The Text/Plain Format and DelSp Parameters
RFC 3676

Document Type RFC - Proposed Standard (February 2004; No errata)
Obsoletes RFC 2646
Was draft-gellens-format-bis (individual in app area)
Last updated 2015-10-14
Stream IETF
Formats plain text html pdf htmlized bibtex
Stream WG state (None)
Document shepherd No shepherd assigned
IESG IESG state RFC 3676 (Proposed Standard)
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Responsible AD Ned Freed
Send notices to (None)
Network Working Group                                         R. Gellens
Request for Comments: 3676                                      Qualcomm
Obsoletes: 2646                                            February 2004
Category: Standards Track

               The Text/Plain Format and DelSp Parameters

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2004).  All Rights Reserved.

Abstract

   This specification establishes two parameters (Format and DelSP) to
   be used with the Text/Plain media type.  In the presence of these
   parameters, trailing whitespace is used to indicate flowed lines and
   a canonical quote indicator is used to indicate quoted lines.  This
   results in an encoding which appears as normal Text/Plain in older
   implementations, since it is in fact normal Text/Plain, yet provides
   for superior wrapping/flowing, and quoting.

   This document supersedes the one specified in RFC 2646, "The
   Text/Plain Format Parameter", and adds the DelSp parameter to
   accommodate languages/coded character sets in which ASCII spaces are
   not used or appear rarely.

Table of Contents

   1.  Introduction. . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in this Document . . . . . . . . . . . . . .   2
   3.  The Problem . . . . . . . . . . . . . . . . . . . . . . . . .   3
       3.1.  Paragraph Text. . . . . . . . . . . . . . . . . . . . .   3
       3.2.  Embarrassing Line Wrap  . . . . . . . . . . . . . . . .   3
       3.3.  New Media Types . . . . . . . . . . . . . . . . . . . .   4
   4.  The Format and DelSp Parameters . . . . . . . . . . . . . . .   5
       4.1.  Interpreting Format=Flowed. . . . . . . . . . . . . . .   6
       4.2.  Generating Format=Flowed  . . . . . . . . . . . . . . .   7
       4.3.  Usenet Signature Convention . . . . . . . . . . . . . .   9
       4.4.  Space-Stuffing  . . . . . . . . . . . . . . . . . . . .   9

Gellens                     Standards Track                     [Page 1]
RFC 3676         Text/Plain Format and DelSp Parameters    February 2004

       4.5.  Quoting . . . . . . . . . . . . . . . . . . . . . . . .   9
       4.6.  Digital Signatures and Encryption . . . . . . . . . . .  11
       4.7.  Examples. . . . . . . . . . . . . . . . . . . . . . . .  12
   5.  Interoperability. . . . . . . . . . . . . . . . . . . . . . .  12
   6.  ABNF. . . . . . . . . . . . . . . . . . . . . . . . . . . . .  13
   7.  Failure Modes . . . . . . . . . . . . . . . . . . . . . . . .  14
       7.1.  Trailing White Space Corruption . . . . . . . . . . . .  14
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  15
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  15
   10. Internationalization Considerations . . . . . . . . . . . . .  15
   11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  15
   12. Normative References. . . . . . . . . . . . . . . . . . . . .  16
   13. Informative References. . . . . . . . . . . . . . . . . . . .  16
   Appendix A: Changes from RFC 2646 . . . . . . . . . . . . . . . .  18
   Author's Address. . . . . . . . . . . . . . . . . . . . . . . . .  19
   Full Copyright Statement. . . . . . . . . . . . . . . . . . . . .  20

1.  Introduction

   Interoperability problems have been observed with erroneous labelling
   of paragraph text as Text/Plain, and with various forms of
   "embarrassing line wrap".  (See Section 3.)

   Attempts to deploy new media types, such as Text/Enriched [Rich] and
   Text/HTML [HTML] have suffered from a lack of backwards compatibility
   and an often hostile user reaction at the receiving end.

   What is required is a format which is in all significant ways
   Text/Plain, and therefore is quite suitable for display as
   Text/Plain, and yet allows the sender to express to the receiver
   which lines are quoted and which lines are considered a logical
   paragraph, and thus eligible to be flowed (wrapped and joined) as
   appropriate.

2.  Conventions Used in this Document

   The key words "REQUIRED", "MUST", "MUST NOT", "SHOULD", "SHOULD NOT",
   and "MAY" in this document are to be interpreted as described in "Key
   words for use in RFCs to Indicate Requirement Levels" [KEYWORDS].

   The term "paragraph" is used here to mean a series of lines which are
   logically to be treated as a unit for display purposes and eligible
   to be flowed (wrapped and joined) as appropriate to fit in the
   display window and when creating text for replies, forwarding, etc.

Gellens                     Standards Track                     [Page 2]
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