A Python implementation of web3.js
- Python 2.7, 3.4, 3.5 support
Read more in the documentation on ReadTheDocs. View the change log on Github.
import json
import web3
from web3 import Web3, HTTPProvider, TestRPCProvider
from solc import compile_source
from web3.contract import ConciseContract
# Solidity source code
contract_source_code = '''
pragma solidity ^0.4.0;
contract Greeter {
string public greeting;
function Greeter() {
greeting = 'Hello';
}
function setGreeting(string _greeting) public {
greeting = _greeting;
}
function greet() constant returns (string) {
return greeting;
}
}
'''
compiled_sol = compile_source(contract_source_code) # Compiled source code
contract_interface = compiled_sol['<stdin>:Greeter']
# web3.py instance
w3 = Web3(TestRPCProvider())
# Instantiate and deploy contract
contract = w3.eth.contract(contract_interface['abi'], bytecode=contract_interface['bin'])
# Get transaction hash from deployed contract
tx_hash = contract.deploy(transaction={'from': w3.eth.accounts[0], 'gas': 410000})
# Get tx receipt to get contract address
tx_receipt = w3.eth.getTransactionReceipt(tx_hash)
contract_address = tx_receipt['contractAddress']
# Contract instance in concise mode
contract_instance = w3.eth.contract(contract_interface['abi'], contract_address, ContractFactoryClass=ConciseContract)
# Getters + Setters for web3.eth.contract object
print('Contract value: {}'.format(contract_instance.greet()))
contract_instance.setGreeting('Nihao', transact={'from': w3.eth.accounts[0]})
print('Setting value to: Nihao')
print('Contract value: {}'.format(contract_instance.greet()))If you would like to hack on web3.py, set up your dev environment with:
sudo apt-get install libssl-dev
# ^ This is for Debian-like systems. TODO: Add more platforms
git clone git@github.com:pipermerriam/web3.py.git
cd web3.py
virtualenv venv
. venv/bin/activate
pip install -r requirements-dev.txt
pip install -e .For different environments, you can set up multiple virtualenvs, like:
Python 2
virtualenv -p python2 venvpy2
. venvpy2/bin/activate
pip install -r requirements-dev.txt
pip install -e .Docs
virtualenv venvdocs
. venvdocs/bin/activate
pip install -r requirements-dev.txt
pip install -e .During development, you might like to have tests run on every file save.
Show flake8 errors on file change:
# Test flake8
when-changed -r web3/ tests/ -c "clear; git diff HEAD^ | flake8 --diff"You can use pytest-watch, running one for every python environment:
pip install pytest-watch
cd venv
ptw --onfail "notify-send -t 5000 'Test failure ⚠⚠⚠⚠⚠' 'python 3 test on web3.py failed'" ../tests ../web3
#in a new console
cd venvpy2
ptw --onfail "notify-send -t 5000 'Test failure ⚠⚠⚠⚠⚠' 'python 2 test on web3.py failed'" ../tests ../web3Or, you can run multi-process tests in one command, but without color:
# in the project root:
py.test --numprocesses=4 --looponfail --maxfail=1
# the same thing, succinctly:
pytest -n 4 -f --maxfail=1For Debian-like systems:
apt install pandoc
TODO other release instructions