[Zope-dev] serialization with Ape

[Christian Scholz]

Hi list! :)

I am just playing around with Ape (very cool, btw :) and wondering
how it can be used from the outside, e.g. not controlled by transactions.
Main idea is to manually copy parts of the ZODB to the filesystem (from
a product).

I first tried the transaction based process, as I found it in
some tests:

    # init (createMapper imported from fsmapper)
    root_mapper, conns = createMapper(fspath)
    conn=conns['fs']
    resource = StaticResource(root_mapper)
    storage = ApeStorage(resource, conns)
    db = ApeDB(storage, resource)
    get_transaction().begin()

    # test object to store
    object = getattr(self,'standard_template.pt')

    c=db.open()
    app=c.root()['Application']
    id=object.getId()
    app._setObject(id,object.aq_base,set_owner=0)
    get_transaction().commit()
    db.close()

which actually stores it but does not seem to me that clean because of
all the transaction stuff. I would here then recursively run through
all the objects and do that inside one transaction.

I then detected the fascades in io.py which I tried to use (dunno if they're
thought to be used for such a purpose actually ;-):

    root_mapper, conns = createMapper(fspath)
    ei=ExportImport(root_mapper,conns)
    ei.exportObject(object)

Unfortunately this results in an exception 

    Type: MappingError
    Error Value: Path keychains require a name

So can maybe somebody point me to the easiest way to serialize an object
using the fsmapper (Shane? ;-) ?

I am also interested in reading a serialized object from the fs again
and writing it to the fs. Also I wonder if I need to delete objects which
have been modified before another export or if there's a possibility to
just change it).

(and the best would be of course some simple methods for reading/writing
a whole directory recursively. I don't know if something like this is already
in there somehow or how it works internally.. seems all a bit magic to me ;-)

So thanks in advance if anybody can help me :)

cheers,
  Christian

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