Re: adding metadata

Hi jw and the rest,

On Monday 13 June 2005 10:39 am, Jan-Wijbrand Kolman wrote:
> Andy Altepeter wrote:
> > Is there a way to conditionally display a metadata set for a content type
> > (silva document)?
> >
> > What I want is to only display the set if the document is located in a
> > specific place.  Can I use the new 'category' property  in 1.3 to achieve
> > this?
>
> I don't think so. The 'category' property is really only useful to
> distinguish metadata sets for a particular use ('content' metadata, vs. for
> example 'layout settings' metadata).
>
> Conditionally showing a metadata set sounds rather difficult to me, in the
> current framework...
>
> Maybe, just maybe, you might be able to do something with the metadata
> 'access handlers'. There're registered in SilvaMetadata/Access.py. If you
> register another access handler that returns only the sets according to the
> conditions you'd like... maybe that's an idea?
>
This works perfectly!  I created an md access handler wich checks the 
content's physical path (via getPhysicalPath) to see if it is contained in a 
certain publication.  If it is not, then I remove my custom set from the 
list.

Access Handlers need to registered during startup; they aren't something that 
is persistent.  I registered the access handler in  my custom products 
__init__.py, in the initialize function.  Here's the code:

from Products.SilvaMetadata.Binding import MetadataBindAdapter
from Products.SilvaMetadata.Compatibility import getContentType
from Products.SilvaMetadata.Exceptions import BindingError
from Products.SilvaMetadata.Access import registerAccessHandler
def kb_metadata_access_handler(tool, content_type, content):
    type_mapping = tool.getTypeMapping()
    metadata_sets = type_mapping.getMetadataSetsFor(content_type)
    if 'kb' not in content.getPhysicalPath():
        metadata_sets = [ m for m in metadata_sets if m.id != 'its-kb' ]
    if not metadata_sets:
        raise BindingError("no metadata sets defined for %s" % content_type)
    return MetadataBindAdapter(content, metadata_sets).__of__(content)

def initialize(context):
  #...
  #add a metadata register access handler.  This function (defined above) is 
called
  #whenever the metadata sets for SDV are retrieved.  This one filters would 
the its-kb
  #set if the version isn't within the knowledgebase container.
  registerAccessHandler('Silva Document Version', kb_metadata_access_handler)

Thanks jw for the suggestion!
Andy