Metadata-Version: 2.1
Name: z3c.template
Version: 3.2
Summary: A package implementing advanced Page Template patterns.
Home-page: https://github.com/zopefoundation/z3c.template
Author: Roger Ineichen and the Zope Community
Author-email: zope-dev@zope.org
License: ZPL 2.1
Keywords: zope3 template layout zpt pagetemplate
Platform: UNKNOWN
Classifier: Development Status :: 5 - Production/Stable
Classifier: Environment :: Web Environment
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: Zope Public License
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: 3.8
Classifier: Programming Language :: Python :: 3.9
Classifier: Programming Language :: Python :: 3.10
Classifier: Programming Language :: Python :: Implementation :: CPython
Classifier: Programming Language :: Python :: Implementation :: PyPy
Classifier: Programming Language :: Python
Classifier: Natural Language :: English
Classifier: Operating System :: OS Independent
Classifier: Topic :: Internet :: WWW/HTTP
Classifier: Framework :: Zope :: 3
Provides-Extra: test
Provides-Extra: chameleon
License-File: LICENSE.txt

==============
 z3c.template
==============


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This package allows you to register templates independently from view code.

In Zope 3, when registering a ``browser:page`` both presentation and computation
are registered together. Unfortunately the registration tangles presentation
and computation so tightly that it is not possible to re-register a different
template depending on context. (You can override the whole registration but
this is not the main point of this package.)

With z3c.template the registration is split up between the view and the
template and allows to differentiate the template based on the skin layer and
the view.

In addition this package lays the foundation to differentiate between
templates that provide specific presentation templates and generic layout
templates.


.. contents::

===============
 Z3C Templates
===============

This package allows us to separate the registration of the view code and the
layout.

A template is used for separate the HTML part from a view. This is done in
z3 via a page templates. Such page template are implemented in the view,
registered included in a page directive etc. But they do not use the adapter
pattern which makes it hard to replace existing templates.

Another part of template is, that they normaly separate one part presenting
content from a view and another part offer a layout used by the content
template.

How can this package make it simpler to use templates?

Templates can be registered as adapters adapting context, request where the
context is a view implementation. Such a template get adapted from the view
if the template is needed. This adaption makes it very pluggable and modular.

We offer two base template directive for register content producing templates
and layout producing tempaltes. This is most the time enough but you also
can register different type of templates using a specific interface. This
could be usefull if your view implementation needs to separate HTMl in
more then one template. Now let's take a look how we an use this templates.


Content template
================

First let's show how we use a template for produce content from a view:

  >>> import os, tempfile
  >>> temp_dir = tempfile.mkdtemp()
  >>> contentTemplate = os.path.join(temp_dir, 'contentTemplate.pt')
  >>> with open(contentTemplate, 'w') as file:
  ...     _ = file.write('<div>demo content</div>')

And register a view class implementing a interface:

  >>> import zope.interface
  >>> from z3c.template import interfaces
  >>> from zope.pagetemplate.interfaces import IPageTemplate
  >>> from zope.publisher.browser import BrowserPage

  >>> class IMyView(zope.interface.Interface):
  ...     pass
  >>> @zope.interface.implementer(IMyView)
  ... class MyView(BrowserPage):
  ...     template = None
  ...     def render(self):
  ...         if self.template is None:
  ...             template = zope.component.getMultiAdapter(
  ...                 (self, self.request), interfaces.IContentTemplate)
  ...             return template(self)
  ...         return self.template()

Let's call the view and check the output:

  >>> from zope.publisher.browser import TestRequest
  >>> request = TestRequest()
  >>> view = MyView(root, request)

Since the template is not yet registered, rendering the view will fail:

  >>> print(view.render())
  Traceback (most recent call last):
  ...
  zope.interface.interfaces.ComponentLookupError: ......

Let's now register the template (commonly done using ZCML):

  >>> from zope import component
  >>> from zope.publisher.interfaces.browser import IDefaultBrowserLayer
  >>> from z3c.template.template import TemplateFactory

The template factory allows us to create a ViewPageTeplateFile instance.

