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/123424/

I want you to notice the ending path /userid/123424/

How do you do this in ASP.NET?

Answer 1

This example 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 uses querystrings and avoids any requirement to modify the code on the aspx page.

Step 1 - add the necessary entries to web.config

<system.web>
<compilation debug="true">
        <assemblies>
            …
            <add assembly="System.Web.Routing, Version=3.5.0.0,    Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
        </assemblies>
    </compilation>
…
    <httpModules>
    …
        <add name="UrlRoutingModule" type="System.Web.Routing.UrlRoutingModule, System.Web.Routing, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
        </httpModules>
</system.web>
<system.webServer>
    …
    <modules>
        …
        <add name="UrlRoutingModule" type="System.Web.Routing.UrlRoutingModule, System.Web.Routing, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
    </modules>
    <handlers
…   
        <add name="UrlRoutingHandler" preCondition="integratedMode" verb="*" path="UrlRouting.axd" type="System.Web.HttpForbiddenHandler,                 System.Web, Version=2.0.0.0, Culture=neutral,              PublicKeyToken=b03f5f7f11d50a3a"/>
    </handlers>
</system.webServer>

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

Add the querystring to the current context before the routing takes place.

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

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

    public string VirtualPath { get; private set; }

    public IHttpHandler GetHttpHandler(RequestContext
          requestContext)
    {
        // Add the querystring to the URL in the current context
        string queryString = "?userid=" + requestContext.RouteData.Values["userid"];
        HttpContext.Current.RewritePath(
          string.Concat(
          VirtualPath,
          queryString)); 

        var page = BuildManager.CreateInstanceFromVirtualPath
             (VirtualPath, typeof(Page)) as IHttpHandler;
        return page;
    }
}

Code from users.aspx

The code on the aspx page for reference.

protected void Page_Load(object sender, EventArgs e)
{
    string id = Page.Request.QueryString["userid"];
    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;
}