使用web3.py的send_raw_transaction方法发送交易失败求助

我在测试web3.py的send_raw_transaction方法，试图将ETH从一个账户转到另一个账户，用Ganache做测试环境。严格按照web3文档步骤操作，但每次都报错，问题出在send_raw_transaction调用上。

原代码 #

from web3 import Web3
from web3.middleware import geth_poa_middleware
import json

# GANACHE. TESTING TRANSACTIONS
ganache_url = "http://127.0.0.1:7545"
w3 = Web3(Web3.HTTPProvider(ganache_url))

# accs and keys
account_1 = "0x72e94DaE4d186639B9Bb2baA89caa4Da5f931231"
account_2 = "0xaB2fF898c56a43f56845180081A0C467f2640332"
privatekey_1 = "0x5af8420db3d42b3fc14a13f64dd8dd490783746fdea406ac68afc9b3b9e51132"

# getting eth balance
balance_gwei = w3.eth.get_balance(account_1)
k = 10 ** 18
balance_eth = balance_gwei/k

nonce = w3.eth.get_transaction_count(account_1)

tx = {
    "nonce": nonce,
    "to":   account_2,
    "value":    w3.to_wei(1, "ether"),
    "gas":  20000000000,
    "gasPrice": w3.to_wei("50", "gwei"),
}


print(balance_eth)
signed_tx = w3.eth.account.sign_transaction(tx, privatekey_1)
tx_hash = w3.eth.send_raw_transaction(signed_tx.rawTransaction)
print(balance_eth)

终端错误输出 #

(venv) PS C:\Users\Kirill\Desktop\PYTHON\CRYPTO_PAYMENTS_PYTHON> python main.py

100.0
Traceback (most recent call last):
  File "C:\Users\Kirill\Desktop\PYTHON\CRYPTO_PAYMENTS_PYTHON\main.py", line 34, in <module>
    tx_hash = w3.eth.send_raw_transaction(signed_tx.rawTransaction)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\Kirill\Desktop\PYTHON\CRYPTO_PAYMENTS_PYTHON\venv\Lib\site-packages\web3\eth\eth.py", line 396, in send_raw_transaction
    return self._send_raw_transaction(transaction)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\Kirill\Desktop\PYTHON\CRYPTO_PAYMENTS_PYTHON\venv\Lib\site-packages\web3\module.py", line 75, in caller
    result = w3.manager.request_blocking(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\Kirill\Desktop\PYTHON\CRYPTO_PAYMENTS_PYTHON\venv\Lib\site-packages\web3\manager.py", line 330, in request_blocking
    return self.formatted_response(
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\Kirill\Desktop\PYTHON\CRYPTO_PAYMENTS_PYTHON\venv\Lib\site-packages\web3\manager.py", line 293, in formatted_response
    raise ValueError(error)
ValueError: {'message': 'exceeds block gas limit', 'stack': 'Error: exceeds block gas limit\n    at TransactionPool.<anonymous> (C:\\Program Files\\WindowsApps\\GanacheUI_2.7.1.0_x64__rb4352f0jd4m2\\app\\resources\\static\\node\\node_modules\\ganache\\dist\\node\\1.js:2:120454)\n    at TransactionPool.prepareTransaction (C:\\Program Files\\WindowsApps\\GanacheUI_2.7.1.0_x64__rb4352f0jd4m2\\app\\resources\\static\\node\\node_modules\\ganache\\dist\\node\\1.js:2:120796)\n    at TransactionManager.add (C:\\Program Files\\WindowsApps\\GanacheUI_2.7.1.0_x64__rb4352f0jd4m2\\app\\resources\\static\\node\\node_modules\\ganache\\dist\\node\\1.js:2:138284)\n    at Blockchain.queueTransaction (C:\\Program Files\\WindowsApps\\GanacheUI_2.7.1.0_x64__rb4352f0jd4m2\\app\\resources\\static\\node\\node_modules\\ganache\\dist\\node\\1.js:2:70776)\n    at EthereumApi.eth_sendRawTransaction (C:\\Program Files\\WindowsApps\\GanacheUI_2.7.1.0_x64__rb4352f0jd4m2\\app\\resources\\static\\node\\node_modules\\ganache\\dist\\node\\1.js:2:88213)\n    at EthereumApi.n.value (C:\\Program Files\\WindowsApps\\GanacheUI_2.7.1.0_x64__rb4352f0jd4m2\\app\\resources\\static\\node\\node_modules\\ganache\\dist\\node\\1.js:2:238968)\n    at Object.execute (C:\\Program Files\\WindowsApps\\GanacheUI_2.7.1.0_x64__rb4352f0jd4m2\\app\\resources\\static\\node\\node_modules\\ganache\\dist\\node\\1.js:2:165607)\n    at RequestCoordinator.<anonymous> (C:\\Program Files\\WindowsApps\\GanacheUI_2.7.1.0_x64__rb4352f0jd4m2\\app\\resources\\static\\node\\node_modules\\ganache\\dist\\node\\1.js:2:165421)\n    at C:\\Program Files\\WindowsApps\\GanacheUI_2.7.1.0_x64__rb4352f0jd4m2\\app\\resources\\static\\node\\node_modules\\ganache\\dist\\node\\1.js:2:165687)\n    at new Promise (<anonymous>)', 'code': -32000}

