|
|
@@ -1,114 +0,0 @@
|
|
|
-%%-----------------------------------------------------------------------------
|
|
|
-%% Copyright (c) 2012-2015, Feng Lee <feng@emqtt.io>
|
|
|
-%%
|
|
|
-%% Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
|
-%% of this software and associated documentation files (the "Software"), to deal
|
|
|
-%% in the Software without restriction, including without limitation the rights
|
|
|
-%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
|
-%% copies of the Software, and to permit persons to whom the Software is
|
|
|
-%% furnished to do so, subject to the following conditions:
|
|
|
-%%
|
|
|
-%% The above copyright notice and this permission notice shall be included in all
|
|
|
-%% copies or substantial portions of the Software.
|
|
|
-%%
|
|
|
-%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
|
-%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
|
-%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
|
-%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
|
-%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
|
-%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
|
|
-%% SOFTWARE.
|
|
|
-%%------------------------------------------------------------------------------
|
|
|
-
|
|
|
--module(emqtt_retained).
|
|
|
-
|
|
|
--author('feng@emqtt.io').
|
|
|
-
|
|
|
-%%TODO: FIXME Later...
|
|
|
-
|
|
|
-%%
|
|
|
-%% <<MQTT_V3.1_Protocol_Specific>>
|
|
|
-
|
|
|
-%% RETAIN
|
|
|
-%% Position: byte 1, bit 0.
|
|
|
-
|
|
|
-%% This flag is only used on PUBLISH messages. When a client sends a PUBLISH to a server, if the Retain flag is set (1), the server should hold on to the message after it has been delivered to the current subscribers.
|
|
|
-
|
|
|
-%% When a new subscription is established on a topic, the last retained message on that topic should be sent to the subscriber with the Retain flag set. If there is no retained message, nothing is sent
|
|
|
-
|
|
|
-%% This is useful where publishers send messages on a "report by exception" basis, where it might be some time between messages. This allows new subscribers to instantly receive data with the retained, or Last Known Good, value.
|
|
|
-
|
|
|
-%% When a server sends a PUBLISH to a client as a result of a subscription that already existed when the original PUBLISH arrived, the Retain flag should not be set, regardless of the Retain flag of the original PUBLISH. This allows a client to distinguish messages that are being received because they were retained and those that are being received "live".
|
|
|
-
|
|
|
-%% Retained messages should be kept over restarts of the server.
|
|
|
-
|
|
|
-%% A server may delete a retained message if it receives a message with a zero-length payload and the Retain flag set on the same topic.
|
|
|
-
|
|
|
--include("emqtt.hrl").
|
|
|
-
|
|
|
--export([start_link/0,
|
|
|
- retain/1,
|
|
|
- lookup/1,
|
|
|
- insert/2,
|
|
|
- delete/1,
|
|
|
- send/2]).
|
|
|
-
|
|
|
--behaviour(gen_server).
|
|
|
-
|
|
|
--export([init/1,
|
|
|
- handle_call/3,
|
|
|
- handle_cast/2,
|
|
|
- handle_info/2,
|
|
|
- terminate/2,
|
|
|
- code_change/3]).
|
|
|
-
|
|
|
--record(state, {}).
|
|
|
-
|
|
|
-start_link() ->
|
|
|
- gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
|
|
|
-
|
|
|
-retain(Msg = #mqtt_message{retain = true}) ->
|
|
|
- Msg;
|
|
|
-
|
|
|
-retain(Msg) -> Msg.
|
|
|
-
|
|
|
-lookup(Topic) ->
|
|
|
- ets:lookup(retained_msg, Topic).
|
|
|
-
|
|
|
-insert(Topic, Msg) ->
|
|
|
- gen_server:cast(?MODULE, {insert, Topic, Msg}).
|
|
|
-
|
|
|
-delete(Topic) ->
|
|
|
- gen_server:cast(?MODULE, {delete, Topic}).
|
|
|
-
|
|
|
-send(Topic, Client) ->
|
|
|
- [Client ! {dispatch, {self(), Msg}} ||{_, Msg} <- lookup(Topic)].
|
|
|
-
|
|
|
-init([]) ->
|
|
|
- ets:new(retained_msg, [set, protected, named_table]),
|
|
|
- {ok, #state{}}.
|
|
|
-
|
|
|
-handle_call(Req, _From, State) ->
|
|
|
- {stop, {badreq,Req}, State}.
|
|
|
-
|
|
|
-handle_cast({insert, Topic, Msg}, State) ->
|
|
|
- ets:insert(retained_msg, {Topic, Msg}),
|
|
|
- {noreply, State};
|
|
|
-
|
|
|
-handle_cast({delete, Topic}, State) ->
|
|
|
- ets:delete(retained_msg, Topic),
|
|
|
- {noreply, State};
|
|
|
-
|
|
|
-handle_cast(Msg, State) ->
|
|
|
- {stop, {badmsg, Msg}, State}.
|
|
|
-
|
|
|
-handle_info(Info, State) ->
|
|
|
- {stop, {badinfo, Info}, State}.
|
|
|
-
|
|
|
-terminate(_Reason, _State) ->
|
|
|
- ok.
|
|
|
-
|
|
|
-code_change(_OldVsn, State, _Extra) ->
|
|
|
- {ok, State}.
|
|
|
-
|
|
|
-
|
Ery Lee