[Zope3-dev] Re: Replacing class refs in ZODB

[Derrick Hudson]

On Fri, Feb 18, 2005 at 11:59:04AM -0500, Jim Fulton wrote:
| Garrett Smith wrote:
| >Jim Fulton wrote:
| >>Garrett Smith wrote:
| >>
| >>>Rather than leave aliases around forever, is there a utlity (or other
| >>>means) one can use to update references to renamed/moved classes in
| >>>the ZODB?
| >>
| >>Not currently.  We'd like a cleaner mechanism, but haven't come up
| >>with one yet.

| >So I take it this is non-trivial. I was hoping it would boil down to a
| >search-and-release in the Data.fs.
| 
| It depends on what "this" is.  One could fairly straightforwardly
| write a script that could convert an off-line database.  I think we
| really want to be able to do this without taking the database off-line.

I tried to do this as a step to solve a problem I had about two weeks
ago.  It didn't work, though.

    #!/usr/bin/python2.3 -i

    from ZODB import FileStorage, DB
    storage = FileStorage.FileStorage( 'Data.fs' )
    db = DB(storage)
    conn = db.open()
    root = conn.root()
    app = root['Application']

    import zwiki, zwiki.wiki
    # setup the alias for the initial load
    sys.modules['zope.app.wiki'] = zwiki

    the_wiki = app.data['the_wiki']
    the_wiki.__class__ = zwiki.wiki.Wiki
    the_wiki._p_changed = True

    # save the changes:
    import transaction ; transaction.commit()

The ZODB (probably pickle, actually) would complain that it didn't
like the object.  I think it is because I changed the class, so some
sanity check failed.  In hindsight I think it is the same error I had
recently with my singleton pattern and Zope2.

If someone has some pointers for me I'm willing to read (docs, code)
and experiment.

-D

-- 
 "Piracy is not a technological issue. It's a behavior issue."
                                                       --Steve Jobs
 
www: http://dman13.dyndns.org/~dman/            jabber: dman at dman13.dyndns.org
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