Pass user information with the op to remote clients.

[maxfortun]

Use case: Visually track change attribution across remote clients.

[#224] allows to store metadata, which contains userId, but falls short of pushing metadata out to remote clients.

Proposed solution:

On a server side:

Retain backend constructor options in order to pass around options.opsOptions to configure metadata behavior.

Include message.m in agent's _sendOp based on backend.options.opsOptions.metadata configuration.

Include op.m in SubmitRequest based on backend.options.opsOptions.metadata configuration.

On a client side:

Emit op.m with every op related event.

this.emit('op', componentOp.op, source, op.src, op.m);

[alecgibson]

I think it might be possible to get this to work without any modifications. You're allowed to set an arbitrary ID on your Connection:

connection = nw Connection(socket);
// Concat with a `uuid` in case the same user has multiple sessions, since
// the Connection ID should be unique per-connection
connection.id = [userId, uuid()].join(':');

Then in remote clients, on the 'op' event, you can check the src:

doc.on('op', (op, source, src) => {
  const [userId] = src.split(':');
  // Do something with userId...
});

[maxfortun]

@alecgibson , thank you for a quick response! I will experiment with your suggestion and it may be good enough for now. I was using userId as a simplified example and was ultimately hoping to pass around a more sophisticated metadata object with multiple fields. Code suggests that that's what op.m is intended for, so I researched that vector. Using a connection id is a cool idea.

[alecgibson]

Yeah that's fair; I've long thought we should be able to facilitate getting op metadata to clients!