joseluistorres / elm-action-cable

Client-side Elm library for ActionCable, part of the Ruby on Rails suite

ActionCable in Elm

This package is an Elm client library for ActionCable, which comes bundled with Ruby on Rails.

Basic Usage

type Msg
    = SubscribeTo String
    | UnsubscribeFrom String
    | HandleData ActionCable.Identifier Json.Decode.Value
    | SendData String String
    | CableMsg ActionCable.WireProtocol



update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
    case msg of
        SubscribeTo roomName ->
            case ActionCable.subscribeTo (channelId roomName) model.cable of
                Ok ( cable, cmd ) ->
                    { model | cable = cable } ! [ Cmd.map CableMsg cmd ]

                Err err ->
                    -- you're probably already subscribed to this channel
                    { model | errorPopup = Just <| ActionCable.errorToString err } ! []

        UnsubscribeFrom roomName ->
            case ActionCable.unsubscribeFrom (channelId roomName) model.cable of
                Ok ( cable, cmd ) ->
                    { model | cable = cable } ! [ Cmd.map CableMsg cmd ]

                Err err ->
                    -- you're probably already unsubscribed from this channel
                    { model | errorPopup = Just <| ActionCable.errorToString err } ! []

        HandleData identifier value ->
            -- value is a Json.Decode.Value. You'll probably want more than `toString`
            { model | messages = toString value :: model.messages } ! []

        SendData roomName aStringToSend ->
            let
                sendCmd =
                    ActionCable.perform
                        "some_channel_action_name"
                        [ ( "jsonKey", Json.Encode.string aStringToSend ) ]
                        (channelId roomName)
                        model.cable
            in
                case sendCmd of
                    Ok toSend ->
                        ( model, toSend )

                    Err err ->
                        -- probably because you haven't subscribed to the channel yet
                        { model | errorPopup = Just <| ActionCable.errorToString err } ! []

        CableMsg cableMsg ->
            -- important to forward on "accounting" messages to the underlying submodel
            { model | cable = ActionCable.update cableMsg model.cable } ! []


channelId : String -> ActionCable.Identifier.Identifier
channelId roomName =
    ID.newIdentifier "ChatChannel" [ ( "room", roomName ) ]



-- subscriptions


subscriptions : Model -> Sub Msg
subscriptions model =
    ActionCable.listen CableMsg HandleData model.cable

License

elm-action-cable is released under the Apache v2 license, the details of which can be found in the LICENSE file.

Author

• Brad Grzesiak, Bendyworks