Web3.Contract.Event

Contract event watching via port subscriptions.

-- Subscribe to Transfer events
subscriptions model =
    Event.watchEvent
        { contract = tokenAddress
        , event = "Transfer"
        , filter = []
        }
        |> Event.decoder transferDecoder
        |> onContractEvent TransferReceived

type alias EventFilter =

{ contract : Address

, event : String

, topics : List (Maybe String)

}

An event subscription filter.

type alias EventLog a =

{ data : a

, contract : Address

, topics : List String

, blockNumber : Int

, txHash : TxHash

, logIndex : Int

}

A decoded event log.

type alias GetLogsQuery =

{ contract : Address

, fromBlock : BlockNumber

, toBlock : BlockNumber

, topics : List (Maybe String)

}

A query for getLogs with fromBlock/toBlock range.

watchEvent : EventFilter -> Value

Create an event watch command.

encode : EventFilter -> Value

Encode an event filter for the JS port.

decoder : Decoder a -> Decoder (EventLog a)

Decode a watchEvent log from the JS port.

Requires the message to have tag: "eventLog" — use logsDecoder for the batch getLogs response which wraps logs in an array.

getLogs : GetLogsQuery -> Value

Encode a getLogs query for the JS port.

logsDecoder : Decoder a -> Decoder (List (EventLog a))

Decode a list of event logs with a custom data decoder.

Decodes the { tag: "logs", logs: [...] } response from getLogs.

intrepidshape/elm-web3/1.4.0

Web3.Contract.Event

Modules