Web3.Query

Typed decoders for on-chain read queries: transaction count (nonce), storage slot reads, contract bytecode, and transaction lookup by hash.

Each query carries a correlation id that is echoed back so responses can be matched when multiple queries are in flight.

-- Send via your port:
web3Cmd (Web3.Query.encode (Web3.Query.getTxCount address "nonce-1"))


-- Receive via your port:
case D.decodeValue Web3.Query.decoder incoming of
    Ok (Web3.Query.GotTxCount id nonce) -> ...
    Ok (Web3.Query.GotStorageAt id val) -> ...
    Ok (Web3.Query.GotCode id bytecode) -> ...
    Ok (Web3.Query.GotTransaction id info) -> ...
    Ok (Web3.Query.TransactionNotFound id) -> ...
    Err _ -> -- not a query response

type Cmd

= RequestTxCount Address String

| RequestStorageAt Address Int String

| RequestCode Address String

| RequestTransaction TxHash String

Commands to send to the JS query port.

type Msg

= GotTxCount String Int

| GotStorageAt String String

| GotCode String String

| GotTransaction String TransactionInfo

| TransactionNotFound String

Messages from the JS query port.

type alias TransactionInfo =

{ hash : TxHash

, from : Address

, to : Maybe Address

, value : Wei

, nonce : Int

, data : String

, gas : Int

, blockNumber : Maybe Int

, blockHash : Maybe String

}

Information about a transaction fetched by hash.

getTxCount : Address -> String -> Cmd

Build a transaction count (nonce) query for address, tagged with id.

getStorageAt : Address -> Int -> String -> Cmd

Build a storage slot query. slot is the integer slot index (converted to hex).

getCode : Address -> String -> Cmd

Build a contract bytecode query for contract, tagged with id.

getTransaction : TxHash -> String -> Cmd

Request a transaction by hash. The second argument is a request ID.

encode : Cmd -> Value

Encode a Cmd for the JS port.

decoder : Decoder Msg

Decode query responses from the JS port.

Handles txCount, storageAt, code, transaction, and transactionNotFound tags. Returns Err for unknown tags.

quietgarden/elm-web3/2.0.1

Web3.Query

Modules