cgi.ebay.co.uk/ws/eBayISAPI.dll
I also went through quite a bit of effort to make sure _my_ links don't break. There are a handful of tools (like a dig wrapper for DNS lookups) which still can be reached as /cgi-bin/dig.cgi, even though they haven't been a standalone CGI script for two decades now. It's still technically CGI (just running as fastcgi nowadays), and the code base is just as good as you'd expect from what started as an experiment to see how much of a text markup parser I can write using perl regexp only.
The eBay example, by the way, is ISAPI, not CGI.
OpenResty is a platform with multiple advantages. It's fast (Nginx), it's async via stackless coroutines (no function coloring), it's again fast (LuaJIT), it's relatively easy to deploy, it's feature-rich (all the Lua packages available), and it integrates well with some other tech like Redis (also Lua-enabled).
On the other hand, Lua is an extension language. It's not designed to support large codebases. You can, of course, with enough discipline, make it work - just as you can, with enough grit, make Perl, JavaScript, Ruby, or older Python work, but you're on your own then. You need to invent your own code organization scheme and adhere to it religiously. You need to reinvent half of the stdlib that Python provides out of the box. The reinventing process extends to the need to create a set of helpers to define classes and inheritance between them, which are only provided as powerful but inconvenient primitives (metatables) in Lua.
It's incredible how much you can do with just 100 sloc in OpenRESTY - it's absolutely amazing as a component of a larger system. However, writing lengthy, uninspiring, yet complicated business logic in Lua under OpenResty is not a good idea.
The Web development I'd done up to that point consisted of raw HTML/CSS, with some ASP.NET or PHP running on the backend. I'd never written a line of JavaScript in my life.
It was at this point that I "discovered" a winning combination: HTML, CSS, and JavaScript running in the user's browser. The backend was a set of C# applications which wrote to standard out, which could be invoked directly by Apache's mod_cgi, since C# compiles down to Windows executables. There were countless better other solutions at this point - ASP.NET/PHP (as I'd already used). FastCGI, WSGI, and others were all a thing at this point, but I'd never heard of them.
I outputted a JavaScript object (I had no idea what JSON was at the time, or that I was effectively outputting it) and read it back into the browser using a thin wrapper around XMLHttpRequest. I then iterated over the outputm and transformed the data into tables. JQuery was a thing at that point, but likewise, I'd never heard of it.
Say what you will about the job, the team, the mentorship (or lack theorof) - it took them three months before they realized I'd written C# at a Java shop, and at that point the thing was already being used widely across engineering.
The important takeaway here was, that "winning combination" of some minimal JavaScript and CGI was the perfect ratio of simple, approachable, and powerful, to enable me to finish the task at hand, and in a way that (at least until anybody saw the architecture) everybody was thrilled with. It didn't require a deeper understanding of a framework to bootstrap it from nothing. Write an HTTP response to standard out, formatted as an object, and you were on your way.
Edit: nvm. It looks like it’s just easier to configure.