##############################################################################
#
# Copyright (c) 2004 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Provider TALES expression"""
import zope.component
import zope.interface
import zope.schema
import zope.event
from zope.location.interfaces import ILocation
from zope.tales import expressions
from zope.contentprovider import interfaces
[docs]def addTALNamespaceData(provider, context):
"""Add the requested TAL attributes to the provider"""
data = {}
for interface in zope.interface.providedBy(provider):
if interfaces.ITALNamespaceData.providedBy(interface):
for name, field in zope.schema.getFields(interface).items():
data[name] = context.vars.get(name, field.default)
provider.__dict__.update(data)
[docs]@zope.interface.implementer(interfaces.ITALESProviderExpression)
class TALESProviderExpression(expressions.StringExpr):
"""
Collect content provider via a TAL namespace.
Note that this implementation of the TALES ``provider`` namespace
does not work with interdependent content providers, since each
content-provider's stage one call is made just before the second
stage is executed. If you want to implement interdependent
content providers, you need to consider a TAL-independent view
implementation such as zope.viewlet that will complete all content
providers' stage one before rendering any of them.
Implements `zope.contentprovider.interfaces.ITALESProviderExpression`
"""
def __call__(self, econtext):
name = super(TALESProviderExpression, self).__call__(econtext)
context = econtext.vars['context']
request = econtext.vars['request']
view = econtext.vars['view']
# Try to look up the provider.
provider = zope.component.queryMultiAdapter(
(context, request, view), interfaces.IContentProvider, name)
# Provide a useful error message, if the provider was not found.
if provider is None:
raise interfaces.ContentProviderLookupError(name)
# add the __name__ attribute if it implements ILocation
if ILocation.providedBy(provider):
provider.__name__ = name
# Insert the data gotten from the context
addTALNamespaceData(provider, econtext)
# Stage 1: Do the state update.
zope.event.notify(interfaces.BeforeUpdateEvent(provider, request))
provider.update()
# Stage 2: Render the HTML content.
return provider.render()