How we brought HTTPS Everywhere to the cloud (part 1)

CloudFlare aims to make HTTPS accessible for all its customers, providing security for their websites, improved ranking on search engines, better performance with HTTP/2, and access to browser features such as geolocation that are being deprecated for plaintext HTTP. To ensure a page is secure and can't be controlled or eavesdropped by third-parties, browsers must ensure that not only the page itself but also all its dependencies are loaded via secure channels. Automatic HTTPS Rewrites project aims to automatically reduce the amount of mixed content on customers' web pages without breaking their websites and without any delay noticeable by end users while receiving a page that is being rewritten on the fly. The solution involves using Ragel, a state machine compiler, to build fast lexers in other pieces of code, and generating C code of a state machine capable of going through characters of URLs, matching hosts, and invoking custom handlers on each found ruleset.