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Differences from draft-melnikov-imap-ext-abnf-01.txt
Internet Draft A. Melnikov
Document: draft-melnikov-imap-ext-abnf Isode Ltd.
Expires: December 2005 Cyrus Daboo
ISAMET, Inc.
June 2005
Collected extensions to IMAP4 ABNF
draft-melnikov-imap-ext-abnf-02
Status of this Memo
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Abstract
Over years many documents from IMAPEXT and LEMONADE working groups,
as well as many individual documents have added syntactic
extensions to many base IMAP commands described in RFC 3501. For
ease of reference this document collects most of such ABNF changes
in one place.
This document updates ABNF in RFC 3501.
Table of Contents
1. Conventions Used in this Document 2
2. IMAP ABNF extensions 3
2.1 Optional parameters with the SELECT/EXAMINE commands 3
2.2 Extensions to FETCH and UID FETCH Commands 4
2.3 Extensions to STORE and UID STORE Commands 4
2.4 Extensions to SEARCH Command 5
2.5 Extensions to APPEND Command 6
3. Formal Syntax 6
4. Security Considerations 9
5. IANA Considerations 9
6. References 9
6.1 Normative References 9
7. Acknowledgments 10
8. Author's Addresses 10
9. Full Copyright Statement 10
10. Intellectual Property 11
11. Appendix A. Editorial. 11
11.1 Change Log 11
1. Conventions Used in this Document
In examples, "C:" and "S:" indicate lines sent by the client and
server respectively.
The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY"
in this document are to be interpreted as defined in "Key words for
use in RFCs to Indicate Requirement Levels" [KEYWORDS].
<<Editorial comments and questions are enclosed like this>>
2. IMAP ABNF extensions
2.1 Optional parameters with the SELECT/EXAMINE commands
This documents adds the ability to include one or more parameters
with the IMAP SELECT or EXAMINE commands, to turn on or off certain
standard behaviour, or to add new optional behaviours required for
a particular extension.
There are two possible modes of operation:
o A global state change where a single use of the optional
parameter will effect the session state from that time on,
irrespective of subsequent SELECT/EXAMINE commands.
o A per-mailbox state change that will effect the session only for
the duration of the new selected state. A subsequent SELECT/
EXAMINE without the optional parameter will cancel its effect
For the newly selected mailbox.
Optional parameters to the SELECT or EXAMINE commands are added as
a parenthesised list of atoms or strings, and appear after the
mailbox name in the standard SELECT or EXAMINE command. The order
of individual parameters is arbitrary. Individual parameters may
consist of one or more atoms or strings in a specific order. If a
parameter consists of more than one atom or string, it MUST appear
in its own parenthesised list. Any parameter not defined by
extensions that the server supports MUST be rejected with a BAD
response.
Example:
C: a SELECT INBOX (ANNOTATE)
S: ...
S: a OK SELECT complete
In the above example, a single parameter is used with the SELECT
command.
Example:
C: a EXAMINE INBOX (ANNOTATE (RESPONSES "UID Responses")
CONDSTORE)
S: ...
S: a OK EXAMINE complete
In the above example, three parameters are used with the EXAMINE
command. The second parameter consists of two items: an atom
followed by a quoted string.
Example:
C: a SELECT INBOX (BLURDYBLOOP)
S: a BAD Unknown parameter in SELECT command
In the above example, a parameter not supported by the server is
used. This results in the BAD response from the
server.
2.2 Extensions to FETCH and UID FETCH Commands
Arguments: sequence set
message data item names or macro
OPTIONAL fetch modifiers
Responses: untagged responses: FETCH
Result: OK - fetch completed
NO - fetch error: can't fetch that data
BAD - command unknown or arguments invalid
This document extends the syntax of the FETCH and UID FETCH
commands (see section 6.4.5 of [IMAP4]) to include optional FETCH
modifiers. No fetch modifiers are defined in this document.
The order of individual modifiers is arbitrary. An individual
modifier may consist of one or more atoms or strings in a specific
order. If a modifier consists of more than one atom or string, it
MUST appear in its own parenthesised list. Any modifiers not
defined by extensions that the server supports MUST be rejected
with a BAD response.
