VRS Webpage Quit on me

Is Virtual Radar Server not behaving itself? If so then please report it here.
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Joined: Tue Jul 01, 2014 3:26 pm

VRS Webpage Quit on me

Post by Mr_Gunny » Tue Jul 01, 2014 3:31 pm

Not sure if this is the correct forum, but its worth a try. I had VRS running fine up until about a week ago. Now when I try to start it, I get an error stating that "the web server cannot be started on port 80...". Here is the error that is recorded in the log;

[2014-07-01 14:22:54.533 UTC] [t1] An unhandled exception was caught: Cannot access a disposed object.
Object name: 'System.Net.HttpListener'.
Full message:System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'System.Net.HttpListener'.
at System.Net.HttpListener.CheckDisposed()
at System.Net.HttpListener.get_Prefixes()
at VirtualRadar.WebServer.WebServer.DefaultProvider.get_ListenerPrefix()
at VirtualRadar.WebServer.WebServer.DefaultProvider.set_ListenerPrefix(String value)
at VirtualRadar.WebServer.WebServer.set_Online(Boolean value)
at VirtualRadar.Library.Presenter.MainPresenter.View_ToggleServerStatus(Object sender, EventArgs args)
at VirtualRadar.WinForms.MainView.OnToggleServerStatus(EventArgs args)
at VirtualRadar.WinForms.MainView.webServerStatusControl_ToggleServerStatus(Object sender, EventArgs e)
at VirtualRadar.WinForms.Controls.WebServerStatusControl.OnToggleServerStatus(EventArgs args)
at VirtualRadar.WinForms.Controls.WebServerStatusControl.buttonToggleServerStatus_Click(Object sender, EventArgs e)
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Has anyone else seen this, or know how to resolve it? Thanks in advance.

Mr Gunny Sends

Posts: 365
Joined: Sat Feb 09, 2013 12:15 pm
Location: Wick St Lawrence

Re: VRS Webpage Quit on me

Post by jonfear » Tue Jul 01, 2014 5:24 pm


Have you tried to change any of the web pages? If not then try a re-install to over write the files, your configuration will remain unaffected.

Best wishes

http://www.360radar.co.uk, the new name for MLAT Radar in the UK and Western Europe.

Former PP feeder Bm. No longer feeding. I do not have time to sort out imaginary problems with NTP
when it has been working fine for 2+ Years.

Posts: 2249
Joined: Fri Feb 17, 2012 3:20 am

Re: VRS Webpage Quit on me

Post by agw » Sat Jul 05, 2014 4:55 pm

Sorry for the delay - what it's saying is that it's starting the web server but when it tries to listen to port 80 computer says no, something else is already listening to port 80. Everything else is happening as a consequence of that.

There are three likely possibilities. The first (and least likely, given that you managed to get it running once) is that you have some anti-virus software installed that isn't letting VRS listen to port 80. If that is the case then you will need to add an exception to the anti-virus to allow it, or you will need to reinstall VRS and in the box that asks what port to listen to (which, by default, is 80) you'll need to choose another port. 8080 is a popular alternative but it can be any value between 1024 and 65535.

The second possibility is that after installing VRS you then installed something else which listens to port 80, and that "something else" is running when you try to start VRS. Anything that has a web server built into it would be a likely culprit. The solution there is to either reconfigure that bit of software to listen to another port or reinstall VRS and tell it to listen to another port.

A third possibility is that when you got VRS running you added a rebroadcast server and you set that rebroadcast server to listen to port 80. At the moment the validation on the rebroadcast servers is a little weak and it will let you do that, even though it's not a terribly good idea - you can end up blocking yourself. The solution there is to wipe your configuration and start again. There is no automated mechanism for this in 2.0.2, you need to go here in Windows Explorer:


and then in that folder either rename or delete the Configuration.xml file.

If you'd rather not wipe your configuration and you're comfortable with XML then you can just edit the XML file with Notepad, find the entry for the rebroadcast server that's causing problems and change its port.

I am buffing up the validation of rebroadcast servers in 2.0.3 to catch this sort of problem, amongst others.

There is already support in 2.0.2 for resetting the configuration on startup but that only gets triggered if the configuration file is corrupt - I'll be extending it so that if there are exceptions during startup (like this one) then you'll be given the option of resetting the configuration from there.

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