file size 'mystery'

[Sami Hangaslammi]

> You are right for this case. But I left out an important part: the 
> "file" is an file-object of Zope (it does not exist in the FS). So I can 
> not use the os module of python.

For file objects and file-like objects that support seek, you can find
out the size of the file by doing f.seek(0,2) and f.tell(). Should be
more efficient than f.read() in most cases.