upload_fileobj closes the file

[josepablog]

Hello,

upload_fileobj has an undocumented behavior that I think it's a bug. It closes the file after uploading the file ! :(

To reproduce this behavior:

import boto3
import cStringIO

f = cStringIO.StringIO("hello")
print f.getvalue()
print f.getvalue() # Second call works!

session = boto3.Session()
s3 = session.resource('s3')
obj = s3.Object(bucket_name, key)

obj.upload_fileobj(f)

print f.getvalue() # Raises an exception

[JordonPhillips]

Thanks for reporting! I've opened the issue in s3transfer which provides the functionality for upload_fileobj. Closing out here.

[saranglakare]

5 years and this issue still exists. No one has even bothered to update the documentation of upload_fileobj to mention that the file pointer will be closed! I just wasted a couple of hours figuring out an issue which was due to this bug :( I request this issue be kept open till it is fixed. Simply delegating it to an issue in another tool is not the solution. At the very least update the documentation! Thanks.