Example router implementation and example for WebCore 2.

routing.py

# encoding: utf-8

import re

from functools import wraps
from collections import namedtuple


re_type = type(re.compile(""))



def route(router, route):
    def inner(func):
        router.register(route, func)
        return func
    
    return inner


class Router(object):
    def __init__(self):
        self.routes = list()
    
    def register(self, route, obj, ctx=None, name=None):
        parsed = self.parse(route)
        
        print "registering", route, parsed
        
        routes = self.routes
        
        for element in parsed:
            for i, (route, children) in enumerate(routes):
                if route is not element:
                    continue
                
                if not isinstance(children, list):
                    children = [(None, children)]
                    routes[i] = (route, children)
                
                routes = children
                break
            
            else:
                routes.append((element, obj))
    
    def parse(self, route):
        parts = route.lstrip('/').split('/')
        
        for i, part in enumerate(parts):
            if '{' not in part:
                continue
            
            elif '}' not in part:
                raise ValueError("Route match must not contain forward slashes.")
            
            sub = list()
            
            while part:
                prefix, _, match = part.partition('{')
                name, _, part = match.partition('}')
                sub.append(prefix)
                
                name, _, regex = name.partition(':')
                sub.append('(?P<%s>%s)' % (name, regex or r'[^/]+'))
            
            parts[i] = re.compile(''.join(sub))
        
        return parts
    
    def route(self, path):
        routes = self.routes
        path = path.lstrip('/').split('/') + [None]
        match = dict()
        
        for i, element in enumerate(path):
            for route, children in routes:
                if isinstance(route, re_type):
                    matched = route.match(element)
                    if not matched: continue
                    match.update(matched.groupdict())
                
                elif route != element:
                    continue
                
                if not isinstance(children, list):
                    return children, [i for i in path[i+1:] if i is not None], match
                
                routes = children
                break
            
            else:
                raise ValueError("Could not find route to satisfy path.")
        
        raise ValueError("Could not find route to satisfy path.")


router = Router()


@route(router, '/')
def index(ctx):
    print "index"

@route(router, '/create')
def create(ctx):
    pass

@route(router, '/{id}')
def show(ctx, id):
    pass

@route(router, '/{id}/modify')
def modify(ctx, id):
    pass

@route(router, '/{id}/delete')
def delete(ctx, id):
    pass


print
__import__('pprint').pprint(router.routes)
print

for i in ('/', '/create', '/27', '/42/modify', '/64/delete', '/64/delete/confirm', '/create/diz'):
    print i, '\t\t' if len(i) < 7 else '\t', router.route(i)


# Results:

"""
registering / ['']
registering /create ['create']
registering /{id} [<_sre.SRE_Pattern object at 0x109152e90>]
registering /{id}/modify [<_sre.SRE_Pattern object at 0x109152e90>, 'modify']
registering /{id}/delete [<_sre.SRE_Pattern object at 0x109152e90>, 'delete']

[('', <function index at 0x1091c3a28>),
 ('create', <function create at 0x1091c3aa0>),
 (<_sre.SRE_Pattern object at 0x109152e90>,
  [(None, <function show at 0x1091c3b18>),
   ('modify', <function modify at 0x1091c3b90>),
   ('delete', <function delete at 0x1091c3c08>)])]

/ 		(<function index at 0x1091c3a28>, [], {})
/create 	(<function create at 0x1091c3aa0>, [], {})
/27 		(<function show at 0x1091c3b18>, [], {'id': '27'})
/42/modify 	(<function modify at 0x1091c3b90>, [], {'id': '42'})
/64/delete 	(<function delete at 0x1091c3c08>, [], {'id': '64'})
/64/delete/confirm 	(<function delete at 0x1091c3c08>, ['confirm'], {'id': '64'})
/create/diz 	(<function create at 0x1091c3aa0>, ['diz'], {})
"""