#!/usr/bin/env python
#-*- encoding:utf-8 -*-
""" 对公众平台发送给公众账号的消息加解密示例代码.
@copyright: Copyright (c) 1998-2014 Tencent Inc.
"""
# ------------------------------------------------------------------------
import base64
import string
import random
import hashlib
import time
import struct
from Crypto.Cipher import AES
import xml.etree.cElementTree as ET
import socket
import logging
from . import ierror
logger = logging.Logger(__name__)
"""
关于Crypto.Cipher模块，ImportError: No module named 'Crypto'解决方案
请到官方网站 https://www.dlitz.net/software/pycrypto/ 下载pycrypto。
下载后，按照README中的“Installation”小节的提示进行pycrypto安装。
"""
[文档]def throw_exception(message, exception_class=FormatException):
"""my define raise exception function"""
raise exception_class(message)
[文档]def to_utf8_bytes(str):
return str.encode("utf8")
[文档]def utf8_bytes_to_str(bytes):
return bytes.decode("utf8")
[文档]class SHA1:
"""计算公众平台的消息签名接口"""
[文档] def getSHA1(self, token, timestamp, nonce, encrypt):
"""用SHA1算法生成安全签名
@param token: 票据
@param timestamp: 时间戳
@param encrypt: 密文
@param nonce: 随机字符串
@return: 安全签名
"""
try:
sortlist = [token, timestamp, nonce, encrypt]
sortlist.sort()
sha = hashlib.sha1()
sha.update(to_utf8_bytes("".join(sortlist)))
return ierror.WXBizMsgCrypt_OK, sha.hexdigest()
except Exception as e:
logger.exception('wechat encryption/decryption error')
return ierror.WXBizMsgCrypt_ComputeSignature_Error, None
[文档]class XMLParse:
"""提供提取消息格式中的密文及生成回复消息格式的接口"""
# xml消息模板
AES_TEXT_RESPONSE_TEMPLATE = """<xml>
<Encrypt><![CDATA[%(msg_encrypt)s]]></Encrypt>
<MsgSignature><![CDATA[%(msg_signaturet)s]]></MsgSignature>
<TimeStamp>%(timestamp)s</TimeStamp>
<Nonce><![CDATA[%(nonce)s]]></Nonce>
</xml>"""
[文档] def generate(self, encrypt, signature, timestamp, nonce):
"""生成xml消息
@param encrypt: 加密后的消息密文
@param signature: 安全签名
@param timestamp: 时间戳
@param nonce: 随机字符串
@return: 生成的xml字符串
"""
resp_dict = {
'msg_encrypt' : encrypt,
'msg_signaturet': signature,
'timestamp' : timestamp,
'nonce' : nonce,
}
resp_xml = self.AES_TEXT_RESPONSE_TEMPLATE % resp_dict
return resp_xml
[文档]class PKCS7Encoder():
"""提供基于PKCS7算法的加解密接口"""
block_size = 32
[文档] def encode(self, text_bytes):
""" 对需要加密的明文进行填充补位
@param text_bytes: 需要进行填充补位操作的明文(bytes)
@return: 补齐明文字符(bytes)
"""
text_length = len(text_bytes)
# 计算需要填充的位数
amount_to_pad = self.block_size - (text_length % self.block_size)
if amount_to_pad == 0:
amount_to_pad = self.block_size
# 获得补位所用的字符
pad = bytearray([amount_to_pad])
return text_bytes + pad * amount_to_pad
[文档] def decode(self, decrypted):
"""删除解密后明文的补位字符
@param decrypted: 解密后的明文
@return: 删除补位字符后的明文
"""
pad = ord(decrypted[-1])
if pad<1 or pad >32:
pad = 0
return decrypted[:-pad]
[文档]class Prpcrypt(object):
"""提供接收和推送给公众平台消息的加解密接口"""
def __init__(self,key):
#self.key = base64.b64decode(key+"=")
self.key = key
# 设置加解密模式为AES的CBC模式
self.mode = AES.MODE_CBC
[文档] def encrypt(self,text,appid):
"""对明文进行加密
@param text: 需要加密的明文
@return: 加密得到的字符串
"""
# 16位随机字符串添加到明文开头
text_bytes = to_utf8_bytes(text)
text_bytes = to_utf8_bytes(self.get_random_str()) + struct.pack("I", socket.htonl(
len(text_bytes))) + text_bytes + to_utf8_bytes(appid)
# 使用自定义的填充方式对明文进行补位填充
pkcs7 = PKCS7Encoder()
text_bytes = pkcs7.encode(text_bytes)
# 加密
cryptor = AES.new(self.key,self.mode,self.key[:16])
try:
ciphertext = cryptor.encrypt(text_bytes)
# 使用BASE64对加密后的字符串进行编码
return ierror.WXBizMsgCrypt_OK, utf8_bytes_to_str(base64.b64encode(ciphertext))
except Exception as e:
logger.exception('wechat encryption/decryption error')
return ierror.WXBizMsgCrypt_EncryptAES_Error,None
