Is it possible to use query_string as filter?

Actually we have a good use for ranked searches.

For example, a user would like to find:

helmet 50life 10chaos

This means, helmet that has around +50 to max life and costs around 10 orb of chaos.

The user would actually care if there's a helmet that's +49 life and is very cheap like 5 orb of chaos.

Would really appreciate any advice (or spoonfeed) of how might I achieve this.

Again, thanks!