Helper views and tools

Introduction

This document explains how to access view and context utilities in Plone.

IPortalState and IContextState

IPortalState defines IContextState view-like interfaces to access miscellaneous information useful for the rendering of the current page.

The views are cached properly, they should access the information effectively.

  • IPortalState is mapped as the plone_portal_state name view.
  • IContextState is mapped as the plone_context_state named view.
  • ITools is mapped as the plone_tools named view.

To see what’s available through the interface, read the documentation in the plone.app.layout.globals.interfaces module.

Example showing how to get the portal root URL:

from zope.component import getMultiAdapter
...

class MyView(BrowserView):

    ...

    def __call__(self):
        # aq_inner is needed in some cases like in the portlet renderers
        # where the context itself is a portlet renderer and it's not on the
        # acquisition chain leading to the portal root.
        # If you are unsure what this means always use context.aq_inner
        context = self.context.aq_inner
        portal_state = getMultiAdapter((context, self.request), name=u'plone_portal_state')

        self.some_url = portal_state.portal_url() + "/my_foo_bar"

Example showing how to get the current language:

from zope.component import getMultiAdapter

...

portal_state = getMultiAdapter((self.context, self.request), name=u'plone_portal_state')
current_language = portal_state.language()

Example showing how to expose portal_state helper to a template:

  1. ZCML includes portal_state in allowed_attributes
<browser:page
    for="*"
    name="test"
    permission="zope2.Public"
    class=".views.MyView"
    allowed_attributes="portal_state"
    />

A Python class exposes the variable:

from Acquisition import aq_inner
from zope.component import getMultiAdapter

class MyView(BrowserView):

    def portal_state(self):
        context = aq_inner(self.context)
        portal_state = getMultiAdapter((context, self.request), name=u'plone_portal_state')
        return portal_state

Templates can use it as follows:

<div>
    The language is <span tal:content="view/portal_state/language" />
</div>

You can directly look up portal_state in templates using acquisition and view traversal, without need of ZCML code or Python view code changes. This is useful e.g. in overridden viewlet templates:

<!--

    During traversal, ``@@`` signals that the traversing
    machinery should look up a view by that name.

    First we look up the view and then use
    it to access the variables defined in
    ``IPortalState`` interface.

-->

<div tal:define="portal_state context/@@plone_portal_state" >
    The language is <span tal:content="portal_state/language" />
</div>

Use in templates and expressions

You can use IContextState and IPortalState in TALES expressions, e.g. portal_actions, as well.

Example portal_actions conditional expression:

python:object.restrictedTraverse('@@plone_portal_state').language() == 'fi'

Tools

Tools are persistent utility classes available in the site root. They are visible in the Management Interface, and sometimes expose useful information or configuration here. Tools include e.g.:

portal_catalog
Search and indexing facilities for content
portal_workflow
Look up workflow status, and do workflow-related actions.
portal_membership
User registration information.

Warning

Portal tools are deprecated and are phased out and being replaced by utilities. The Removal of selected portal tools PLIP is created to migrate from tools to utilities.

Get a portal tool using plone.api

It is recommended to use plone.api to get a portal tool:

from plone import api
catalog = api.portal.get_tool(name='portal_catalog')

The plone.api package exposes functionality from portal tools, it is not longer necessary to directly call a tool. For example; the API can be used the get the workflow state, change the workflow state, get a member and get the member properties.

ITools interface

plone.app.layout.globals.interfaces.ITools interface and Tools BrowserView provide cached access for the most commonly needed tools.

ITools is mapped as the plone_tools view for traversing.

Example:

from Acquisition import aq_inner
from zope.component import getMultiAdapter

context = aq_inner(self.context)
tools = getMultiAdapter((context, self.request), name=u'plone_tools')

portal_url = tools.url()

# The root URL of the site is got by using portal_url.__call__()
# method

the_current_root_url_of_the_site = portal_url()

IPlone

Products.CMFPlone.browser.interfaces.IPlone provides some helper methods for Plone specific functionality and user interface.

  • IPlone helper views is registered under the name plone

getToolByName

getToolByName is the old-fashioned way of getting tools, using the context object as a starting point. It also works for tools which do not implement the ITools interface.

getToolByName gets any Plone portal root item using acquisition.

Example:

from Products.CMFCore.WorkflowCore import WorkflowException

# Do the workflow transition "submit" for the current context
workflowTool = getToolByName(self.context, "portal_workflow")
workflowTool.doActionFor(self.context, "submit")