.. module:: rpc

===
RPC
===

This module allows calling the JSON-RPC endpoints of a geth node. ::


    from blockchain.ethereum import rpc

    ...

    address = "0x84db76Ea20C2f55F94A87440fBE825fBE5476da1"

    # setup node address
    eth = rpc.RPC("ethereum.zerynth.com:8545")

    # retrieve balance
    print("Balance:",eth.getBalance(address))
    print("Gas Price:",eth.getGasPrice())
    nonce = eth.getTransactionCount(address)
    print("Transaction Count:",nonce)
    print("Chain:",eth.getChainId())



    
.. _lib.blockchain.ethereum.rpc:
=========
RPC class
=========

.. class:: RPC(host)

    Initialize a RPC instance with the geth node at *host*.
    *host* must also contain the port and the protocol (i.e. :samp:`https://mynode.com:8545`)

    
.. method:: call(method,params=(),retry=10)

    :param method: the endpoint to call
    :param params: the list of parameters for the endpoint
    :param retry: the number of call retries before failing

    Call endpoint *method* with params *params*. Return the :samp:`result` field of the
    endpoint json response or None in case of error. Error reason can be retrieved in :samp:`self.last_error`.

        
.. method:: getBalance(address,block_number="latest")

    :params address: Ethereum address
    :params block_number: the point in the blockchain up to which balance is calculated

    Return the current balance for address *address*. Previous balances can be retrieved by specifying a different *block_number*

        
.. method:: getGasPrice()

    Return the current gas price estimated by the Ethereum node. Return 0 on error.

        
.. method:: getChainId()

    Return the Ethereum network id
        
.. _lib.blockchain.ethereum.rpc.getTransactionCount:
.. method:: getTransactionCount(address,block_number="latest")

        :param address: Ethereum address
        :param block_number: the point in the blockchain up to which the transaction count is calculated

        Return the current transaction count for address *address*. The returned value can be used as nonce for the next transaction.
        Transaction counts at specific points in time can be retrieved by specifying a different *block_number*.

        
.. method:: sendTransaction(tx,retry=10)

        :param tx: the hexadecimal hash of a signed transaction
        :param retry: the number of retries

        Send the raw transaction to the geth node in order to broadcast it to all nodes in the network. If correct, it will be eventually added to a mined block.

        
.. method:: simpleCall(tx,block_number,retry=10)

        :param tx: the hexadecimal hash of a signed transaction
        :param block_number: the point in the blockchain up to which make the call
        :param retry: the number of retries

        Executes a new message call immediately without creating a transaction on the block chain.