This version is based on the work of Tim McCall, found at https://github.com/mccalltd/AttributeRouting

It brings a richer syntax that you can use in your route URL to specify constraints inline.

You can use the following syntax to constraint the parameter to be of the required type:

// Restrict the 'id' parameter to digits only
// Restrict the 'name' parameter to any string with a maximum length of 50-
[GET("my-url/{id:int}/{name:string(50)}")]

Here is the full list of built-in type restrictions:

string(max-length), bool, int, long, float, double, decimal

You can also add a regular expression constraint by using the following syntax:

// Restrict 'someParam' to letters only
[GET("my-url/{someParam:regex(^[a-zA-Z]+$)}")

You can easily add your own type of constraints. For example, here's how to create a constraint for even numbers:

1. Create a new class that implements IRouteConstraint:

   public class EvenRouteConstraint : IRouteConstraint
   {
       public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection)
       {
           var value = values[parameterName];
           if (value == null)
               return true;
   
           int intValue;
           if (!int.TryParse(value.ToString(), out intValue))
               return false;
   
           return intValue % 2 == 0;
       }
   }
   

2. Register this constraint, somewhere in your Application_Start:

   using AttributeRouting.Constraints;
   ...
   
   protected void Application_Start()
   {
       RouteConstraintFactory.RegisterConstraintType("even", typeof(EvenRouteConstraint));
   }
   

3. Use the constraint:

   // Restricts 'someParam' to be an even number
   [GET("my-url/{someParam:even}")]
   

You can restrict a parameter to the values of an enum:

1. Create an enum:

   public enum Colors
   {
       Red,
       Green,
       Blue
   }
   

2. Register the new constraint type:

   RouteConstraintFactory.RegisterConstraintType("color", typeof(EnumRouteConstraint<Colors>));
   

3. Apply the constraint to a URL parameter:

   // Restrict 'someParam' to values 'red', 'green' and 'blue'
   [GET("my-url/{someParam:color}")]