Imap, Pine and Continuous Error Loops

Imap, Pine and Continuous Error Loops

Post by Bruce Toew » Sun, 24 Dec 2000 07:25:11



Hi. I'm hoping someone can help me. I am using Pine to access an Imap
server. I have encountered this problem with versions 4.21, 4.30 and 4.31,
and I am of the opinion that this is an Imap server problem. On the off
chance that it is not, or if someone can help me in telling the provider
what the problem is, here's the issue.

On some messages that I read, and there doesn't seem to be a discernible
pattern to this, I get an error message to the effect that there is junk
at end of envelope information. Then I get some error messages about
certain words not being recognized message properties, and it cycles
through the header like this over and over again without stopping. The
only way I know how to stop this is to exit my Unix shell. Does anyone
have an idea what is going on here? If the problem is indeed with my Imap
provider, what do I tell them? Thank you very much.

Bruce

 
 
 

Imap, Pine and Continuous Error Loops

Post by Mark Crispi » Sun, 24 Dec 2000 14:46:41



> On some messages that I read, and there doesn't seem to be a discernible
> pattern to this, I get an error message to the effect that there is junk
> at end of envelope information. Then I get some error messages about
> certain words not being recognized message properties, and it cycles
> through the header like this over and over again without stopping.

Assuming that the message is "Junk at end of envelope", it indeed
indicates that the IMAP server is in violation of the IMAP protocol.
Pine's IMAP client code is expecting the closing parenthesis that
indicates the end of an IMAP token called the "envelope"; it got something
else instead, so it issues the error message and proceeds as if the
expected closing parenthesis was there.

Unfortunately, what usually has happened is that the IMAP server and
Pine's IMAP client code are in complete disagreement about what it is
parsing, and so as Pine attempts to parse more of the message data from
the server it will encounter further errors.  The errors *will* presently
stop, but there can be a lot of them.  It's like in a C program, one
little typo can lead to hundreds of C compilation errors...  ;-)

The syntax of the IMAP protocol is quite strict on what is permitted and
what is not; in general, there is a One True Syntax with no variations
permitted.  Behavior of IMAP servers is somewhat more relaxed with a
modest amount leeway allowed for implementation choices, although in
general IMAP is somewhat stricter than other protocols in its requirements
on server behavior.

Yes, you should report this problem to the manager of the IMAP server
and/or to the vendor of the IMAP server software.  You're on pretty solid
grounds with your report, because the author of Pine's IMAP client code is
the same fellow who invented IMAP and wrote the IMAP specification.  :-)

Alternatively, if you would like to give me access to your server and to a
mailbox which demonstrates the problem, I have been willing to analyze the
IMAP traffic and come up with a statement about what's wrong.  Most IMAP
server vendors are pretty good in making their servers comply and fix
discovered problems quickly.

-- Mark --

http://staff.washington.edu/mrc
Science does not emerge from voting, party politics, or public debate.