[Zope3-Users] Re: proxied list object in a schema

[Jürgen Kartnaller]

Hi Tim,
Chat must implement IChat

Jürgen

Tim Terlegård wrote:
> Would someone like to explain how to use a list in a schema object
> without getting ForbiddenAttribute? This is my use case.
> 
> class IChat(Interface):
>     messages = Attribute('Chat messages')
> 
> class Chat(Persistent):
>     def __init__(self):
>         self.messages = persistent.list.PersistentList()
> 
> <class class=".chat.Chat">
>     <require permission="zope.View" interface=".interfaces.IChat" />
>     <require permission="zope.View" set_schema=".interfaces.IChat" />
> </class>
> 
> I have a Chat class that implements IChat and that is declared in
> configure.zcml. Both the chat object and the 'messages' attribute are
> proxied automatically, right? The <require /> tags in configure.zcml
> adds security declarations to the chat object, but not to the 'messages'
> attribute. Am I correct this far?
> 
> When I call self.context.messages.append(...) (in a browser page for
> IChat) I get ForbiddenAttribute on append. I should get this, so this
> is ok. But list or PersistentList has no interface I can use in IChat
> instead of Attribute. So I tried using zope.schema.List instead, but
> the interface of that was a small subset of what list provides and
> doesn't have append either. So I don't know how to add these security
> declarations to the 'messages' attribute.
> 
> How can I use a list without getting security proxy problems? Do I have
> to make my own list implementation and interface?
> 
> Tim