Short URL Generator

Python implementation for generating Tiny URL- and bit.ly-like URLs.

A bit-shuffling approach is used to avoid generating consecutive, predictable URLs. However, the algorithm is deterministic and will guarantee that no collisions will occur.

The URL alphabet is fully customizable and may contain any number of characters. By default, digits and lower-case letters are used, with some removed to avoid confusion between characters like o, O and 0. The default alphabet is shuffled and has a prime number of characters to further improve the results of the algorithm.

The block size specifies how many bits will be shuffled. The lower BLOCK_SIZE bits are reversed. Any bits higher than BLOCK_SIZE will remain as is. BLOCK_SIZE of 0 will leave all bits unaffected and the algorithm will simply be converting your integer to a different base.

The intended use is that incrementing, consecutive integers will be used as keys to generate the short URLs. For example, when creating a new URL, the unique integer ID assigned by a database could be used to generate the URL by using this module. Or a simple counter may be used. As long as the same integer is not used twice, the same short URL will not be generated twice.

The module supports both encoding and decoding of URLs. The min_length parameter allows you to pad the URL if you want it to be a specific length.

Sample Usage:

>>> import short_url
>>> url = short_url.encode_url(12)
>>> print url
LhKA
>>> key = short_url.decode_url(url)
>>> print key
12

Use the functions in the top-level of the module to use the default encoder. Otherwise, you may create your own UrlEncoder object and use its encode_url and decode_url methods.

Install

short_url is also available at pypi:

http://pypi.python.org/pypi/short_url

Give a try to your finger:

$ pip install short_url

And done ;)

Tests

short_url is tested on both python2 and python3, to run the tests:

$ tox