问题分析 #

错误信息明确指出exceeds block gas limit（超出区块gas限制），问题出在你设置的gas参数上：代码里写的20000000000远大于Ganache默认的区块gas限制（通常是6721975左右），而且普通ETH转账只需要固定的21000 gas。

修复后的代码 #

方法1：手动设置正确的gas值 #

把gas改成21000即可：

from web3 import Web3
from web3.middleware import geth_poa_middleware
import json

# GANACHE. TESTING TRANSACTIONS
ganache_url = "http://127.0.0.1:7545"
w3 = Web3(Web3.HTTPProvider(ganache_url))

# accs and keys
account_1 = "0x72e94DaE4d186639B9Bb2baA89caa4Da5f931231"
account_2 = "0xaB2fF898c56a43f56845180081A0C467f2640332"
privatekey_1 = "0x5af8420db3d42b3fc14a13f64dd8dd490783746fdea406ac68afc9b3b9e51132"

# getting eth balance
balance_gwei = w3.eth.get_balance(account_1)
k = 10 ** 18
balance_eth = balance_gwei/k

nonce = w3.eth.get_transaction_count(account_1)

tx = {
    "nonce": nonce,
    "to":   account_2,
    "value":    w3.to_wei(1, "ether"),
    "gas":  21000,  # 普通ETH转账固定需要21000 gas
    "gasPrice": w3.to_wei("50", "gwei"),
}


print(balance_eth)
signed_tx = w3.eth.account.sign_transaction(tx, privatekey_1)
tx_hash = w3.eth.send_raw_transaction(signed_tx.rawTransaction)
print(f"交易哈希: {w3.to_hex(tx_hash)}")
# 查询转账后余额
new_balance = w3.eth.get_balance(account_1)/k
print(f"转账后余额: {new_balance}")

方法2：自动估算gas（更推荐） #

用w3.eth.estimate_gas()方法自动计算当前交易需要的gas，避免手动设置错误：

from web3 import Web3
from web3.middleware import geth_poa_middleware
import json

# GANACHE. TESTING TRANSACTIONS
ganache_url = "http://127.0.0.1:7545"
w3 = Web3(Web3.HTTPProvider(ganache_url))

# accs and keys
account_1 = "0x72e94DaE4d186639B9Bb2baA89caa4Da5f931231"
account_2 = "0xaB2fF898c56a43f56845180081A0C467f2640332"
privatekey_1 = "0x5af8420db3d42b3fc14a13f64dd8dd490783746fdea406ac68afc9b3b9e51132"

# getting eth balance
balance_gwei = w3.eth.get_balance(account_1)
k = 10 ** 18
balance_eth = balance_gwei/k

nonce = w3.eth.get_transaction_count(account_1)

# 先构造不带gas的交易对象
tx = {
    "nonce": nonce,
    "to":   account_2,
    "value":    w3.to_wei(1, "ether"),
    "gasPrice": w3.to_wei("50", "gwei"),
}

# 自动估算gas
tx["gas"] = w3.eth.estimate_gas(tx)

print(balance_eth)
signed_tx = w3.eth.account.sign_transaction(tx, privatekey_1)
tx_hash = w3.eth.send_raw_transaction(signed_tx.rawTransaction)
print(f"交易哈希: {w3.to_hex(tx_hash)}")
# 查询转账后余额
new_balance = w3.eth.get_balance(account_1)/k
print(f"转账后余额: {new_balance}")

说明 #

• 普通ETH转账（仅转ETH，不调用合约）的gas消耗是固定21000，这是以太坊网络的规则。
• 如果你调用智能合约，gas消耗会根据合约执行的代码逻辑变化，此时必须用estimate_gas来计算。
• Ganache的区块gas限制可以在设置里调整，但没必要为了一个普通转账修改，用正确的gas值即可。

内容的提问来源于stack exchange，提问作者zlbr