  >>> factory = TemplateFactory(contentTemplate, 'text/html')
  >>> factory
  <z3c.template.template.TemplateFactory object at ...>

We register the factory on a view interface and a layer.

  >>> component.provideAdapter(
  ...     factory,
  ...     (zope.interface.Interface, IDefaultBrowserLayer),
  ...     interfaces.IContentTemplate)
  >>> template = component.getMultiAdapter((view, request),
  ...     interfaces.IPageTemplate)

  >>> template
  <...ViewPageTemplateFile...>

Now that we have a registered layout template for the default layer we can
call our view again.

  >>> print(view.render())
  <div>demo content</div>

Now we register a new template on the specific interface of our view.

  >>> myTemplate = os.path.join(temp_dir, 'myTemplate.pt')
  >>> with open(myTemplate, 'w') as file:
  ...     _ = file.write('<div>My content</div>')
  >>> factory = TemplateFactory(myTemplate, 'text/html')
  >>> component.provideAdapter(
  ...     factory,
  ...     (IMyView, IDefaultBrowserLayer), interfaces.IContentTemplate)
  >>> print(view.render())
  <div>My content</div>

It is possible to provide the template directly.

We create a new template.

  >>> viewContent = os.path.join(temp_dir, 'viewContent.pt')
  >>> with open(viewContent, 'w') as file:
  ...     _ = file.write('<div>view content</div>')

and a view:

  >>> from z3c.template import ViewPageTemplateFile
  >>> @zope.interface.implementer(IMyView)
  ... class MyViewWithTemplate(BrowserPage):
  ...     template = ViewPageTemplateFile(viewContent)
  ...     def render(self):
  ...         if self.template is None:
  ...             template = zope.component.getMultiAdapter(
  ...                 (self, self.request), interfaces.IContentTemplate)
  ...             return template(self)
  ...         return self.template()
  >>> contentView = MyViewWithTemplate(root, request)

If we render this view we get the implemented layout template and not the
registered one.

  >>> print(contentView.render())
  <div>view content</div>


Layout template
===============

First we nee to register a new view class calling a layout template. Note,
that this view uses the __call__ method for invoke a layout template:

  >>> class ILayoutView(zope.interface.Interface):
  ...     pass
  >>> @zope.interface.implementer(ILayoutView)
  ... class LayoutView(BrowserPage):
  ...     layout = None
  ...     def __call__(self):
  ...         if self.layout is None:
  ...             layout = zope.component.getMultiAdapter(
  ...                 (self, self.request), interfaces.ILayoutTemplate)
  ...             return layout(self)
  ...         return self.layout()
  >>> view2 = LayoutView(root, request)

Define and register a new layout template:

  >>> layoutTemplate = os.path.join(temp_dir, 'layoutTemplate.pt')
  >>> with open(layoutTemplate, 'w') as file:
  ...     _ = file.write('<div>demo layout</div>')
  >>> factory = TemplateFactory(layoutTemplate, 'text/html')

We register the template factory on a view interface and a layer providing the
ILayoutTemplate interface.

  >>> component.provideAdapter(factory,
  ...     (zope.interface.Interface, IDefaultBrowserLayer),
  ...      interfaces.ILayoutTemplate)
  >>> layout = component.getMultiAdapter(
  ...     (view2, request), interfaces.ILayoutTemplate)

  >>> layout
  <...ViewPageTemplateFile...>

Now that we have a registered layout template for the default layer we can
call our view again.

  >>> print(view2())
  <div>demo layout</div>

Now we register a new layout template on the specific interface of our view.

  >>> myLayout = os.path.join(temp_dir, 'myLayout.pt')
  >>> with open(myLayout, 'w') as file:
  ...     _ = file.write('<div>My layout</div>')
  >>> factory = TemplateFactory(myLayout, 'text/html')
  >>> component.provideAdapter(factory,
  ...     (ILayoutView, IDefaultBrowserLayer),
  ...      interfaces.ILayoutTemplate)
  >>> print(view2())
  <div>My layout</div>

It is possible to provide the layout template directly.

