Minesh Shah (Netcel)
Feb 28, 2023
(4 votes)

URL Rewrites in CMS12 (.Net 6)

URL rewriting is a common technique used in web applications to create user-friendly URLs that are easier to understand, provide consistency and have SEO benefits. In the past, URL rewriting was commonly accomplished using IIS URL Rewrite module. However, with the release of .NET Core, the process of rewriting URLs has undergone some changes.

Microsoft has introduced a new URL rewriting middleware called Microsoft.AspNetCore.Rewrite. This middleware is part of the ASP.NET Core framework and is designed to rewrite URLs in a much more flexible and efficient way.

One of the key benefits of using the Microsoft.AspNetCore.Rewrite middleware is that it allows URL rewriting without requiring IIS or any other web server. This means that we can create Optimizely Solutions that are completely self-contained and can be run on any platform.

Here is an example of how to use the Microsoft.AspNetCore.Rewrite middleware in .NET 6 to handle some common conventions like redirecting to https, enforcing lowercase urls and adding trailing slash to the end of all URLs:

Lower Case URL – Implement IRule Base Rule

    public class LowercaseUrlsRule : IRule
        public int StatusCode { get; } = (int)HttpStatusCode.MovedPermanently;

        public void ApplyRule(RewriteContext context)
            HttpRequest request = context.HttpContext.Request;
            PathString path = context.HttpContext.Request.Path;
            HostString host = context.HttpContext.Request.Host;

            if (path.HasValue && path.Value.Any(char.IsUpper) || host.HasValue && host.Value.Any(char.IsUpper))
                HttpResponse response = context.HttpContext.Response;
                response.StatusCode = StatusCode;
                response.Headers[HeaderNames.Location] = (request.Scheme + "://" + host.Value + request.PathBase.Value + request.Path.Value).ToLower() + request.QueryString;
                context.Result = RuleResult.EndResponse;
                context.Result = RuleResult.ContinueRules;

Use Rules in Middleware Startup.cs

In the example below we are using the RewriteOptions class to define paths that should be negated, and adding the rules for forcing HTTPS, Lowercase and Trailing Slashes. I have explicitly added below app.UseStaticFiles() so the rules do not get added to files like css, javascript or images.


        var options = new RewriteOptions()
            .Add(context =>
                    if (context.HttpContext.Request.Path.StartsWithSegments("/util") || 
                        context.HttpContext.Request.Path.StartsWithSegments("/episerver") || 
                        context.Result = RuleResult.SkipRemainingRules;
            // Redirect to HTTPS
            // Enforce lower case. 
            .Add(new LowercaseUrlsRule())
            // Enforce trailing slash.
            .AddRedirect("(.*[^/])$", "$1/");


These techniques are not Optimizely specific and can be applied to any .Net Solution, more info on IRule based rewrites can be found here

Feb 28, 2023


Please login to comment.
Latest blogs
Optimizely finally releases new and improved list properties!

For years, the Generic PropertyList has been widely used, despite it being unsupported. Today a better option is released!

Tomas Hensrud Gulla | Mar 28, 2023 | Syndicated blog

Official List property support

Introduction Until now users were able to store list properties in three ways: Store simple types (int, string, DateTime, double) as native...

Bartosz Sekula | Mar 28, 2023

New dashboard implemented in CMS UI 12.18.0

As part of the CMS UI 12.18.0 release , a new dashboard has been added as a ‘one stop shop’ to enable editors to access all of their content items,...

Matthew Slim | Mar 28, 2023

How to Merge Anonymous Carts When a Customer Logs In with Optimizely Commerce 14

In e-commerce, it is common for users to browse a site anonymously, adding items to their cart without creating an account. Later, when the user...

Francisco Quintanilla | Mar 27, 2023