On Wed, 23 Aug 2017, Toerless Eckert wrote:
Er, not really. See RFC 4155. There are way too many not quite
compatible versions of mbox. If I wanted a file format for a
multi-file archive, I'd probably use POSIX ustar which is an actual
standard.
Sure, but that would not be a complete spec because it does not cover
the format of individual messages nor any semantics of file names.
Whats the least restrictive sufficiently well specified generic mail encoding ?
Anything that would also pass via rfc822+mime ?
We already have a perfectly good mail encoding, the one defined in RFC
5322 and its predecessors. (Recall that MIME is entirely hidden inside
the 5322 message structure.) I suppose you could come up with a
convention for filenames, but it hardly matters since anything interesting
about the message is within the message itself.
As I noted, the current filenames are based on months, but the mail in the
files only approximantely was sent during the months the names suggest.
Doesn't matter.
Might also be nice to have some well-known-filename with metadata
about the archive content, eg: self-URL, previous, next URL, contact
URL (if any), archive owner signed checksums of files. Template
spec of filenames (%YYYY-%MM.mail),...
URL? This is mail, not a web site. In any event, if you want to make
indexes and such on top of an archive, go ahead but it's not part of the
archive.
See above: metadata that would help you figure out if you have a
complete set of archive files.
A file listing the other files with hashes or checksums is all you need
for that.
R's,
John