I am trying to prevent the client from disconnecting from the server. So before the user closes the window on which the app is open, I do:
$(window).bind("beforeunload", function() {
return("Close the app?");
});
But the problem is that no matter if the user chooses to leave or stay on the page where the app is open, the client get's disconnected (stops listening) from the server, before even I chose an option. So if the user chooses to stay on the page, nothing will be sent or received from the server.
Why can this be? How can this be prevented?
I had exactly the same problem in my project.
When you call socket.connect(), you should set sync disconnect on unload parameter of your connection to false (it is true by default):
var conn_options = {
'sync disconnect on unload':false
};
socket = io.connect(url, conn_options);
You can find more connection options here: https://github.com/LearnBoost/socket.io/wiki/Configuring-Socket.IO
P.S. Hope it's still actual for you :)
UPD.
Since the doc was changed, false is now the default value of sync disconnect on unload
You might not be able to avoid the problem as there are no other events triggering before "beforeunload" at window close that i know of. However,you could work around it by asking the socket to reconnect in the callback of the window close dialog when the user chooses to not exit the page. Reconnecting is pretty easy, just:
socket.connect()
Here's another question that describes reconnecting in more detail:
How to reconnect as soon as disconnect happens
Related
I'm trying to connect at asterisk websocket, using socket.io-client
socket = io.connect(url ,{
transports: ['websocket'],
secure: true,
'force new connection' : false,
'reconnect' : true,
});
It works, but everytime I change or refresh page, websocket connection disconnect and reconnect (obviusly). My app is not "one-page-app".
There is a way for keep connection alive?
There is a way for keep connection alive?
No. Not if you allow the page to change in the browser.
When the browser changes pages, it will close all resources associated with the old page (including webSockets) and then it will initialize and open the new page. You cannot change that.
The only way to keep a webSocket open is to put it in a window that does not change. That would entail either converting to a single page app (that doesn't change pages) or putting the webSocket in a frame or window that doesn't change. You could have the user install a browser extension (which can maintain persistent connections), but I assume that isn't what you're asking about.
Otherwise, you have to just manage things on your server to handle the fact that a page change within your site will close the old webSocket and open a new one.
I'm using SignalR 2 and I'm having problems when I open multiple tabs of the same page. After opening 4 or 5 tabs, all the requests get in pending status, like if I had exceeded the maximum allowed by the browser. If I close a few tabs, everything works again. Even with all the tabs opened, if I open a different browser it works. This happens both in Chrome and Firefox. If I disable SignalR, I can open as many tabs as I want.
This is my code:
// Reference the auto-generated proxy for the hub.
notificator.hub = $.connection.messageHub;
// Create a function that the hub can call back to display messages.
notificator.hub.client.refreshNotifications = function () {
// business code
};
$.connection.hub.start().done(function () {
notificator.hubStarted = true;
});
$.connection.hub.disconnected(function () {
notificator.hubStarted = false;
setTimeout(function () {
$.connection.hub.start();
}, 2000); // Restart connection after 2 seconds.
});
If I remove the handler for disconnected event, the problem persists. The notification system works correctly so SignalR is doing its job but it's causing me issues in the app. It's even slower.
I found two solutions:
1) In my case, it's an intranet web application so I know that everybody supports WebSockets and WebSockets doesn't have the connection limitation. But, why this was not working? well, first I added logging to SignalR by adding this line:
$.connection.hub.logging = true;
Then I tried to force using WebSockets:
$.connection.hub.start({ transport: 'webSockets' }).done(function () { .. });
But, checking the logs I found out that WebSockets were not supported because they were not installed in the server. So, I followed these steps in Windows 2012 and installed it:
Open Server Manager.
Under the Manage menu, click Add Roles and Features.
Select Role-based or Feature-based Installation, and then click
Next.
Select the appropriate server, (your local server is selected by
default), and then click Next.
Expand Web Server (IIS) in the Roles tree, then expand Web Server,
and then expand Application Development.
Select WebSocket Protocol, and then click Next.
Click Install.
Source: http://www.iis.net/learn/get-started/whats-new-in-iis-8/iis-80-websocket-protocol-support
After that, everything worked. In Chrome, under Network tab, you'll find a WS filter. Click on it and you should see the websocket.
2) Using IWC-SignalR:
https://github.com/slimjack/IWC-SignalR
It works this way:
One of the windows becomes a connection owner (choosen randomly) and
holds the real SignalR connection. If connection owner is closed or
crashed another window becomes a connection owner - this happens
automatically. Inter-window communication is done by means of IWC.
