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64 lines
1.1 KiB
Elm
64 lines
1.1 KiB
Elm
module WsMessage exposing (..)
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import Json.Decode exposing (Decoder, andThen, decodeString, fail, field, map2, map3, string, succeed)
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type Action
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= Publish
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strToAction : String -> Decoder Action
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strToAction str =
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if str == "Publish" then
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succeed Publish
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else
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fail ("invalid action '" ++ str ++ "'")
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type alias Publisher =
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{ uuid : String
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, name : String
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}
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type alias WsMessage =
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{ action : Action
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, publisher : Publisher
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, payload : String
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}
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-- DECODERS
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publisherDecoder : Decoder Publisher
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publisherDecoder =
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map2 Publisher
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(field "uuid" string)
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(field "name" string)
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msgDecoder : Decoder WsMessage
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msgDecoder =
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map3 WsMessage
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actionDecoder
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(field "publisher" publisherDecoder)
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(field "payload" string)
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actionDecoder : Decoder Action
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actionDecoder =
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field "action" string |> andThen strToAction
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decode : String -> Maybe WsMessage
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decode str =
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case decodeString msgDecoder str of
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Ok msg ->
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Just msg
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Err _ ->
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Nothing
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