[Zope] C&C hasRole, has_role, allowed, has_permission?

[Terry Hancock]

Hi all,

I was tracking down a weird but very repeatable "IOError 5"
bug which still baffles me, but it led me to a section of
code where I have used "hasRole()" to find out if a user
is supposed to be able to manage a particular object.

For whatever reason the bug didn't show up until I switched
to 2.5.1 (From 2.4.3).

Reading the Zope source, I found a deprecation warning on
this method, but rather confusing suggestions as to what
to use instead. I also found a note about it on zope.org
which mentions yet another method.

So I was wondering if anyone could tell me what the
significant differences are between the following options:

allowed
has_role
has_permission

(the last is mentioned on the zope.org site, though I
didn't see it in the source (as yet)).

They all seem pretty much the same to me, though there
are minor API differences, and a hint that they represent
different security models. (e.g. what's an "object role"?
Not the same as "local role" I would guess?). Note that
this is in Zope 2.5.1 and I'm migrating from 2.4.3.  

I've called _.SecurityGetUser() to get my user (not sure
why this is safer than AUTHENTICATED_USER, but I am told
that it is).  Then I'm asking whether that user is
supposed to be able to see the "Edit" button on my page.
If they have a local role of "Moderator", they should.

Thanks,
Terry

-- 
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Terry Hancock
hancock@anansispaceworks.com       
Anansi Spaceworks                 
http://www.anansispaceworks.com 
P.O. Box 60583                     
Pasadena, CA 91116-6583
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