I'm making a collaborative whiteboard app so that when someone is drawing and uses a rectangle for example, a rectangle packet is sent to the server with parameters like
x, y, width, height, color and then that packet is sent to everyone else in the room so that a rectangle is drawn on their screen.
So far everything works perfectly and there's also a stack on each client of all the commands thus far for infinite undo and redo. However, there server does not contain this stack because all it has to do is forward commands to clients in the room.
Everything is working perfectly so far and everyone can see everyone else drawing in real time but I'd like to implement a feature where if someone joins a room late they can see the current whiteboard. That is, the entire command stack would have to be sent to someone. However, this data isn't stored on the server, but each client has their own (identical copy).
Would it be bad for when someone joined to have the server ask one of the clients (which? round-robin?) to send his command stack to the server and have the server forward it to the client? My concerns are the delay and teh amount of data being sent in one go (congestion).
What do you all think? Are there any other options?