mail() - message lines <= 70 chars

[Matthew]

I'm using PHP version 4.4.3.

The manual page for PHP's mail() function (URL below) says that for the
message (IE. email body) "Each line should be separated with a LF (\n).
Lines should not be larger than 70 characters."

http://uk2.php.net/manual/en/function.mail.php

To see what happened I just sent an email using mail() with one of its
lines exactly 100 chars. It was sent perfectly by sendmail as a line of
100 chars and no newline. PHP did not seem to mind at all.

Why the limitation of <= 70 chars per line, and why does my version of PHP
not seem to care?

Thanks all.

[John Dunlop]

Matthew:

The manual page for PHP's mail() function (URL below) says that for the
message (IE. email body) "Each line should be separated with a LF (\n).

Should be CRLF.

http://www.apps.ietf.org/rfc/rfc2822.html#sec-2.1

Lines should not be larger than 70 characters."

Should be 78.

http://www.apps.ietf.org/rfc/rfc2822.html#sec-2.1.1

--
Jock

[Matthew]

John Dunlop emailed this:

Matthew:

>The manual page for PHP's mail() function (URL below) says that for the
message (IE. email body) "Each line should be separated with a LF (\n).

Should be CRLF.

http://www.apps.ietf.org/rfc/rfc2822.html#sec-2.1

>Lines should not be larger than 70 characters."

Should be 78.

http://www.apps.ietf.org/rfc/rfc2822.html#sec-2.1.1

--
Jock

Thanks.

Why do the long lines of 100 chars work for me anyway?

[Rik Wasmus]

On Thu, 22 Nov 2007 18:13:52 +0100, Matthew <ma*****@spamkiller.comwrote:

John Dunlop emailed this:

>Matthew:

>>The manual page for PHP's mail() function (URL below) says that for the
message (IE. email body) "Each line should be separated with a LF (\n).

Should be CRLF.
http://www.apps.ietf.org/rfc/rfc2822.html#sec-2.1

>>Lines should not be larger than 70 characters."

Should be 78.
http://www.apps.ietf.org/rfc/rfc2822.html#sec-2.1.1

Why do the long lines of 100 chars work for me anyway?

1. PHP doesn't check it: you, as the programmer, should take care of it.
2. Most email clients/servers ar robust enough to handle more characters.
The fact that almost all can is still not a reason to let the number of
characters slide though.
--
Rik Wasmus

[Matthew]

Rik Wasmus emailed this:

On Thu, 22 Nov 2007 18:13:52 +0100, Matthew <ma*****@spamkiller.comwrote:

>John Dunlop emailed this:

>>Matthew:
The manual page for PHP's mail() function (URL below) says that for the
message (IE. email body) "Each line should be separated with a LF (\n).
Should be CRLF.
http://www.apps.ietf.org/rfc/rfc2822.html#sec-2.1

Lines should not be larger than 70 characters."
Should be 78.
http://www.apps.ietf.org/rfc/rfc2822.html#sec-2.1.1

Why do the long lines of 100 chars work for me anyway?

1. PHP doesn't check it: you, as the programmer, should take care of it.
2. Most email clients/servers ar robust enough to handle more
characters. The fact that almost all can is still not a reason to let
the number of characters slide though.

Thanks Rik. I'll just add a newline every 70 chars then.

[Toby A Inkster]

Matthew wrote:

Thanks Rik. I'll just add a newline every 70 chars then.

PHP has a function called wordwrap() that may be useful for you.

--
Toby A Inkster BSc (Hons) ARCS
[Geek of HTML/SQL/Perl/PHP/Python/Apache/Linux]
[OS: Linux 2.6.17.14-mm-desktop-9mdvsmp, up 17:53.]

It'll be in the Last Place You Look
http://tobyinkster.co.uk/blog/2007/11/21/no2id/

[C. (http://symcbean.blogspot.com/)]

On 22 Nov, 16:47, John Dunlop <[e-mail]:

Matthew:

The manual page for PHP's mail() function (URL below) says that for the
message (IE. email body) "Each line should be separated with a LF (\n).

Should be CRLF.

http://www.apps.ietf.org/rfc/rfc2822.html#sec-2.1

Lines should not be larger than 70 characters."

