Content types

Description

Plone's content type subsystems and creating new content types programmatically.

Introduction

Plone has two kind of content types subsystems:

  • Archetypes-based
  • Dexterity (covered in the Plone 4 documentation)
  • See also Plomino (later in this document).

Flexible architecture allows other kinds of content type subsystems as well.

Type information registry

Plone maintains available content types in the portal_types tool.

portal_types is a folderish object which stores type information as child objects, keyed by the portal_type property of the types.

portal_factory is a tool responsible for creating the persistent object representing the content.

TypesTool source code.

Listing available content types

Often you need to ask the user to choose specific Plone content types.

Plone offers two Zope 3 vocabularies for this purpose:

plone.app.vocabularies.PortalTypes
a list of types installed in portal_types
plone.app.vocabularies.ReallyUserFriendlyTypes
a list of those types that are likely to mean something to users.

If you need to build a vocabulary of user-selectable content types in Python instead, here's how: 

from Acquisition import aq_inner
from zope.app.component.hooks import getSite
from zope.schema.vocabulary import SimpleVocabulary, SimpleTerm
from Products.CMFCore.utils import getToolByName

def friendly_types(site):
    """ List user-selectable content types.

    We cannot use the method provided by the IPortalState utility view,
    because the vocabulary factory must be available in contexts where
    there is no HTTP request (e.g. when installing add-on product).

    This code is copied from
    https://github.com/plone/plone.app.layout/blob/master/plone/app/layout/globals/portal.py

    @return: Generator for (id, type_info title) tuples
    """

    context = aq_inner(site)
    site_properties = getToolByName(context, "portal_properties").site_properties
    not_searched = site_properties.getProperty('types_not_searched', [])

    portal_types = getToolByName(context, "portal_types")
    types = portal_types.listContentTypes()

    # Get list of content type ids which are not filtered out
    prepared_types = [t for t in types if t not in not_searched]

    # Return (id, title) pairs
    return [ (id, portal_types[id].title) for id in prepared_types ]

Creating a new content type

These instructions apply to Archetypes-based content types.

Install ZopeSkel

Add ZopeSkel to your buildout.cfg and run buildout:

[buildout]
...
parts =
    instance
    zopeskel

...
[zopeskel]
recipe = zc.recipe.egg
eggs =
   PasteScript
   ZopeSkel

Create an archetypes product

Run the following command and answer the questions e.g. for the project name use my.product: 

./bin/paster create -t archetype

Install the product

Adjust your buildout.cfg and run buildout again:

[buildout]
develop = my.product
...
parts =
    instance
    zopeskel

...
[instance]
eggs = my.product

Note

You need to install your new product using buildout before you can add a new content type in the next step. Otherwise paster complains with the following message: "Command 'addcontent' not known".

Create a new content type

Change into the directory of the new product and then use paster to add a new content type: 

cd my.product
../bin/paster addcontent contenttype

Related how-tos:

Note

Creating types by hand is not worth the trouble. Please use a code generator to create the skeleton for your new content type.

Warning

The content type name must not contain spaces. Neither the content type name or the description may contain non-ASCII letters. If you need to change these please create a translation catalog which will translate the text to one with spaces or international letters.

Debugging new content type problems

Creating types by hand is not worth the trouble.

Creating new content types through-the-web

There exist solutions for non-programmers and Plone novices to create their content types more easily.

Dexterity

Plomino (Archetypes-based add-on)

Implicitly allowed

Implictly allowed is a flag specifying whether the content is globally addable or must be specifically enabled for certain folders.

The following example allows creation of Large Plone Folder anywhere at the site (it is disabled by default). For available properties, see TypesTool._advanced_properties.

Example:

portal_types = self.context.portal_types
lpf = portal_types["Large Plone Folder"]
lpf.global_allow = True # This is "Globally allowed" property

Constraining the addable types per type instance

For the instances of some content types, the user may manually restrict which kinds of objects may be added inside. This is done by clicking the Add new... link on the green edit bar and then choosing Restrictions....

This can also be done programmatically on an instance of a content type that supports it.

First, we need to know whether the instance supports this.

Example:

from Products.Archetypes.utils import shasattr # To avoid acquisition
if shasattr(context, 'canSetConstrainTypes'):
    # constrain the types
    context.setConstrainTypesMode(1)
    context.setLocallyAllowedTypes(('News Item',))

If setConstrainTypesMode is 1, then only the types enabled by using setLocallyAllowedTypes will be allowed.

The types specified by setLocallyAllowedTypes must be a subset of the allowable types specified in the content-type's FTI (Factory Type Information) in the portal_types tool.

If you want the types to appear in the :guilabel: Add new.. dropdown menu, then you must also set the immediately addable types. Otherwise, they will appear under the more submenu of Add new...

Example:

context.setImmediatelyAddableTypes(('News Item',))

The immediately addable types must be a subset of the locally allowed types.

To retrieve information on the constrained types, you can just use the accessor equivalents of the above methods.

Example:

context.getConstrainTypesMode()
context.getLocallyAllowedTypes()
context.getImmediatelyAddableTypes()
context.getDefaultAddableTypes()
context.allowedContentTypes()

Be careful of Acquisition. You might be acquiring these methods from the current instance's parent. It would be wise to first check whether the current object has this attribute, either by using shasattr or by using hasattr on the object's base (access the base object using aq_base).

The default addable types are the types that are addable when constrainTypesMode is 0 (i.e not enabled).

For more information, see Products/CMFPlone/interfaces/constraints.py