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 in <ZEO.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.