Gateway adapter for RPC.

Creates a command and a response channel, which has to be connected to a RPC processor.

It also has Method Caller lists to call directly and can be chained

Options:

• context — Use the given context, if none, creates one
• method_caller: [mc|nil|false] — Use the given method caller, if nil create one, false dont use.

method_caller: false is needed when connecting with an endpoint that provides all method calling, for example a remote side.

Example of use

It can be used in a blocking fasion

iex> alias MOM.{Message, Channel, RPC}
iex> {:ok, rpc} = RPC.start_link
iex> {:ok, caller} = RPC.Endpoint.Caller.start_link(rpc)
iex> Channel.subscribe(rpc.request, fn msg ->
...>  Channel.send(rpc.reply, %Message{ payload: msg.payload.params, id: msg.id })
...>   :ok
...>   end, front: true) # dirty echo rpc.
iex> RPC.Endpoint.Caller.call(caller, "echo", "Hello world!")
{:ok, "Hello world!"}

Returns {:error, :unkown_method} when method does not exist

iex> alias MOM.RPC
iex> {:ok, rpc} = RPC.start_link
iex> {:ok, caller} = RPC.Endpoint.Caller.start_link(rpc)
iex> RPC.Endpoint.Caller.call(caller, "echo", "Hello world!")
{:error, :unknown_method}

dir is a method caller functionality, so no method caller, no dir.

iex> alias MOM.RPC
iex> {:ok, rpc} = RPC.start_link method_caller: false
iex> {:ok, caller} = RPC.Endpoint.Caller.start_link(rpc)
iex> RPC.Endpoint.Caller.call(caller, "dir", [])
{:error, :unknown_method}