We create a new template.

  >>> viewLayout = os.path.join(temp_dir, 'viewLayout.pt')
  >>> with open(viewLayout, 'w') as file:
  ...     _ = file.write('''<div>view layout</div>''')

  >>> @zope.interface.implementer(ILayoutView)
  ... class LayoutViewWithLayoutTemplate(BrowserPage):
  ...     layout = ViewPageTemplateFile(viewLayout)
  ...     def __call__(self):
  ...         if self.layout is None:
  ...             layout = zope.component.getMultiAdapter((self, self.request),
  ...                 interfaces.ILayoutTemplate)
  ...             return layout(self)
  ...         return self.layout()
  >>> layoutView = LayoutViewWithLayoutTemplate(root, request)

If we render this view we get the implemented layout template and not the
registered one.

  >>> print(layoutView())
  <div>view layout</div>


Since we return the layout template in the sample views above, how can we get
the content from the used view? This is not directly a part of this package
but let's show some pattern were can be used for render content in a used
layout template. Note, since we offer to register each layout template for
a specific view, you can always very selectiv this layout pattern. This means
you can use the defualt z3 macro based layout registration in combination with
this layout concept if you register a own layout template.

The simplest concept is calling the content from the view in the layout
template is to call it from a method. Let's define a view providing a layout
template and offer a method for call content.

  >>> class IFullView(zope.interface.Interface):
  ...     pass

  >>> @zope.interface.implementer(IFullView)
  ... class FullView(BrowserPage):
  ...     layout = None
  ...     def render(self):
  ...         return u'rendered content'
  ...     def __call__(self):
  ...         if self.layout is None:
  ...             layout = zope.component.getMultiAdapter((self, self.request),
  ...                 interfaces.ILayoutTemplate)
  ...             return layout(self)
  ...         return self.layout()
  >>> completeView = FullView(root, request)

Now define a layout for the view and register them:

  >>> completeLayout = os.path.join(temp_dir, 'completeLayout.pt')
  >>> with open(completeLayout, 'w') as file:
  ...     _ = file.write('''
  ...   <div tal:content="view/render">
  ...     Full layout
  ...   </div>
  ... ''')

  >>> factory = TemplateFactory(completeLayout, 'text/html')
  >>> component.provideAdapter(factory,
  ...     (IFullView, IDefaultBrowserLayer), interfaces.ILayoutTemplate)

Now let's see if the layout template can call the content via calling render
on the view:

  >>> print(completeView.__call__())
  <div>rendered content</div>


Content and Layout
==================

Now let's show how we combine this two templates in a real use case:

  >>> class IDocumentView(zope.interface.Interface):
  ...     pass

  >>> @zope.interface.implementer(IDocumentView)
  ... class DocumentView(BrowserPage):
  ...     template = None
  ...     layout = None
  ...     attr = None
  ...     def update(self):
  ...         self.attr = u'content updated'
  ...     def render(self):
  ...         if self.template is None:
  ...             template = zope.component.getMultiAdapter(
  ...                 (self, self.request), IPageTemplate)
  ...             return template(self)
  ...         return self.template()
  ...     def __call__(self):
  ...         self.update()
  ...         if self.layout is None:
  ...             layout = zope.component.getMultiAdapter((self, self.request),
  ...                 interfaces.ILayoutTemplate)
  ...             return layout(self)
  ...         return self.layout()

Define and register a content template...

