Simulating Apache mod_include for Vercel
For my Hugo static site hosted on Vercel, I wanted a simple way to include server-side logic, like a copyright notice, without setting up a full backend.  I created a function that mimics Apache's mod_include to inject dynamic content. It rewrites HTML requests through a handler that parses files for <!--#include ... --> directives. The file command injects file content, while the virtual command fetches content from the /api directory (like a modern /cgi-bin/). Caching is crucial for performance.  Check out the demo and code.  A more robust solution like Cloudflare Workers' HTMLRewriter would be ideal, but this works for simple use cases.