Installation

    def deps do
      [{:exw3, "~> 0.1.2"}]
    end

Overview

ExW3 is a wrapper around ethereumex to provide a high level, user friendly json rpc api. It currently only supports Http. The primary feature it provides is a handy abstraction for working with smart contracts.

Usage

Ensure you have an ethereum node to connect to at the specified url in your config. An easy local testnet to use is ganache-cli:

ganache-cli

Make sure your config includes:

config :ethereumex,
  url: "http://localhost:8545"

Currently, ExW3 supports a handful of json rpc commands. Mostly just the useful ones. If it doesn't support a specific commands you can always use the Ethereumex commands.

Check out the documentation

iex(1)> accounts = ExW3.accounts()
["0xb5c17637ccc1a5d91715429de76949fbe49d36f0",
 "0xecf00f60a29acf81d7fdf696fd2ca1fa82b623b0",
 "0xbf11365685e07ad86387098f27204700d7568ee2",
 "0xba76d611c29fb25158e5a7409cb627cf1bd220cf",
 "0xbb209f51ef097cc5ca320264b5373a48f7ee0fba",
 "0x31b7a2c8b2f82a92bf4cb5fd13971849c6c956fc",
 "0xeb943cee8ec3723ab3a06e45dc2a75a3caa04288",
 "0x59315d9706ac567d01860d7ede03720876972162",
 "0x4dbd23f361a4df1ef5e517b68e099bf2fcc77b10",
 "0x150eb320428b9bc93453b850b4ea454a35308f17"]
iex(2)> ExW3.balance(Enum.at(accounts, 0))
99999999999962720359
iex(3)> ExW3.block_number()
835
iex(4)> simple_storage_abi = ExW3.load_abi("test/examples/build/SimpleStorage.abi")
%{
  "get" => %{
    "constant" => true,
    "inputs" => [],
    "name" => "get",
    "outputs" => [%{"name" => "", "type" => "uint256"}],
    "payable" => false,
    "stateMutability" => "view",
    "type" => "function"
  },
  "set" => %{
    "constant" => false,
    "inputs" => [%{"name" => "_data", "type" => "uint256"}],
    "name" => "set",
    "outputs" => [],
    "payable" => false,
    "stateMutability" => "nonpayable",
    "type" => "function"
  }
}
iex(5)> ExW3.Contract.start_link(SimpleStorage, abi: simple_storage_abi)
{:ok, #PID<0.239.0>}
iex(6)> {:ok, address} = ExW3.Contract.deploy(SimpleStorage, bin: ExW3.load_bin("test/examples/build/SimpleStorage.bin"), options: %{gas: 300000, from: Enum.at(accounts, 0)})
{:ok, "0xd99306b81bd61cb0ecdd3f2c946af513b3395088"}
iex(7)> ExW3.Contract.at(SimpleStorage, address)
:ok
iex(8)> ExW3.Contract.call(SimpleStorage, :get)
{:ok, 0}
iex(9)> ExW3.Contract.send(SimpleStorage, :set, [1], %{from: Enum.at(accounts, 0)})
{:ok, "0xb7e9cbdd2cec8ca017e675059a3af063d754496c960f156e1a41fe51ea82f3b8"}
iex(10)> ExW3.Contract.call(SimpleStorage, :get)                                
{:ok, 1}

Compiling Soldity

To compile the test solidity contracts after making a change run this command:

solc --abi --bin --overwrite -o test/examples/build test/examples/contracts/*.sol