How to evaluate url search request

Hi i have a problem i need to resolve, whereby i need to filter search requests looking for requests that contain less than 3 characters and if they do

return a standard search result.

An example is below of a search request is below:-

http://test.domain.com:9999/RTEFacade_RIGHTV/SearchVideos?

client=xml&expression=The&field_name=name&identity=5BTWmZd8VMc88GDqunvytFa%2B%2FA4kIu9kXhHL27Iwje%2

BVsrpnZmwDn5jZj7VbrHEDiinYpfiIZvwVXDD2pjxJwUv96uPxwHx6c66EVFxL0cGCvplvCQUKyAxsmKyFH28eNErrR1OREweC

Nzk6m2JLYFS3C0Me5hLf&language_code=sv&limited=false&match_partial=true&max_results=30&root_id=605&securit

y=false

The field that i need to look at is marked in bold above, is this has less than 3 characters then we need to return the following url instead

http://test.domain.com:9999/SearchVideos/Result.html

Any ideas how i would achieve this ?

/Regards Craig