  >>> template = os.path.join(temp_dir, 'template.pt')
  >>> with open(template, 'w') as file:
  ...     _ = file.write('''
  ...   <div tal:content="view/attr">
  ...     here comes the value of attr
  ...   </div>
  ... ''')

  >>> factory = TemplateFactory(template, 'text/html')
  >>> component.provideAdapter(factory,
  ...     (IDocumentView, IDefaultBrowserLayer), IPageTemplate)

and define and register a layout template:

  >>> layout = os.path.join(temp_dir, 'layout.pt')
  >>> with open(layout, 'w') as file:
  ...     _ = file.write('''
  ... <html>
  ...   <body>
  ...     <div tal:content="structure view/render">
  ...       here comes the rendered content
  ...     </div>
  ...   </body>
  ... </html>
  ... ''')

  >>> factory = TemplateFactory(layout, 'text/html')
  >>> component.provideAdapter(factory,
  ...     (IDocumentView, IDefaultBrowserLayer), interfaces.ILayoutTemplate)

Now call the view and check the result:

  >>> documentView = DocumentView(root, request)
  >>> print(documentView())
  <html>
    <body>
      <div>
        <div>content updated</div>
      </div>
    </body>
  </html>


Macros
======

Use of macros.

  >>> macroTemplate = os.path.join(temp_dir, 'macroTemplate.pt')
  >>> with open(macroTemplate, 'w') as file:
  ...     _ = file.write('''
  ...   <metal:block define-macro="macro1">
  ...     <div>macro1</div>
  ...   </metal:block>
  ...   <metal:block define-macro="macro2">
  ...     <div>macro2</div>
  ...     <div tal:content="options/div2">the content of div 2</div>
  ...   </metal:block>
  ...   ''')

  >>> factory = TemplateFactory(macroTemplate, 'text/html', 'macro1')
  >>> print(factory(view, request)())
  <div>macro1</div>
  >>> m2factory = TemplateFactory(macroTemplate, 'text/html', 'macro2')
  >>> print(m2factory(view, request)(div2="from the options"))
  <div>macro2</div>
  <div>from the options</div>


Why didn't we use named templates from the ``zope.formlib`` package?

While named templates allow us to separate the view code from the template
registration, they are not registrable for a particular layer making it
impossible to implement multiple skins using named templates.


Use case ``simple template``
============================

And for the simplest possible use we provide a hook for call registered
templates. Such page templates can get called with the getPageTemplate method
and return a registered bound ViewTemplate a la ViewPageTemplateFile or
NamedTemplate.

The getViewTemplate allows us to use the new template registration
system with all existing implementations such as `zope.formlib` and
`zope.viewlet`.

  >>> from z3c.template.template import getPageTemplate
  >>> class IUseOfViewTemplate(zope.interface.Interface):
  ...     pass
  >>> @zope.interface.implementer(IUseOfViewTemplate)
  ... class UseOfViewTemplate(object):
  ...
  ...     template = getPageTemplate()
  ...
  ...     def __init__(self, context, request):
  ...         self.context = context
  ...         self.request = request

By defining the "template" property as a "getPageTemplate" a lookup for
a registered template is done when it is called.

  >>> simple = UseOfViewTemplate(root, request)
  >>> print(simple.template())
  <div>demo content</div>

Because the demo template was registered for any ("None") interface we see the
demo template when rendering our new view. We register a new template
especially for the new view. Also note that the "macroTemplate" has been
created earlier in this test.

  >>> factory = TemplateFactory(contentTemplate, 'text/html')
  >>> component.provideAdapter(factory,
  ...     (IUseOfViewTemplate, IDefaultBrowserLayer), IPageTemplate)
  >>> print(simple.template())
  <div>demo content</div>


Context-specific templates
==========================

The ``TemplateFactory`` can be also used for (view, request, context)
lookup. It's useful when you want to override a template for specific
content object or type.

Let's define a sample content type and instantiate a view for it.

  >>> class IContent(zope.interface.Interface):
  ...     pass
  >>> @zope.interface.implementer(IContent)
  ... class Content(object):
  ...     pass

  >>> content = Content()
  >>> view = UseOfViewTemplate(content, request)

Now, let's provide a (view, request, context) adapter using TemplateFactory.

