• Powerful platform for building APIs that expose services and data.
• ASP.NET Web API is a framework for building RESTful web APIs on top of the .NET Framework.

• Web API that supports CRUD Operations
• MVC
• Models
• Views
• Controllers
• Contexts

• Create, Read, Update, Delete (CRUD)

• Plain Old CLR Object (POCO)

 public class Product
 {
     public int ProductId { get; set; }
     public string ProductName { get; set; }

     public int PersonId { get; set; }
 }
 public class Person
 {
     public int PersonId { get; set; }
     public string FirstName { get; set; }
     public string LastName { get; set; }
      public virtual ICollection<Product> Products { get; set; }
 }

• A Controller is a class that handles HTTP requests from the clients.

 private MVC4WebApiContext db = new MVC4WebApiContext();

 // GET api/Persons
 public IEnumerable<Person> GetPeople()
 {
    return db.People.AsEnumerable();
 }

• DbContext: Primary object for interacting with a database using a specific Model.
• DbSet: Used to perform CRUD operations against a specific type from a Model.

 public class MVC4WebApiContext : DbContext
 {
     public MVC4WebApiContext() : base("name=MVC4WebApiContext")
     {
     }

     public DbSet<Person> People { get; set; }
     public DbSet<Product> Products { get; set; }
 }

• Routing Tables

 public static void Register(HttpConfiguration config)
 {
      config.Routes.MapHttpRoute(
          name: "DefaultApi",
          routeTemplate: "api/{controller}/{id}",
          defaults: new { id = RouteParameter.Optional }
      );

      config.Routes.MapHttpRoute(
          name: "ActionApi",
          routeTemplate: "api/{controller}/{action}/{id}",
          defaults: new { id = RouteParameter.Optional }
      );
 }

    
[HttpGet][ActionName("Beer")]// GET api/Products/Beer
public IEnumerable<Product> GetProducts()
{
 return db.Products.AsEnumerable().Where(x => x.productName == "Beer");
}

• Using [FromUri]

 public HttpResponseMessage PostProduct([FromUri] int id){}

• Using [FromBody]

 public HttpResponseMessage PostProduct([FromBody] Product product){}

• IModelBinder

 public Product GetProduct([ModelBinder(typeof(CustomModelBinder))]string id){}

 public class CustomModelBinder : IModelBinder
    {
        public bool BindModel(System.Web.Http.Controllers.HttpActionContext actionContext, ModelBindingContext bindingContext)
        {
            ValueProviderResult val = bindingContext.ValueProvider.GetValue(
                bindingContext.ModelName);

            if (val == null)
            {
                return false;
            }

            string newVal = "Hello!";

            bindingContext.Model = newVal;
            return true;
        }
    }

1. Authorization Filters
2. Action Filters
3. Result Filters
4. Exception Filters

 public class CustomActionFilter : ActionFilterAttribute
 {
    public override void OnActionExecuted(        HttpActionExecutedContext actionExecutedContext){}

    public override void OnActionExecuting(           HttpActionContextactionContext){} }
[CustomActionFilter]
 public class ProductsController : ApiController {}