From a7a6d7568546dcc88d836653cce8e69916f1e442 Mon Sep 17 00:00:00 2001 From: Chris McDonough Date: Fri, 1 May 2009 08:02:55 +0000 Subject: - The ``repoze.bfg.location.LocationProxy`` class and the ``repoze.bfg.location.ClassAndInstanceDescr`` class have both been removed in order to be able to eventually shed a dependency on ``zope.proxy``. Neither of these classes was ever an API. - In all previous releases, the ``repoze.bfg.location.locate`` function worked like so: if a model did not explicitly provide the ``repoze.bfg.interfaces.ILocation`` interface, ``locate`` returned a ``LocationProxy`` object representing ``model`` with its ``__parent__`` attribute assigned to ``parent`` and a ``__name__`` attribute assigned to ``__name__``. In this release, the ``repoze.bfg.location.locate`` function simply jams the ``__name__`` and ``__parent__`` attributes on to the supplied model unconditionally, no matter if the object implements ILocation or not, and it never returns a proxy. This was done because the LocationProxy behavior has now moved into an add-on package (``repoze.bfg.traversalwrapper``), in order to eventually be able to shed a dependency on ``zope.proxy``. - In all previous releases, by default, if traversal was used (as opposed to URL-dispatch), and the root object supplied the``repoze.bfg.interfaces.ILocation`` interface, but the children returned via its ``__getitem__`` returned an object that did not implement the same interface, :mod:`repoze.bfg` provided some implicit help during traversal. This traversal feature wrapped subobjects from the root (and thereafter) that did not implement ``ILocation`` in proxies which automatically provided them with a ``__name__`` and ``__parent__`` attribute based on the name being traversed and the previous object traversed. This feature has now been removed from the base ``repoze.bfg`` package for purposes of eventually shedding a dependency on ``zope.proxy``. In order to re-enable the wrapper behavior for older applications which cannot be changed, register the "traversalwrapper" ``ModelGraphTraverser`` as the traversal policy, rather than the default ``ModelGraphTraverser``. To use this feature, you will need to install the ``repoze.bfg.traversalwrapper`` package (an add-on package, available at http://svn.repoze.org/repoze.bfg.traversalwrapper) Then change your application's ``configure.zcml`` to include the following stanza: When this ITraverserFactory is used instead of the default, no object in the graph (even the root object) must supply a ``__name__`` or ``__parent__`` attribute. Even if subobjects returned from the root *do* implement the ILocation interface, these will still be wrapped in proxies that override the object's "real" ``__parent__`` and ``__name__`` attributes. See also changes to the "Models" chapter of the documentation (in the "Location-Aware Model Instances") section. --- docs/narr/models.rst | 38 ++++++++++++++++++++++---------------- 1 file changed, 22 insertions(+), 16 deletions(-) (limited to 'docs') diff --git a/docs/narr/models.rst b/docs/narr/models.rst index 624a29002..61e313830 100644 --- a/docs/narr/models.rst +++ b/docs/narr/models.rst @@ -124,31 +124,37 @@ and so on. .. note:: If you'd rather not manage the ``__name__`` and ``__parent__`` - attributes of your models "by hand", :mod:`repoze.bfg`` can help you - do this. - - In order to use this helper feature, you must first register the - ``WrappingModelGraphTraverser`` as the traversal policy, rather than - the default ``ModelGraphTraverser``. To register the - ``WrappingModelGraphTraverser`` as the traversal policy, your - application will need to have the following in its - ``configure.zcml`` file: + attributes of your models "by hand", an add-on package to + :mod:`repoze.bfg`` named :mod:`repoze.bfg.traversalwrapper` can help + you do this. + + In order to use this helper feature, you must first install the + :mod:`repoze.bfg.traversalwrapper` package (available from + `http://svn.repoze.org/repoze.bfg.traversalwrapper + `_), then + register its ``ModelGraphTraverser`` as the traversal policy, rather + than the default BFG ``ModelGraphTraverser``. To register the + :mod:`repoze.bfg.traversalwrapper` ``ModelGraphTraverser`` as the + traversal policy, your application will need to have the following + in its ``configure.zcml`` file: .. code-block:: xml - If this statement is made in ZCML, you don't need to manage the - ``__parent__`` and ``__name__`` attributes on graph objects "by + If this statement is made in ZCML, you will no longer need to manage + the ``__parent__`` and ``__name__`` attributes on graph objects "by hand". Instead, as necessary, during traversal :mod:`repoze.bfg` - will wrap each object in a ``LocationProxy`` which will dynamically - assign a ``__name__`` and a ``__parent__`` to the traversed object - (based on the last traversed object and the name supplied to - ``__getitem__``). + will wrap each object (even the root object) in a ``LocationProxy`` + which will dynamically assign a ``__name__`` and a ``__parent__`` to + the traversed object (based on the last traversed object and the + name supplied to ``__getitem__``). The root object will have a + ``__name__`` attribute of ``None`` and a ``__parent__`` attribute + of ``None``. :mod:`repoze.bfg` API Functions That Act Against Models ------------------------------------------------------- -- cgit v1.2.3