(cubicweb.web.views.urlpublishing)
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:
Note
Actionpath executes a query whose results is lost because of redirecting instead of direct traversal.
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.
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.
Parameters: |
|
---|---|
Return type: | tuple(str, cubicweb.rset.ResultSet or None) |
Returns: | the publishing method identifier and an optional result set |
Raises NotFound: | |
if no handler is able to decode the given path |
You can write your own URLPathEvaluator class to handle custom paths. For instance, if you want /my-card-id to redirect to the corresponding card’s primary view, you would write:
class CardWikiidEvaluator(URLPathEvaluator):
priority = 3 # make it be evaluated *before* RestPathEvaluator
def evaluate_path(self, req, segments):
if len(segments) != 1:
raise PathDontMatch()
rset = req.execute('Any C WHERE C wikiid %(w)s',
{'w': segments[0]})
if len(rset) == 0:
# Raise NotFound if no card is found
raise PathDontMatch()
return None, rset
On the other hand, you can also deactivate some of the standard evaluators in your final application. The only thing you have to do is to unregister them, for instance in a registration_callback in your cube:
def registration_callback(vreg):
vreg.unregister(RestPathEvaluator)
You can even replace the cubicweb.web.views.urlpublishing.URLPublisherComponent class if you want to customize the whole toolchain process or if you want to plug into an early enough extension point to control your request parameters:
class SanitizerPublisherComponent(URLPublisherComponent):
"""override default publisher component to explicitly ignore
unauthorized request parameters in anonymous mode.
"""
unauthorized_form_params = ('rql', 'vid', '__login', '__password')
def process(self, req, path):
if req.session.anonymous_session:
self._remove_unauthorized_params(req)
return super(SanitizerPublisherComponent, self).process(req, path)
def _remove_unauthorized_params(self, req):
for param in req.form.keys():
if param in self.unauthorized_form_params:
req.form.pop(param)
def registration_callback(vreg):
vreg.register_and_replace(SanitizerPublisherComponent, URLPublisherComponent)
handle path of the form:
<publishing_method>?parameters...
handle path with the form:
<eid>
tries to find a rewrite rule to apply
URL rewrite rule definitions are stored in URLRewriter objects
handle path with the form:
<etype>[[/<attribute name>]/<attribute value>]*
handle path with the form:
<any evaluator path>/<action>
(cubicweb.web.views.urlrewrite)
Base class for URL rewriters.
Url rewriters should have a rules dict that maps an input URI to something that should be used for rewriting.
The actual logic that defines how the rules dict is used is implemented in the rewrite method.
A priority attribute might be used to indicate which rewriter should be tried first. The higher the priority is, the earlier the rewriter will be tried.
The SimpleReqRewriters uses a rules dict that maps input URI (regexp or plain string) to a dictionary to update the request’s form.
If the input uri is a regexp, group substitution is allowed.
for each input, output `in rules, if `uri matches input, req’s form is updated with output
Here, the rules dict maps regexps or plain strings to callbacks that will be called with inputurl, uri, req, schema as parameters.
SimpleReqRewriter is enough for a certain number of simple cases. If it is not sufficient, SchemaBasedRewriter allows to do more elaborate things.
Here is an example of SimpleReqRewriter usage with plain string:
from cubicweb.web.views.urlrewrite import SimpleReqRewriter
class TrackerSimpleReqRewriter(SimpleReqRewriter):
rules = [
('/versions', dict(vid='versionsinfo')),
]
When the url is <base_url>/versions, the view with the __regid__ versionsinfo is displayed.
Here is an example of SimpleReqRewriter usage with regular expressions:
from cubicweb.web.views.urlrewrite import (
SimpleReqRewriter, rgx)
class BlogReqRewriter(SimpleReqRewriter):
rules = [
(rgx('/blogentry/([a-z_]+)\.rss'),
dict(rql=('Any X ORDERBY CD DESC LIMIT 20 WHERE X is BlogEntry,'
'X creation_date CD, X created_by U, '
'U login "%(user)s"'
% {'user': r'\1'}), vid='rss'))
]
When a url matches the regular expression, the view with the __regid__ rss which match the result set is displayed.
Here is an example of SchemaBasedRewriter usage:
from cubicweb.web.views.urlrewrite import (
SchemaBasedRewriter, rgx, build_rset)
class TrackerURLRewriter(SchemaBasedRewriter):
rules = [
(rgx('/project/([^/]+)/([^/]+)/tests'),
build_rset(rql='Version X WHERE X version_of P, P name %(project)s, X num %(num)s',
rgxgroups=[('project', 1), ('num', 2)], vid='versiontests')),
]