Proxy Pattern

by
  • Structural pattern
  • The intent of this pattern is to provide a surrogate or placeholder for another object to control access to it.
  • If you intent to control access to the other object due to performance/security reason or other reason , then proxy pattern is the best choice.
  • Best example – when you add service reference — it generates proxy to interact with an API.
  • Proxy is responsible to control the actual remote API.
  • Why not directly call the actual API ?? Proxy can take the responsibility of executing the code before or after calling the API.
  • Proxy :-  provides and interface identical to subject. It maintains a reference of the real subject.
  • Subject:- Defines the common interface between the real subject and the proxy.
  • Real Subject:- Defines the real object that proxy represents.
  •  You can have more than one proxies. You can chain it.
  • This pattern adds a layer between client and actual object.
  • It allows addition of new proxies without chaning the client code:-  OC principle is maintained.
				
					namespace proxydesignpattern
{
    interface IService
    {
        void SignIn(int age);
    }

    public class ActualService : IService
    {
        public void SignIn(int age)
        {
            Console.WriteLine($"You have signed in. Your age is {age}");
        }
    }

    class ProxyService : IService
    {
        private readonly IService _service;

        public ProxyService(IService service)
        {
            _service = service;
        }

        public void SignIn(int age)
        {
            if(age < 18)
            {
                Console.WriteLine("You are too young!!");
            }
            else
            {
                _service.SignIn(age);
            }
        }
    }
}

				
			
				
					// See https://aka.ms/new-console-template for more information



using proxydesignpattern;

IService serviceObj = new ActualService();
IService proxy = new ProxyService(serviceObj);

proxy.SignIn(12);
proxy.SignIn(21);

You are too young

You have signed in. Your age is 21.

https://github.com/AnuragDaCoder/proxy

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