  >>> contextTemplate = os.path.join(temp_dir, 'context.pt')
  >>> with open(contextTemplate, 'w') as file:
  ...     _ = file.write('<div>context-specific</div>')
  >>> factory = TemplateFactory(contextTemplate, 'text/html')

  >>> component.provideAdapter(factory,
  ...     (IUseOfViewTemplate, IDefaultBrowserLayer, IContent),
  ...     interfaces.IContentTemplate)

First. Let's try to simply get it as a multi-adapter.

  >>> template = zope.component.getMultiAdapter((view, request, content),
  ...                 interfaces.IContentTemplate)
  >>> print(template(view))
  <div>context-specific</div>

The ``getPageTemplate`` and friends will try to lookup a context-specific
template before doing more generic (view, request) lookup, so our view
should already use our context-specific template:

  >>> print(view.template())
  <div>context-specific</div>


Use case ``template by interface``
==================================

Templates can also get registered on different interfaces then IPageTemplate
or ILayoutTemplate.

  >>> from z3c.template.template import getViewTemplate
  >>> class IMyTemplate(zope.interface.Interface):
  ...     """My custom tempalte marker."""

  >>> factory = TemplateFactory(contentTemplate, 'text/html')
  >>> component.provideAdapter(factory,
  ...     (zope.interface.Interface, IDefaultBrowserLayer), IMyTemplate)

Now define a view using such a custom template registration:

  >>> class IMyTemplateView(zope.interface.Interface):
  ...     pass
  >>> @zope.interface.implementer(IMyTemplateView)
  ... class MyTemplateView(object):
  ...
  ...     template = getViewTemplate(IMyTemplate)
  ...
  ...     def __init__(self, context, request):
  ...         self.context = context
  ...         self.request = request

  >>> myTempalteView = MyTemplateView(root, request)
  >>> print(myTempalteView.template())
  <div>demo content</div>


Use case ``named template``
===========================

Templates can also get registered on names. In this expample we use a named
template combined with a custom template marker interface.

  >>> class IMyNamedTemplate(zope.interface.Interface):
  ...     """My custom template marker."""

  >>> factory = TemplateFactory(contentTemplate, 'text/html')
  >>> component.provideAdapter(factory,
  ...     (zope.interface.Interface, IDefaultBrowserLayer), IMyNamedTemplate,
  ...     name='my template')

Now define a view using such a custom named template registration:

  >>> class IMyNamedTemplateView(zope.interface.Interface):
  ...     pass
  >>> @zope.interface.implementer(IMyNamedTemplateView)
  ... class MyNamedTemplateView(object):
  ...
  ...     template = getViewTemplate(IMyNamedTemplate, 'my template')
  ...
  ...     def __init__(self, context, request):
  ...         self.context = context
  ...         self.request = request

  >>> myNamedTempalteView = MyNamedTemplateView(root, request)
  >>> print(myNamedTempalteView.template())
  <div>demo content</div>


Use case ``named layout template``
==================================

We can also register a new layout template by name and use it in a view:

  >>> from z3c.template.template import getLayoutTemplate

  >>> editLayout = os.path.join(temp_dir, 'editLayout.pt')
  >>> with open(editLayout, 'w') as file:
  ...     _ = file.write('''
  ...   <div>Edit layout</div>
  ...   <div tal:content="view/render">content</div>
  ... ''')
  >>> factory = TemplateFactory(editLayout, 'text/html')
  >>> component.provideAdapter(factory,
  ...     (zope.interface.Interface, IDefaultBrowserLayer),
  ...      interfaces.ILayoutTemplate, name='edit')

Now define a view using such a custom named template registration:

  >>> class MyEditView(BrowserPage):
  ...
  ...     layout = getLayoutTemplate('edit')
  ...
  ...     def render(self):
  ...         return u'edit content'
  ...
  ...     def __call__(self):
  ...         if self.layout is None:
  ...             layout = zope.component.getMultiAdapter((self, self.request),
  ...                 interfaces.ILayoutTemplate)
  ...             return layout(self)
  ...         return self.layout()

  >>> myEditView = MyEditView(root, request)
  >>> print(myEditView())
  <div>Edit layout</div>
  <div>edit content</div>


Cleanup
=======

  >>> import shutil
  >>> shutil.rmtree(temp_dir)


Pagelet
=======

See ``z3c.pagelet`` for another template based layout generating implementation.