2.3 Extensions to STORE and UID STORE Commands
Arguments: message set
OPTIONAL store modifiers
message data item name
value for message data item
Responses: untagged responses: FETCH
Result: OK - store completed
NO - store error: can't store that data
BAD - command unknown or arguments invalid
This document extends the syntax of the STORE and UID STORE
commands (see section 6.4.6 of [IMAP4]) to include optional STORE
modifiers. No store modifiers are defined in this document.
The order of individual modifiers is arbitrary. Individual
modifier may consist of one or more atoms or strings in a specific
order. If a modifier consists of more than one atom or string, it
MUST appear in its own parenthesised list. Any modifiers not
defined by extensions that the server supports MUST be rejected
with a BAD response.
2.4 Extensions to SEARCH Command
Arguments: OPTIONAL result specifier
OPTIONAL [CHARSET] specification
searching criteria (one or more)
Responses: REQUIRED untagged response: SEARCH (*)
Result: OK - search completed
NO - search error: can't search that [CHARSET] or
criteria
BAD - command unknown or arguments invalid
This section updates definition of the SEARCH command described in
section 6.4.4 of [IMAP4].
The SEARCH command is extended to allow for result options. This
document doesn't define any result option.
The order of individual options is arbitrary. Individual options
may optionally contain parameters enclosed in parenthesises. If an
option has parameters, they consist of one or more atoms or strings
in a specific order. Any options not defined by extensions that the
server supports MUST be rejected with a BAD response.
(*) - An extension to SEARCH command may require another untagged
response, or no untagged response to be returned.
2.5 Extensions to APPEND Command
The APPEND command is extended to allow the client to append data
containing NULs by using the <literal8> syntax. The ABNF was
rewritten to allow for easier extensibility by IMAP extensions.
3. Formal Syntax
The following syntax specification uses the Augmented Backus-Naur
Form (ABNF) notation as specified in [ABNF].
Non-terminals referenced but not defined below are as defined by
[IMAP4].
Except as noted otherwise, all alphabetic characters are case-
insensitive. The use of upper or lower case characters to define
token strings is for editorial clarity only. Implementations MUST
accept these strings in a case-insensitive fashion.
append = "APPEND" SP mailbox 1*append-message
;; only a single append-message may appear
;; if MULTIAPPEND [MULTIAPPEND] capability
;; is not present
append-message = append-opts SP append-data
append-ext = append-opt-name SP append-opt-val
append-opt-comp = astring /
append-opt-comp
*(SP append-opt-comp) /
"(" append-opt-comp ")"
append-opt-name = atom
append-opt-val = astring / "(" append-opt-comp ")"
<<Should we allow for empty "append-opt-comp"?>>
append-data = literal / literal8
<<if append-data is extended, the extended part should use the
syntax for append-ext, i.e. a mandatory label followed by
parameters>>
append-opts = [SP flag-list] [SP date-time] *(SP append-ext)
examine = "EXAMINE" SP mailbox [select-params]
;; modifies the original IMAP EXAMINE command
;; to accept optional parameters
fetch = "FETCH" SP sequence-set SP ("ALL" / "FULL" /
"FAST" / fetch-att /
"(" fetch-att *(SP fetch-att) ")")
[SP fetch-modifiers]
;; modifies the original IMAP4 FETCH command to
;; accept optional modifiers
fetch-modifiers = "(" fetch-modifier *(SP fetch-modifier) ")"
fetch-modifier = fetch-modifier-name
[ SP ( astring /
"(" fetch-modif-params
")" ) ]
;; modifiers to FETCH may contain a modifier
;; name followed by zero or more atoms or
;; strings - multiple items are always
;; parenthesised, nesting is allowed
<<the syntax hasn't changed, but the rule was rewritten for
consistency with store/search modifiers.
Same structure as store-modif-params, with one exception: the
thing in () can't be empty.>>
fetch-modif-params = astring *(SP astring) /
"(" fetch-modif-params
*(SP fetch-modif-params) ")"
<<This is not quite as flexible as store-modparam-comp, for
example the following is not allowed:
("foo") ("bar")
>>
fetch-modifier-name = atom
literal8 = "~{" number "}" CRLF *OCTET
;; A string that might contain NULs.
