A path-to-options mapper with a difference.

1. Totally backend-agnostic. You don't need controllers, HTTP headers, or anything. Only the desire to map paths to options and back again.

2. Performance. PathMapper has been written from the ground up to be as fast as possible. Path mapping should be invisible and easy, regardless of how many routes you may have.

3. Awesomeness. Yeah. Pretty good.

The best-case scenario is that you want to map a simple string -- say '/home' -- to a set of options:

mapper.connect('/home', { 'controller': 'home', 'action': 'index' })

PathMapper places these static paths in a hash table, which has a roughly O(1) access time. Regardless of how many static paths you specify, the complexity remains the same. This is blazing fast.

A bit slower than static paths are component paths:

mapper.connect('/:controller/:action/:id')

These are compiled into a prefix tree (or "trie"), which has a O(m) access time, where m is the number of path elements. So looking up /posts/show/1 requires two comparisons. This is fast, but we're not done yet. The prefix tree is used to narrow the number of possible routes down to those which could potentially match. (In practice, this tends to be :id vs :id.:format comparisons.) This matching algorithm is O(n), but the n is usually no more than two or three.

The last check which is done is against regular expression paths:

mapper.connect(re.compile('/[a-z]{4,6}/DINGO'), { 'controller': 'funkenstein', 'action': 'dingo_hater' })

There's no good way of organizing these, so it's a O(n) comparison. Not a bad tradeoff for much more powerful pattern matching.