video');
var remoteVideo = document.getElementById('to-video');
// stop video stream
if (localStream != null) {
let tracks = localStream.getTracks();
tracks.forEach(function(track) {
track.stop();
});
}
// kill all connections
if (localPeerConnection != null) {
localPeerConnection.getSenders().forEach(function(sender){
localStream.getTracks().forEach(function(track){
if(track == sender.track){
localPeerConnection.removeTrack(sender);
}
})
});
localPeerConnection.close();
signallingServer.close();
localVideo.src = "";
remoteVideo.src = "";
}
}
// WEBRTC STUFF STARTS HERE
// Set objects as most are currently prefixed
window.RTCPeerConnection = window.RTCPeerConnection || window.mozRTCPeerConnection ||
window.webkitRTCPeerConnection || window.msRTCPeerConnection;
window.RTCSessionDescription = window.RTCSessionDescription || window.mozRTCSessionDescription ||
window.webkitRTCSessionDescription || window.msRTCSessionDescription;
navigator.getUserMedia = navigator.getUserMedia || navigator.mozGetUserMedia ||
navigator.webkitGetUserMedia || navigator.msGetUserMedia;
window.SignallingServer = window.SignallingServer;
var sdpConstraints = {
optional: [],
mandatory: {
OfferToReceiveVideo: true,
}
}
function connect_video(room) {
// create peer connection
localPeerConnection = new RTCPeerConnection(server);
// create local data channel, send it to remote
navigator.getUserMedia({
video: true,
audio: true
}, function(stream) {
// get and save local stream
trace('Got stream, saving it now and starting RTC conn');
// must add before calling setRemoteDescription() because then
// it triggers 'addstream' event
localPeerConnection.addStream(stream);
localStream = stream;
// show local video
var localVideo = document.getElementById('from-video');
localVideo.srcObject = stream;
localVideo.onloadedmetadata = function(e) {
localVideo.play();
};
// can start once have gotten local video
establishRTCConnection(room);
}, errorHandler)
}
function connect_audio(room) {
// create peer connection
localPeerConnection = new RTCPeerConnection(server);
// create local data channel, send it to remote
navigator.getUserMedia({
video: false,
audio: true
}, function(stream) {
// get and save local stream
trace('Got stream, saving it now and starting RTC conn');
// must add before calling setRemoteDescription() because then
// it triggers 'addstream' event
localPeerConnection.addStream(stream);
localStream = stream;
// show local video
var localVideo = document.getElementById('from-video');
localVideo.srcObject = stream;
localVideo.onloadedmetadata = function(e) {
localVideo.play();
};
// can start once have gotten local video
establishRTCConnection(room);
}, errorHandler)
}
function establishRTCConnection(room) {
// create signalling server
signallingServer = new SignallingServer(room, serverIP);
signallingServer.connect();
// a remote peer has joined room, initiate sdp exchange
signallingServer.onGuestJoined = function() {
trace('guest joined!')
// set local description and send to remote
localPeerConnection.createOffer(function(sessionDescription) {
trace('set local session desc with offer');
localPeerConnection.setLocalDescription(sessionDescription);
// send local sdp to remote
signallingServer.sendSDP(sessionDescription);
});
}
// got sdp from remote
signallingServer.onReceiveSdp = function(sdp) {
// get stream again
localPeerConnection.addStream(localStream);
trace(localStream)
// if local was the caller, set remote desc
if (localIsCaller) {
trace('is caller');
trace('set remote session desc with answer');
localPeerConnection.setRemoteDescription(new RTCSessionDescription(
sdp));
}
// if local is joining a call, set remote sdp and create answer
else {
trace('set remote session desc with offer');
localPeerConnection.setRemoteDescription(new RTCSessionDescription(
sdp), function() {
trace('make answer')
localPeerConnection.createAnswer(function(
sessionDescription) {
// set local description
trace('set local session desc with answer');
localPeerConnection.setLocalDescription(
sessionDescription);
// send local sdp to remote too
signallingServer.sendSDP(sessionDescription);
});
});
}
}
// when received ICE candidate
signallingServer.onReceiveICECandidate = function(candidate) {
trace('Set remote ice candidate');
localPeerConnection.addIceCandidate(new RTCIceCandidate(candidate));
}
// when room is full
signallingServer.onRoomFull = function(room) {
console.log('Room "' + room +
'"" is full! Please join or create another room');
}
// get ice candidates and send them over
// wont get called unless SDP has been exchanged
localPeerConnection.onicecandidate = function(event) {
if (event.candidate) {
//!!! send ice candidate over via signalling channel
trace("Sending candidate");
signallingServer.sendICECandidate(event.candidate);
}
}
// when stream is added to connection, put it in video src
localPeerConnection.ontrac = function(data) {
var remoteVideo = document.getElementById('to-video');
remoteVideo.srcObject = data.stream;
remoteVideo.onloadedmetadata = function(e) {
remoteVideo.play();
};
}
}
function errorHandler(error) {
console.log('Something went wrong!');
console.log(error);
}
function trace(text) {
console.log(text);
}
and another file like signalling.js, adapter.js, socket.io.js

