Amazon S3 Add METADATA to existing KEY

Question

In S3 REST API I am adding metadata to an existing object by using the PUT (Copy) command and copying a key to the same location with 'x-amz-metadata-directive' = 'REPLACE'

What I want to do is change the download file name by setting:

Content-Disposition: attachment; filename=foo.bar;

This sets the metadata correctly but when I download the file it still uses the keyname instead of 'foo.bar'

I use a software tool S3 Browser to view the metadata and it looks correct (apart from 'Content-Disposition' being all lower case as that's was S3 ask me to sign)

Then using S3 Browser I just pressed, then save without changing anything and now it works???

What am I missing how come setting a metadata 'Content-Disposition: attachment; filename=foo.bar;' from my web app does not work but does work from S3 Browser?

Answer 1

SOLVED:

The Doco at http://docs.amazonwebservices.com/AmazonS3/latest/dev/index.html?RESTAuthentication.html

seems to be wrong it says:

Notice how the 'x-amz-' headers are sorted, white-space trimmed, converted tolowercase, and multiple headers with the same name have been joined using a comma toseparate values.

Note how only the Content-Type and Content-MD5HTTPentity headers appear in the StringToSign .The otherContent-* entity headers do not. However Content-Disposition must be set specifically and not included as : x-amz-meta-Content-Disposition

It now works fine.