Constructor section

A constructor pipeline section is the heart of a transmogrifier content import pipeline. It constructs Plone content based on the items it processes. The constructor section blueprint name is collective.transmogrifier.sections.constructor. Constructor sections do only one thing, they construct new content. No schema changes are made. Also, constructors create content without restrictions, no security checks or containment constraints are checked.

Construction needs 2 pieces of information: the path to the item (including the id for the new item itself) and it’s portal type. To determine both of these, the constructor section inspects each item and looks for 2 keys, as described below. Any item missing any of these 2 pieces will be skipped. Similarly, items with a path for a container or type that doesn’t exist will be skipped as well; make sure that these containers are constructed beforehand. Because a constructor section will only construct new objects, if an object with the same path already exists, the item will also be skipped.

For the object path, it’ll look (in order) for _collective.transmogrifier.sections.constructor_[sectionname]_path, _collective.transmogrifier.sections.constructor_path, _[sectionname]_path, and _path, where [sectionname] is replaced with the name given to the current section. This allows you to target the right section precisely if needed. Alternatively, you can specify what key to use for the path by specifying the path-key option, which should be a list of keys to try (one key per line, use a re: or regexp: prefix to specify regular expressions).

For the portal type, use the type-key option to specify a set of keys just like path-key. If omitted, the constructor will look for _collective.transmogrifier.sections.constructor_[sectionname]_type, _collective.transmogrifier.sections.constructor_type, _[sectionname]_type, _type, portal_type and Type (in that order, with [sectionname] replaced).

Unicode paths will be encoded to ASCII. Using the path and type, a new object will be constructed using invokeFactory; nothing else is done. Paths are always interpreted as relative to the context object, with the last path segment being the id of the object to create.

By default the constructor section will log a warning if the container for the item is missing and the item can’t be constructed. However if you add a required = True key to the constructor section it will instead raise a KeyError.

>>> import pprint
>>> constructor = """
... [transmogrifier]
... pipeline =
...     contentsource
...     constructor
...     logger
...
... [contentsource]
... blueprint = collective.transmogrifier.sections.tests.contentsource
...
... [constructor]
... blueprint = collective.transmogrifier.sections.constructor
...
... [logger]
... blueprint = collective.transmogrifier.sections.logger
... name = logger
... level = INFO
... """
>>> registerConfig('collective.transmogrifier.sections.tests.constructor',
...                constructor)
>>> transmogrifier('collective.transmogrifier.sections.tests.constructor')
>>> print(handler)
logger INFO
  {'_path': '/eggs/foo', '_type': 'FooType'}
logger INFO
  {'_path': '/spam/eggs/foo', '_type': 'FooType'}
logger INFO
  {'_path': '/foo', '_type': 'FooType'}
logger INFO
  {'_path': '/unicode/encoded/to/ascii', '_type': 'FooType'}
logger INFO
    {'_path': 'not/existing/bar',
   '_type': 'BarType',
   'title': 'Should not be constructed, not an existing path'}
logger INFO
    {'_path': '/spam/eggs/existing',
   '_type': 'FooType',
   'title': 'Should not be constructed, an existing object'}
logger INFO
    {'_path': '/spam/eggs/incomplete',
   'title': 'Should not be constructed, no type'}
logger INFO
    {'_path': '/spam/eggs/nosuchtype',
   '_type': 'NonExisting',
   'title': 'Should not be constructed, not an existing type'}
logger INFO
    {'_path': 'spam/eggs/changedByFactory',
   '_type': 'FooType',
   'title': 'Factories are allowed to change the id'}
>>> pprint.pprint(plone.constructed)
[('eggs', 'foo', 'FooType'),
 ('spam/eggs', 'foo', 'FooType'),
 ('', 'foo', 'FooType'),
 ('unicode/encoded/to', 'ascii', 'FooType'),
 ('spam/eggs', 'changedByFactory', 'FooType')]

>>> constructor = """
... [transmogrifier]
... pipeline =
...     contentsource
...     constructor
...     logger
...
... [contentsource]
... blueprint = collective.transmogrifier.sections.tests.contentsource
...
... [constructor]
... blueprint = collective.transmogrifier.sections.constructor
... required = True
...
... [logger]
... blueprint = collective.transmogrifier.sections.logger
... name = logger
... level = INFO
... """
>>> registerConfig('collective.transmogrifier.sections.tests.constructor2',
...                constructor)
>>> handler.clear()
>>> try:
...     transmogrifier('collective.transmogrifier.sections.tests.constructor2')
...     raise AssertionError("Required constructor did not raise an error for missing folder")
... except KeyError:
...     pass
>>> print(handler)
logger INFO
  {'_path': '/eggs/foo', '_type': 'FooType'}
logger INFO
  {'_path': '/spam/eggs/foo', '_type': 'FooType'}
logger INFO
  {'_path': '/foo', '_type': 'FooType'}
logger INFO
  {'_path': '/unicode/encoded/to/ascii', '_type': 'FooType'}