The RFC which describes POP3 seems to be a bit uninformative when it
comes to the TOP command.  I realize the point of TOP is so that the
client only needs to download a few lines from the server, rather than
an entire email message.  But what constitutes a line?  The RFC seems
to imply that all email messages are neatly delineated by CRLF pairs.
But an email message can go on for paragraphs sometimes without a
CRLF.  So what is a "line" then?  Can TOP be implemented by simply
picking an arbitrary number of characters, and counting that as a
line?  Or do POP3 servers always parse email messages so that the body
of the message is divided up by CRLF pairs?

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In article <1179650011.594153.124490@n59g2000hsh.googlegroups.com>,
chsalvia@gmail.com wrote:

> The RFC which describes POP3 seems to be a bit uninformative when it
> comes to the TOP command.  I realize the point of TOP is so that the
> client only needs to download a few lines from the server, rather than
> an entire email message.  But what constitutes a line?  The RFC seems
> to imply that all email messages are neatly delineated by CRLF pairs.
> But an email message can go on for paragraphs sometimes without a
> CRLF.  So what is a "line" then?  Can TOP be implemented by simply
> picking an arbitrary number of characters, and counting that as a
> line?  Or do POP3 servers always parse email messages so that the body
> of the message is divided up by CRLF pairs?

Section 3 says:

Responses to certain commands are multi-line.  In these cases, which
are clearly indicated below, after sending the first line of the
response and a CRLF, any additional lines are sent, each terminated
by a CRLF pair.

That seems to be the only definition of "line" in the RFC.

BTW, why are you asking a network protocol question in a Unix newsgroup?
comp.protocols.tcp-ip would seem to be more appropriate.

--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
*** PLEASE don't copy me on replies, I'll read them in the group ***

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