# 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/>.
"""Associate url's path to view identifier / rql queries.
CubicWeb finds all registered URLPathEvaluators, orders them according
to their ``priority`` attribute and calls their ``evaluate_path()``
method. The first that returns something and doesn't raise a
``PathDontMatch`` exception wins.
Here is the default evaluator chain:
1. :class:`cubicweb.web.views.urlpublishing.RawPathEvaluator` handles
unique url segments that match exactly one of the registered
controller's *__regid__*. Urls such as */view?*, */edit?*, */json?*
fall in that category;
2. :class:`cubicweb.web.views.urlpublishing.EidPathEvaluator` handles
unique url segments that are eids (e.g. */1234*);
3. :class:`cubicweb.web.views.urlpublishing.URLRewriteEvaluator`
selects all urlrewriter components, sorts them according to their
priorty, call their ``rewrite()`` method, the first one that
doesn't raise a ``KeyError`` wins. This is where the
:mod:`cubicweb.web.views.urlrewrite` and
:class:`cubicweb.web.views.urlrewrite.SimpleReqRewriter` comes into
play;
4. :class:`cubicweb.web.views.urlpublishing.RestPathEvaluator` handles
urls based on entity types and attributes : <etype>((/<attribute
name>])?/<attribute value>)? This is why ``cwuser/carlos`` works;
5. :class:`cubicweb.web.views.urlpublishing.ActionPathEvaluator`
handles any of the previous paths with an additional trailing
"/<action>" segment, <action> being one of the registered actions'
__regid__.
.. note::
Actionpath executes a query whose results is lost
because of redirecting instead of direct traversal.
"""
__docformat__ = "restructuredtext en"
from rql import TypeResolverException
from cubicweb import RegistryException, typed_eid
from cubicweb.web import NotFound, Redirect, component
class PathDontMatch(Exception):
"""exception used by url evaluators to notify they can't evaluate
a path
"""
class URLPublisherComponent(component.Component):
"""Associate url path to view identifier / rql queries, by
applying a chain of urlpathevaluator components.
An evaluator is a URLPathEvaluator subclass with an .evaluate_path
method taking the request object and the path to publish as
argument. It will either return a publishing method identifier
and an rql query on success or raise a `PathDontMatch` exception
on failure. URL evaluators are called according to their
`priority` attribute, with 0 as the greatest priority and greater
values as lower priority. The first evaluator returning a result
or raising something else than `PathDontMatch` will stop the
handlers chain.
"""
__regid__ = 'urlpublisher'
vreg = None # XXX necessary until property for deprecation warning is on appobject
def __init__(self, vreg, default_method='view'):
super(URLPublisherComponent, self).__init__()
self.vreg = vreg
self.default_method = default_method
evaluators = []
for evaluatorcls in vreg['components']['urlpathevaluator']:
# instantiation needed
evaluator = evaluatorcls(self)
evaluators.append(evaluator)
self.evaluators = sorted(evaluators, key=lambda x: x.priority)
def process(self, req, path):
"""Given an url (essentialy caracterized by a path on the
server, but additional information may be found in the request
object), return a publishing method identifier
(e.g. controller) and an optional result set.
:type req: `cubicweb.web.request.CubicWebRequestBase`
:param req: the request object
:type path: str
:param path: the path of the resource to publish. If empty, None or "/"
"view" is used as the default path.
:rtype: tuple(str, `cubicweb.rset.ResultSet` or None)
:return: the publishing method identifier and an optional result set
:raise NotFound: if no handler is able to decode the given path
"""
parts = [part for part in path.split('/')
if part != ''] or (self.default_method,)
if req.form.get('rql'):
if parts[0] in self.vreg['controllers']:
return parts[0], None
return 'view', None
for evaluator in self.evaluators:
try:
pmid, rset = evaluator.evaluate_path(req, parts[:])
break
except PathDontMatch:
continue
else:
raise NotFound(path)
if pmid is None:
pmid = self.default_method
return pmid, rset
class URLPathEvaluator(component.Component):
__abstract__ = True
__regid__ = 'urlpathevaluator'
vreg = None # XXX necessary until property for deprecation warning is on appobject
def __init__(self, urlpublisher):
self.urlpublisher = urlpublisher
self.vreg = urlpublisher.vreg
class RawPathEvaluator(URLPathEvaluator):
"""handle path of the form::
<publishing_method>?parameters...
