tsloughter / epubnub

Erlang PubNub API

README

Author: Tristan Sloughter [e-mail] website: http://blog.erlware.org

Version: 0.1.0

Quick Start

• Build

Install rebar3.

$ rebar3 compile

• Test

$ rebar3 shell
1> application:ensure_all_started(epubnub).
ok
2> epubnub:publish(<<"hello_world">>, <<"hello">>).
{[1,<<"Sent">>,<<"13612809348896246">>]}

Examples to publish / see history on channels other than default channels, define a record epn as under (or can be abstracted)
3> rd(epn, {origin, pubkey, subkey, secretkey, client, is_ssl}).
epn
4>  EPN = #epn{origin= <<"pubsub.pubnub.com">>, pubkey = <<"pub-abcd">>, subkey = <<"sub-abcd">>,secretkey= <<"sec-abcd">>,is_ssl=false}.
#epn{origin = <<"pubsub.pubnub.com">>,
     pubkey = <<"pub-abcd">>,
     subkey = <<"sub-abcd">>,
     secretkey = <<"sec-abcd">>,
     client = undefined,is_ssl = false}
5> erpubnub:publish(EPN,<<"channel_name">>,<<"message">>).
{[1,<<"Sent">>,<<"12345566.....">>],#Ref<0.0.0.1234>}
6> epubnub:history(EPN,<<"channel_name">>,1).
{[<<"message">>],#Ref<0.0.0.2403>}

Examples

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.