Fixing external links (replace escaped ? and =)

Thanks all for helping me get the gears turning. I think I have a solution and I'd like some expert feedback (in case it's just a bad approach).

Here is the rule I came up with:

when HTTP_REQUEST { 
set ::theuri [HTTP::uri] 
log local0. "the URI is $::theuri"
switch -glob $::theuri {
     "*%3[fFdD]*" {
    set ::myuri [string map -nocase {"%3f" "?" "%3d" "="} $::theuri]
    HTTP::redirect "http://[HTTP::host]$::myuri"
  }
   }
}

Let me know what you think.

Thanks, Mike