110 lines
3.5 KiB
Python
110 lines
3.5 KiB
Python
import re
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import time
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import hashlib
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import base64
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import json
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from urllib.parse import urlparse
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from cryptography.hazmat.primitives import serialization, hashes
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from cryptography.hazmat.primitives.asymmetric import padding
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from cryptography.hazmat.backends import default_backend
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from Crypto.Cipher import AES
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from django.conf import settings
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import os
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def load_private_key():
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"""加载私钥（支持 PKCS#1 和 PKCS#8）"""
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key_path = settings.WECHAT_PAY_V3_CONFIG['PRIVATE_KEY_PATH']
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with open(key_path, 'rb') as f:
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key_data = f.read()
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# cryptography 自动识别格式
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private_key = serialization.load_pem_private_key(
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key_data,
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password=None,
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backend=default_backend()
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)
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return private_key
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def build_authorization(method, url, body):
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"""生成V3接口的Authorization头"""
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private_key = load_private_key()
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mchid = settings.WECHAT_PAY_V3_CONFIG['MCHID']
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serial_no = settings.WECHAT_PAY_V3_CONFIG['CERT_SERIAL_NO']
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parsed = urlparse(url)
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path = parsed.path
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if parsed.query:
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path += '?' + parsed.query
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timestamp = str(int(time.time()))
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nonce = hashlib.md5((timestamp + 'wechat').encode()).hexdigest()[:32]
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# 构造签名串
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message = '\n'.join([method, path, timestamp, nonce, body]) + '\n'
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# 使用 cryptography 签名
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signature = private_key.sign(
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message.encode('utf-8'),
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padding.PKCS1v15(),
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hashes.SHA256()
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)
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signature_b64 = base64.b64encode(signature).decode('utf-8')
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auth = f'WECHATPAY2-SHA256-RSA2048 mchid="{mchid}",nonce_str="{nonce}",timestamp="{timestamp}",serial_no="{serial_no}",signature="{signature_b64}"'
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return auth
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def verify_wechat_sign(headers, body):
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"""验证微信回调签名（需提前下载平台证书）"""
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# 这部分使用 rsa 库验签，也可以改用 cryptography，但 rsa 已足够
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import rsa
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serial = headers.get('Wechatpay-Serial')
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signature = headers.get('Wechatpay-Signature')
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timestamp = headers.get('Wechatpay-Timestamp')
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nonce = headers.get('Wechatpay-Nonce')
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if not all([serial, signature, timestamp, nonce]):
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return False
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if not re.match(r'^[A-Za-z0-9-]+$', serial):
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return False
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try:
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ts = int(headers.get('Wechatpay-Timestamp', '0'))
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if abs(time.time() - ts) > 300: # 5分钟有效期
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return False
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except (ValueError, TypeError):
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return False
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message = '\n'.join([timestamp, nonce, body]) + '\n'
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cert_path = f"{settings.WECHAT_PAY_V3_CONFIG['PLATFORM_CERT_DIR']}/{serial}.pem"
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if not os.path.exists(cert_path):
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return False
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with open(cert_path, 'rb') as f:
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pub_key = rsa.PublicKey.load_pkcs1_openssl_pem(f.read())
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signature_bytes = base64.b64decode(signature)
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try:
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rsa.verify(message.encode('utf-8'), signature_bytes, pub_key)
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return True
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except rsa.VerificationError:
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return False
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def decrypt_callback_ciphertext(associated_data, nonce, ciphertext):
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"""解密回调数据（使用 AES-GCM）"""
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api_v3_key = settings.WECHAT_PAY_V3_CONFIG['API_V3_KEY'].encode('utf-8')
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nonce_bytes = nonce.encode('utf-8')
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ciphertext_bytes = base64.b64decode(ciphertext)
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cipher = AES.new(api_v3_key, AES.MODE_GCM, nonce=nonce_bytes)
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if associated_data:
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cipher.update(associated_data.encode('utf-8'))
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plaintext = cipher.decrypt_and_verify(ciphertext_bytes[:-16], ciphertext_bytes[-16:])
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return plaintext.decode('utf-8')
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