Folders section

The collective.transmogrifier.sections.constructor blueprint can construct new content, based on a type (_type key) and a path (_path key). However, it will bail if it is asked to create an item for which the parent folder does not exist.

One way to work around this is to ensure that the folders already exist, for example by sending the instruction to construct them through the pipeline before any contents of that folder. This requires sorted input, of course.

Alternatively, you can use the collective.transmogrifier.sections.folders blueprint. This will look at the path of each incoming item and construct parent folders if needed. This implies that all folders (that do not yet exist), are of the same type. That type defaults to Folder, although you can supply an alternative type. The folder will be created without an id only, but a subsequent schema updated section for a subsequent item may have the opportunity to update it (but not change its type.)

This blueprint can take the following options, all of the optional:

path-key

The name of the key holding the path. This defaults to the same semantics as those used for the constructor section. Just use _path and you’ll be OK.

new-type-key

The type key to use when inserting a new item in the pipeline to create folders. The default is _type. Change it if you need to target a specific constructor section.

new-path-key

The path key to use when inserting a new item in the pipeline to create folders. The default is to use the same as the incoming path key. Change it if you need to target a specific constructor section.

folder-type

The name of the portal type to use for new folders. Defaults to Folder, which is the default folder type in CMF and Plone.

cache

By default, the section will keep a cache in memory of each folder it has checked (and possibly created) to know whether it already exists. This saves a lot of traversal, especially if you have many items under a particular folder. This will use a small amount of memory. If you have millions of objects, you can trade memory for speed by setting this option to false.

Here is how it might look by default:

>>> import pprint
>>> constructor = """
... [transmogrifier]
... pipeline =
...     contentsource
...     folders
...     logger
...
... [contentsource]
... blueprint = collective.transmogrifier.sections.tests.folderssource
...
... [folders]
... blueprint = collective.transmogrifier.sections.folders
...
... [logger]
... blueprint = collective.transmogrifier.sections.logger
... name = logger
... level = INFO
... """
>>> registerConfig(u'collective.transmogrifier.sections.tests.folders',
...                constructor)
>>> transmogrifier(u'collective.transmogrifier.sections.tests.folders')
>>> print handler
logger INFO
    {'_path': '/foo', '_type': 'Document'}
logger INFO
    {'_path': '/existing/foo', '_type': 'Document'}
logger INFO
    {'_path': '/nonexisting', '_type': 'Folder'}
logger INFO
    {'_path': '/nonexisting/alpha', '_type': 'Folder'}
logger INFO
    {'_path': '/nonexisting/alpha/foo', '_type': 'Document'}
logger INFO
    {'_path': '/nonexisting/beta', '_type': 'Folder'}
logger INFO
    {'_path': '/nonexisting/beta/foo', '_type': 'Document'}
logger INFO
    {'_type': 'Document'}
logger INFO
    {'_folders_path': '/delta', '_type': 'Folder'}
logger INFO
    {'_folders_path': '/delta/foo', '_type': 'Document'}

To specify alternate types and keys, we can do something like this:

>>> import pprint
>>> constructor = """
... [transmogrifier]
... pipeline =
...     contentsource
...     folders
...     logger
...
... [contentsource]
... blueprint = collective.transmogrifier.sections.tests.folderssource
...
... [folders]
... blueprint = collective.transmogrifier.sections.folders
... folder-type = My Folder
... new-type-key = '_folderconstructor_type
... new-path-key = '_folderconstructor_path
...
... [logger]
... blueprint = collective.transmogrifier.sections.logger
... name = logger
... level = INFO
... """
>>> registerConfig(u'collective.transmogrifier.sections.tests.folders2',
...                constructor)
>>> handler.clear()
>>> plone.exists.clear()
>>> transmogrifier(u'collective.transmogrifier.sections.tests.folders2')
>>> print handler
logger INFO
  {'_path': '/foo', '_type': 'Document'}
logger INFO
  {'_path': '/existing/foo', '_type': 'Document'}
logger INFO
    {"'_folderconstructor_path": '/nonexisting',
   "'_folderconstructor_type": 'My Folder'}
logger INFO
    {"'_folderconstructor_path": '/nonexisting/alpha',
   "'_folderconstructor_type": 'My Folder'}
logger INFO
    {'_path': '/nonexisting/alpha/foo', '_type': 'Document'}
logger INFO
    {"'_folderconstructor_path": '/nonexisting/beta',
   "'_folderconstructor_type": 'My Folder'}
logger INFO
    {'_path': '/nonexisting/beta/foo', '_type': 'Document'}
logger INFO
    {'_type': 'Document'}
logger INFO
    {"'_folderconstructor_path": '/delta',
    "'_folderconstructor_type": 'My Folder'}
logger INFO
    {'_folders_path': '/delta/foo', '_type': 'Document'}