Should be 78.

http://www.apps.ietf.org/rfc/rfc2822.html#sec-2.1.1

--
Jock

No - that's SMTP which is a specific transport mechanism for email
(actually its a whole family of protocols but lets not go there) its
up to the MUA ('mail' command on Unix or the SMTP implementation
within PHP for |MSWin) to **convert** the message to a suitable format
for the MTA, which may in turn encode the message in a different
format depending on the carrier protocol.

Perhaps historically the SMTP implementation in PHP couldn't
accomodate this.

If you sniff the SMTP connection you'll see that long lines do get
wrapped - but the original message is restored when it comes out the
MUA at the other end.

C.

[John Dunlop]

C. (http://symcbean.blogspot.com/):

No - that's SMTP which is a specific transport mechanism for email
(actually its a whole family of protocols but lets not go there) its
up to the MUA ('mail' command on Unix or the SMTP implementation
within PHP for |MSWin) to **convert** the message to a suitable format
for the MTA, which may in turn encode the message in a different
format depending on the carrier protocol.

Right.

Perhaps historically the SMTP implementation in PHP couldn't
accomodate this.

If you sniff the SMTP connection you'll see that long lines do get
wrapped - but the original message is restored when it comes out the
MUA at the other end.

I wonder where PHP's figure 70 came from? If long lines do get
wrapped but you still recommended a limit, would you not recommend
78, in line with the transfer protocol?

On the other note, line endings seem a bit messy: \n for the message
body but \r\n for headers, whereas the transfer protocol demands \r\n
across the board. Then, I suppose, the whole business of line ending
conventions is messy.

--
Jock

[Matthew]

Toby A Inkster emailed this:

Matthew wrote:

>Thanks Rik. I'll just add a newline every 70 chars then.

PHP has a function called wordwrap() that may be useful for you.

Thanks Toby. I already found it looking through the string functions in
the manual for an appropriate function to use.

Cheers.

[Matthew]

John Dunlop emailed this:

C. (http://symcbean.blogspot.com/):

>No - that's SMTP which is a specific transport mechanism for email
(actually its a whole family of protocols but lets not go there) its
up to the MUA ('mail' command on Unix or the SMTP implementation
within PHP for |MSWin) to **convert** the message to a suitable format
for the MTA, which may in turn encode the message in a different
format depending on the carrier protocol.

Right.

>Perhaps historically the SMTP implementation in PHP couldn't
accomodate this.

If you sniff the SMTP connection you'll see that long lines do get
wrapped - but the original message is restored when it comes out the
MUA at the other end.

I wonder where PHP's figure 70 came from? If long lines do get
wrapped but you still recommended a limit, would you not recommend
78, in line with the transfer protocol?

On the other note, line endings seem a bit messy: \n for the message
body but \r\n for headers, whereas the transfer protocol demands \r\n
across the board. Then, I suppose, the whole business of line ending
conventions is messy.

It seems a strange for PHP to place an extra limitation like this on line
lengths. It's not really a problem as line wrapping at 70 chars looks
perfectly neat in all email clients I've ever used. As it happens between
70 and 75 chars are the settings I've always used when manually setting
word wrap in my email client's options.

My question was why PHP places this restriction at all. It's not even
sending the mail itself anyway, just passing the email to 'sendmail',
surely then it should simply be concerned with whatever line length
restrictions 'sendmail' imposes.

I've just looked in the sendmail manual which says it conforms to RFC 821,
this is the SMTP standard, URL - http://www.ietf.org/rfc/rfc0821.txt

The relevant bit of the RFC 821 SMTP standard says:

"Text Line - The maximum total length of a text line including the <CRLF>
is 1000 characters (but not counting the leading dot duplicated for
transparency)."

AFAICT SMTP does not place any further restrictions on message body line
lengths (though other fields do have text length restrictions such as the
reply line being a max. of 512 chars). I can't find any reference in the
protocol to message body lines (or any other lines) being further limited
to either 70 or 78 characters.

With that said, why is PHP concerned with further limits? Why not just let
the user enter their own newlines, the programmer add a CRLF at 998 chars
if necessary, and let the recipient's email client handle line wrapping as
per it's own settings/user options?

Any comments?

Regards, etc..

Matthew