How to deal with temporary storage of uploaded files

Question

In my django application I have a multi step registration, with few conditional parameters. Because of this I figured out to store data from forms in session. Unfortunatelly sessions serialize data using pickle, which doesn't support file serialization and causes
PicklingError: Can't pickle <type 'cStringIO.StringO'>: attribute lookup cStringIO.StringO failed . How to get around this problem ? Should I send image as a variable to all following views, or send it as a GET parameter or do it in some other way ? I'm not sure if any sample code is needed since problems seems pretty clear.

Answer 1

If the files that are being uploaded are larger than a few KB in size, then you probably don't want to store them in the session (and you definitely don't want to send them back to the browser via a GET).

I can think of a few options:

• You could rewrite your registration form so that uploaded files come last.
• You can make your form a single step, and fake the multi-step with javascript (by hiding and showing DIV's, for example).
• You could keep the temporary files on disk, and store the file names in the session (remembering to clean up old files periodically)
• You could simplify your registration, and do the file upload on a "profile" page (perhaps enforcing a "you have to fill out the profile" requirement before allowing access to the rest of the site).