[Zope] acquisition-based class initialization on Zope startup

[Andy McKay]

Stick a call at the end of z2.py after Zope has loaded.

Cheers.
--
  Andy McKay.


----- Original Message -----
From: "Mitchell Model" <mlm@acm.org>
To: <zope@zope.org>
Sent: Wednesday, October 31, 2001 4:18 PM
Subject: [Zope] acquisition-based class initialization on Zope startup


> Here's an interesting hole I dug for myself; any ideas on how to get out?
The question comes down to: is there any (reasonable) way to invoke a Zope
Python Script automatically every time the server starts up.  I realize this
is a little weird, since Python scripts, DTML methods, and the like are for
creating client-side pages, but I've found it convenient to also use them
for site setup, editing meta-information such as properties for classes,
etc.  Is there perhaps something like a product's __init__.py that gets
invoked late enough to be able to do Zope.app().unrestrictedTraverse, or
perhaps another way to get at the Zope scripts and methods?
>
> Here's what I did that makes me want a solution to this challenge.  I have
some classes defined in my product.  Initialization of these classes
includes setting up some properties.  Originally, the properties were
defined in a file, and my product's __init__.py called a function that read
the contents of the file and did Zope API stuff to setup the properties.
>
> Then I decided that the properties should be web-editable, not in a file
in the product implementation, so I moved the file contents into Zope DTML
methods (by the way, what *is* the preferred Zope type of straight text?),
and I wrote a Python Script that initialized the properties for the classes
based on the Zope methods.  This way, a site manager can edit the
properties, execute that Python script, and immediately have all instances
of the class see the changes.
>
> I discovered to my chagrin that when I restart Zope, all the class
properties have disappeared (of course), and my __init__.py no longer
recreates them.  So I have to add back in to __init__.py a call to something
to recreate the properties, but that something has to either call the Zope
Python script or get the contents of the DTML methods that define the
properties, and during product loadup it's too early to try to navigate the
Zope object hierarchy (which I normally do via
Zope.app().unrestrictedTraverse, which I can give a path to my Zope Python
script, and follow it with () to invoke it, which works in the debugger
after Zope has started, but not while my product is being loaded; in fact,
Zope doesn't even have an 'app' yet at that point).
>
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