Downloadiong and file dates

[Lennart Borgman]

When downloading a file from Launchpad's repository's web interface
the downloaded file does not get the right modified/creation time.

The headers in a buffer downloaded with url-retrieve-synchronously says

HTTP/1.1 200 OK
Date: Mon, 04 Jan 2010 01:50:08 GMT
Server: PasteWSGIServer/0.5 Python/2.5.2
Content-Type: application/octet-stream
Content-Length: 13071
Content-Disposition: attachment; filename*=utf-8''foldit.el
Via: 1.1 bazaar.launchpad.net
Keep-Alive: timeout=15, max=100
Connection: Keep-Alive
Content-Language: el


The "Date" is obviously now when I tested. That seems correct. However
it would be good to have the modification time for the file too. There
is a "Last-Modified" header that perhaps could be used for this. Would
that be correct use for that header?

And how does url-copy-file handle this? This function has an argument
named `keep-time' but it is not easy to see where and how it is used.
>From the doc string it looks liike it preserves the date of an old
local file.

Does url-copy-file take care of "Last-Modified" if present? Should it?