如何在 Django 中获取更新的类变量值

Posted 2023-02-22

【中文标题】如何在 Django 中获取更新的类变量值

【英文标题】：How to get updated class variable value in Django

【发布时间】：2022-01-06 23:53:21

【问题描述】：

我无法获取类变量的更新值。

当p_request函数执行后调用ConnectTestAPI时，result和orderNo的类变量应该在post函数中更新。

然后我想通过在p_request函数中循环while语句来接收类变量的更新值。

但是，尽管用post请求设置了类变量的值，但是当while语句运行时，对应的值仍然分别为空和0值，

因此，while 语句无法终止并导致超时错误。 这是我的源代码。提前谢谢！

class ConnectTestAPI(APIView):
   result=""
   orderNo=0
   
   def post(self, request):
      data = request.data
      ConnectTestAPI.result = data['result'] 
      ConnectTestAPI.orderNo = data['orderNo'] 
      print(ConnectTestAPI.result) # I could successfully get data from POST request here!
      print(ConnectTestAPI.orderNo) # I could successfully get data from POST request here!
      return HttpResponse("ok")

   def p_request():
      data = 
         "a" : 1234,
         "b" : 5678
      
      data = json.dumps(data,ensure_ascii=False).encode('utf-8')
      con = redis.StrictRedis(outside_server['ip'],outside_server['port'])
      con.set("data_dict", data)
      while True:
         if ConnectTestAPI.result != "" and ConnectTestAPI.orderNo != 0:
            break
      res_result = ConnectTestAPI.result
      res_orderNo = ConnectTestAPI.orderNo
      return res_result, res_orderNo

【参考方案1】：

您需要使用self访问类变量：

class ConnectTestAPI(APIView):
   result=""
   orderNo=0
   
   def post(self, request):
      data = request.data
      self.result = data['result'] 
      self.orderNo = data['orderNo'] 
      print(self.result) # I could successfully get data from POST request here!
      print(self.orderNo) # I could successfully get data from POST request here!
      return HttpResponse("ok")

   def p_request():
      data = 
         "a" : 1234,
         "b" : 5678
      
      data = json.dumps(data,ensure_ascii=False).encode('utf-8')
      con = redis.StrictRedis(outside_server['ip'],outside_server['port'])
      con.set("data_dict", data)
      while True:
         if self.result != "" and self.orderNo != 0:
            break
      res_result = self.result
      res_orderNo = self.orderNo
      return res_result, res_orderNo

注意：不建议使用这种类属性。您正在改变一个类属性，该属性对该类的所有实例都有副作用。在您的情况下，在 __ init__() 中初始化的普通属性就可以了：

class ConnectTestAPI(APIView):
   def __init__(self):
      self.result=""
      self.orderNo=0
   
   def post(self, request):
      data = request.data
      self.result = data['result'] 
      self.orderNo = data['orderNo'] 
      print(self.result) # I could successfully get data from POST request here!
      print(self.orderNo) # I could successfully get data from POST request here!
      return HttpResponse("ok")

   def p_request():
      data = 
         "a" : 1234,
         "b" : 5678
      
      data = json.dumps(data,ensure_ascii=False).encode('utf-8')
      con = redis.StrictRedis(outside_server['ip'],outside_server['port'])
      con.set("data_dict", data)
      while True:
         if self.result != "" and self.orderNo != 0:
            break
      res_result = self.result
      res_orderNo = self.orderNo
      return res_result, res_orderNo

【讨论】：

感谢您的回答！！我刚刚尝试了您上传的两个答案，但“self.result”和“self.orderNo”仍然是初始值......我该如何解决？

我认为，您需要显示实例化和使用类的代码。上面定义的类就ok了。