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# Copyright (c) 2005 Allan Saddi <allan@saddi.com>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $Id$
__author__ = 'Allan Saddi <allan@saddi.com>'
__version__ = '$Revision$'
import re
from resolver import *
__all__ = ['ObjectPathResolver', 'expose']
class NoDefault(object):
pass
class ObjectPathResolver(Resolver):
"""
Inspired by CherryPy <http://www.cherrypy.org/>. :) For an explanation
of how this works, see the excellent tutorial at
<http://www.cherrypy.org/wiki/CherryPyTutorial>. We support the index and
default methods, though the calling convention for the default method
is different - we do not pass PATH_INFO as positional arguments. (It
is passed through the request/environ as normal.)
Also, we explicitly block certain function names. See below. I don't
know if theres really any harm in letting those attributes be followed,
but I'd rather not take the chance. And unfortunately, this solution
is pretty half-baked as well (I'd rather only allow certain object
types to be traversed, rather than disallow based on names.) Better
than nothing though...
"""
index_page = 'index'
default_page = 'default'
def __init__(self, root, index=NoDefault, default=NoDefault,
favorIndex=True):
"""
root is the root object of your URL hierarchy. In CherryPy, this
would be cpg.root.
When the last component of a path has an index method and some
object along the path has a default method, favorIndex determines
which method is called when the URL has a trailing slash. If
True, the index method will be called. Otherwise, the default method.
"""
self.root = root
if index is not NoDefault:
self.index_page = index
if default is not NoDefault:
self.default_page = default
self._favorIndex = favorIndex
# Certain names should be disallowed for safety. If one of your pages
# is showing up unexpectedly as a 404, make sure the function name doesn't
# begin with one of these prefixes.
_disallowed = re.compile(r'''(?:_|im_|func_|tb_|f_|co_).*''')
def _exposed(self, obj, redirect):
# If redirecting, allow non-exposed objects as well.
return callable(obj) and (getattr(obj, 'exposed', False) or redirect)
def resolve(self, request, redirect=False):
path_info = request.pathInfo.split(';')[0]
path_info = path_info.split('/')
assert len(path_info) > 0
assert not path_info[0]
current = self.root
current_default = None
i = 0
for i in range(1, len(path_info)):
component = path_info[i]
# See if we have an index page (needed for index/default
# disambiguation, unfortunately).
current_index = None
if self.index_page:
current_index = getattr(current, self.index_page, None)
if not self._exposed(current_index, redirect):
current_index = None
if self.default_page:
# Remember the last default page we've seen.
new_default = getattr(current, self.default_page, None)
if self._exposed(new_default, redirect):
current_default = (i - 1, new_default)
# Test for trailing slash.
if not component and current_index is not None and \
(self._favorIndex or current_default is None):
# Breaking out of the loop here favors index over default.
break
# Respect __all__ attribute. (Ok to generalize to all objects?)
all = getattr(current, '__all__', None)
current = getattr(current, component, None)
# Path doesn't exist
if current is None or self._disallowed.match(component) or \
(all is not None and component not in all and not redirect):
# Use path up to latest default page.
if current_default is not None:
i, current = current_default
break
# No default at all, so we fail.
return None
func = None
if self._exposed(current, redirect): # Exposed?
func = current
else:
# If not, see if it as an exposed index page
if self.index_page:
index = getattr(current, self.index_page, None)
if self._exposed(index, redirect): func = index
# How about a default page?
if func is None and self.default_page:
default = getattr(current, self.default_page, None)
if self._exposed(default, redirect): func = default
# Lastly, see if we have an ancestor's default page to fall back on.
if func is None and current_default is not None:
i, func = current_default
if func is not None:
self._updatePath(request, i)
return func
def expose(func):
"""Decorator to expose functions."""
func.exposed = True
return func
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