ietf-822
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Re: The TEXT/HTML Content Type in e-mail

1995-11-21 01:02:41
Ned wrote:
Using the ANBF notations and definitions of RFC 822 and RFC 1521, the
syntax of the URL parameter Is as follows:

URL-parameter := <"> URL-word *(*LWSP-char URL-word) <">

URL-word := token
; Must not exceed 40 characters in length

Question: Why the arbitrary limit of 40 characters for folding ?  Why not
let the URL-word be as long as the current line will allow.

Because you cannot control the folding that will be applied by agents along the
transport path, and if the token is too long they may damage it when they are
forced to hack at it to fold it. Counting on agents folding on whitespace
is one thing, counting on them breaking a token apart and forcibly inserting
whitespace is quite another.

Some agents may fold at 1000 characters, others may fold at 80, some may even
fold at 70. I doubt that it will be less than 70, but you never know...

The last time this issue came up was in the context of encoded-words, ala
RFC1522, and since 40 was chosen as the "maximum safe" length then that's what
I chose to use as well.

I'm not particularly wedded to 40 as a value, but not having a specific
value isn't a good idea.

On another point:
The use of a URL in a message/external is interesting but I don't
see how it solves the problem of sending HTML in mail.  Unless of course
HTML is never included in the body of a message and only external references
are made to a page.  Is that what you are proposing?

This has nothing to do with sending HTML around in email. Its an entirely
separate proposal, solving a completely different problem. I only mentioned
it in this context because it has to solve the same subproblem -- how to
embed a URL string in a header field -- that the HTML in email scheme also
has to deal with.

                                Ned