gwsocket is a simple, standalone, language-agnostic, RFC6455 compliant WebSocket Server, written in C.
Very simple, just redirect the output from your application (stdout) to a file (named pipe) and let gwsocket transfer the data to the browser — That's it.
For example, tailing your server's logs into the browser couldn't be easier
tail -f /var/log/nginx/access.log | gwsocket
You can also get the client's data into (stdin) your application. In fact, you can even send your favorite ncurses program's output to the browser. See this.
I was looking for a fast, simple, no-dependencies, no libraries, RFC6455 compliant WebSocket Server written in C that I could use for version 1.0 of GoAccess by simply piping data in and out — WebSockets made easy!
gwsocket is language agnostic, look at the Man Page for more details and examples on how to receive data from the browser and how to send it to the browser.