Author: Tristan Sloughter t@crashfast.com website: http://blog.erlware.org
Version: 0.1.0
- Build
$ ./rebar3 compile- Test
$ ./rebar3 shell
1> application:ensure_all_started(epubnub).
ok
2> epubnub:publish(<<"hello_world">>, <<"hello">>).
{[1,<<"Sent">>,<<"13612809348896246">>]}src/epn_example_client has a simple example of a gen_server subscribing to a channel. The init function takes an EPN record, created with epubsub:new() in start_link and requests to subscribe to the "hello_world" channel and sends its PID with the self() function so new messages are sent to this process.
init([EPN]) ->
{ok, PID} = epubnub_sup:subscribe(EPN, <<"hello_world">>, self()),
{ok, #state{pid=PID}}.
Since currently the subscribe loop sends the message with the bang (!) the gen_server will handle the new message in handle_info. The example simply prints out the contents of the message:
handle_info({message, Message}, State) ->
io:format("~p~n", [Message]),
{noreply, State}.
To unscribe we call the module stop function that sends an async stop message to the process. The handle_cast function handles this message and return stop telling the gen_server to go to terminate. In terminate we take the PID of the subscribed process to the epubnub unsubscribe function which sends it a terminate message and it exits.
stop() ->
gen_server:cast(?SERVER, stop).
handle_cast(stop, State) ->
{stop, normal, State}.
terminate(_Reason, #state{pid=PID}) ->
epubnub:unsubscribe(PID),
ok.