# -*- coding: utf-8 -*-
#
# Copyright (C) 2003-2009 Edgewall Software
# Copyright (C) 2003-2004 Jonas Borgstrm <jonas@edgewall.com>
# Copyright (C) 2005 Christopher Lenz <cmlenz@gmx.de>
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://trac.edgewall.org/wiki/TracLicense.
#
# This software consists of voluntary contributions made by many
# individuals. For the exact contribution history, see the revision
# history and logs, available at http://trac.edgewall.org/log/.
#
# Author: Jonas Borgstrm <jonas@edgewall.com>
# Christopher Lenz <cmlenz@gmx.de>
from urllib import quote,urlencode
from trac.util.text import unicode_quote,unicode_urlencode
class Href(object):
"""Implements a callable that constructs URLs with the given base. The
function can be called with any number of positional and keyword
arguments which than are used to assemble the URL.
Positional arguments are appended as individual segments to
the path of the URL:
>>> href = Href('/trac')
>>> href('ticket', 540)
'/trac/ticket/540'
>>> href('ticket', 540, 'attachment', 'bugfix.patch')
'/trac/ticket/540/attachment/bugfix.patch'
>>> href('ticket', '540/attachment/bugfix.patch')
'/trac/ticket/540/attachment/bugfix.patch'
If a positional parameter evaluates to None, it will be skipped:
>>> href('ticket', 540, 'attachment', None)
'/trac/ticket/540/attachment'
The first path segment can also be specified by calling an attribute
of the instance, as follows:
>>> href.ticket(540)
'/trac/ticket/540'
>>> href.changeset(42, format='diff')
'/trac/changeset/42?format=diff'
Simply calling the Href object with no arguments will return the base URL:
>>> href()
'/trac'
Keyword arguments are added to the query string, unless the value is None:
>>> href = Href('/trac')
>>> href('timeline', format='rss')
'/trac/timeline?format=rss'
>>> href('timeline', format=None)
'/trac/timeline'
>>> href('search', q='foo bar')
'/trac/search?q=foo+bar'
Multiple values for one parameter are specified using a sequence (a list or
tuple) for the parameter:
>>> href('timeline', show=['ticket', 'wiki', 'changeset'])
'/trac/timeline?show=ticket&show=wiki&show=changeset'
Alternatively, query string parameters can be added by passing a dict or
list as last positional argument:
>>> href('timeline', {'from': '02/24/05', 'daysback': 30})
'/trac/timeline?daysback=30&from=02%2F24%2F05'
The usual way of quoting arguments that would otherwise be interpreted
as Python keywords is supported too:
>>> href('timeline', from_='02/24/05', daysback=30)
'/trac/timeline?from=02%2F24%2F05&daysback=30'
If the order of query string parameters should be preserved, you may also
pass a sequence of (name, value) tuples as last positional argument:
>>> href('query', (('group', 'component'), ('groupdesc', 1)))
'/trac/query?group=component&groupdesc=1'
>>> params = []
>>> params.append(('group', 'component'))
>>> params.append(('groupdesc', 1))
>>> href('query', params)
'/trac/query?group=component&groupdesc=1'
By specifying an absolute base, the function returned will also generate
absolute URLs:
>>> href = Href('http://trac.edgewall.org')
>>> href('ticket', 540)
'http://trac.edgewall.org/ticket/540'
>>> href = Href('https://trac.edgewall.org')
>>> href('ticket', 540)
'https://trac.edgewall.org/ticket/540'
In common usage, it may improve readability to use the function-calling
ability for the first component of the URL as mentioned earlier:
>>> href = Href('/trac')
>>> href.ticket(540)
'/trac/ticket/540'
>>> href.browser('/trunk/README.txt', format='txt')
'/trac/browser/trunk/README.txt?format=txt'
"""
def __init__(self, base):
self.base = base.rstrip('/')
self._derived = {}
def __call__(self, *args, **kw):
href = self.base
params = []
def add_param(name, value):
if type(value) in (list, tuple):
for i in [i for i in value if i is not None]:
params.append((name, i))
elif value is not None:
params.append((name, value))
if args:
lastp = args[-1]
if lastp and type(lastp) is dict:
for k, v in lastp.items():
add_param(k, v)
args = args[:-1]
elif lastp and type(lastp) in (list, tuple):
for k, v in lastp:
add_param(k, v)
args = args[:-1]
# build the path
path = '/'.join([unicode_quote(unicode(arg).strip('/')) for arg in args
if arg is not None])
if path:
href += '/' + path
# assemble the query string
for k, v in kw.items():
add_param(k.endswith('_') and k[:-1] or k, v)
if params:
href += '?' + unicode_urlencode(params)
return href
def __getattr__(self, name):
if name not in self._derived:
self._derived[name] = lambda *args, **kw: self(name, *args, **kw)
return self._derived[name]
def __add__(self, rhs):
if rhs.startswith('/'):
return self.base + rhs
if rhs:
return self.base + '/' + rhs
return self.base or '/'
if __name__ == '__main__':
import doctest, sys
doctest.testmod(sys.modules[__name__])
|