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grokcore.viewlet 1.11

Grok-like configuration for zope viewlets

This package provides support to write and register Zope Viewlets directly in Python (without ZCML). It’s designed to be used with grokcore.view which let you write and register Zope Views.

Setting up grokcore.viewlet

This package is set up like the grokcore.component package. Please refer to its documentation for more details. The additional ZCML lines you will need are:

<include package="grokcore.viewlet" file="meta.zcml" />
<include package="grokcore.viewlet" />

Put the first line somewhere near the top of your root ZCML file.


First we need a view to call our viewlet manager:

from grokcore import viewlet

class Index(viewlet.View):

index = viewlet.Page Template("""
<div tail:content="structure provider:content">

After that we could define only a manager which display something:

class Content(viewlet.ViewletManager):

    def render(self):
        return u'<h1>Hello World</h1>'

Or a completely different example:

class AdvancedContent(viewlet.ViewletManager):'content')

And some viewlets for that one:

class StaticData(viewlet.Viewlet):

    def render(self):
        return u'<p> Data from %s</p>'


class SecretData(viewlet.Viewlet):

secretdata = viewlet.PageTemplate("""
<p>Nothing to see here.</p>

The way templates are binded to components works exactly the way than in grokcore.view, for more information refer to its documentation.

API Overview

Base classes


Define a new viewlet manager. You can either provide a render method, a template, which can or not use registered viewlets.

If you define a template, view is added as a reference to the current view for which the manager is rendering in the template’s namespace. It is available as well as an attribute on the manager object.


Define a new viewlet. You can either provide a template or a render method on it. Like in views, you can define an update method to process needed data.

Like for manager, view is added to the template namespace if used. viewletmanager is defined as well as a reference to the manager in the template’s namespace and as an attribute on the viewlet object.


You can use directives from grokcore.view to register your viewlet or viewlet manager: name, context, layer and require (for security on a viewlet).

To that is added:

Select for which view is registered a viewlet or a viewlet manager.
Select for which viewlet manager is registered a viewlet.
Define a rendering order for viewlets in a viewlet manager. This should be a number, the smaller order render first, bigger last.

Additionally, the grokcore.viewlet package exposes the grokcore.component, and grokcore.view APIs.


1.11 (2012-09-04)

  • Make the has_render() and has_no_render() symmetrical to those in grokcore.view, grokcore.layout and grokcore.formlib, where a render.base_method attribute is checked.

1.10.1 (2012-05-02)

  • Do not require the role extra from

1.10 (2012-05-02)

  • Use the component registration api from grokcore.component.
  • Update how the static resources are found on a ViewletManager and a Viewlet, following the new name __static_name__ set by the template association.

1.9 (2011-06-28)

  • Introduce the available() method on viewlet component. The viewlet manager will filter out unavailable viewlet by calling this method. The available() method is called after the viewlet’s update() is called, but before the render() is called.

1.8 (2010-12-16)

  • Update to use TemplateGrokker from grokcore.view to associate viewlet and viewletmanager templates.

1.7 (2010-11-03)

  • The computed default value for the viewletmanager directive is now defined in the directiv itself, not as a separate function that needs to be passed along.

1.6 (2010-11-01)

  • Upped version requirements for martian, grokcore.component, and grokcore.view.
  • Move the order directive to grokcore.component.
  • Move the view directive to grokcore.view.

1.5 (2010-10-18)

  • Make package comply to repository policy.
  • Update functional tests to use Browser implementation of instead of
  • Reduce dependencies ( no longer necessary).

1.4.1 (2010-02-28)

  • Dropped the dependency on
  • Cleaned the code to remove unused imports and ensure the pep8 syntax.
  • Updated tests to have a return value consistency. The grokcore.viewlet viewlet manager implementation requires viewlets to return unicode strings. Now, viewlets return unicode strings in the test packages.

1.4 (2010-02-19)

  • Define test requires.

1.3 (2009-09-17)

  • Reverted the use of grokcore.view.CodeView. We now require grokcore.view 1.12.1 or newer. As of grokcore.view 1.12, the CodeView/View separation has been undone.

1.2 (2009-09-16)

  • Remove the reference to the grok.View permission that is no longer in 1.2
  • Use the information instead of our own copy of versions.cfg, for easier maintenance.

1.1 (2009-07-20)

  • Adapted tests to new grokcore.view release: switched from View to CodeView.
  • Add grok.View permissions to functional tests (requires 1.1)

1.0 (2008-11-15)

  • Created grokcore.viewlet in November 2008 by factoring zope.viewlet-based components, grokkers and directives out of Grok.
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