Readme

This project gives a basic idea of how to implement pre/post/alternate hook. What this means is that we can have the ability to execute an alternate code before/after/or instead of an existing code just by marking the function with a custom attribute. We use Castle.Core's dynamicproxies to accomplish this http://www.castleproject.org/projects/dynamicproxy/

Steps to follow/What I did

1. Create a latest .net standard project. This is an API
2. Add references to Castle.Core
3. Create AddProxiedScoped() as extenstion to IServiceCollection
4. Create a custom attribute. In this case HookAttribute
5. The method that need to be hooked should have this attribute. Make sure the method is virtual or the class with the method implements an interface. This this case its IStudent and Student class and the method is GetFirstLetterOfName()
6. Create your interceptor. In this case HookInterceptor is the interceptor class
7. Register everything. Below lines were added to Program.cs

   builder.Services.AddSingleton(new ProxyGenerator());  
   builder.Services.AddScoped<IInterceptor, HookInterceptor>();  
   builder.Services.AddProxiedScoped<IStudent, Student>();

8. Now place debugger in the attribute, the interceptor and controller method to see how the code gets into custom code if hookattribute is found for a method in the student class and skipped when its not found. SetName() doesnt have the attribute but GetFirstLetterOfName() has.
9. Search for 'Info:' to see comments related to hook specific code change