No you can't. You'll need hosting that has nodejs support or one in which you can run a vm.
These scripts are server-side scripts and they need to run on the server at all times.
Making them run client-side makes no sense as there would be no place to connect to.

WebSocket connection established, onopen never runs

I'm trying to learn WebSockets and I've created a websocket server in Node and am now working on the browser implementation. I have tested that the server works and responds how I want using a chrome extension called Smart WebSocket Client.
The console in the browser says Button pressed! when you press the button and Connection lost! (1000) when I end the Node process but never has it said Connection Established!.
Edit: The client code is running on a site secured with HTTPS and that serves the HSTS header while the server code (currently, but won't continue to be) is running on localhost over normal HTTP, if it's any concern.
Server Code:
const websock = require('./node_modules/ws');
const HashMap = require('./node_modules/hashmap');
const jsonparse = require('./node_modules/jsonparse');
const randomstring = require('./node_modules/randomstring');
class Session {
constructor(server) {
this.server = server;
this.clients = [];
}
}
var connections = new HashMap();
const json = new jsonparse();
const wss = new websock.Server({ port: 36245 });
process.on('SIGINT',function () {
console.log("Recieved SIGINT, stopping gracefully...");
wss.clients.forEach(function (ws) {
console.log("-Ended connection with "+ws.upgradeReq.socket.remoteAddress+" (1001)");
ws.closeReasonCode = 1001;
ws.close();
});
process.exit(1);
});
wss.on('connection',function connection(ws,conn) {
console.log("+Recieved connection from "+ws._socket.remoteAddress);
ws.upgradeReq = conn;
ws.hasHandshook = false;
ws.onmessage = function message(msg) {
var message;
try {
message = JSON.parse(msg.data);
} catch (ex) {
ws.send("{\"e\":\"Invalid json.\"}");
return;
}
if (!ws.hasHandshook) {
ws.hasHandshook = true;
if (message.type === "client") {
//ensure code was provided and has a room
if (typeof message.code === 'undefined' || !connections.has(message.code)) {
ws.send("{\"e\":\"Invalid game code.\"}");
ws.closeReasonCode = 4001;
ws.closeDescription = "Invalid game code.";
console.log("-Ended connection with "+ws._socket.remoteAddress+ " (4001)");
ws.close();
}
if (typeof message.name === 'undefined') {
//TODO error out, no player name provided
}
//attach client to game session
ws.clientType = "client";
ws.gameCode = message.code;
ws.playerName =
connections.get(message.code).clients.add(ws);
ws.send("{\"joingame\":\"true\"}");
} else {
ws.send("{\"e\":\"Invalid type provided on handshake message.\"}");
ws.closeReasonCode = 4000;
ws.closeDescription = "Invalid type provided on handshake message.";
console.log("-Ended connection with "+ws._socket.remoteAddress+" (4000)");
ws.close();
}
}
};
ws.onclose = function close() {
console.log("-Ended connection with "+ws.upgradeReq.socket.remoteAddress+" (Client Closed)");
}
});
Client Code, which is successfully run on the press of a button on the page:
function DoJoinGame () {
console.log("Button pressed!");
gameCode = document.getElementById('base-gameCode').value.toUpperCase();
playerName = document.getElementById('base-playerName').value;
var ws = new WebSocket("ws://localhost:36245");
ws.onopen = function (event) {
console.log("Connection Established!");
ws.send("{\"type\":\"client\",\"code\":\""+gameCode+"\",\"name\":\""+playerName+"\"");
};
ws.onmessage = function (msg) {
let message = JSON.parse(msg.data);
if (message.joingame) { //if this is a "client added to session" message, set display: none; on the codeEntry div
document.getElementById('codeEntry').style.display = "none";
}
//TODO handle message
};
ws.onclose = function (evt) {
console.log("Connection lost! ("+evt.code+":"+evt.reason+")");
};
}
Thank you for your help!