;; <number> represents the number of OCTETs
;; in the response string.
search = "SEARCH" [search-return-opts]
[SP "CHARSET" SP astring] 1*(SP search-key)
;; CHARSET argument to SEARCH MUST be
;; registered with IANA
search-return-opts = "RETURN" SP "(" [search-return-opt
*(SP search-return-opt)] ")"
;; SEARCH return options, e.g. MIN
search-return-opt = search-modifier-name
[SP search-mod-params]
;; MUST start with atom (label)
search-modifier-name = atom
search-mod-params = astring / "(" [search-mod-comp] ")"
search-mod-comp = astring /
search-mod-comp
*(SP search-mod-comp) /
"(" search-mod-comp ")"
;; same structure as for store-modparam-comp
select = "SELECT" SP mailbox [select-params]
;; modifies the original IMAP SELECT command to
;; accept optional parameters
select-params = SP "(" select-param *(SP select-param) ")"
select-param = astring / "(" astring 1*(SP astring) ")"
;; parameters to SELECT may contain one or
;; more atoms or strings - multiple items
;; are always parenthesised
status = "STATUS" SP mailbox SP
"(" status-att-req *(SP status-att-req) ")"
;; redefine STATUS command syntax defined in
;; [IMAP4]
status-att-list = status-rsp-info *(SP status-rsp-info)
;; Redefines status-att-list from RFC 3501
status-att-req = status-att
status-rsp-info = status-att SP number
store = "STORE" SP sequence-set store-modifiers
SP store-att-flags
;; extend [IMAP4] STORE command syntax
;; to allow for optional store-modifiers
store-modifiers = [ SP "(" store-modifier *(SP store-modifier)
")" ]
store-modifier = store-modifier-name [SP store-modif-params]
;; MUST start with atom (label)
store-modif-params = astring / "(" [store-modparam-comp] ")"
store-modparam-comp = astring /
store-modparam-comp
*(SP store-modparam-comp) /
"(" store-modparam-comp ")"
<<This differs from how fetch-modif-params is defined. Is this
desirable? Or should we use something simpler, e.g select-
param?>>
store-modifier-name = atom
<<Add LOGIN/AUTHENTICATE, LOGOUT and CREATE?>>
4. Security Considerations
It is believed that this document doesn't add any new security
concerns that were not already identified in RFC 3501.
5. IANA Considerations
This document doesn't define any new IMAP extension, so no action
from IANA is required.
6. References
6.1 Normative References
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[IMAP4] Crispin, M., "Internet Message Access Protocol - Version
4rev1", RFC 3501, University of Washington, March 2003.
[ABNF] Crocker, D. (Ed.) and P. Overell , "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, November 1997. <<Needs updating>>
[CHARSET] Freed, N. and J. Postel, "IANA Character Set Registration
Procedures", RFC 2978, October 2000.
[MULTIAPPEND] Crispin, M., "Internet Message Access Protocol
(IMAP) - MULTIAPPEND Extension", RFC 3502, March 2003.
7. Acknowledgments
This documents is based on ideas proposed by Pete Resnick, Mark
Crispin, Ken Murchison, Philip Guenther, Randall Gellens and Lyndon
Nerenberg.
However all errors and omissions must be attributed to the authors
of the document.
Some text was borrowed from draft-ietf-imapext-annotate-12.txt.
literal8 syntax was taken verbatim from RFC 3516.
8. Author's Addresses
Alexey Melnikov
Isode Limited
5 Castle Business Village
36 Station Road
Hampton, Middlesex, TW12 2BX
UK
Email: Alexey.Melnikov@isode.com
Cyrus Daboo
ISAMET, Inc.
5001 Baum Blvd.
Suite 650
Pittsburgh, PA 15213
US
EMail: daboo@isamet.com
9. Full Copyright Statement
Copyright (C) The Internet Society (2005).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on
an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT
THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR
ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE.
10. Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed
to pertain to the implementation or use of the technology described
in this document or the extent to which any license under such
rights might or might not be available; nor does it represent that
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Information on the procedures with respect to rights in RFC
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The IETF invites any interested party to bring to its attention any
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Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
11. Appendix A. Editorial.
<<Note that this section will be deleted before publication>>
11.1 Change Log
00 Initial Revision.
01 Added Cyrus as co-author. Added BINARY literals. Added section
about APPEND. Clarified that the order of all parameters/modifiers is
arbitrary. Unrecognized SELECT/EXAMINE parameter should cause the BAD,
not the NO response.
02 Updated boilerplate. Extended SEARCH modifiers to be consistent
with STORE modifiers. Rewrote FETCH modifier syntax for consistency.
| PAFTECH AB 2003-2026 | 2026-04-24 08:22:11 |