Question

I have decorator for my views which creates new instance of SomeClass and calls original view function with this param.

def decorator(orig_func):
    def inner_func(request, *args, **kwargs):
        api = SomeClass(request)
        return orig_func(request, api, *args, **kwargs)

The problem is that properties (variables) inside SomeClass seem to be persistent across many requests – for example when view_one is executed it sets some properties inside apu (SomeClass) class. In the second request to view_two those properties are still set with values from first request. How I can avoid this? I need simple solution.

---

here is SomeClass:

class SomeClass:
    some_variable = None

    def __init__(self,value):
        #self.some_variable = None

    def setVariable(self,value):
        self.some_variable = value

    def getVariable(self):
        return self.some_variable

My proble was that when request was executed and the commented line was commented, some_variable was not neccessery None – it had the value set during previous request. So I wrote this commented line to “clear” the variable.

Now I have a question – is this safe? Is there a possibility that one request will clear this variable during another request is executed and it will be overriden in this another request to None?

Answer 1

The following is the correct class definition you want.

class SomeClass:
    def __init__(self,value):
        self.some_variable = value

    def setVariable(self,value):
        self.some_variable = value

    def getVariable(self):
        return self.some_variable

This will set the attribute on the instance rather than on the class object.

>>> a = SomeClass(5)
>>> a.some_variable # Just as expected
5
>>> b = SomeClass(10)
>>> b.some_variable # This is its own variable
10
>>> b.some_variable = 20 # This won't change 'a'
>>> a.some_variable # Hasn't changed
5

I might also want to note that getters and setters are often not want you want when writing python since you can do instance.some_variable = 5 without the need of a getter or setter.