[Dovecot] Slightly OT : Maildir format (silly) questions
Hello,
I was asking what was the motivation for not having the envelope From in the Maildir format, as defined in the qmail spec :
"The message is delivered without an extra UUCP- style From_ line, without any >From quoting, and without an extra blank line at the end."
which may sound silly since we lose an important piece of information.
Same question about the motivation in Courrier (Maildir++) for emulating a hierarchy for subfolders (like in .folder.subfolder.subsubfolder) instead of (note : I know about layout=FS, I'm not talking about that) implementing a real filesystem hierarchy.
I understand dovecot kept those for compatibility reasons but I'd like to know what was the authors of thoses specs thinking when deciding this.
Thanks
-- Thomas Hummel | Institut Pasteur hummel@pasteur.fr | Pôle informatique - systèmes et réseau
Thomas Hummel wrote:
I was asking what was the motivation for not having the envelope From in the Maildir format, as defined in the qmail spec :
"The message is delivered without an extra UUCP- style From_ line, without any >From quoting, and without an extra blank line at the end."
which may sound silly since we lose an important piece of information.
You can always add an extra header that contains what you want. (Exim's default for that is Return-path:). The From_ line in mbox is used as a message delimiter. AFAIK it's not even treated like a header, so it's not sent to the (POP3/IMAP-)MUA.
Same question about the motivation in Courrier (Maildir++) for emulating a hierarchy for subfolders (like in .folder.subfolder.subsubfolder) instead of (note : I know about layout=FS, I'm not talking about that) implementing a real filesystem hierarchy.
Don't know about that, probably better to ask Sam Varshavchik on the Courier list. One reason probably is because it's easier to get a complete folder list by scanning a single folder than recursively scanning all folders. The starting dot '.' is clear, I guess, otherwise you couldn't have folders named cur, new and tmp.
On Thu, 2009-03-26 at 10:47 +0100, Thomas Hummel wrote:
Same question about the motivation in Courrier (Maildir++) for emulating a hierarchy for subfolders (like in .folder.subfolder.subsubfolder) instead of (note : I know about layout=FS, I'm not talking about that) implementing a real filesystem hierarchy.
This is most likely because of Maildir++ quota. So for example if you tell MDA to deliver mail to /foo/bar, should it use /foo/bar/maildirsize or /foo/maildirsize file? It's especially problematic if the file doesn't already exist. The solution was to have a "maildirfolder" file, and if it exists it uses the parent directory's maildirsize file. This wouldn't work at least as easily if it had to go multiple parent dirs up.
On Thu, Mar 26, 2009 at 11:23:44AM -0400, Timo Sirainen wrote:
This is most likely because of Maildir++ quota. So for example if you tell MDA to deliver mail to /foo/bar, should it use /foo/bar/maildirsize or /foo/maildirsize file? It's especially problematic if the file doesn't already exist.
In your example (sorry I haven't had to use quota), you mean that both /foo et /foo/bar would have a quota ?
-- Thomas Hummel | Institut Pasteur hummel@pasteur.fr | Pôle informatique - systèmes et réseau
On Mar 26, 2009, at 1:00 PM, Thomas Hummel wrote:
On Thu, Mar 26, 2009 at 11:23:44AM -0400, Timo Sirainen wrote:
This is most likely because of Maildir++ quota. So for example if you tell MDA to deliver mail to /foo/bar, should it use /foo/bar/ maildirsize or /foo/maildirsize file? It's especially problematic if the file doesn't already exist.
In your example (sorry I haven't had to use quota), you mean that
both /foo et /foo/bar would have a quota ?
No. Maybe a more understandable example would have been ~/Maildir/ and
~/Maildir/.bar/. If MDA only gets that one path (so it doesn't know
the "maildir root dir"), it uses a simple rule to figure out where to
update maildirsize file: Do I have maildirfolder file? If so, use
parent dir. If not, use current dir.
On Thu, Mar 26, 2009 at 06:23:28PM -0400, Timo Sirainen wrote:
No. Maybe a more understandable example would have been ~/Maildir/ and
~/Maildir/.bar/. If MDA only gets that one path (so it doesn't know
the "maildir root dir"), it uses a simple rule to figure out where to
update maildirsize file: Do I have maildirfolder file? If so, use
parent dir. If not, use current dir.
You mean the only reason to use a flat layout (hierarchy emulation like .folder.subfolder.subsubfolder) is to know where to update the file which store the Maildir size ?
Sounds strange : why not calculate Maildir size ? And regarding quotas : can I have a quota on some folder and a quota on some of its subfolder(s) ? If yes, wouldn't that change the problem ?
-- Thomas Hummel | Institut Pasteur hummel@pasteur.fr | Pôle informatique - systèmes et réseau
On Fri, 2009-03-27 at 10:45 +0100, Thomas Hummel wrote:
On Thu, Mar 26, 2009 at 06:23:28PM -0400, Timo Sirainen wrote:
No. Maybe a more understandable example would have been ~/Maildir/ and
~/Maildir/.bar/. If MDA only gets that one path (so it doesn't know
the "maildir root dir"), it uses a simple rule to figure out where to
update maildirsize file: Do I have maildirfolder file? If so, use
parent dir. If not, use current dir.You mean the only reason to use a flat layout (hierarchy emulation like .folder.subfolder.subsubfolder) is to know where to update the file which store the Maildir size ?
Yes.
Sounds strange : why not calculate Maildir size ?
What "Maildir size"? The MDA doesn't necessarily know what the "root maildir" is. The path may not have "Maildir/" string anywhere in it. For example if you told MDA to deliver a mail to Maildir in /foo/bar/baz, should it write the maildirsize to /foo, /foo/bar or /foo/bar/baz?
And regarding quotas : can I have a quota on some folder and a quota on some of its subfolder(s) ? If yes, wouldn't that change the problem ?
You mean separate quotas for different mailboxes? No, not possible currently.
Thomas Hummel wrote:
Hello,
I was asking what was the motivation for not having the envelope From in the Maildir format, as defined in the qmail spec :
"The message is delivered without an extra UUCP- style From_ line, without any >From quoting, and without an extra blank line at the end."
which may sound silly since we lose an important piece of information.
People who believe by hart "Maildirs do not require locking." and "Maildir is a faster and more efficient way to store mail." could do plenty of really strange things ;)
-- Dmitry Samersoff dms@samersoff.net, http://devnull.samersoff.net
- There will come soft rains ...
participants (4)
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Dmitry Samersoff
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Jakob Hirsch
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Thomas Hummel
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Timo Sirainen