[Zope] Zope 2.5 and TransparentFolder incompatibility

Howard Hansen zope@halfmagic.com
Tue, 11 Jun 2002 22:46:00 -0700

Thanks for the code!  This makes a great start.  I've got it showing up in
the Products folder, but not in the insert dropdown.  My copy of the Zope
Bible is on its way and I hear that once I read through that, the scales
will fall from my eyes and I will be able to figure out Products.  I'll
hard-code the filtering to start, as you've done, but then I think we'll see
hiding based on meta type and regular expression matches for id.  And having
all of those extra objects cluttering things up will create a strong
incentive to get it done!

Oh, and as an update to my original question.  I've heard from two people
who have TransparentFolders working on Zope 2.5, so it's possible.  Both had
cases where it failed, and then it mysteriously started working.  So it's a

Thanks for everyone's help!

Howard Hansen

----- Original Message -----
From: <sean.upton@uniontrib.com>
To: <zope@halfmagic.com>; <sean.upton@uniontrib.com>;
Cc: <zope@zope.org>; <ct@gocept.com>
Sent: Tuesday, June 11, 2002 12:25 PM
Subject: RE: [Zope] Zope 2.5 and TransparentFolder incompatibility

> All I'm saying is there are other ways to cope, since I don't think TF can
> be 'fixed.'
> Eventually, I think it is likely that I will write a product that will do
> something to allow "views" of folder to be a native characteristic of the
> for the product, but I don't currently have time.
> Creating your own product and subclassing folder should pose no real
> since the main thing you would be hacking would be just the UI (all the
> functionality of ObjectManager derived classes would still be there via
> inheritance).  You would add an extra DTML method on the filesystem within
> your product to provide a limited view of the folder, using some crieteria
> to filter (I don't think underscore is doable, so you will have to come up
> with another filter scheme, by substing in id, or meta_type, or something
> else).  Some example code (not guaranteed to work, but a place to start)
> below.  It assumes that you subclass folder, and create a few methods to
> filter results of ObjectManager API calls, and use these filtered results
> DTML replacing manage_main for your custom folder.
> Good Luck, and I hope this makes some sense.
> Sean
> ###############################
> import Globals
> from OFS import Folder, SimpleItem, ObjectManager, PropertyManager
> from Globals import Persistent, Acquisition
> import AccessControl
> class CustomFilteredFolder(Folder):
> """Custom Folder with Enhanced UI"""
> __ac_permissions__=(
>         ('View management screens', ('manage_main',
> 'manage_viewall')),
>         ('View', ('index_html')),
>         )
> manage_allcontents = Folder.manage_main #standard manage_main is now
> going to be another tab
> manage_main        = Globals.HTMLFile('dtml/filteredContents',
> globals()) #file dtml/filteredContents.dtml
> #ZMI Tabs, customized: code copied from OFS.Folder and modified
>       manage_options=(
>   ({'label':'Filtered Contents', 'action':'manage_main'},
>    {'label':'All Contents', 'action':'manage_allcontents'},
>          {'label':'View', 'action':'index_html',
>          'help':('OFSP','Folder_View.stx')},
>         )+
>         PropertyManager.PropertyManager.manage_options+
>         AccessControl.Role.RoleManager.manage_options+
>         SimpleItem.Item.manage_options+
>         FindSupport.FindSupport.manage_options
>         )
> meta_type="Filtered View Folder"
> def __init__(self, id):
> """Initialize CustomFilteredFolder Instance"""
> Folder.__init__(self, id)
> self.hiddenObjectsIdPattern  = ('sql')
> #assumption would be that if the string 'sql' appeared
> within
> #the id, that it would be hidden/filtered
> self.hiddenObjectsMetaTypes  = ('Z SQL Method')
> #or, this could be done with a meta_type
> def objectItemsFiltered(self):
> """Filter results of OM.objectItems"""
> #unimplemented do something here
> def objectIdsFiltered(self):
> """Filter results of OM.objectIds"""
> #unimplemented do something here
> def objectValuesFiltered(self):
> """Filter results of OM.objectValues"""
> #unimplemented do something here
> ### Note: DTML for the filtered views would use objectItemsFiltered,
> where
> ### normally, it would use objectItems() instead (i.e.
> manage_allcontents
> ### would still use OM methods.
> -----Original Message-----
> From: Howard Hansen [mailto:zope@halfmagic.com]
> Sent: Monday, June 10, 2002 4:59 PM
> To: sean.upton@uniontrib.com; dirk.datzert@rasselstein-hoesch.de
> Cc: zope@zope.org; ct@gocept.com
> Subject: Re: [Zope] Zope 2.5 and TransparentFolder incompatibility
> Thanks for the response Sean, but could we try this again?  This is not
> answer I want to hear.  Could you start your message with something like:
> "I've patched TF so it will work perfectly with 2.5 and all subsequent
> versions...." ;-)
> Seriously, this is not the first time I've heard the "TransparentFolders
> Considered Harmful" argument, and at some level I'm inclined to agree.
> not at the level of someone who has to wade through tons of dinky objects
> his ZMI, nor at the level of someone who has to change lots of his code to
> account for other changes.
> It's too bad we can't use an underscore at the beginning of an object's
> Then we could have a "Hidden Contents" tab in the ZMI and view them that
> way.  This would give us one transparent folder in each folder.  A boy can
> dream.
> This leads me to a different question: how safe (or stable) is it to
> subclass folder and add some new behaviors to it?  People blithely talk
> about doing it all the time, but my Zope sites total between 2000 and 5000
> hits an hour.  I get concerned about maintaining stability and
> Obviously bad coding = bad performance and/or instability, but assuming
> competent coding, can I expect my subclassed folder to work as well as
> Folder?
> Howard Hansen
> http://howardsmusings.com/categories/zope
> ----- Original Message -----
> From: <sean.upton@uniontrib.com>
> To: <zope@halfmagic.com>; <dirk.datzert@rasselstein-hoesch.de>
> Cc: <zope@zope.org>; <ct@gocept.com>
> Sent: Monday, June 10, 2002 3:34 PM
> Subject: RE: [Zope] Zope 2.5 and TransparentFolder incompatibility
> > TFs are bad bad bad... too much magic to the namespace stack.  They
> > Core Session Tracking in Zope < 2.5, and likely don't work with sessions
> in
> > Zope 2.5.  The reason for this is that with the session id manager
> in
> > CST has to have the same name every time), you cannot have more than one
> > (because TF screws up the namespace stack globally, and makes the
> id
> > managers appear to already exist for a folder that they don't, or
> something
> > like that, I can't remember exactly)...  If you really want the benefits
> of
> > TF without the headache and unpredictability, your best bet if you want
> > hide/sort objects in a folder is to create your own product, subclass
> > folder, and hack the dtml files in the product for the UI to only show
> what
> > you want (perhaps putting everything else into another ZMI tab or
> > something?).
> >
> > Sean