Package: grokcore.viewlet
This package provides support to write and register Zope Viewlets
directly in Python (without ZCML). It’s designed to be used withgrokcore.viewwhich let you write and register Zope Views.ContentsSetting upgrokcore.viewletExamplesAPI OverviewBase classesDirectivesChanges4.0 (2023-08-28)3.1.0 (2018-02-05)3.0.1 (2018-01-12)3.0.0 (2018-01-04)1.11 (2012-09-04)1.10.1 (2012-05-02)1.10 (2012-05-02)1.9 (2011-06-28)1.8 (2010-12-16)1.7 (2010-11-03)1.6 (2010-11-01)1.5 (2010-10-18)1.4.1 (2010-02-28)1.4 (2010-02-19)1.3 (2009-09-17)1.2 (2009-09-16)1.1 (2009-07-20)1.0 (2008-11-15)Setting upgrokcore.viewletThis package is set up like thegrokcore.componentpackage. 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.ExamplesFirst we need a view to call our viewlet manager:from grokcore import viewlet

class Index(viewlet.View):
    pass

index = viewlet.Page Template("""
<html>
  <head>Test</head>
  <body>
    <div tail:content="structure provider:content">
    </div>
  </body>
</html>
""")After that we could define only a manager which display something:class Content(viewlet.ViewletManager):
    viewlet.View(Index)

    def render(self):
        return u'<h1>Hello World</h1>'Or a completely different example:class AdvancedContent(viewlet.ViewletManager):
    viewlet.name('content')
    viewlet.view(Index)And some viewlets for that one:class StaticData(viewlet.Viewlet):
    viewlet.view(Index)
    viewlet.viewletmanager(AdvancedContent)

    def render(self):
        return f'<p> Data from {self.context.id}</p>'Or:class SecretData(viewlet.Viewlet):
    viewlet.view(Index)
    viewlet.viewletmanager(AdvancedContent)
    viewlet.require('agent.secret')

secretdata = viewlet.PageTemplate("""
  <p>Nothing to see here.</p>
""")The way templates are bound to components works exactly the way as
ingrokcore.view, for more information refer to its
documentation.API OverviewBase classesViewletManagerDefine 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,viewis 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.ViewletDefine 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,viewis added to the template namespace if
used.viewletmanageris defined as well as a reference to the
manager in the template’s namespace and as an attribute on the
viewlet object.DirectivesYou can use directives fromgrokcore.viewto register your
viewlet or viewlet manager:name,context,layerandrequire(for security on a viewlet).To that is added:viewSelect for which view is registered a viewlet or a viewlet manager.viewletmanagerSelect for which viewlet manager is registered a viewlet.orderDefine a rendering order for viewlets in a viewlet manager. This
should be a number, the smaller order render first, bigger last.Additionally, thegrokcore.viewletpackage exposes thegrokcore.component,grokcore.securityandgrokcore.viewAPIs.Changes4.0 (2023-08-28)Add support for Python 3.7, 3.8, 3.9, 3.10, 3.11.Drop support for Python 2.7, 3.4, 3.5, 3.6.3.1.0 (2018-02-05)viewletmanager.viewlets should be a list so we can iterate over it several
times in consumer code instead of having to remember it’s an iterable we can
only list once.3.0.1 (2018-01-12)Rearrange tests such that Travis CI can pick up all functional tests too.3.0.0 (2018-01-04)Python 3 compatibility.1.11 (2012-09-04)Make thehas_render()andhas_no_render()symmetrical to those
in grokcore.view, grokcore.layout and grokcore.formlib, where arender.base_methodattribute is checked.1.10.1 (2012-05-02)Do not require the role extra from grokcore.security.1.10 (2012-05-02)Use the component registration api from grokcore.component.Update how the static resources are found on aViewletManagerand aViewlet, following the new name__static_name__set by
the template association.1.9 (2011-06-28)Introduce theavailable()method on viewlet component. The viewlet
manager will filter out unavailable viewlet by calling this method. Theavailable()method is calledafterthe viewlet’supdate()is called,
butbeforetherender()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 zope.org repository policy.Update functional tests to use Browser implementation of zope.app.wsgi
instead of zope.app.testing.Reduce dependencies (zope.app.pagetemplate no longer necessary).1.4.1 (2010-02-28)Dropped the dependency onzope.app.zcmlfiles.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 requiregrokcore.view1.12.1 or newer. As ofgrokcore.view1.12, 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
grokcore.security 1.2Use the grok.zope.org/releaseinfo information instead of our own
copy ofversions.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 grokcore.security
1.1)1.0 (2008-11-15)Createdgrokcore.viewletin November 2008 by factoringzope.viewlet-based components, grokkers and directives out of
Grok.