Publisher helper scaffold.

Simply use Envio.Publisher in the module that should publish messages. The broadcast/2 function becomes available. If the optional channel: argument is passed to use Envio.Publisher, this channel is considered the default one and broadcast/1 function appears to publish directly to the default channel.

The ready-to-copy-paste example of usage would be:

defmodule MyPub do
  use Envio.Publisher, channel: :main

  def publish(channel, what), do: broadcast(channel, what)
  def publish(what), do: broadcast(what)
end

All the subscribers of the particular channel the message was published to, will either receive a message (in the case of :pub_sub) or called back with the function provided on subscription (:dispatch).

Since v0.8.0 Envío supports Phoenix.PubSub for distributed message broadcasting.

The publisher does not wrap :via functionality since it makes not much sense.

For how to subscribe, see Envio.Subscriber.