A2UI.Transport behaviour (A2UI v0.3.0)

Behaviour for A2UI message transport.

A transport handles bidirectional communication between a client (LiveView or external) and an agent:

Client → Agent: connect/1, send_action/3, send_error/3, disconnect/1
Agent → Client: deliver_message/2

On connect/1, the transport creates an A2UI.Connection struct and registers with the agent. The agent dispatches messages back through deliver_message/2 using the connection's transport module and ref.

Dispatch Helpers

Instead of calling a specific transport module directly, you can use the dispatch functions on this module:

A2UI.Transport.send_action(transport, action, metadata)

These dispatch to the correct implementation based on the transport struct.

Summary

Types

t()

Callbacks

connect(opts)

deliver_message(ref, message)

Delivers an A2UI protocol message to the connected client.

disconnect(t)

send_action(t, t, metadata)

send_error(t, t, metadata)

Functions

disconnect(transport)

Disconnects the transport. Dispatches based on the struct module.

send_action(transport, action, metadata)

Sends an action through the transport. Dispatches based on the struct module.

send_error(transport, error, metadata)

Sends an error through the transport. Dispatches based on the struct module.

Types

t()

@type t() :: struct()

Callbacks

connect(opts)

(optional)

@callback connect(opts :: keyword()) :: {:ok, t()} | {:error, any()}

deliver_message(ref, message)

@callback deliver_message(ref :: term(), message :: struct()) :: :ok | {:error, any()}

Delivers an A2UI protocol message to the connected client.

Called by A2UI.Agent.send_message/2 using the connection's transport module and ref. The ref argument is transport-specific — for Local transport it is the LiveView pid; for SSE it is the handler process pid.

disconnect(t)

(optional)

@callback disconnect(t()) :: :ok

send_action(t, t, metadata)

(optional)

@callback send_action(t(), A2UI.Protocol.Messages.Action.t(), metadata :: map()) ::
  :ok | {:error, any()}

send_error(t, t, metadata)

(optional)

@callback send_error(t(), A2UI.Protocol.Messages.Error.t(), metadata :: map()) ::
  :ok | {:error, any()}

Functions

disconnect(transport)

@spec disconnect(t()) :: :ok

Disconnects the transport. Dispatches based on the struct module.

send_action(transport, action, metadata)

@spec send_action(t(), A2UI.Protocol.Messages.Action.t(), map()) ::
  :ok | {:error, any()}

Sends an action through the transport. Dispatches based on the struct module.

send_error(transport, error, metadata)

@spec send_error(t(), A2UI.Protocol.Messages.Error.t(), map()) ::
  :ok | {:error, any()}

Sends an error through the transport. Dispatches based on the struct module.