I suppose I'm havin' a beginner's problem regarding websocket connection.
Here's the thing, I'm researching on using websocket and I followed this code:
<!DOCTYPE HTML>
<html>
<head>
<script type="text/javascript">
function WebSocketTest()
{
if ("WebSocket" in window)
{
alert("WebSocket is supported by your Browser!");
// Let us open a web socket
var ws = new WebSocket("ws://172.16.0.195:8080/echo");
ws.onopen = function()
{
// Web Socket is connected, send data using send()
ws.send("Message to send");
alert("Message is sent...");
};
ws.onmessage = function (evt)
{
var received_msg = evt.data;
alert("Message is received...");
};
ws.onclose = function()
{
// websocket is closed.
alert("Connection is closed...");
};
}
else
{
// The browser doesn't support WebSocket
alert("WebSocket NOT supported by your Browser!");
}
}
</script>
</head>
<body>
<div id="sse">
Run WebSocket
</div>
</body>
</html>
... which I copied from the internet. When I tested it, Firefox said that my browser supports websocket feature but it DOESN'T ESTABLISH CONNECTION TO MY SERVER. I try to telnet our server in port 80 and I could gain connection to it. But if I am to use websocket connection in my page,it does not establish connection anymore.
Thank you very much in advance for any inputs/help.
[EDIT]
** by the way, does ".../echo" in my specified websocket connection has to do something with it? I mean, do I have to have some echo.php in my server?
This tutorial helped me a lot:
Getting started with HTML5′s Web Sockets
Now I have my server set up already.
Related
Recently a post was featured in Hacker News about websites abusing WebSockets to find open ports on the client's machine.
The post does not go into any details, so I decided give it a try.
I opened a web server on port 8080 and tried running this script in Chrome's console:
function test(port) {
try {
var start = performance.now();
var socket = new WebSocket('ws://localhost:' + port);
socket.onerror = function (event) {
console.log('error', performance.now() - start, event);
}
socket.addEventListener('close', function(event) {
console.log('close', performance.now() - start, event);
})
socket.addEventListener('open', function (event) {
console.log('open', performance.now() - start, event);
socket.send('Hello Server!');
});
socket.addEventListener('message', function (event) {
console.log('message ', performance.now() - start, event);
});
} catch(ex) {
console.log(ex)
}
}
Indeed Chrome logs different a error message (ERR_CONNECTION_REFUSED) when I try to connect to a port that is not open:
test(8081)
VM1886:3 WebSocket connection to 'ws://127.0.0.1:8081/' failed: Error in connection establishment: net::ERR_CONNECTION_REFUSED
And when I try to connect to a port that is open but is not listening to WebSockets (Unexpected response code: 200):
test(8080)
WebSocket connection to 'ws://127.0.0.1:8080/' failed: Error during WebSocket handshake: Unexpected response code: 200
But I can't find any way to access and read these errors in JavaScript.
Control flow does not reach the catch clause catch(ex) { console.log(ex) } and the event objects that Chrome passes to socket.onerror do not seem to be any different whether the port is open or not.
Timing attacks also don't seem to be helping at least in Chrome. Delta time between onerror and new Socket() creation seems to increase after calling test(...) a few times.
So is there actually a way for a web page to determine if a port is open on my computer?
The presentation slides linked to below show it was well known in 2016 and lack of a timing difference in your tests show mitigations may have been applied upstream.
https://datatracker.ietf.org/meeting/96/materials/slides-96-saag-1/
It might only work on windows:
https://blog.avast.com/why-is-ebay-port-scanning-my-computer-avast
I am using IIS on my Windows Server 2012 R2 program. I have a static IP, and I've binded it to a port and enabled port forwarding so it is accessible online. Here's the thing, on localhost my XHR request produces the desired output. But when I search my static IP in the URL, and attempt the request, it does not produce anything. Here are the files:
<!DOCTYPE html>
<html>
<body>
<h1>The XMLHttpRequest Object</h1>
<button type="button" onclick="loadDoc()">Request data</button>
<p id="demo"></p>
<script>
function loadDoc() {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
document.getElementById("demo").innerHTML = this.responseText;
}
};
xhttp.open("GET", "demo_get.txt", true);
xhttp.send();
}
</script>
</body>
</html>
And here's my desired output "demo_get.txt":
<p>This Content was requested using the GET method.</p>
So can someone please guide me in making my XHR request functional when I enter my Static IP into the url? Thanks.
