When you convert an existing ASP.NET application to ASP.NET MVC you will sooner or later want to handle legacy URLs.
Imagine an ASP.NET application containing the page "YourPage.aspx".
Now you want to redirect request to that legacy URL to the new MVC Action: "Home/YourPage".
I have looked at several implementations on the internet, but none of them was really simple.
Thus I implemented another solution which is really easy to configure.
For the URL "YourPage.aspx" (see above) you only have to add one line to your Global.asax.cs:
routes.Add(new LegacyRoute("YourPage.aspx", "Home/YourPage"));
Quite simple, isn’t it? But what happens behind the scenes? Let’s have a look at the source:
The class LegacyRoute derives from Route and its constructor takes a second argument "target", which will be the RedirectLocation:
public class LegacyRoute : Route
{
public LegacyRoute(string url, string target)
: base(url, new LegacyRouteHandler())
{
this.Target = target;
}
public string Target { get; private set; }
public override VirtualPathData GetVirtualPath(RequestContext requestContext, RouteValueDictionary values)
{
return null;
}
}
The constructor in LegacyRoute uses LegacyRouteHandler, this class simply creates instances of LegacyHandler:
public class LegacyRouteHandler : IRouteHandler
{
public IHttpHandler GetHttpHandler(RequestContext requestContext)
{
return new LegacyHandler(requestContext);
}
}
And finally the LegacyHandler which is responsible for the redirect:
public class LegacyHandler : MvcHandler
{
public LegacyHandler(RequestContext requestContext)
: base(requestContext)
{
}
protected override void ProcessRequest(HttpContextBase httpContext)
{
var legacyRoute = RequestContext.RouteData.Route as LegacyRoute;
httpContext.Response.Status = "301 Moved Permanently";
httpContext.Response.RedirectLocation = legacyRoute.Target;
}
}
Now if you call "YourPage.aspx" the LegacyRoute matches the request. Instead of the regular MVCHandler a LegacyHandler redirects the request to "Home/YourPage".
I have attached the full source code including a demo website so you see the above code in action.
Updates
07.01.2011: In Visual Studio 2010/.NET 4.0 the ProcessRequest of the LegacyHandler never gets executed. Use the following code to get it working again:
public class LegacyHandler : MvcHandler
{
public LegacyHandler(RequestContext requestContext)
: base(requestContext)
{
}
protected override System.IAsyncResult BeginProcessRequest(HttpContext httpContext, System.AsyncCallback callback, object state)
{
var legacyRoute = RequestContext.RouteData.Route as LegacyRoute;
httpContext.Response.Status = "301 Moved Permanently";
httpContext.Response.RedirectLocation = legacyRoute.Target;
httpContext.Response.End();
return null;
}
}
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