This is a small monkey patch to add blob support to OFS.Image and File

This adds a new method called resave_to_blob that can be called on any Image
or File to save them as a blob to the filesystem instead.

This is my suggested upgrade script. It will convert all File and Image objects

for id, obj in container.ZopeFind(container, obj_metatypes=['File', 'Image'], search_sub=1):
    resave_to_blob = getattr(obj, 'resave_to_blob', None)
    if resave_to_blob is not None:
        resave_to_blob()
return 'Done'


If you have a large database or a system where the above script could cause a timeout that would
cause problems I have created a script that you can run from zopectl

bin/zopectl run /path/to/upgrade_blob.py

The upgrade_blob.py file is part of the included files

The only requirements I know of is having zope 2.13 installed and working and blob support setup.
This patch should work on zope 2.12 also but I don't know for sure.

example zope.conf db section for blobs

<zodb_db main>
    mount-point /
    cache-size 5000
    <zeoclient>
      blob-dir /var/lib/zope2.12/blobs
      shared-blob-dir true

      server /var/lib/zope2.12/zeo/main/main.soc
      storage 1
      name main
      var $INSTANCE/var
      cache-size 0 
    </zeoclient>
  </zodb_db>


example zeo.conf db section for blobs

<blobstorage 1>
<filestorage>
  path $INSTANCE/var/Data.fs
</filestorage>
blob-dir /var/lib/zope2.12/blobs
</blobstorage>


A pure zope example I don't have right now.

The above setup with zeo makes it so that zope and zeo will share the same blob dir so that blobs
are not sent over zeo.