As suggested by others, I went into the Developer Tools and found that no request was being sent on the Network Tab. So, I investigated my security settings on my local intranet. I enabled some settings, and that's all it took for the XHR requests to function. Thank you everyone for your input!
I am new to API methodology so sorry for asking such silly question which it may be.I am running Windows 10 on my machine and have setup a Ubuntu VM on Oracle VM VirtualBox. I want to hit the url in AJAX/REST way to get the JSON.I am able to get that JSON data in browser when I am hitting the url within VM environment. How can I accomplish the same via desktop?
I am running a separate server utility on VM which accepts the following url
localhost:8998/sessions
and it provides me data in form of JSON.
I have written the following code with help of W3Schools.
<!DOCTYPE html>
<html>
<body>
<h2>The XMLHttpRequest Object</h2>
<button type="button" onclick="loadDoc()">Request data</button>
<p id="demo"></p>
<script>
function loadDoc() {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
document.getElementById("demo").innerHTML = this.responseText;
}
};
xhttp.open("GET", "192.168.56.780:8998/sessions", true);
xhttp.send();
}
</script>
</body>
</html>
This should return json file in output in the same way as that when I run in browser in VM environment but no output is there on it in specified section.
UPDATE:
I have made changes in "Network" settings of VM making Adapter 2 as below and started the image:
Now I am able to putty it through new IP address 192.168.56.780 assigned automatically by it.Will this solve the above problem.
I'm trying to use STOMP with Apache AMQ as I was hoping web sockets would give me a better performance than the typicalorg.activemq.Amq Ajax connection.
Anyway, my activemq config file has the proper entry
<transportConnector name="ws" uri="ws://0.0.0.0:61614?maximumConnections=1000&wireFormat.maxFrameSize=104857600"/>
And I'm connecting to it via the following means:
function amqWebSocketConn() {
var url = "ws://my.ip.address:61614/stomp";
var client = Stomp.client(url);
var connect_callback = function() {
alert('connected to stomp');
client.subscribe("topic://MY.TOPIC",callback);
var callback = function(message) {
if (message.body) {
alert("got message with body " + message.body);
} else { alert("got empty message"); }
};
};
client.connect("", "", connect_callback);
}
When I first open up the web browser & navigate to http://localhost:8161/admin/connections.jsp It shows the following:
Name Remote Address Active Slow
ID:mymachine-58770-1406129136930-4:9 StompSocket_657224557 true false
Shortly there after - it removes itself. Is there something else I need such as a heart beat to keep the connection alive?
Using
var amq = org.activemq.Amq;
amq.init({
uri : '/myDomain/amq',
timeout : 50,
clientId : (new Date()).getTime().toString()
});
Kept the connection up for the TCP AJAX Connection
I have faced similar problem, solved it using this
client.heartbeat.incoming = 0;
client.heartbeat.outgoing = 0;
You have to add these two lines before connect.
Even after this I have seen disconnection after 5-10 minutes, if there are no incoming messages. To solve that you have to implement ondisconnect call back of connect method.
client.connect('','',connect_callback,function(frame){
//Connection Lost
console.log(frame);
//Reconnect and subscribe again from here
});
This is successfully working in my application.
I just started learning WebSockets today. I am using Safari and the following C# as my WebSocket server (http://www.codeproject.com/KB/webservices/c_sharp_web_socket_server.aspx).
My client is as simple as the following:
<script type="text/javascript">
try{
var socket = new WebSocket('ws://localhost:8181');
alert(socket.readyState);
socket.onopen = function() {
alert('opened...');
};
socket.onclose = function() {
alert('closed');
};
socket.onerror = function(){
alert('error!');
}; }
catch(exception){
alert(exception);
}
</script>
On Safari, am getting the message "Closed" which means the event onclose was raised before the onopen(). I suspecting that the server is closing the connection, any idea? Also, what's the best way to investigate issues like this? any error or reason code?
Thanks!
I guess I figured it out. On Safari you can enable Developer Tools and I was getting missing Sec-WebSocket-Origin header so I went ahead and changed the following:
WebSocket-Origin changed to Sec-WebSocket-Origin