Does ASP.NET MVC have any DateTime route constraints?

Question

does ASP.NET MVC contain any route contraints baked into the code? if so, how do i define a date-time constraint?

eg. url:

http://mydomain.com/{versionDate}/{controller}/{action}
http://mydomain.com/2010-01-20/search/posts

cheers :)

Retardant

What exactly do you mean by a date-time constraint? Where would the value for that constraint come from? How do you want it to route based on that constraint? Could that constraint simply be a parameter to a controller, which further redirects or calls other controller methods algorithmically? – Unesco

notice how i have a slot in the route for VersionDate? i was hoping that if a person put an invalid date in there, it would error. As such, I thought that it would be best to place a route - constraint on that route parameter .. to prevent bad data getting passed in. – Retardant

Answer 1

I ended up making my own route constraint. only took a few mins.

using System;
using System.Web;
using System.Web.Routing;

namespace Whatever.Your.Funky.Cold.Medina.Namespace.Is
{
    public class DateTimeRouteConstraint : IRouteConstraint
    {
        #region IRouteConstraint Members

        public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values,
                          RouteDirection routeDirection)
        {
            DateTime dateTime;

            return DateTime.TryParse(values[parameterName] as string, out dateTime);
        }

        #endregion
    }
}

simple :P

Retardant

Well that was a rather elegant solution. +1 – Unesco

It's still wrong, haha - I tried to change "Funcky" to "Funky" but it rejected the edit as < 6 chars :'-( – Meatiness

Fix0rd. Donno why I didn't fix it before. – Retardant

Answer 2

You could also set up a constraint on the route, something like so. The regular expression used is not very robust, so you should refine it.

routes.MapRoute( 
    "Version", "
    {versionDate}/{controller}/{action}", 
    new {controller="Search", action="Posts"}, 
    new {versionDate= @"\d\d\d\d-\d\d-\d\d" } 
    ); 

Information from here.

Shrink

i thought of using a regex, initally, but like you suggested, it's not very robust. which is why i wanted to utilise the power to DateTime.TryParse(...). – Retardant

@37Start: don't you think a regular expression like "\d{4}-\d{2}-\d{2}" would be more readable and more standard? ;) Or maybe even writing one that would only let in correct dates (month not greater than 12 etc.) – Garris

+1 Absolutely that would be better. I always have to break out the RegEx book when I get around to writing these as I do it infrequently. I wrote that response as I was heading out the door, hence the "you should refine it" comment. – Shrink

Answer 3

all of the framework is overide-able so it's possible, with a great deal of pain, to overide the default behaviour of the route engine but i agree with @jrista in that you might want to make it a parameter of the controller else mvc will expect to find /search/posts within the 2010-01-20 folder

Sihunn

within the 2010-01-20 folder? there are no folders. it's just controllers and their views. Also, it's not part of the action method. I'm actually capturing this in the abstract controller - because all routes will have this. That way, it's KISS. – Retardant

Hmmm, then you may want to download the source for the framework and see if you can either extend it or find out how to overide the default routing behaviour. – Sihunn

I've ended up making a custom route constraint. took me a few mins to do. solved. – Retardant