Carries a board's ephemeral traffic — where people's cursors are, and where a shape is while it is still being dragged.
Separate from the LiveView socket on purpose. Both kinds of traffic are high-rate and worthless a moment later, and putting them through a LiveView means every position pays for a render and a diff, queued behind that process's real work: saving edits, uploads, link previews. A channel is a message in and a message out.
Nothing here is persisted or authoritative. The durable path is unchanged —
the client still emits etcher:annotations-changed to its LiveView when an
edit is finished, and that is what is stored and broadcast to peers. This
socket only makes the time before the edit finishes visible.
Mounting it
Sockets are declared on the endpoint, which belongs to the host, so this
needs one line in endpoint.ex:
socket "/phoenix_kit/board", PhoenixKitBoards.Web.BoardSocket, websocket: trueNothing more: connect/3 takes the peer from the signed token and reads no
connect_info, so there is none to declare.
It is optional. A host that hasn't added it loses nothing that worked before: the client notices the socket isn't there and falls back to relaying cursors through its LiveView, which is where they used to go.
Who may join
A board page mints a short-lived signed token naming the board and the peer, and hands it to the client. The channel re-derives the peer from the token rather than believing anything the client says about itself — so a client cannot join a board it was never shown, and cannot present as somebody else.
Summary
Functions
Where the host mounted this socket.
The endpoint line names the path, so a host that mounts it somewhere else says so with:
config :phoenix_kit_boards, board_socket_path: "/somewhere/else"The client is told the answer rather than guessing it.
Mint the token a board page hands to its client.
Carries the peer's identity, so the channel never has to take the client's word for who it is.