I had some free time recently and decided to learn a truly wonderful library SignalR. SignalR provides the “ability to have your server-side code push content to the connected clients as it happens, in real-time.” It eliminates the extra work of checking browser compatibility with whatever technology you decide to use for pushing the events to the client (WebSockets, EventSource, Long Polling, Forever Frame).

I implemented a simple Chat application using tutorial from Tim Teebken. It worked beautifully on local machine. However, when deployed to GoDaddy my application went down with System.Security.SecurityException. As it turns out, SignalR can run only in Full Trust mode. What I didn’t realize is that to enable full trust you have to explicitly specify Trust Level in Web.Config:

<configuration>
    <system.web>
        <trust level="Full" />
    </system.web>
</configuration>

Once this line was added to the configuration and deployed, my simple Chat client started working.