Local short urls to avoid a short_urls table

gistfile1.rb

class ShortId  
    
  # We cut out vowels to avoid shortened strings from mistakenly 
  # forming words  
  Alphabet = 'bcdfghjklmnpqrstvwxyz0123456789BCDFGHJKLMNPQRSTVWXYZ'  
  AlphabetLength = Alphabet.length  
  
  # Encode a numeric ID  
  def self.encode(id)  
    alpha = ''  
    while id != 0  
      alpha = Alphabet[id % AlphabetLength].chr + alpha  
      id /= AlphabetLength  
    end  
    alpha  
  end  
  
  # Decode an ID created with self.encode  
  def self.decode(alpha)  
    alpha = alpha.dup; id = 0  
    0.upto(alpha.length - 1) do |i|  
      id += Alphabet.index(alpha[-1]) * (AlphabetLength ** i)  
      alpha.chop!  
    end  
    id  
  end  
  
end