[Zope3-Users] Schema fields vs custom metadata

[Svenn Helge Grindhaug]

On Friday 23 February 2007 15:59:59 Christophe Combelles wrote:

> The information about the course (I guess) is the main important
> information of your object, so it is not metadata. It would be better to
> store it as schema fields. Metadata is great to store additional
> information brought by an optional interface you put on object. Such as
> comments, rating, author, etc.
>
> The fact that the object is a container doesn't not prevent you from adding
> any attributes you want. It just means that ICourse is derived from (and
> extends) IContainer.  You can also define a separate ICourseDetail with
> interesting fields, and implement both ICourse and ICourseDetail in your
> Course object.

This is what I thought as well, but I got stuck leading me to think I should 
implement the information as meta data. I get a forbiddenAttribute error (see 
below) after adding a course and trying to enter the newly created folder. 
Could you please tell me what I missing here.

Many thanks!

Svenn.

<!-- Interface -->

class ICourse(IContainer):
    """Store information about the course and store participants"""
    
    contains('cr.interfaces.IParticipant')
        
    shortDesc = TextLine(
        title = u'Short description',
        description = u'Short description about the course.',
        required = True
        )

class IParticipant ... etc.

<!-- Implementation -->

class Course(BTreeContainer):
    implements(ICourse)

    shortDesc = u''
    
class CourseEditForm(EditForm):
    form_fields = Fields(ICourse)
    label = u'Edit course'

<!-- Configuration -->

    <class class=".course.Course">
        <implements
            interface="zope.annotation.interfaces.IAttributeAnnotatable"
            />
        <require
            permission="zope.View"
            interface="zope.app.container.interfaces.IReadContainer"
            />
        <require
            permission="zope.View"
            interface="zope.app.container.interfaces.IWriteContainer"
            />
    </class>
            
    <browser:page
        for="cr.interfaces.ICourse"
        name="edit.html"
        class=".course.CourseEditForm"
        permission="zope.ManageContent"
        menu="zmi_views" title="Edit"
        />
    
    <browser:addMenuItem
        title="Add course"
        class=".course.Course"
        permission="zope.ManageContent"
        />
    
    <browser:containerViews
        for="cr.interfaces.ICourse"
        contents="zope.ManageContent"
        index="zope.View"
        add="zope.ManageContent"        
        />


<!-- Error message -->

2007-02-23T18:23:17 ERROR SiteError 
http://127.0.0.1:8080/zope%20course/@@edit.html
Traceback (most recent call last):
  
File "/usr/local/src/Zope-3.3.0/build/lib.linux-i686-2.4/zope/publisher/publish.py", 
line 133, in publish
    result = publication.callObject(request, obj)
  
File "/usr/local/src/Zope-3.3.0/build/lib.linux-i686-2.4/zope/app/publication/zopepublication.py", 
line 161, in callObject
    return mapply(ob, request.getPositionalArguments(), request)
  
File "/usr/local/src/Zope-3.3.0/build/lib.linux-i686-2.4/zope/publisher/publish.py", 
line 108, in mapply
    return debug_call(obj, args)
   - __traceback_info__: <security proxied 
zope.app.publisher.browser.viewmeta.CourseEditForm instance at 0x9a530ec>
  
File "/usr/local/src/Zope-3.3.0/build/lib.linux-i686-2.4/zope/publisher/publish.py", 
line 114, in debug_call
    return obj(*args)
  
File "/usr/local/src/Zope-3.3.0/build/lib.linux-i686-2.4/zope/formlib/form.py", 
line 751, in __call__
    self.update()
  
File "/usr/local/src/Zope-3.3.0/build/lib.linux-i686-2.4/zope/formlib/form.py", 
line 720, in update
    self.setUpWidgets()
  
File "/usr/local/src/Zope-3.3.0/build/lib.linux-i686-2.4/zope/formlib/form.py", 
line 783, in setUpWidgets
    adapters=self.adapters, ignore_request=ignore_request
  
File "/usr/local/src/Zope-3.3.0/build/lib.linux-i686-2.4/zope/formlib/form.py", 
line 385, in setUpEditWidgets
    value = field.get(adapter)
  
File "/usr/local/src/Zope-3.3.0/build/lib.linux-i686-2.4/zope/schema/_bootstrapfields.py", 
line 171, in get
    return getattr(object, self.__name__)
ForbiddenAttribute: ('shortDesc', <cr.course.Course object at 0x9c0c2ac>)
127.0.0.1 - - [23/Feb/2007:18:23:17 +0200] "GET /zope%20course/@@edit.html 
HTTP/1.1" 500 84 "http://127.0.0.1:8080/@@contents.html" "Mozilla/5.0 (X11; 
U; Linux i686; en-US; rv:1.8.0.9) Gecko/20070209 Fedora/1.5.0.9-3.fc6 
Firefox/1.5.0.9 pango-text"