"""
priority = 0
def evaluate_path(self, req, parts):
if len(parts) == 1 and parts[0] in self.vreg['controllers']:
return parts[0], None
raise PathDontMatch()
class EidPathEvaluator(URLPathEvaluator):
"""handle path with the form::
<eid>
"""
priority = 1
def evaluate_path(self, req, parts):
if len(parts) != 1:
raise PathDontMatch()
try:
rset = req.execute('Any X WHERE X eid %(x)s', {'x': typed_eid(parts[0])})
except ValueError:
raise PathDontMatch()
if rset.rowcount == 0:
raise NotFound()
return None, rset
class RestPathEvaluator(URLPathEvaluator):
"""handle path with the form::
<etype>[[/<attribute name>]/<attribute value>]*
"""
priority = 3
def evaluate_path(self, req, parts):
if not (0 < len(parts) < 4):
raise PathDontMatch()
try:
etype = self.vreg.case_insensitive_etypes[parts.pop(0).lower()]
except KeyError:
raise PathDontMatch()
cls = self.vreg['etypes'].etype_class(etype)
if parts:
if len(parts) == 2:
attrname = parts.pop(0).lower()
try:
cls.e_schema.subjrels[attrname]
except KeyError:
raise PathDontMatch()
else:
attrname = cls.cw_rest_attr_info()[0]
value = req.url_unquote(parts.pop(0))
return self.handle_etype_attr(req, cls, attrname, value)
return self.handle_etype(req, cls)
def set_vid_for_rset(self, req, cls, rset):# cls is there to ease overriding
if rset.rowcount == 0:
raise NotFound()
# we've to set a default vid here, since vid_from_rset may try to use a
# table view if fetch_rql include some non final relation
if rset.rowcount == 1:
req.form.setdefault('vid', 'primary')
else: # rset.rowcount >= 1
req.form.setdefault('vid', 'sameetypelist')
def handle_etype(self, req, cls):
rset = req.execute(cls.fetch_rql(req.user))
self.set_vid_for_rset(req, cls, rset)
return None, rset
def handle_etype_attr(self, req, cls, attrname, value):
st = cls.fetch_rqlst(req.user, ordermethod=None)
st.add_constant_restriction(st.get_variable('X'), attrname,
'x', 'Substitute')
if attrname == 'eid':
try:
rset = req.execute(st.as_string(), {'x': typed_eid(value)})
except (ValueError, TypeResolverException):
# conflicting eid/type
raise PathDontMatch()
else:
rset = req.execute(st.as_string(), {'x': value})
self.set_vid_for_rset(req, cls, rset)
return None, rset
class URLRewriteEvaluator(URLPathEvaluator):
"""tries to find a rewrite rule to apply
URL rewrite rule definitions are stored in URLRewriter objects
"""
priority = 2
def evaluate_path(self, req, parts):
# uri <=> req._twreq.path or req._twreq.uri
uri = req.url_unquote('/' + '/'.join(parts))
evaluators = sorted(self.vreg['urlrewriting'].all_objects(),
key=lambda x: x.priority, reverse=True)
for rewritercls in evaluators:
rewriter = rewritercls(req)
try:
# XXX we might want to chain url rewrites
return rewriter.rewrite(req, uri)
except KeyError:
continue
raise PathDontMatch()
class ActionPathEvaluator(URLPathEvaluator):
"""handle path with the form::
<any evaluator path>/<action>
"""
priority = 4
def evaluate_path(self, req, parts):
if len(parts) < 2:
raise PathDontMatch()
# remove last part and see if this is something like an actions
# if so, call
# XXX bad smell: refactor to simpler code
try:
actionsreg = self.vreg['actions']
requested = parts.pop(-1)
actions = actionsreg[requested]
except RegistryException:
raise PathDontMatch()
for evaluator in self.urlpublisher.evaluators:
if evaluator is self or evaluator.priority == 0:
continue
try:
pmid, rset = evaluator.evaluate_path(req, parts[:])
except PathDontMatch:
continue
else:
try:
action = actionsreg._select_best(actions, req, rset=rset)
if action is not None:
raise Redirect(action.url())
except RegistryException:
pass # continue searching
raise PathDontMatch()