[Zope-CMF] Re: custom WebDAV upload handling

[yuppie]

Hi Raphael!


Raphael Ritz wrote:
> First, one needs to understand the processing chain:

[Zope]
> 1. FTP/DAV uploads call 'PUT' from 'webdav.NullResource'

[CMF]
> 2. This gets the 'PUT_factory' from the parent in spe
>    (the target) folder.
>    For CMF this is usually the one from 'PortalFolder'.

[CMF]
> 3. The 'PUT_factory' contacts the 'content_type_registry' to
>    figure out what content type should be created for this
>    particular upload.

[CMF]
> 4. If a valid type is found, an _empty_ instance thereof is
>    created using 'parent.invokeFactory'.

[CMF]
> 5. Then this object is removed from the parent where it just has
>    been created. This now "kind of homeless" object is returned to
>    the calling 'PUT' from  'webdav.NullResource'

[Zope]
> 6. Calling 'parent._verifyObjectPaste' it is now checked whether
>    it is actually allowed to put the "homeless" object into the
>    parent and if so ...

[Zope]
> 7. ... it is placed in there.
> 
> (Why is this back-and-forth handling needed at all?)

CMF builds on top of Zope, so CMF's PortalFolder has to return a bare 
and empty object as required by Zope's webdav machinery.

Hence the question is: Why does PortalFolder's PUT_factory use 
invokeFactory, a method that obviously does more than we want?

AFAICS this was the easiest way to implement PUT_factory. TypesTool or 
TypeInfos don't provide a better method.


Cheers,

	Yuppie