Hi, I haven't played much with WebSockets, but I have been building a protocol on top of HTTP. I haven't yet run into an issue that made me think to try an effects module.
Instead of having custom subscriptions, my package has an `update` function that takes any msgs resulting from its commands and returns some appropriate stuff (in my case, that is an optional output value that the caller can do something with, and also another Cmd to run). For the Cmds, I do have to use the Tasks portion of the HTTP API so that I can compose and chain things together (though I do in the end return a Cmd for most functions in my protocol's API). For WebSockets, I see there's http://package.elm-lang.org/packages/elm-lang/websocket/1.0.2/WebSocket-LowLevel which provides Tasks instead of Cmds, so it's likely you could use that for what you need. I don't know if those things will address all the needs of your WebSockets protocol, but those approaches have worked for what I've been building. (Sorry, it's not open-source, so can't share the code.) --Aaron V. On Tue, May 16, 2017 at 7:30 AM, Christophe de Vienne < christo...@cdevienne.info> wrote: > Hi everyone, > > I am attempting to implement the pub/sub NATS (https://nats.io) protocol > on top of the WebSocket API as a TEA component. > > I have a hard time finding an API for subscriptions: for each > subscription some context must be kept, a unique subscription ID > generated and in some case a unique reply subject too, and I would like > each subscription to generate custom messages for the component which > made it. > > I suspect it would be a lot more natural with an effect module, with > which I could (hopefully) write, in any part of the application: > > subscriptions : Model -> Sub Msg > subscriptions model = > Nats.Subscribe model.endpoint "some.subject" MyMessage > > or, for req/rep (a pub + a short-living sub expecting a result): > > myrequest : Model -> Cmd Msg > myrequest model = > Nats.request model.endpoint "a.request.subject" MyReply > > > Another difficulty I have is that in some cases I need to send 2 or 3 > messages through the websocket, in the right order, but WebSocket.send > returns a Cmd. So I have to concat the 3 commands in 1 message, which > works but oblige > > Am I wrong being tempted by using an effect module for this kind of module > ? > If so how can I mimick such an API with a TEA approach ? > If not is there any documentation I can read to get familiar with them ? > > Is there any existing module that does this kind of thing for another > protocol ? > > Thanks! > > -- > Christophe de Vienne > > -- > You received this message because you are subscribed to the Google Groups > "Elm Discuss" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to elm-discuss+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
