AttributeRouting.cs

public IQueryable<CustomerPurchases> GetPurchases(int customerID)
{
return _purchaseService.GetPurchases(customerID);
}

AttributeRouting10.cs

public class CouponCodeConstraint : IHttpRouteConstraint
    {
      public bool Match(HttpRequestMessage request, IHttpRoute route, string parameterName,
       IDictionary<string, object> values, HttpRouteDirection routeDirection)
        {
            object o;

            if (values.TryGetValue(parameterName, out o) && o != null)
            {
                if (!values.TryGetValue(parameterName, out o) || o == null)
                    return false;
                ///Coupon Code must be in format c#####c, i.e. A12345D
                return (Regex.Match(Convert.ToString(o), "^[a-zA-Z][0-9]{5}[a-zA-Z]$").Success);
            }
            return false;
        }
    }

AttributeRouting11.cs

public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            // Web API configuration and services
            var constraintResolver = new DefaultInlineConstraintResolver();
            constraintResolver.ConstraintMap.Add("coupon", typeof(CouponCodeConstraint));

            // Web API routes
            config.MapHttpAttributeRoutes(constraintResolver);

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

AttributeRouting12.cs

[HttpGet, Route("{couponCode:coupon}")]
public HttpResponseMessage GetCoupon(String couponCode)
{
    ...
}

AttributeRouting2.cs

[HttpGet, Route("api/customer/{customerID}/purchases")]

AttributeRouting3.cs

[HttpGet, Route("api/customer/{customerID}/purchases")]
public IQueryable<CustomerPurchases> GetPurchases(int customerID)
{
return _purchaseService.GetPurchases(customerID);
}

AttributeRouting4.cs

[RoutePrefix("api/customer")]
public class CustomerController : ApiController

AttributeRouting5.cs

[HttpGet, Route("{customerID}")]

AttributeRouting6.cs

[HttpGet, Route("api/customer/{customerID:guid}/purchases")]

AttributeRouting7.cs

[Route("api/pages/{pageNum:int=1}")]

AttributeRouting8.cs

[Route("api/pages/{pageNum:int?}")]

AttributeRouting9.cs

[Route("{customerID:minlength(1):alpha}")]