This is a simple example of a web socket based communication between the server and the clients, exchanging JSON-serialized messages. Note that it does not come packed with Gradle wrapper, so make sure to install it on your own.
Client uses LibGDX (obviously) along with gdx-websocket library. Desktop uses gdx-websocket-common natives library, while GWT project depends on gdx-websocket-gwt. Server is built with a few lines of code thanks to the amazing Vert.x framework.
The server should listen to web socket connections on 8000 port, wait a bit and send a simple message after each request, and disconnect every user after 5 seconds. Clients should connect with the server, send a simple JSON message after successful connection and keep on printing current message on the screen.
Server can be run using ServerLauncher class in the server project; desktop client uses standard DesktopLauncher class, partially generated by the gdx-setup app in the desktop project.
You can also check out application's behavior without an IDE thanks to Gradle tasks:
gradle server:runlaunches the server.gradle desktop:runlaunches desktop client. Note thatgdx-websocket-commonlibrary should also work on Android (hence the name), so Android code and dependencies would be similar.gradle html:superDevcompiles GWT application and provides the web client version on8080port. Visithttp://localhost:8080to check it out.
Note that this example sends JSON as byte arrays. Although binary format might not be supported by some browsers, WebGL would probably be unavailable there anyway, so this is the preferred way. If you want to send JSON data as string web socket frames, use WebSocket#setSerializeAsString method.