Zope mailing lists wrote:

I have a specialist (actually, EMarket has a specialist <grin>) that manages objects that from a design point of view I think should have a couple of Images as attributes (thumbnail and fullsized images of the product). The question is, how do I implement this using ZPatterns? Currently all of the other object data is pulled from an SQL database. I don't mind storing the Images in the ZODB, but I'm having a hard time finguring out how I would implement that. Pointers or alternate design suggestions welcome.

Here's the simplest approach that I can think of. Stick all your images in a BTree Folder somewhere convenientm like /Images. Name all the images "image-NNNNNN" where NNNNNN is a unique number. Make a couple of columns in your database (or whatever) for thumbnail_id and large_image_id. You'll store the image ids in these. Use some SkinScript in that Specialist you mentioned that gets the thumbnail_id and large_image_id for a particular object, and also makes available the thumbnail and large_image. WITH QUERY get_thumbnail_for_object_SQL(primary_key=self.id) COMPUTE thumbnail_id=thumbnail_id, thumbnail=Images[thumbnail_id] OTHERWISE LET thumbnail_id='', thumbnail=Images.missing_thumbnail Note here that I could have had just "thumbnail_id," at line 2. Also, note that I'm assuming you have an image called missing_thumbnail in the Images folder. Do likewise for large images. This approach assumes that you're not considering images or thumbnails to be first-class domain objects in your system, but just attributes of your main objects. Thus, you won't be wanting to store other data that is pertinent to images. If you do want to do this, you should use a more complex design where Images have their own specialist. -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net

RDM wrote:

I have a specialist (actually, EMarket has a specialist <grin>) that manages objects that from a design point of view I think should have a couple of Images as attributes (thumbnail and fullsized images of the product). The question is, how do I implement this using ZPatterns? Currently all of the other object data is pulled from an SQL database. I don't mind storing the Images in the ZODB, but I'm having a hard time finguring out how I would implement that.

I've been thinking about my own need for a massive searchable image archive, and have been wondering if I could reimplement the ZPhotoAlbum TTW product (which inherits from ZCatalog and ObjectManager) as a Specialist with a Rack of Photo objects (Photo is a 'normal' Python Product), but I'm unsure of how to go about this. I've also been considering creating an ImageArchive ZClass that inherits from ZCatalog and BTree folder, so I have infrastructure that is better suited to managing thousands (potentially hundreds of thousands) of objects. Any ideas would be welcome. Michael Bernstein.