How do I create a URL shortener?

Question

I want to create a URL shortener service where you can write a long URL into an input field and the service shortens the URL to \"http://www.example.org/abcdef\

Answer 1

Why not just translate your id to a string? You just need a function that maps a digit between, say, 0 and 61 to a single letter (upper/lower case) or digit. Then apply this to create, say, 4-letter codes, and you've got 14.7 million URLs covered.