Azure Front Door server variable enhancement generally available

Azure Front Door rules set and server variable allows dynamic modification of request and responses at the edge. For example, you can redirect clients to different pages based on information in the request, or rewrite the URLs, paths and query string;  you can insert, modify or delete HTTP headers in the request or response; you can implement security headers to prevent browser-based vulnerabilities; route requests from different country or devices to different origins; apply different caching polices for different content type, and many more, learn more in What is a rule set? - Azure Front Door | Microsoft Learn.

We are also adding more flexibility by adding support for URL path segment capture and lowercase/uppercase transformation in URL redirect and rewrite. Suppose your incoming URL path is "/abc/<tenantID>/<otherID>/index.html" where both tenantID and otherID are variable-length GUIDs. You wish to extract tenantID and insert elsewhere in the URL path. You can easily achieve this with a URL Rewrite rule where source is "/" and destination is "{url_path:seg1}" which results in the outgoing path of "/<tenantID>". For more information on capturing a range of segments, using negative values to backtrack from the end of the path, and more, refer to the documentation. 

Learn more in Server variables - Azure Front Door | Microsoft Learn.