Question

To aid in serializing to JSON, I commonly build a class that inherits from the python dict class. If the class is supposed to have specific fields, I want there to be methods to get & set.

Currently, I construct a class like:

class MyRequest(dict):
    def __init__(self, firstName=None, lastName=None):
        self['firstName'] = firstName
        self['lastName'] = lastName

    def get_firstName(self):
        return self['firstName']
    def set_firstName(self, firstName):
        self['firstName'] = firstName

    def get_lastName(self):
        return self['lastName']
    def set_lastName(self, lastName):
        self['lastName'] = lastName

But this is really cumbersome to work with. Since the underlying ‘storage’ is a dictionary, I can’t just access fields like

myReq.firstName = "Foo"
print myReq.lastName

But is there a way to get to there while still keeping the dict backing?

Answer 1

Yes, there is a way to do what you want. Use properties:

class MyRequest(dict):
    def __init__(self, firstName=None, lastName=None):
        self['firstName'] = firstName
        self['lastName'] = lastName

    @property
    def firstName(self):
        return self['firstName']

    @firstName.setter
    def firstName(self, firstName):
        self['firstName'] = firstName

    @property
    def lastName(self):
        return self['lastName']

    @lastName.setter
    def lastName(self, lastName):
        self['lastName'] = lastName

request = MyRequest('John', 'Connor')
print request.firstName, request.lastName
request.firstName = 'Sarah'
print request.firstName, request.lastName