微信小程序登录 该死的官方文档TypeError: the JSON object must be str, not 'bytes'

官方文档代码

class WXBizDataCrypt:

    def __init__(self, appid, session_key):
        self.appid = appid
        self.session_key = session_key

    def decrypt(self, encrypted_data, iv):
        '''
        aes decode
        将加密后的信息解密
        @param encrypted_data: 包括敏感数据在内的完整用户信息的加密数据
        @param iv: 加密算法的初始向量
        @return: 解密后数据
        '''
        session_key = base64.b64decode(self.session_key)
        encrypted_data = base64.b64decode(encrypted_data)
        iv = base64.b64decode(iv)

        cipher = AES.new(session_key, AES.MODE_CBC, iv)

        decrypted = json.loads(self._unpad(cipher.decrypt(encrypted_data)))

        if decrypted['watermark']['appid'] != self.appid:
            raise Exception('Invalid Buffer')

        return decrypted

    def _unpad(self, s):
        return s[:-ord(s[len(s)-1:])]

该死的官网文档
"""
ERROR exception 135 Internal Server Error: /apple/login/
Traceback (most recent call last):
  File "/home/python/.virtualenvs/py3/lib/python3.5/site-packages/django/core/handlers/exception.py", line 41, in inner
    response = get_response(request)
  File "/home/python/.virtualenvs/py3/lib/python3.5/site-packages/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/python/.virtualenvs/py3/lib/python3.5/site-packages/django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/python/.virtualenvs/py3/lib/python3.5/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
    return view_func(*args, **kwargs)
  File "/home/python/.virtualenvs/py3/lib/python3.5/site-packages/django/views/generic/base.py", line 68, in view
    return self.dispatch(request, *args, **kwargs)
  File "/home/python/.virtualenvs/py3/lib/python3.5/site-packages/rest_framework/views.py", line 483, in dispatch
    response = self.handle_exception(exc)
  File "/home/python/.virtualenvs/py3/lib/python3.5/site-packages/rest_framework/views.py", line 443, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/home/python/.virtualenvs/py3/lib/python3.5/site-packages/rest_framework/views.py", line 480, in dispatch
    response = handler(request, *args, **kwargs)
  File "/home/python/Desktop/dongliang/dongliang/apps/wechat/views.py", line 661, in post
    response = applet.decrypt(encryptedData, iv)
  File "/home/python/Desktop/dongliang/dongliang/apps/wechat/applet_utls.py", line 45, in decrypt
    decrypted = json.loads(self._unpad(cipher.decrypt(encryptedData)))
  File "/usr/lib/python3.5/json/__init__.py", line 312, in loads
    s.__class__.__name__))
TypeError: the JSON object must be str, not 'bytes'
ERROR basehttp 124 "POST /apple/login/ HTTP/1.1" 500 22510

问题：

decrypted = json.loads(self._unpad(cipher.decrypt(encryptedData)))

self._unpad(cipher.decrypt(encrypted_data)) 这个方法是得到一个 bytes 类型数据所以需要解码

json.loads()　　这个方法需要str 是不会 bytes 否则报错
json.loads()　　是json格式处理函数（可以这么理解，json是字符串）
json.loads()   用于解码 JSON 数据。该函数返回 Python 字段的数据类型。
json.loads() 　如果字符串不是字典格式的字符串的时候，执行json.loads会报错! 

解决办法：

　

class WXBizDataCrypt:

    def __init__(self, appid, session_key):
        self.appid = appid
        self.session_key = session_key

    def decrypt(self, encrypted_data, iv):
        '''
        aes decode
        将加密后的信息解密
        @param encrypted_data: 包括敏感数据在内的完整用户信息的加密数据
        @param iv: 加密算法的初始向量
        @return: 解密后数据
        '''
        session_key = base64.b64decode(self.session_key)
        encrypted_data = base64.b64decode(encrypted_data)
        iv = base64.b64decode(iv)

        cipher = AES.new(session_key, AES.MODE_CBC, iv)

        decrypted = json.loads(self._unpad(cipher.decrypt(encrypted_data)).decode())

        if decrypted['watermark']['appid'] != self.appid:
            raise Exception('Invalid Buffer')

        return decrypted

    def _unpad(self, s):
        return s[:-ord(s[len(s)-1:])]