【Web3初识系列】如何连接 Binance Smart Chain通过交易对绘制 k 线？

连接 Binance Smart Chain通过交易对绘制 k 线

安装 web3

bash 复制代码

pip install web3

连接到 Binance Smart Chain

使用公共的 BSC 节点 URL。

python 复制代码

from web3 import Web3

# 连接到 BSC 公共节点
bsc_url = "https://bsc-dataseed.binance.org/"
web3 = Web3(Web3.HTTPProvider(bsc_url))

# 检查连接是否成功
if web3.is_connected():
    print("Successfully connected to Binance Smart Chain")
else:
    print("Failed to connect to Binance Smart Chain")

# 获取链上信息，例如当前区块号
block_number = web3.eth.block_number
print(f"Current block number: {block_number}")

获取代币的合约实例

需要代币合约的 ABI 和地址。

python 复制代码

# PPIG 代币合约的 ABI 
token_abi = '''
[
    {
        "constant": true,
        "inputs": [],
        "name": "name",
        "outputs": [{"name": "", "type": "string"}],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
    },
    {
        "constant": true,
        "inputs": [],
        "name": "symbol",
        "outputs": [{"name": "", "type": "string"}],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
    },
    {
        "constant": true,
        "inputs": [],
        "name": "decimals",
        "outputs": [{"name": "", "type": "uint8"}],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
    },
    {
        "constant": true,
        "inputs": [{"name": "_owner", "type": "address"}],
        "name": "balanceOf",
        "outputs": [{"name": "balance", "type": "uint256"}],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
    },
    {
        "constant": true,
        "inputs": [],
        "name": "totalSupply",
        "outputs": [{"name": "", "type": "uint256"}],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
    }
]
'''

# 创建代币合约实例
token_contract = web3.eth.contract(address=token_address, abi=token_abi)

# 获取代币信息
token_name = token_contract.functions.name().call()
token_symbol = token_contract.functions.symbol().call()
token_decimals = token_contract.functions.decimals().call()
token_total_supply = token_contract.functions.totalSupply().call()

print(f"Token Name: {token_name}")
print(f"Token Symbol: {token_symbol}")
print(f"Token Decimals: {token_decimals}")
print(f"Token Total Supply: {web3.from_wei(token_total_supply, 'ether')} {token_symbol}")

监听特定事件

监听 PPIG 交易对的 Swap 事件。

python 复制代码

# 添加 Geth POA 中间件（如果使用的是 PoA 网络）
web3.middleware_onion.inject(geth_poa_middleware, layer=0)

# PPIG/WBNB 交易对合约的 ABI
pair_abi = '''
[
    {
        "anonymous": false,
        "inputs": [
            {"indexed": true, "name": "sender", "type": "address"},
            {"indexed": false, "name": "amount0In", "type": "uint256"},
            {"indexed": false, "name": "amount1In", "type": "uint256"},
            {"indexed": false, "name": "amount0Out", "type": "uint256"},
            {"indexed": false, "name": "amount1Out", "type": "uint256"},
            {"indexed": true, "name": "to", "type": "address"}
        ],
        "name": "Swap",
        "type": "event"
    }
]
'''

# 创建交易对合约实例
pair_contract = web3.eth.contract(address=pair_address, abi=pair_abi)

# 创建 Swap 事件过滤器
swap_event_filter = pair_contract.events.Swap.create_filter(fromBlock='latest')


# 处理事件的回调函数
def handle_event(event):
    print(event)
    # 提取事件数据
    timestamp = web3.eth.get_block(event['blockNumber'])['timestamp']
    dt_object = datetime.fromtimestamp(timestamp)
    amount0In = web3.from_wei(event['args']['amount0In'], 'ether')
    amount1In = web3.from_wei(event['args']['amount1In'], 'ether')
    amount0Out = web3.from_wei(event['args']['amount0Out'], 'ether')
    amount1Out = web3.from_wei(event['args']['amount1Out'], 'ether')

    # 根据具体需求处理数据，这里只是打印出来
    print(
        f"Time: {dt_object}, amount0In: {amount0In}, amount1In: {amount1In}, amount0Out: {amount0Out}, amount1Out: {amount1Out}")


# 轮询新事件
def log_loop(event_filter, poll_interval):
    while True:
        for event in event_filter.get_new_entries():
            handle_event(event)
        time.sleep(poll_interval)

生成 K 线图

收集一段时间后，我们可以使用 Pandas 和 Matplotlib 生成 K 线图。

python 复制代码

import pandas as pd
import matplotlib.pyplot as plt
from datetime import datetime


data = {
    'timestamp': [datetime(2024, 6, 19, 12, 0), datetime(2024, 6, 19, 12, 5), datetime(2024, 6, 19, 12, 10)],
    'price': [10, 12, 11],
    'volume': [100, 150, 120]
}

df = pd.DataFrame(data)

# 设置时间为索引
df.set_index('timestamp', inplace=True)

# 生成 K 线图
plt.figure(figsize=(10, 5))
plt.plot(df.index, df['price'], marker='o')
plt.title('PPIG/WBNB Price')
plt.xlabel('Time')
plt.ylabel('Price')
plt.grid()
plt.show()

注意事项

生成k线时，使用到了模拟数据，在实际的环境中注意换成实时数据包装。