Implement WebSockets in Android using Native Sockets

Question

There is a javascript code residing in my Android app's webkit container. This code makes use of WebSockets to communicate with the server. The same JS code works in other platforms such as iOS, but in Android 2.3, it doesn't. I read somewhere that the webkit in Android does not support WebSockets, and support will come only in Jelly Bean onwards.

In view of this, I need to provide a wrapper from the native layer (in Java) making use of plain sockets. From the little I know about sockets, it seems straightforward to support the usual APIs such as open(), send(), receive(), etc.

Is there anything else I need to know that the WebSocket protocol needs, which I will need to provide from the wrapper code? After all, the server talks to the client (my android app) as if it is a WebSocket, and not a native socket.

Some notes to consider: a) I cannot make use of any third-party library - it will have to be developed in-house. b) There will not be any binary data transferred; only text.

Thanks,
Rajath

Answer 1

Websockets are not raw sockets, they require an initial handshake then simple per-message framing. See the protocol spec for details. The sections on handshake and data framing will be most relevant.

I know you said you can't use third party libraries but be aware that projects like Java-Websocket might be interesting to you. It's liberally licensed so suitable for inclusion in any closed source app. Or you might find it useful as a reference while debugging your own code.

• Rajath: Thank you. I'll go through the links you you have mentioned
• Rajath: the spec links you sent were very useful, especially to see that it involved some work. Finally, we went with the Java-Websocket library that you mention. Thanks again.