====================
 Template directive
====================

Show how we can use the template directive. Register the meta configuration for
the directive.

  >>> import sys
  >>> from zope.configuration import xmlconfig
  >>> import z3c.template
  >>> context = xmlconfig.file('meta.zcml', z3c.template)


PageTemplate
============

We need a custom content template

  >>> import os, tempfile
  >>> temp_dir = tempfile.mkdtemp()
  >>> content_file = os.path.join(temp_dir, 'content.pt')
  >>> with open(content_file, 'w') as file:
  ...     _ = file.write('''<div>content</div>''')

and a interface

  >>> import zope.interface
  >>> class IView(zope.interface.Interface):
  ...     """Marker interface"""

and a view class:

  >>> from zope.publisher.browser import TestRequest
  >>> @zope.interface.implementer(IView)
  ... class View(object):
  ...     def __init__(self, context, request):
  ...         self.context = context
  ...         self.request = request
  >>> request = TestRequest()
  >>> view = View(object(), request)

Make them available under the fake package ``custom``:

  >>> sys.modules['custom'] = type(
  ...     'Module', (),
  ...     {'IView': IView})()

and register them as a template within the ``z3c:template`` directive:

  >>> context = xmlconfig.string("""
  ... <configure
  ...     xmlns:z3c="http://namespaces.zope.org/z3c">
  ...   <z3c:template
  ...       template="%s"
  ...       for="custom.IView"
  ...       />
  ... </configure>
  ... """ % content_file, context=context)

Let's get the template

  >>> import zope.component
  >>> from z3c.template.interfaces import IContentTemplate
  >>> template = zope.component.queryMultiAdapter(
  ...     (view, request),
  ...     interface=IContentTemplate)

and check them:

  >>> from z3c.template.template import ViewPageTemplateFile
  >>> isinstance(template, ViewPageTemplateFile)
  True
  >>> isinstance(template.content_type, str)
  True

  >>> print(template(view))
  <div>content</div>

Errors
------

If we try to use a path to a template that does not exist, we
get an error:

  >>> context = xmlconfig.string("""
  ... <configure
  ...     xmlns:z3c="http://namespaces.zope.org/z3c">
  ...   <z3c:template
  ...       template="this_file_does_not_exist"
  ...       for="custom.IView"
  ...       />
  ... </configure>
  ... """, context=context)
  Traceback (most recent call last):
  ...
  ConfigurationError: ('No such file', '...this_file_does_not_exist')
  File "<string>", line 4.2-7.8

Layout template
===============

Define a layout template

  >>> layout_file = os.path.join(temp_dir, 'layout.pt')
  >>> with open(layout_file, 'w') as file:
  ...     _ = file.write('''<div>layout</div>''')

and register them as a layout template within the ``z3c:layout`` directive:

  >>> context = xmlconfig.string("""
  ... <configure
  ...     xmlns:z3c="http://namespaces.zope.org/z3c">
  ...   <z3c:layout
  ...       template="%s"
  ...       for="custom.IView"
  ...       />
  ... </configure>
  ... """ % layout_file, context=context)

Let's get the template

  >>> from z3c.template.interfaces import ILayoutTemplate
  >>> layout = zope.component.queryMultiAdapter((view, request),
  ...     interface=ILayoutTemplate)

and check them:

  >>> isinstance(layout, ViewPageTemplateFile)
  True
  >>> isinstance(layout.content_type, str)
  True

  >>> print(layout(view))
  <div>layout</div>


Context-specific template
=========================

Most of views have some object as their context and it's ofter very
useful to be able register context-specific template. We can do that
using the ``context`` argument of the ZCML directive.

