proxypattern.py

from abc import ABC, abstractmethod

class EmployeeDAO(ABC):

    try:
        @abstractmethod
        def create(self, client, employeeObj):
            pass

        @abstractmethod
        def delete(self, client, employeeId):
            pass

        @abstractmethod
        def get(self, client, employeeId):
            pass
    except Exception as e:
        print(e)

class EmployeeDAOImpl(EmployeeDAO):
    def create(self, client, employeeObj):
        # creates a new row
        print('created a new row in employee table')

    def delete(self, client, employeeId):
        # delete a row
        print('deleted a row with employee id: ', employeeId)

    def get(self, client, employeeId):
        # fetch row
        print('fetching data from the DB')
        return EmployeeDO()

class EmployeeDAOProxy(EmployeeDAO):
    employeeDAOObj = None

    def __init__(self):
        self.employeeDAOObj = EmployeeDAOImpl()

    def create(self, client, employeeObj):
        if client == 'ADMIN':
            self.employeeDAOObj.create(client, employeeObj)
            return 
        
        raise Exception('Access Denied!')

    def delete(self, client, employeeId):
        if client == 'ADMIN':
            self.employeeDAOObj.delete(client, employeeId)
            return 
        
        raise Exception('Access Denied!')

    def get(self, client, employeeId):
        if client == 'ADMIN' or client == 'USER':
            return self.employeeDAOObj.get(client, employeeId)
        
        raise Exception('Access Denied!')

class EmployeeDO():
    name = None
    id = None

    def __init__(self, name, id):
        self.name = name
        self.id = id
    
class ProxyDesignPattern:
    try:
        employeeTableObj = EmployeeDAOProxy()
        employeeTableObj.create('USER', EmployeeDO('John', '23'))
        # employeeTableObj.delete('ADMIN', EmployeeDO('Doe', '54').id)
        print('operation executed successfully')
    except Exception as e:
        print(e)