def btInfoHash
      result = nil
      @params['xt'].each do |topic|
        if topic =~ /urn:btih:(.*)/
          hash = $1
          if hash.length == 40
            # Hex-encoded info hash. Convert to binary.
            result = [hash].pack "H*" 
          else
            # Base32 encoded
            result = Base32.decode hash
          end
          break
        end
      end
      result
    end
def btInfoHash
      result = nil
      @params['xt'].each do |topic|
        if topic =~ /urn:btih:(.*)/
          hash = $1
          if hash.length == 40
            # Hex-encoded info hash. Convert to binary.
            result = [hash].pack "H*" 
          else
            # Base32 encoded
            result = Base32.decode hash
          end
          break
        end
      end
      result
    end
Return the first Bittorrent info hash found in the magnet URI. The returned
 info hash is in binary format.