Re: [Evolution] options on download

["Adam Sleight" <adams linearcorp com>]

On Thu, 01 Jun 2000 21:12:25 -0700
 Ron Chmara <ron Opus1 COM> wrote:
#John Griffiths wrote:
#> allow me to illustrate;
#> i receive about 300 messages a day of which maybe 10% will have 500kb+ pdf
#files attached to them
#> at home i'm on a 28kbs line
#> if evolution insists on downloading the entirety of every message i will be
#forced with great sadness to look elsewhere for an email client. It's just not
#an option for me.
#> people like me may be a small part of your prospective user group.
#> but do you really want to lose all of us?
#> 
#> At 11:28 PM 6/1/2000 EDT, Jeffrey Stedfast wrote:
#> >No...
#> >I can picture it now...
#> >"Why is my message truncated!?! Bug in Evolution!!!"
#> >this wouldn't be a good thing :)
#> >Jeff
#
#My dos centavos...
#
#Standard (default)for POP3:
#Download all of the message block, with an option to stop the
#current message download, with a follow up dialog (DO you wish to
#cancel entire session?). Put stop buttons in the progress window.
#List overall size, and use a proportional (by size) progress bar.
#
#Cool POP3 _options_:
#Offer a "first 10K only" preference. I have to respectfully disagree that
#stopping a sesion and starting a new one is too inefficient, it is much, much,
#more efficient than downloading a 30Mb mailbox. Yes, I can (and do) get
#30Mb of mail in one day. On a modem, it takes a while.

POP3 is very limited in what it can do...here's my limited understanding..
--it can't read status flags...such as new, deleted, flagged, etc.
--it can only pull messages from the INBOX and can't read from any other folders


anyway been playing around with it...looking at p.148 of Programming Internet
Email about POP... here's the valid commands for a POP session
btw..anyone know what the XTND and XMIT commands are for?
http://www.oreilly.com/catalog/progintemail/

STAT--Request that the server send a drop listing of the mailbox
LIST <msg#>--Requests that the server to send a scan listing of all messages or
of just the message given
RETR <msg#>--REquests that the server send the message indicated.
DELE <msg#>--Requests that the server delete the message indicated.
NOOP--Does nothing (no operation).
RSET--Unmarks any messages marked for deletion.
QUIT--Informs the server that the client is closing the session.  Requests that
any messages marked for deletion be deleted.

Optional commands
TOP <msg#><#of lines>--Requests that the server send the headers and the first n
lines of the message indicated.
UIDL <msg#>--Requests that the server send a unique-id for the message indicated
or for all messages in the mailbox if no argument is given.

So it may or may not be possible (I wouldn't know).  I played around with the
TOP command like
TOP 1 6 TOP 2 6 TOP 3 6
which shows the headers of messages 1, 2, and 3 and the first 6 lines of the
message.

Perhaps in Evolution one could choose the # of lines to scan and even filter out
the full headers and only show FROM, To, Cc, Bcc, Subject, etc.

Now once you retrieve that information perhaps it could scan for
attachments....or simply the LIST command would provide the bytes of each
message.  Then anything over 9999 bytes would not be retrieved RETR until an
option in Evolution said allow downloading of whatever size messages.  And the
messages that weren't downloaded (too big) would be issued a RSET command so
they wouldn't be deleted.

Below #6 is around 270KB and #8 is around 44KB...so it would go like so


(as you can see LIST shows message # with bytes in each message)
LIST
+OK 15 messages
1 2418
2 1338
3 2762
4 6952
5 1102
6 274522
7 1943
8 45456
9 3714
10 3269
11 4106
12 2495
13 2818
14 6815
15 1947
.
parse the LIST info and retrieve all except #6 and #8

RETR 1 RETR 2 RETR 3 RETR 4 RETR 5 RETR 7 RETR 9 RETR 10 RETR 11 RETR 12 RETR 13
RETR 14 RETR 15

RSET 6
RSET 8

I have no idea if this works...let's say after 13 messages are retrieved is #6
and #8 renamed to #1 and #2 and if so then perhaps that's where the UDIL command
might come in handy.

Are they're any clients that can do this now?  I use IMAP so wouldn't have a
clue.

LAST  (the LAST command allows the Leave on Server option for messages)
+OK 15 is last seen
+OK Valid commands: QUIT, NOOP, STAT, LIST, UIDL, DELE, RSET, RETR, TOP, LAST,
XTND XMIT, HELP

here's the logs from my mail server with a POP session.

POP Connection request from [xxx.xxx.xxx.xxx], socket=12
got connection on [xxx.xxx.xxx.xxx]
out: +OK POP3 Server 3.3b1 ready 
inp: USER johnny
out: +OK please send the PASS\r\n
inp: PASS whoknows
out: +OK 17 messages in queue\r\n
inp: STAT
out: +OK 17 378128\r\n
inp: LIST
out: +OK 17 messages\r\n1 2418\r\n2 1338\r\n3 2762\r\n4 6952\r\n5 1102\r\n6
274522\r\n7 1943\r\n8 45456\r\n9 3714\r\n10 3269\r\n11 4106\r\n12 2495\r\n13
2818\r
inp: UIDL
out: +OK 17 messages\r\n1 1350\r\n2 1437\r\n3 1458\r\n4 1484\r\n5 1487\r\n6
1497\r\n7 1502\r\n8 1503\r\n9 1505\r\n10 1512\r\n11 1516\r\n12 1518\r\n13
1521\r\n1
inp: RETR 16
out: +OK message follows\r\n
15 {1536} retrieved, 1868 bytes
inp: RETR 17
out: +OK message follows\r\n
22:32:07.07 2 POP-07536([216.103.9.240]) 16 {1537} retrieved, 14609 bytes
inp: QUIT
disconnecting


--------------------------------------------------------------------------------

snipped from
http://www.imap.org/papers/imap.vs.pop.brief.html

IMAP has constructs to permit online performance optimization, especially over
low-speed links. These include the ability to fetch the structure of a message
without downloading it, to selectively fetch individual message parts, and the
ability to use the server for searching in order to minimize data transfer
between client and server.

Especially when connecting to a mail server via low-bandwidth lines, it is
useful to be able to defer transferring messages or parts of messages that are
not of immediate interest until a more propitious time. With multimedia or
multipart MIME messages, transferring selected parts of a message can be a huge
advantage, as when one is in a hotel room and has just received a short text
message with a 10MB video clip attached. Efficient processing of MIME messages
is a significant advantage of IMAP over POP. (MIME stands for Multipurpose
Internet Mail Extensions. It is the Internet standard method for sending
arbitrary files as attachments to SMTP and RFC-822 compatible Internet mail
messages.)
---end of snip----