Representation of a Phoenix Channel

Topic of channel

Initialize a channel to a given topic.

init "room:lobby"

Attach a payload to the join message. You can use this to submit e.g. a user id or authentication infos. This will be the second argument in your join/3 callback on the server.

payload =
    Json.Encode.object [("user_id", "123")]


init "room:lobby"
    |> withPayload payload

Register an event handler for a event.

type Msg = NewMsg Value | ...


init "roomy:lobby"
    |> on "new_msg" NewMsg

Set a callback which will be called after you sucessfully joined the channel. It will also be called after you rejoined the channel after a disconnect unless you specified an onRejoin handler.

type Msg =
    IsOnline Json.Encode.Value | ...


init "room:lobby"
    |> onJoin IsOnline

Set a callback which will be called after you request to join the channel.

type Msg =
    JoinLobbyRequested


init "room:lobby"
    |> onRequestJoin JoinLobbyRequested

Set a callback which will be called if the server declined your request to join the channel.

type Msg =
    CouldNotJoin Json.Encode.Value | ...


init "room:lobby"
    |> onJoinError CouldNotJoin

Note: If a channel declined a request to join a topic the effect manager won_t try again.

Set a callback which will be called if the channel process on the server crashed. The effect manager will automatically rejoin the channel after a crash.

type Msg =
     ChannelCrashed | ...


init "room:lobby"
    |> onError ChannelCrashed

Set a callback which will be called after you sucessfully left a channel.

type Msg =
    LeftLobby Json.Encode.Value | ...


init "room:lobby"
    |> onLeave LeftLobby

Set a callback which will be called if the server declined your request to left a channel. _(It seems that Phoenix v1.2 doesn_t send this)_

Print all status changes.

Set a callback which will be called when there is a change in the presence state caused by "presence_state" and "presence_diff" events.

type Msg =
    PresenceChange (Dict String (List Json.Encode.Value)) | ...


init "room:lobby"
    |> onPresenceChange PresenceChange

Composes each callback with the function a -> b.