Web3 It’s a high level, user-friendly and support middleware Ethereum JSON-RPC Client.
Features
- [x] Ethereum JSON-RPC Client
- [x] Interacting smart contracts
- [ ] Querying past events
- [ ] Event monitoring as Streams
- [ ] Websockets
Example 1
# Defining the application
defmodule MyApp.Application do
use Web3, rpc_endpoint: "<PATH_TO_RPC_ENDPOINT>"
# middleware (optional)
middleware MyApp.Middleware.Logger
# dispatch (optional)
dispatch :eth_getBalance, args: 2
# contract (optinnal)
contract :FirstContract, contract_address: "0xdAC17F958D2ee523a2206206994597C13D831ec7", abi_path: "path_to_abi.json"
end
# (Optional) If you need to customise your middleware.
defmodule MyApp.Middleware.Logger do
@moduledoc false
@behaviour Web3.Middleware
require Logger
alias Web3.Middleware.Pipeline
import Pipeline
@doc "Before Request HTTP JSON RPC"
def before_dispatch(%Pipeline{} = pipeline) do
# Set metadata assigns here.
Logger.info("MyApp before_dispatch")
pipeline
end
@doc "After Request HTTP JSON RPC"
def after_dispatch(%Pipeline{} = pipeline) do
Logger.info("MyApp after_dispatch")
pipeline
end
@doc "When after request HTTP JSON RPC failed"
def after_failure(%Pipeline{} = pipeline) do
Logger.info("MyApp after_failure")
pipeline
end
end
# Get latest block number
iex> MyApp.Application.eth_blockNumber
{:ok, 15034908}
# Get address balance.
iex> MyApp.Application.eth_getBalance("0xF4986360a6d873ea02F79eC3913be6845e0308A4", "latest")
{:ok, 0}
# Get multi-addresses balance.
iex> MyApp.Application.eth_getBalance(["0xF4986360a6d873ea02F79eC3913be6845e0308A4", "0xF4986360a6d873ea02F79eC3913be6845e0308A4"], "latest")
{:ok,
%{
errors: [],
params: ["0xF4986360a6d873ea02F79eC3913be6845e0308A4", "0xF4986360a6d873ea02F79eC3913be6845e0308A4"],
result: [0, 0]
}
}
# Query Contract
iex> MyApp.Application.FirstContract.balanceOf_address_("0xF4986360a6d873ea02F79eC3913be6845e0308A4")
{:ok, 0}
# Make Transaction
iex> MyApp.Application.FirstContract.approve_address_uint256_(
"0x0000000000000000000000000000000000000000",
10,
gas_price: 12_000_000_000,
gas_limit: 300_000,
chain_id: 1,
nonce: 1,
priv_key: "xxxxxxxxxxxxxxxxxxxxxxxxx"
)
{:ok, true}
More information on web3.
Thank you for reading, have a good day. 
