[Zope-dev] HowTo: Make an Image/File a DataSkin ???

10 Jul 2001

      Hello .. sorry I bother you again with my ZPatterns
related Questions .. 

I just try it once again ;-)

I have a Folder w/Customizer in that I want to store Objects
of type Image or File (CMFDefault.Image to be correct) in it.

The inline doku of CMFDefault.File/Image says the following:

----------------------------------------------------------
class File(OFS.Image.File
          , PortalContent
          , DefaultDublinCoreImpl
          ):
    """
        A Portal-managed File
    """

    # The order of base classes is very significant in this case.
    # Image.File does not store it's id in it's 'id' attribute.
    # Rather, it has an 'id' method which returns the contents of the
    # instnace's __name__ attribute.  Inheriting in the other order
    # obscures this method, resulting in much pulling of hair and
    # gnashing of teeth and fraying of nerves.  Don't do it.
    #
    # Really.
    # 
    # Note that if you use getId() to retrieve an object's ID, you will avoid
    # this problem altogether. getId is the new way, accessing .id is
    # deprecated.

----------------------------------------------------------

this is fairly true. I needed to make the DataSkin the "first" subclass
of File to ensure the datamanager-machinery will work (not_found v_dm)

for example:
class File(DataSkin
          , OFS.Image.File
          , PortalContent
          , DefaultDublinCoreImpl
          ):

this basically works fine except when I rename this object the different behaviour
of Dataskin (stores its id in self.id) and Image/File (stores its id in self.__name__ 
and recommends the use of ob.getId() to get the id).

Has anyone used a Image/File/ExtFile class for combining it with ZPatterns.DataSkin
and perhaps give me a hint ??

thanks 

Ulrich Eck
net-labs