WebSockets in Atomic Data

WebSockets are a very fast and efficient way to have a client and server communicate in an asynchronous fashion. They are used in Atomic Data to allow real-time updates, which makes it possible to create things like collaborative applications and multiplayer games. These have been implemented in atomic-server and atomic-data-browser (powered by @tomic/lib).

Initializing a WebSocket connection

Send an HTTP GET request to the /ws endpoint of an atomic-server. The Server should update that request to a secure WebSocket (wss) connection. Use x-atomic authentication headers (read more here) and use ws as a subject when signing. The WebSocket-Protocol is AtomicData.

Client to server messages

• SUBSCRIBE ${subject} tells the Server that you'd like to receive Commits about this Subject.
• UNSUBSCRIBE ${subject} tells the Server that you'd like to stop receiving Commits about this Subject.
• GET ${subject} fetch an individual resource.
• AUTHENTICATE ${authenticationResource} to set a user session for this websocket and allow authorized messages. The authenticationResource is a JSON-AD resource containing the signature and more, see Authentication.

Server to client messages

• COMMIT ${CommitBody} an entire Commit for a resource that you're subscribed to.
• RESOURCE ${Resource} a JSON-AD Resource as a response to a GET message. If there is something wrong with this request (e.g. 404), return a Error Resource with the requested subject, similar to how the HTTP protocol server does this.`
• ERROR ${ErrorBody} an Error resource is sent whenever something goes wrong. The ErrorBody is a plaintext, typically English description of what went wrong.

Considerations

• For many messages, there is no response to give if things are processed correctly. If a message is unknown or there is a different problem, return an ERROR.

Example implementations

• Example client implementation in Typescript (@tomic/lib).
• Example server implementation in Rust using Actix-Web