On 4/26/11 7:40 AM, William Heymann wrote:
I am working on a patch for Blob support in OFS.Image/File and I am running
into a small problem. What is the correct way to detect if the current ZODB
supports blobs?
If I just do
self.data = ZODB.blob.Blob(data)
in update_data in OFS.Image
and a system does not support blobs
I get this error
Traceback (innermost last):
Module ZPublisher.Publish, line 134, in publish
Module Zope2.App.startup, line 301, in commit
Module transaction._manager, line 89, in commit
Module transaction._transaction, line 329, in commit
Module transaction._transaction, line 443, in _commitResources
Module ZODB.Connection, line 563, in commit
Module ZODB.Connection, line 619, in _commit
Module ZODB.Connection, line 662, in _store_objects
Unsupported: Storing Blobs inZEO.ClientStorage.ClientStorage object at
0x3248590 is not supported.
which does not even mention OFS.Image anywhere
I tried putting in
try:
self.data = ZODB.blob.Blob(data)
except zExceptions.Unsupported:
self.data = data
and this of course did not work since the error is not actually occurring
here.
What I am trying to do is make is to that Blobs are used if blobs are
supported and not used if they are not currently supported. For all of my
systems this is not an issue since I only support blobs but for a patch to be
accepeted it seems that it would need to work either way.
I considered putting in a configuration switch in zope.conf to say if blobs
should be used or not so that it is up to the developer to set the switch and
enable blob support and the system would just give errors if setup incorrectly
but that does not seem like a good idea.
You can get (persistent object)._p_jar.db().storage and check if it
provides ZODB.interfaces.IBlobStorage.
--
David Glick
Web Developer
davidgl...@groundwire.org
206.286.1235x32
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