On Mon, 16 Aug 2004 22:47:52 EDT, Tony Hansen said:
> The claim in Appendix A is that there were no authoritative sources of
> documentation for the mbox formats and otherwise it's "only documented
> in anecdotal form". I'm sorry, but the the definitions ARE there, and
> ARE almost always authoritative for those systems.
Somehow, I can't get thrilled by the concept of saying a format is documented
because we have (for example) 3 systems, and each has an authoritative
definition of the version it uses, and the definitions are incompatible (and
yes, the Solaris 'content-length:' scheme and '>from ' escaping are basically
incompatible - there exist messages that can't be converted from one to the
other without information loss).
> Because Solaris 8 is System Vr4-derived, you should look at 'man mail'
> for the definitive definition. You'll find Content-Length: documented there.
It says:
A letter is composed of some header lines followed by a
blank line followed by the message content. The header lines
section of the letter consists of one or more UNIX post-
marks:
From sender date_and_time [remote from
remote_system_name]
followed by one or more standardized message header lines of
the form:
keyword-name: [printable text]
where keyword-name is comprised of any printable, non-
whitespace characters other than colon (`:'). A Content-
Length: header line, indicating the number of bytes in the
message content will always be present unless the letter
consists of only header lines with no message content.
For bonus points - is the 'crlf-crlf' between the header and the body included
in the Content-Length:? There's other issues as well - what if the
Content-Length: is computed across a non-canonified message - how do
you send it across the wire?
'man mail' doesn't mention escaping a 'From ' inside a message,
except for this:
The default mode for printing messages is to display only
those header lines of immediate interest. These include, but
are not limited to, the UNIX From and >From postmarks,
From:, Date:, Subject:, and Content-Length: header lines,
and any recipient header lines such as To:, Cc:, Bcc:, and
so forth. After the header lines have been displayed, mail
Of course, that's because Solaris doesn't use '>From ' escaping
because it has Content-Length instead.
Should other systems trust the value of a Content-Length:?
Should other systems be required to include a Content-Length?
Should other systems escape a 'From ' iff there's no Content-Length?
What if an mbox file has a Content-Length on some items but not others?
How do you recover from a corrupted Content-Length?
So - where is the *one true canonical* definition of an mbox that actually
answers all these basic questions that an implementer *needs* to know the
answer to?
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