How to access nested dict using @property-CodePudding

I am able to set class attributes by using @property decorator using the following code, however I am not able to set attributes(in a hierarchy) in case it is a nested dict. For example if we need to print the value of 'port' which is within nested 'credentials' dict then how can I use print(obj.credentials.port) rather than using print(obj.port)

class TestDec:
    def __init__(self,value) -> None:
        self.value = value
    @property
    def description(self):
        return self.value["description"]
    @property
    def credentials(self):
        return self.value["credentials"]
    @property
    def username(self):
        return self.value["credentials"]["username"]  
    @property
    def password(self):
        return self.value["credentials"]["password"]   
    @property
    def port(self):
        try:
            return self.value["credentials"]["port"]      
        except KeyError:
            pass                    

obj = TestDec({"description":"test decorator","credentials":{"username":"abc","password":"xxxx","port":"5432"}})
print(obj.description)
print(obj.credentials)
print(obj.username)
print(obj.password)
print(obj.port)

CodePudding user response：

Either you have an error with obj.username and similar and it should be obj.credentials.username (like in my example below), or you want to recursively search for key, which I don't think is a good idea. But for this nested dot accessing elements of dictionary, this could be sufficient.

from collections import UserDict


class MyDict(UserDict):
    def __getattr__(self, arg):
        try:
            result = self.data[arg]
        except KeyError as error:
            raise AttributeError from error

        if isinstance(result, dict):
            return MyDict(result)
        return result


obj = MyDict(
    {
        "description": "test decorator",
        "credentials": {"username": "abc", "password": "xxxx", "port": "5432"},
    }
)
print(obj.description)
print(obj.credentials)
print(obj.credentials.username)
print(obj.credentials.password)
print(obj.credentials.port)