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Viewlets based on ZPT macros.

Project description

Macro viewlets are Zope 3 UI components. In particular they allow the developer to specify viewlets based on macros instead of entire templates.

Macro Provider

This package provides a ZCML directive which allows you to register a macro defined in a template as a viewlet. Such a macro based viewlet acts 100% the same as a other viewlets. It could be very handy if you want to write a layout template in one page template and define selective parts as viewlets without adding any additional HTML. Let me show what this will look like:

The layout/master template can look like this:

<!DOCTYPE ...>
<html xmlns="" xml:lang="en" lang="en"
<tal:block replace="structure provider:ITitle">
  <metal:block define-macro="title">
    <title>The title</title>
<body tal:define="applicationURL request/getApplicationURL">
<div id="content">
  <tal:block content="structure provider:pagelet">content</tal:block>

The tempalte above defines an ITitle provider which contains the definition for a macro within itself. You have to define a viewlet manager within the zope.viewlet ZCMl directive which provides ITitle as a viewlet manager. After that, you can register the template above as a layout template wthin the z3c:layout ZCML directive like this:


Then you can register the macro viewlet for the ITitle viewlet manager like this:


As you can see, the ZCML configuration directive above uses title as the macro attribute and uses ITitle as the viewlet manager. This will use the following part of the

<title>Pagelet skin</title>

and registers it as a viewlet. This viewlet gets rendered in the ITitle provider. As you can see, you can use a complete layout tempalte and use it as it is. And here it comes, you can offer an included viewlet manager rendering the viewlet which can be overriden for other contexts or views etc. You also can register more than one viewlet for the ITitle viewlet manager. Which of course makes no sense in our special title tag example.

Let’s show this in some tests. We’ll start by creating a content object that is used as a view context later:

>>> import zope.interface
>>> import zope.component
>>> from zope.publisher.interfaces.browser import IBrowserView
>>> from zope.publisher.interfaces.browser import IDefaultBrowserLayer
>>> class Content(object):
...     zope.interface.implements(zope.interface.Interface)

>>> content = Content()

We also create a temp dir for sample templates which will be defined later for testing:

>>> import os, tempfile
>>> temp_dir = tempfile.mkdtemp()

And we register a security checker for the MacroViewlet class:

>>> from zope.configuration.xmlconfig import XMLConfig
>>> import
>>> import z3c.macroviewlet
>>> XMLConfig('meta.zcml',
>>> XMLConfig('configure.zcml', z3c.macroviewlet)()

Layout template

We define a template including a macro definition and using a provider:

>>> path = os.path.join(temp_dir, '')
>>> open(path, 'w').write('''
... <html>
... <body>
... <head>
... <tal:block replace="structure provider:ITitle">
...   <metal:block define-macro="title">
...     <title>The title</title>
...   </metal:block>
... </tal:block>
... </head>
... <body tal:define="applicationURL request/getApplicationURL">
...   content
... </body>
... </html>
... ''')

Let’s register a view class using the view template:

>>> import zope.interface
>>> from import viewpagetemplatefile
>>> from zope.publisher.interfaces.browser import IBrowserView
>>> class View(object):
...     zope.interface.implements(IBrowserView)
...     def __init__(self, context, request):
...        self.context = context
...        self.request = request
...     def __call__(self):
...         return viewpagetemplatefile.ViewPageTemplateFile(path)(self)

Let’s prepare the view:

>>> from zope.publisher.browser import TestRequest
>>> request = TestRequest()
>>> view = View(content, request)

Let’s define the viewlet manager ITitle:

>>> from zope.viewlet.interfaces import IViewletManager
>>> from zope.viewlet.manager import ViewletManager
>>> class ITitle(IViewletManager):
...     """Viewlet manager located in the title tag."""

>>> title = ViewletManager('title', ITitle)

Let’s register the viewlet manager:

>>> from zope.viewlet.interfaces import IViewletManager
>>> manager = zope.component.provideAdapter(
...     title,
...     (zope.interface.Interface, TestRequest, IBrowserView),
...     IViewletManager,
...     name='ITitle')


Before we register the macro viewlet, we check the rendered page without any registered macro viewlet:

>>> print view()

As you can see there is no title rendered. Now we can define the macro viewlet…:

>>> from import viewpagetemplatefile
>>> from z3c.macroviewlet import zcml
>>> macroViewlet = zcml.MacroViewletFactory(path, 'title', 'text/html')

and register them as adapter:

>>> from zope.viewlet.interfaces import IViewlet
>>> zope.component.provideAdapter(
...     macroViewlet,
...     (zope.interface.Interface, IDefaultBrowserLayer, IBrowserView,
...      ITitle),
...     IViewlet,
...     name='title')

Now we are ready to test it again:

>>> print view()
    <title>The title</title>

As you can see, the title gets rendered as a viewlet into the ITitle provider.


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


1.1.0 (2010-07-14)

  • Fixed tests to run with current package versions (metaconfigure.registerType moved from to zope.browserpage). Thus requiring zope.browserpage now.
  • No longer use depreacted zope.testing.doctest and zope.testing.doctestunit.
  • Removed ZPKG and ZCML slugs.
  • Fixed RST formatting in README.

1.0.0 (2007-09-21)

  • Initial Release

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