[ZPatterns] HowTo: Make an Image/File a DataSkin ???

[Steve Spicklemire]

Hi Ulrich,

	Hmm.. can you just call DataSkin.__init__(self, id) in the File's constructor?

-steve

Ulrich Eck wrote:
> 
> 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
> 
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