README.md

web3

The humble beginnings of a Nim library similar to web3.[js|py]

Installation

You can install the development version of the library through nimble with the following command

nimble install https://github.com/status-im/nim-web3@#master

Development

First, fetch the submodules:

git submodule update --init --recursive

Install nodemon globally, hardhat locally and create a hardhat.config.js file:

npm install -g nodemon
npm install hardhat
echo "module.exports = {};" > hardhat.config.js

Then you should run ./simulator.sh which runs hardhat node

This creates a local simulated Ethereum network on your local machine and the tests will use this for their E2E processing

ABI encoder / decoder

Implements encoding of parameters according to the Ethereum Contract ABI Specification using nim-serialization interface.

Usage

import
  serialization,
  stint,
  web3/[encoding, decoding]

# encode unsigned integers, booleans, enums
Abi.encode(42'u8)

# encode uint256
Abi.encode(42.u256)

# encode byte arrays and sequences
Abi.encode([1'u8, 2'u8, 3'u8])
Abi.encode(@[1'u8, 2'u8, 3'u8])

# encode tuples
Abi.encode( (42'u8, @[1'u8, 2'u8, 3'u8], true) )

# decode values of different types
Abi.decode(bytes, uint8)
Abi.decode(bytes, UInt256)
Abi.decode(bytes, array[3, uint8])
Abi.decode(bytes, seq[uint8])

# decode tuples
Abi.decode(bytes, (uint32, bool, seq[byte]))

# custom type
type Contract = object
  a: uint64
  b {.dontSerialize.}: string
  c: bool

let encoded = Abi.encode(x)
let decoded = Abi.decode(encoded, Contract)

# encoded.a == decoded.a
# encoded.b == ""
# encoded.c == decoded.c

License

Licensed and distributed under either of

• MIT license: LICENSE-MIT or http://opensource.org/licenses/MIT

or

• Apache License, Version 2.0, (LICENSE-APACHEv2 or http://www.apache.org/licenses/LICENSE-2.0)

at your option. This file may not be copied, modified, or distributed except according to those terms.