Friendly URLs for ASP.NET

Question

Python frameworks always provide ways to handle URLs that convey the data of the request in an elegant way, like for example http://somewhere.overtherainbow.com/userid/12342

Answer 1

This is an alternative example that also uses ASP.NET Routing to implement friendly URLs.

Examples of the mappings that the application handles are:

http://samplesite/userid/1234 - http://samplesite/users.aspx?userid=1234
http://samplesite/userid/1235 - http://samplesite/users.aspx?userid=1235

This example does not use querystrings but requires additional code on the aspx page.

Step 1 - add the necessary entries to web.config

        
            …
            
        
    
…
    
    …
        
        


    …
    
        …
        
    
    
    

Step 2 - add a routing table in global.asax

Define the mapping from the friendly URL to the aspx page, saving the requested userid for later use.

void Application_Start(object sender, EventArgs e)
{
    RegisterRoutes(RouteTable.Routes);
}

public static void RegisterRoutes(RouteCollection routes)
{
    routes.Add("UseridRoute", new Route
    (
       "userid/{userid}",
       new CustomRouteHandler("~/users.aspx")
    ));
}

Step 3 - implement the route handler

Pass the routing context, containing the parameter, to the page. (Note the definition of IRoutablePage)

using System.Web.Compilation;
using System.Web.UI;
using System.Web;
using System.Web.Routing;

public interface IRoutablePage
{
    RequestContext RequestContext { set; }
}

public class CustomRouteHandler : IRouteHandler
{
    public CustomRouteHandler(string virtualPath)
    {
        this.VirtualPath = virtualPath;
    }

    public string VirtualPath { get; private set; }

    public IHttpHandler GetHttpHandler(RequestContext
          requestContext)
    {
        var page = BuildManager.CreateInstanceFromVirtualPath
             (VirtualPath, typeof(Page)) as IHttpHandler;

        if (page != null)
        {
            var routablePage = page as IRoutablePage;

            if (routablePage != null) routablePage.RequestContext = requestContext;
        }

        return page;
    }
}

Step 4 - Retrieve the parameter on the target page

Note the implemetation of IRoutablePage.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.Routing;

public partial class users : System.Web.UI.Page, IRoutablePage
{
    protected RequestContext requestContext;

    protected object RouteValue(string key)
    {
        return requestContext.RouteData.Values[key];
    }

    protected void Page_Load(object sender, EventArgs e)
    {
        string id = RouteValue("userid").ToString();
        switch (id)
        {
            case "1234":
                lblUserId.Text = id;
                lblUserName.Text = "Bill";
                break;
            case "1235":
                lblUserId.Text = id;
                lblUserName.Text = "Claire";
                break;
            case "1236":
                lblUserId.Text = id;
                lblUserName.Text = "David";
                break;
            default:
                lblUserId.Text = "0000";
                lblUserName.Text = "Unknown";
                break;
        }
    }

    #region IRoutablePage Members

    public RequestContext RequestContext
    {
        set { requestContext = value; }
    }

    #endregion
}