[erlang-questions] Push a message to cowboy websockets
AD
straightflush@REDACTED
Fri Mar 16 21:56:22 CET 2012
Sigh, no. Thanks, its working perfectly now.
-AD
On Fri, Mar 16, 2012 at 4:18 PM, Loïc Hoguin <essen@REDACTED> wrote:
> Did you start gproc? application:start(gproc)
>
>
> On 03/16/2012 09:05 PM, AD wrote:
>
>> Thanks, getting some stacktraces though...
>>
>> ** Handler ad_test terminating in websocket_init/3
>> for the reason error:badarg
>>
>> i have
>>
>> /-define(WSBroadcast,"**wsbroadcast")./
>>
>> then in websocket_init
>>
>> /gproc:reg({p, l, {?MODULE, ?WSBroadcast}})/
>> /
>>
>> /
>> then in my handle() method in cowboy for a certain path
>>
>> /{URLPath,_Req2} = cowboy_http_req:path(Req),/
>> / case lists:nth(1,URLPath) of/
>> /<<"sendit">> -> /
>> /%io:format("Sending websocket !!~n"),/
>> /Msg = "Test broadcast",/
>> /gproc:send({p, l, {?MODULE,?WSBroadcast}}, {self(),
>> {?MODULE,?WSBroadcast}, Msg});/
>> /
>> /
>> then in websocket_info
>>
>> w/ebsocket_info({_PID,{_**MODULE,_WSBroadcast},Msg},Req,**State) ->/
>> /{reply, {text, <<Msg>>}, Req, State, hibernate}./
>>
>>
>> Any thoughts ? Looks like something with ets:insert
>>
>> ** Stacktrace: [{ets,insert_new,
>> [gproc,
>> [{{{p,l,{ad_test,"wsbroadcast"**}},<0.153.0>},
>> <0.153.0>,undefined},
>> {{<0.153.0>,{p,l,{ad_test,"**wsbroadcast"}}},[]}]],
>> []},
>>
>> Thanks again for the help
>> -AD
>>
>> On Fri, Mar 16, 2012 at 2:06 PM, Loïc Hoguin <essen@REDACTED
>> <mailto:essen@REDACTED>> wrote:
>>
>> Just like you would catch any message, you match:
>>
>> websocket_info({Pid, {Module, WSBroadcast}, Msg}, Req, State)
>>
>> When using gproc:send/2, the second arg is what you want to match in
>> the first arg of websocket_info/3. All messages the websocket
>> process receives are given to you in websocket_info/3.
>>
>> Didn't try the new pubsub, it looks interesting though.
>>
>>
>> On 03/16/2012 07:01 PM, AD wrote:
>>
>> Thanks, so in websocket/init
>>
>> gproc:reg({p, l, {?MODULE, WSBroadcast}}).
>>
>> Then in my webservice i can do
>>
>> Msg = "Test broadcast".
>> gproc:send({p, l, {?MODULE,WSBroadcast}}, {self(),
>> {?MODULE,WSBroadcast}, Msg}).
>>
>> How do you catch this in websocket_info/3 to formulate a reply?
>>
>> Also noticed a new pub/sub module for gproc not sure if this helps
>> simplify some of this
>> https://github.com/uwiger/__**gproc/blob/master/src/gproc___**
>> ps.erl <https://github.com/uwiger/__gproc/blob/master/src/gproc___ps.erl>
>>
>> <https://github.com/uwiger/**gproc/blob/master/src/gproc_**ps.erl<https://github.com/uwiger/gproc/blob/master/src/gproc_ps.erl>
>> >
>>
>> Thanks!
>> -AD
>>
>> On Fri, Mar 16, 2012 at 12:20 PM, Loïc Hoguin
>> <essen@REDACTED <mailto:essen@REDACTED>
>> <mailto:essen@REDACTED <mailto:essen@REDACTED>>> wrote:
>>
>> Hey!
>>
>> The general idea is to have your websocket handler register
>> itself
>> using gproc[1] (or through a central gen_server) inside the
>> websocket_init/3 callback, and then have your service push
>> messages
>> to all registered handlers which you can then catch in
>> websocket_info/3.
>>
>> I mention gproc because it's infinitely easier with it, as
>> you only
>> have to register all your processes under one property and
>> then send
>> a message to that property which will multicast it to all
>> registered
>> processes. And when your websocket closes, gproc takes care of
>> removing your process from the list of registered processes,
>> so you
>> really have to worry only about 2 lines of code to do
>> everything you
>> need.
>>
>> Good luck!
>>
>> [1] https://github.com/uwiger/____**gproc<https://github.com/uwiger/____gproc>
>> <https://github.com/uwiger/__**gproc<https://github.com/uwiger/__gproc>
>> >
>>
>> <https://github.com/uwiger/__**gproc<https://github.com/uwiger/__gproc>
>> <https://github.com/uwiger/**gproc<https://github.com/uwiger/gproc>
>> >>
>>
>>
>>
>> On 03/16/2012 05:11 PM, AD wrote:
>>
>> Hello,
>>
>> I have cowboy setup and working to send/receive
>> websockets over a
>> socket connection. I am trying to figure out how to
>> initiate a
>> message
>> server side over that channel (without it just being a
>> reply). I am
>> envisioning exposing a webservice on the cowboy service
>> that
>> would then
>> push a message to all connected users (or maybe a subset
>> based
>> on some
>> criteria).
>>
>> Does anyone know if this is possible and if so how to
>> implement?
>>
>> Cheers,
>> -AD
>>
>>
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>>
>>
>> --
>> Loďc Hoguin
>> Erlang Cowboy
>> Nine Nines
>>
>>
>>
>>
>> --
>> Loïc Hoguin
>> Erlang Cowboy
>> Nine Nines
>>
>>
>>
>
> --
> Loïc Hoguin
> Erlang Cowboy
> Nine Nines
>
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