1、安装

pip install web3

2、使用Web3

测试提供商

from web3 import Web3, EthereumTesterProvider
w3 = Web3(EthereumTesterProvider())

本地提供商

from web3 import Web3

# IPCProvider:
w3 = Web3(Web3.IPCProvider(./path/to/geth.ipc))

# HTTPProvider:
w3 = Web3(Web3.HTTPProvider(http://127.0.0.1:8545))

# WebsocketProvider:
w3 = Web3(Web3.WebsocketProvider(wss://127.0.0.1:8546))

远程提供商

与以太坊区块链交互的最快方法是使用远程节点提供商，如Infura、Alchemy或QuickNode。您可以通过指定端点连接到远程节点，就像本地节点一样：

from web3 import Web3
w3 = Web3(Web3.HTTPProvider(https://<your-provider-url>))
w3 = Web3(Web3.WebsocketProvider(wss://<your-provider-url>))

判断连接状态

w3.isConnected()

3、创建账户

使用web3创建账户

account = w3.eth.account.create()
print(account.address)

使用eth_account创建账户

效果与 web3 一致，安装web3.py会自动安装 eth-account

from eth_account import Account

account = Account.create()
print(account.address)
# 账户的私钥
print(account.key.hex())

通过private_key导入账户

from eth_account import Account
import json

key = ...
account = Account.from_key(key)
print(account.address)

获取账户列表

accounts = w3.eth.accounts

获取默认账户

w3.eth.default_account

4、常用方法

获取最新区块

w3.eth.get_block(latest)

获取区块数量

w3.eth.block_number

获取区块交易

w3.eth.get_transaction_by_block(46147, 0)

获取余额

balance = w3.eth.getBalance(account)

发送转账交易

params = {
    from:accounts[0],
    to:accounts[1],
    value:w3.toWei(1, "ether")
}
tx_hash = w3.eth.sendTransaction(params)

获取交易信息

tx = w3.eth.getTransaction(tx_hash)

获取交易收据

如果交易处于pending状态，则返回null。

tx = w3.eth.getTransactionReceipt(tx_hash)

获取Nonce

nonce = w3.eth.getTransactionCount(account)

5、合约调用

合约实例化

filePath = "../contracts/usdt.json"
text = open(filePath, encoding=utf-8).read()
jsonObj = json.loads(text)
usdt_contract_addr = 合约地址
usdt = w3.eth.contract(address=usdt_contract_addr, abi=jsonObj[abi])

合约读操作

balance = usdt.functions.balanceOf(accounts[0]).call()

合约写操作

option = {
    from: accounts[0],
    gas: 1000000
}
usdt.functions.approve(usdt_contract_addr, 2000000).transact(option)

带签名的合约写操作

options = {
    gas: 1000000,
    gasPrice: w3.toWei(21, gwei),
    from: account.address,
    nonce: w3.eth.getTransactionCount(account.address)
}
tx = usdt.functions.approve(usdt_contract_addr, 2000000).buildTransaction(options)
signed = account.signTransaction(tx) # 用账户对交易签名	
tx_id = w3.eth.sendRawTransaction(signed.rawTransaction) # 交易发送并获取交易id
print(tx_id.hex())