Let's define some content type:

  >>> class IContent(zope.interface.Interface):
  ...     pass
  >>> @zope.interface.implementer(IContent)
  ... class Content(object):
  ...     pass

  >>> sys.modules['custom'].IContent = IContent

Now, we can register a template for this class. Let's create one and
register:

  >>> context_file = os.path.join(temp_dir, 'context.pt')
  >>> with open(context_file, 'w') as file:
  ...     _ = file.write('''<div>i'm context-specific</div>''')

  >>> context = xmlconfig.string("""
  ... <configure
  ...     xmlns:z3c="http://namespaces.zope.org/z3c">
  ...   <z3c:template
  ...       template="%s"
  ...       for="custom.IView"
  ...       context="custom.IContent"
  ...       />
  ... </configure>
  ... """ % context_file, context=context)

We can now lookup it using the (view, request, context) discriminator:

  >>> content = Content()
  >>> view = View(content, request)

  >>> template = zope.component.queryMultiAdapter((view, request, content),
  ...     interface=IContentTemplate)

  >>> print(template(view))
  <div>i'm context-specific</div>

The same will work with layout registration directive:

  >>> context_layout_file = os.path.join(temp_dir, 'context_layout.pt')
  >>> with open(context_layout_file, 'w') as file:
  ...     _ = file.write('''<div>context-specific layout</div>''')
  >>> context = xmlconfig.string("""
  ... <configure
  ...     xmlns:z3c="http://namespaces.zope.org/z3c">
  ...   <z3c:layout
  ...       template="%s"
  ...       for="custom.IView"
  ...       context="custom.IContent"
  ...       />
  ... </configure>
  ... """ % context_layout_file, context=context)

  >>> layout = zope.component.queryMultiAdapter((view, request, content),
  ...     interface=ILayoutTemplate)

  >>> print(layout(view))
  <div>context-specific layout</div>


Named template
==============

Its possible to register template by name. Let us register a pagelet with the
name edit:

  >>> editTemplate = os.path.join(temp_dir, 'edit.pt')
  >>> with open(editTemplate, 'w') as file:
  ...     _ = file.write('''<div>edit</div>''')

  >>> context = xmlconfig.string("""
  ... <configure
  ...     xmlns:z3c="http://namespaces.zope.org/z3c">
  ...   <z3c:template
  ...       name="edit"
  ...       template="%s"
  ...       for="custom.IView"
  ...       />
  ... </configure>
  ... """ % editTemplate, context=context)

And call it:

  >>> from z3c.template.interfaces import ILayoutTemplate
  >>> template = zope.component.queryMultiAdapter(
  ...     (view, request),
  ...     interface=IContentTemplate, name='edit')

  >>> print(template(view))
  <div>edit</div>


Custom template
===============

Or you can define own interfaces and register templates for them:

  >>> from zope.pagetemplate.interfaces import IPageTemplate
  >>> class IMyTemplate(IPageTemplate):
  ...     """My template"""

Make the template interface available as a custom module class.

  >>> sys.modules['custom'].IMyTemplate = IMyTemplate

Dfine a new template

  >>> interfaceTemplate = os.path.join(temp_dir, 'interface.pt')
  >>> with open(interfaceTemplate, 'w') as file:
  ...     _ = file.write('''<div>interface</div>''')

  >>> context = xmlconfig.string("""
  ... <configure
  ...     xmlns:z3c="http://namespaces.zope.org/z3c">
  ...   <z3c:template
  ...       template="%s"
  ...       for="custom.IView"
  ...       provides="custom.IMyTemplate"
  ...       />
  ... </configure>
  ... """ % interfaceTemplate, context=context)

Let's see if we get the template by the new interface:

  >>> from z3c.template.interfaces import ILayoutTemplate
  >>> template = zope.component.queryMultiAdapter((view, request),
  ...     interface=IMyTemplate,)

  >>> print(template(view))
  <div>interface</div>


Cleanup
=======

Now we need to clean up the custom module.

  >>> del sys.modules['custom']

=========
 CHANGES
=========

3.2 (2022-03-25)
================

- Add support for Python 3.8, 3.9, and 3.10.

