put_attachment issue

[dedalus2000]

When I upload one file the code looks like:

doc = db.put_attachment(doc, file_object)

Ok, but now I want to update one field:

doc['onefield'] = 'newcontent'
doc = db.save(doc)

et voilà, the previously uploaded file has been deleted!

This happens because "put_attachment" doesn't update the doc['_attachment'] , so if I save it later I will delete any new attachment.

The problem is that "put_attachment" can't fill the "doc" with all the informations: content_type, revpos, digest, length. In fact couchdb doesn't help us: when we put an attachment it responds only with id, rev and status. Nothing more.

Probably is not a good idea to let put_attachment does the couchdb job (calculating all the file informations).

The only solution seems to be to read the document again from the db.

[dedalus2000]

As far Couchdb as no transaction we cannot write a simple "self.get(id)" after a "resource.put" expecting a good ("congruous") answer: in fact between them someone else can had modified the document.

So I think we have two ways:

• check revision after the "get". It has to be the same returned by the "put"
• execute a get(id, rev=returned_revision) so we are sure we are getting the modified we made (if the database has not been compacted between the "put" and the "get")

I prefer the second way