Assuming the web server does not actually store and serve pages in a conventional sense, but rather acts like an application that can render the results of parsing and processing user's input, I wonder what are legal implications.

I can generate a Google link with an infohash in the same fashion: https://www.google.com/search?q=1548262051907755713575797913...

A few years ago, google stopped returning good links for strings that looked like bittorrent infohashes. Prior to that, it was actually a useful way to find information on and potentially trackers for an infohash you had

Yandex is the only search engine that's even marginal useful for that now.