Years ago I wrote a DNS-over-HTTPS proxy as an nginx / OpenResty module in Lua. The Lua code included a very stripped-down DNS message parser. The 1-based indexes and closed (instead of half-open) intervals were a massive pain in the arse. The code has a tricky mixture of odd and even offsets that would all have been even in C, and it would have been much easier to replace the magic numbers with named constants.

https://github.com/fanf2/doh101/blob/master/roles/doh101/fil...