[文档] def decrypt(self,text,appid):
"""对解密后的明文进行补位删除
@param text: 密文
@return: 删除填充补位后的明文
"""
try:
cryptor = AES.new(self.key,self.mode,self.key[:16])
# 使用BASE64对密文进行解码，然后AES-CBC解密
plain_text = cryptor.decrypt(base64.b64decode(text))
except Exception as e:
logger.exception('wechat encryption/decryption error')
return ierror.WXBizMsgCrypt_DecryptAES_Error,None
try:
pad = plain_text[-1]
# 去掉补位字符串
#pkcs7 = PKCS7Encoder()
#plain_text = pkcs7.encode(plain_text)
# 去除16位随机字符串
content = plain_text[16:-pad]
xml_len = socket.ntohl(struct.unpack("I",content[ : 4])[0])
xml_content = content[4 : xml_len+4]
from_appid = utf8_bytes_to_str(content[xml_len+4:])
except Exception as e:
logger.exception('wechat encryption/decryption error')
return ierror.WXBizMsgCrypt_IllegalBuffer,None
if from_appid != appid:
return ierror.WXBizMsgCrypt_ValidateAppid_Error,None
return 0,xml_content
[文档] def get_random_str(self):
""" 随机生成16位字符串
@return: 16位字符串
"""
rule = string.ascii_letters + string.digits
str = random.sample(rule, 16)
return "".join(str)
[文档]class WXBizMsgCrypt(object):
#构造函数
#@param sToken: 公众平台上，开发者设置的Token
# @param sEncodingAESKey: 公众平台上，开发者设置的EncodingAESKey
# @param sAppId: 企业号的AppId
def __init__(self,sToken,sEncodingAESKey,sAppId):
try:
self.key = base64.b64decode(sEncodingAESKey+"=")
assert len(self.key) == 32
except:
throw_exception("[error]: EncodingAESKey unvalid !", FormatException)
#return ierror.WXBizMsgCrypt_IllegalAesKey)
self.token = sToken
self.appid = sAppId
#验证URL
#@param sMsgSignature: 签名串，对应URL参数的msg_signature
#@param sTimeStamp: 时间戳，对应URL参数的timestamp
#@param sNonce: 随机串，对应URL参数的nonce
#@param sEchoStr: 随机串，对应URL参数的echostr
#@param sReplyEchoStr: 解密之后的echostr，当return返回0时有效
#@return：成功0，失败返回对应的错误码
[文档] def VerifyURL(self, sMsgSignature, sTimeStamp, sNonce, sEchoStr):
sha1 = SHA1()
ret,signature = sha1.getSHA1(self.token, sTimeStamp, sNonce, sEchoStr)
if ret != 0:
return ret, None
if not signature == sMsgSignature:
return ierror.WXBizMsgCrypt_ValidateSignature_Error, None
pc = Prpcrypt(self.key)
ret,sReplyEchoStr = pc.decrypt(sEchoStr,self.appid)
return ret,sReplyEchoStr
[文档] def EncryptMsg(self, sReplyMsg, sNonce, timestamp = None):
#将公众号回复用户的消息加密打包
#@param sReplyMsg: 企业号待回复用户的消息，xml格式的字符串
#@param sTimeStamp: 时间戳，可以自己生成，也可以用URL参数的timestamp,如为None则自动用当前时间
#@param sNonce: 随机串，可以自己生成，也可以用URL参数的nonce
#sEncryptMsg: 加密后的可以直接回复用户的密文，包括msg_signature, timestamp, nonce, encrypt的xml格式的字符串,
#return：成功0，sEncryptMsg,失败返回对应的错误码None
pc = Prpcrypt(self.key)
ret,encrypt = pc.encrypt(sReplyMsg, self.appid)
if ret != 0:
return ret,None
if timestamp is None:
timestamp = str(int(time.time()))
# 生成安全签名
sha1 = SHA1()
ret,signature = sha1.getSHA1(self.token, timestamp, sNonce, encrypt)
if ret != 0:
return ret,None
xmlParse = XMLParse()
return ret,xmlParse.generate(encrypt, signature, timestamp, sNonce)
[文档] def DecryptMsg(self, sPostData, sMsgSignature, sTimeStamp, sNonce):
# 检验消息的真实性，并且获取解密后的明文
# @param sMsgSignature: 签名串，对应URL参数的msg_signature
# @param sTimeStamp: 时间戳，对应URL参数的timestamp
# @param sNonce: 随机串，对应URL参数的nonce
# @param sPostData: 密文，对应POST请求的数据
# xml_content: 解密后的原文，当return返回0时有效
# @return: 成功0，失败返回对应的错误码
# 验证安全签名
xmlParse = XMLParse()
ret,encrypt,touser_name = xmlParse.extract(sPostData)
if ret != 0:
return ret, None
sha1 = SHA1()
ret,signature = sha1.getSHA1(self.token, sTimeStamp, sNonce, encrypt)
if ret != 0:
return ret, None
if not signature == sMsgSignature:
return ierror.WXBizMsgCrypt_ValidateSignature_Error, None
pc = Prpcrypt(self.key)
ret,xml_content = pc.decrypt(encrypt,self.appid)
return ret,xml_content