"""associate url's path to view identifier / rql queries
It currently handle url's path with the forms
* <publishing_method>
* minimal REST publishing:
* <eid>
* <etype>[/<attribute name>/<attribute value>]*
* folder navigation
You can actually control URL (more exactly path) resolution using URL path
evaluator.
XXX actionpath and folderpath execute a query whose results is lost
because of redirecting instead of direct traversal
:organization: Logilab
:copyright: 2001-2009 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
"""
__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's path to view identifier / rql queries,
by applying a chain of urlpathevaluator components.
An evaluator is a URLPathEvaluator subclass with a .evaluate_path
method taking the request object and the path to publish as
argument. It will either returns a publishing method identifier
and a rql query on success or raises 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 (eg controller) and an optional result
set
:type req: `cubicweb.web.Request`
:param req: the request object
:type path: str
:param path: the path of the resource to publish
:rtype: tuple(str, `cubicweb.common.utils.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])}, 'x')
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 = 2
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.subject_relation(attrname)
except KeyError:
raise PathDontMatch()
else:
attrname = cls._rest_attr_info()[0]
value = req.url_unquote(parts.pop(0))
rset = self.attr_rset(req, etype, attrname, value)
else:
rset = self.cls_rset(req, cls)
if rset.rowcount == 0:
raise NotFound()
return None, rset
def cls_rset(self, req, cls):
return req.execute(cls.fetch_rql(req.user))
def attr_rset(self, req, etype, attrname, value):
rql = u'Any X WHERE X is %s, X %s %%(x)s' % (etype, attrname)
if attrname == 'eid':
try:
rset = req.execute(rql, {'x': typed_eid(value)}, 'x')
except (ValueError, TypeResolverException):
# conflicting eid/type
raise PathDontMatch()
else:
rset = req.execute(rql, {'x': value})
return rset
class URLRewriteEvaluator(URLPathEvaluator):
"""tries to find a rewrite rule to apply
URL rewrite rule definitions are stored in URLRewriter objects
"""
priority = 3
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)
except RegistryException:
continue
else:
# XXX avoid redirect
raise Redirect(action.url())
raise PathDontMatch()