- Drop support for Python 3.4.


3.1.0 (2019-02-05)
==================

- Adapt tests to `zope.configuration >= 4.2`.
- Add support for Python 3.7.


3.0.0 (2017-10-18)
==================

- Add support for PyPy.
- Add support for Python 3.4, 3.5 and 3.6.
- Drop support for Python 2.6 and 3.3.
- Make bound page templates have ``__self__`` and ``__func__``
  attributes to be more like Python 3 bound methods. (``im_func`` and
  ``im_self`` remain available.) See `issue 3
  <https://github.com/zopefoundation/z3c.template/issues/3>`_.
- Depend on Chameleon >= 3.0, z3c.pt >= 2.1 and z3c.ptcompat >= 2.1.0
  due to possible rendering issues. See `PR 2
  <https://github.com/zopefoundation/z3c.template/pull/2>`_.

2.0.0 (2015-11-09)
==================

- Standardize namespace ``__init__``


2.0.0a2 (2013-02-25)
====================

- Make sure the of the templates content type is a native string instead
  forced bytes.


2.0.0a1 (2013-02-22)
====================

- Added support for Python 3.3.

- Replaced deprecated ``zope.interface.implements`` usage with equivalent
  ``zope.interface.implementer`` decorator.

- Dropped support for Python 2.4 and 2.5.


1.4.1 (2012-02-15)
==================

- Remove hooks to use ViewPageTemplateFile from z3c.pt because this breaks when
  z3c.pt is available, but z3c.ptcompat is not included. As recommended by notes
  below.


1.4.0 (2011-10-29)
==================

- Moved z3c.pt include to extras_require chameleon. This makes the package
  independent from chameleon and friends and allows to include this
  dependencies in your own project.

- Upgrade to chameleon 2.0 template engine and use the newest z3c.pt and
  z3c.ptcompat packages adjusted to work with chameleon 2.0.

  See the notes from the z3c.ptcompat package:

  Update z3c.ptcompat implementation to use component-based template engine
  configuration, plugging directly into the Zope Toolkit framework.

  The z3c.ptcompat package no longer provides template classes, or ZCML
  directives; you should import directly from the ZTK codebase.

  Note that the ``PREFER_Z3C_PT`` environment option has been
  rendered obsolete; instead, this is now managed via component
  configuration.

  Also note that the chameleon CHAMELEON_CACHE environment value changed from
  True/False to a path. Skip this property if you don't like to use a cache.
  None or False defined in buildout environment section doesn't work. At least
  with chameleon <= 2.5.4

  Attention: You need to include the configure.zcml file from z3c.ptcompat
  for enable the z3c.pt template engine. The configure.zcml will plugin the
  template engine. Also remove any custom built hooks which will import
  z3c.ptcompat in your tests or other places.


1.3.0 (2011-10-28)
==================

- Update to z3c.ptcompat 1.0 (and as a result, to the z3c.pt 2.x series).

- Using Python's ``doctest`` module instead of depreacted
  ``zope.testing.doctest``.


1.2.1 (2009-08-22)
==================

* Corrected description of ``ITemplateDirective.name``.

* Added `zcml.txt` to ``long_description`` to show up on pypi.

* Removed zpkg helper files and zcml slugs.


1.2.0 (2009-02-26)
==================

* Add support for context-specific templates. Now, templates can be
  registered and looked up using (view, request, context) triple.
  To do that, pass the ``context`` argument to the ZCML directives.
  The ``getPageTemplate`` and friends will now try to lookup context
  specific template first and then fall back to (view, request) lookup.

* Allow use of ``z3c.pt`` using ``z3c.ptcompat`` compatibility layer.

* Forward the template kwargs to the options of the macro

* Changed package's mailing list address to zope-dev at zope.org
  instead of retired one.

1.1.0 (2007-10-08)
==================

* Added an ``IContentTemplate`` interface which is used for
  ``<z3c:template>``.

1.0.0 (2007-??-??)
==================

* Initial release.


