View helpers

You usually need access parts of Plone config and user session data from your view.

Here are some useful tips how to do it.

IPortalState and IContextState

IPortalState define IContextState view-like interfaces to access miscencancellous information useful for the current page render. The views are cached properly, so they should access the information quite effective manner

IPortalState is mapped as plone_portal_state view for traversing.

IContextState is mapped as plone_context_state view for traversing.

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

Example how to get the current language:

from Acquisition import aq_inner
from zope.component import getMultiAdapter

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

current_language = portal_state.language()

Example how to expose portal_state to template:

ZCML includes allowed_attributes:

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

Python class exposes the variable:

from Acquisition import aq_inner
from zope.component import getMultiAdapter

class MyView(BrowserView):

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

Template can use it:

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

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

<!--

    In traversing @@ marks that the traversing
    machine 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>

Tools

Tools are persistent utility classes available in the site root. They are visible in ZMI. Tools include things like

• portal_catalog - Search and indexing facilities for content
• portal_workflow - Inquiry and do workflow related actions
• portal_membership - User registration information

ITools interface

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

ITools is mapped as 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()

getToolByName

getToolByName is old-fashioned way of getting tools the context object as a start point. It also works for tools which are not defined in 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")