I downloaded the red5-recorder (http://www.red5-recorder.com/) , which fails to allow me to start recording. After debugging I found that the netconnection, needed to record to a media server, created does not fire a NetStatusEvent event, so essentially it fails silently. I have implemented the connection with the following minimal working example:
trace("make net connection");
nc = new NetConnection();
nc.client = { onBWDone: function():void{ trace("bandwidth check done.") } };
trace("add event listener");
nc.addEventListener(NetStatusEvent.NET_STATUS, function(event:NetStatusEvent) {
trace("handle");
});
trace("connect!");
nc.connect("rtmp://localshost/oflaDemo/test/");
trace("connect done");
The output of this piece of code is:
make net connection
add event listener
connect!
connect done
The actionscript api states that the connect-call always fires such an event:
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/net/NetConnection.html#includeExamplesSummary
Moreover, the netconnection is not 'connected' (a state of the NetConnection object) 10 seconds after the call. I also took a look at this: NetConnect fails silently in Flash when called from SilverLight But the fix suggested by the author, swapping rtmp and http in the connection uri, do not work. Also, I tested the uri and in fact the exact same code sniplet in a personal project, where it did work. I just can not seem to find why connecting to a media server fails silently in the red5-recorder project.
The awkward part is that if I pass some random string as a conenction uri, still nothing happens (no event, no exception, no crash). Also not setting nc.client becore nc.connect(), which caused exceptions in my experience, did not cause exceptions.
Any suggestions are welcome.
You are setting the address to localshost instead localhost.
nc.connect("rtmp://localshost/oflaDemo/test/");
Correct address:
nc.connect("rtmp://localhost/oflaDemo/test/");
I have long poll Ajax request. Browser, at least but not last IE doesn't terminate the request at page leaving, so request remains open and active even if a user visits some other site. Say more, a browser can successfully process responses from this connection, although their result go nowhere. General recommendations as call htmlxml connection abort or stop for a window obviously do not work.
So my implementation is adding extra Ajax call on unload to notify server connection holder that page is on leave, so it can send some dummy response and a browser will return the connection to pool of available after. This approach works but looks for me over engineered. Unfortunately I can observe a similar problem with some other programs, like GMAIL, it also does long poll and as result after some reloading it stops working. So if somebody found some good approach to address the problem without switching to short poll or assign connection timeout, then share your solution.
There's an abort() method on IE's XHR which will manually disconnect it.
It's a bit hacky, but you could try something like:
<body onbeforeunload="AbortMyAjax()">
and use that method to abort any active long-polls.
For reference, here's a bit of code from a project of mine:
$this.lp = null;
function _LongPoll() {
$.ajaxSetup({ cache: false });
$this.lp = $.getJSON(m_PollUrl, _LongPollCallback);
}
And in the body beforeunload:
if(!!QueueManager.lp && !!QueueManager.lp.abort) QueueManager.lp.abort('PAGE_CLOSED');
This is a weird bug, and I'm not even sure how to begin figuring out what's going on.
We are using Cake 1.3.8 with our sessions in the database. I am not using ACL or any other access control. If we navigate into the application and click around a bit, and then rapidly click the browser back button twice (I've tried in Firefox and Chrome) the user is logged out more often than not and receives the error message 'You are not authorized to access that location'.
All of my searches thus far have involved people wanting to make the page inaccessible if a user logged out and then used the back button. I'm not seeing anything reported with regards to the issue I'm seeing.
Does anybody know if this is a Cake issue or have any thoughts on debugging what is going wrong?
Update: I found where the problem is. I have the security set to high, because we need the session to be closed whenever somebody closes the browser. I also have the timeout set very high because we do large binary uploads to S3, and don't want the user logged out while it's uploading or downloading. The specific block of code in cake_sessions.php that's causing the problem is:
$time = $this->read('Config.time');
$this->write('Config.time', $this->sessionTime);
if (Configure::read('Security.level') === 'high') {
$check = $this->read('Config.timeout');
$check -= 1;
$this->write('Config.timeout', $check);
if (time() > ($time - (Security::inactiveMins() * Configure::read('Session.timeout')) + 2) || $check < 1) {
$this->renew();
$this->write('Config.timeout', 10);
}
}
$this->valid = true;
I would guess this is because session IDs are regenerated between requests when security = high. Source:
http://book.cakephp.org/compare/44/CakePHP-Core-Configuration-Variables/cakephp/cakephp1x
You only need one out of sync request, say for a missing image and you will lose the session. I've generally found it unworkable because it's not possible to prevent users double-clicking on links and buttons and invalidating their session.
I would think about using medium security, setting the session timeout fairly short and using an AJAX script to refresh the session at regular intervals (eg every 60s). That way the user will be logged out quickly if the tab/window is closed.
If security is a priority I would suggest hacking the core to make sure the session cookies are set to http_only to help guard against session hijacking by XSS attacks. Cakephp 1.x supports PHP4 so probably isn't setting this by default.
http://php.net/manual/en/function.setcookie.php
It's possible that the session is erased and before it can be written again, the back button is clicked removing the auth from the session variables.
Page loads -> Back Button Clicks -> sessions is erased (but before session is rewritten) -> Back button clicks -> Session checks no existing session.
The only thing that I can think is happening is that when you're going back a page too quickly your code can't validate the person quickly enough (round trip from checking credentials) and throws an error that gets displayed on the next page that is loaded (second backed-to page).
Are you sure the person is actually logged out, or is it just the error being thrown?
Without seeing any code, it will be difficult to nail it down any further.