The hyperdb.FileClass type is used to represent file content. It
provides interfaces for storing and retrieving files into / from a database.

In some contexts it may be desirable to allow external tools to manage
the file itself, yet allow Roundup to include it in its schema (allow
other types to link to it), and serve the file the same way it serves
'internal' content.

To implement this, I propose the following:

Add a hyperdb.ExternalFileClass type (possibly deriving it from
hyperdb.FileClass) that, instead of a 'content' attribute, has a
'filename' (or perhaps generalized: 'url') attribute. The implementation
of internal file access is handled by backends/blobfiles.py, very
similar to how FileClass is handled right now.

The frontends themselves are not affected by this, as to the user there
is no distinction between external and internal files (this is the whole
point !)

Stefan have you seen issue2550677? It's a neat way of enhancing the
class interface. In it's current form it augments
FileClass and implements transparent compressed file contents.

I could see it accepting an external url in the content field
and returning the content of the url upon a get.

-- rouilj

I had a query about integrating roundup with s3 for image file storage.
This is a use case for this proposal.