[CWEP002] introduce RQLRelationRewriter
Refactor existing RQLRewriter for later reuse of rewriting relation as specified
by CWEP002. Work is different because we simply want to replace a relation by
another rql snippet and we don't have to bother with EXISTS, subqueries and all.
This rewriter is not yet plugged into the querier.
Depends on yams 0.40 API.
Related to #3546717
# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb. If not, see <http://www.gnu.org/licenses/>.
"""This package contains all WSGI specific code for cubicweb
NOTE: this package borrows a lot of code to Django
(http://www.djangoproject.com) and to the wsgiref module
of the python2.5's stdlib.
WSGI corresponding PEP: http://www.python.org/dev/peps/pep-0333/
"""
__docformat__ = "restructuredtext en"
from email import message, message_from_string
from Cookie import SimpleCookie
from StringIO import StringIO
from cgi import parse_header
from pprint import pformat as _pformat
def pformat(obj):
"""pretty prints `obj` if possible"""
try:
return _pformat(obj)
except Exception:
return u'<could not parse>'
def normalize_header(header):
"""returns a normalized header name
>>> normalize_header('User_Agent')
'User-agent'
"""
return header.replace('_', '-').capitalize()
def safe_copyfileobj(fsrc, fdst, length=16*1024, size=0):
"""
THIS COMES FROM DJANGO
A version of shutil.copyfileobj that will not read more than 'size' bytes.
This makes it safe from clients sending more than CONTENT_LENGTH bytes of
data in the body.
"""
if not size:
return
while size > 0:
buf = fsrc.read(min(length, size))
if not buf:
break
fdst.write(buf)
size -= len(buf)