Problem fixed. I was attempting to connect to a non secure websocket server from a secure origin and chrome & co. wasn't a fan.

NodeJs Assertion failed on HTTP call (Mac)

var client = require('http');
var endpoint = apiEndpoint;
var request = client.get(endpoint, function(responseFromApi) {
var responseString = '';
responseFromApi.setEncoding('utf-8');
responseFromApi.on('data', function(data) {
responseString += data;
});
// To reformat the string response into Json...
responseFromApi.on('end', function() {
var jsonResponse = JSON.parse(responseString);
callback(jsonResponse);
});
});
I am making API calls using the method above, however on random instances my call fails due to the Assertion fail like below. Anyone has any idea how to fix this?
Assertion failed: (handle->type == UV_TCP || handle->type == UV_TTY || handle->type == UV_NAMED_PIPE), function uv___stream_fd, file ../deps/uv/src/unix/stream.c, line 1568.
Environment: Mac, Nodejs
Note: I have tested the same code on an AWS lambda server and never faced this issue. I am guessing this is a Mac only instance. Lord Google informed me that it is a Mac desync issue.
Same is true if trying to get data from a dynamoDB sitting on Amazon server using the code below...
// To get userID.
var userId = getUserIdFromContext(this);
if (!userId) {
callback('userId is not set.');
}
// To get table name.
var table = constants.dynamoDBTableName;
if(!table) {
callback('DynamoDB Table name is not set.');
}
// To set the DocumentClient.
if(!doc) {
doc = new aws.DynamoDB.DocumentClient({apiVersion: '2012-08-10'});
}
// To set the params.
var params = {
Key: {
CustomerId: userId
},
TableName: table,
ConsistentRead: true
};
// To get data from table.
var skillContext = this;
doc.get(params, function(err, data){
if(err) {
console.log('get error: ' + JSON.stringify(err, null, 4));
callback(err);
} else {
if(isEmptyObject(data)) {
callback('The object is empty.');
} else {
var userData = JSON.parse(data.Item['Data']);
extractUserData(skillContext, userData, callback);
}
}
});
}

How do I close a sockjs connection on the server side?

So, every time I refresh the page, it seems like sockjs is creating a new connection.
I am saving every message to my mongodb on every channel.onmessage, so if I refresh my page 7 times and send a message, I would save 7 messages of the same content into my mongodb.
This is very problematic because when I retrieve those messages when I go into the chat room, to see the log, I would see bunch of duplicate messages.
I want to keep track of all connections that are 'active', and if a user tries to make another connections, I want to be able to force close on the old one from the server side, so there is only 1 connection listening to each message at a time
How do I do this ?
var connections = {};
//creating the sockjs server
var chat = sockjs.createServer();
//installing handlers for sockjs server instance, with the same url as client
chat.installHandlers(server, {prefix:'/chat/private'});
var multiplexer = new multiplexServer.MultiplexServer(chat);
var configChannel = function (channelId, userId, userName){
var channel = multiplexer.registerChannel(channelId);
channel.on('connection', function (conn) {
// console.log('connection');
console.log(connections);
connections[channelId] = connections[channelId] || {};
if (connections[channelId][userId]) {
//want to close the extra connection
} else {
connections[channelId][userId] = conn;
}
// }
// if (channels[channelId][userId]) {
// conn = channels[channelId][userId];
// } else {
// channels[channelId][userId] = conn;
// }
// console.log('accessing channel! ', channels[channelId]);
conn.on('new user', function (data, message) {
console.log('new user! ', data, message);
});
// var number = connections.length;
conn.on('data', function(message) {
var messageObj = JSON.parse(message);
handler.saveMessage(messageObj.channelId, messageObj.user, messageObj.message);
console.log('received the message, ', messageObj.message);
conn.write(JSON.stringify({channelId: messageObj.channelId, user: messageObj.user, message: messageObj.message }));
});
conn.on('close', function() {
conn.write(userName + ' has disconnected');
});
});
return channel;
};

Simply use .close:
if (connections[channelId][userId]) {
// want to close the extra connection
connections[channelId][userId].close();
} else {
connections[channelId][userId] = conn;
}