Maple Leaves

This release introduce changes in account system of library. Accounts is a big deal for any crypto(currency) library. Previously hs-web3 support node managed accounts only. Currently library support three types of accounts:

• Default account (node managed, typically first of accounts list, should be unlocked)
• Personal account (node managed accounts available via JSON-RPC personal_* API)
• Local account (derived from secp256k1 private key and use JSON-RPC sendRawTransaction call)

Transaction sending code have a lot of changes too. Introduced Account typeclass in Network.Ethereum.Account module that looks like:

class MonadTrans t => Account a t | t -> a where
    -- | Run computation with given account credentials
    withAccount :: JsonRpc m => a -> t m b -> m b

    -- | Send transaction to contract, like a 'write' command
    send :: (JsonRpc m, Method args) => args -> t m TxReceipt

    -- | Call constant method of contract, like a 'read' command
    call :: (JsonRpc m, Method args, AbiGet result) => args -> t m result

This is mean that sending transaction from multiple accounts simultaneously using withAccount function is not a problem now.

... = do
  withAccount () $ ...
  withAccount (Personal "0x..." "password") $ ...

Transaction parametrisation was too hard previously and forced to carry a lot of vars. Currently withParam function exported in account module use state monad for transaction parametrisation. It make code looks good and more powerful.

    withAccount () $
            -- Set transaction value
            withParam (value .~ halfBalance) $ do
                -- Send transaction to alice account
                withParam (to .~ alice) $ send ()
                -- Send transaction to bob account
                withParam (to .~ bob) $ send ()

Finally in this release contract creation is supported via using truffle generated smart contract artifacts. Example available in tests.

Added

• Support for Ethereum cryptography
• Local private key transaction signer
• Generalized JSON-RPC monad for API methods
• Support for multiple transaction sending methods via one Account api
• Monad based transaction sending parametrization
• Experimental support for solidity compiler (disabled by default)
• Support for Ethereum mainnet ENS resolver
• Contract typeclass with api/bytecode getters
• Contract typeclass TH generator
• Function for creating contracts
• Event single/multi filters
• HexString data type
• Personal api calls
• Address checksum

Changed

• package.yaml instead web3.cabal package descriptor
• Solidity related data types and codecs moved to Data.Solidity
• Solidity related parsers and compiler moved to Language.Solidity
• Modules in Network.Ethereum.Web3 moved to Network.Ethereum.Api
• fromWei/toWei from Unit typeclass now operates over Integral

Removed

• convert function from Unit typeclass