I was creating a project the other day that used anonymous pages for users and I wanted to make it a little less “guessable” but more human friendly than a SHA1 hash, so I decided to make a small home-brew URL shortener similar in format to Tiny URL.
The neat thing about ruby is that when you turn a Fixnum to a String with
to_s you can specify the base, and when you turn a String back to a Fixnum you can also specify a base in
to_i. This lends itself perfectly to turning (large) IDs into a shortened URL thats easier to remember.
In the first gist you can see how this would work with a model to make simple url shortening in rails – or, you can use randomized values to generate more user friendly “unique” tokens (as opposed to using SHA1 hashes for user confirmation/password reset pages).
# You can use the model's ID (PK/Serial) to generate a token which can be reversed: # Example: # Url.find(7213).shortened #=> 5kd # Url.find_by_shortened("5kd") #=> #<Url id: 7213...> class Url < ActiveRecord::Base Radix = 36 # convert ID into a shortened version def shortened id.to_s(Radix) end # unconvert the shortened version back to an ID def self.shortened_to_id(shortened) shortened.to_i(Radix) end # convert and lookup def self.find_by_shortened(shortened) find shortened_to_id(shortened) end end
# make tinyurl-ish tokens for pages so you dont have a goofy MD5 running amuck # Example: # make_token #=> "32uelywr" # NOTE: the longer the number, the longer the token def make_token ("%d%d" % [rand(100), Time.now.to_i]).to_i.to_s(36) end