Message ORGanization Working Group B. Leiba Internet-Draft Huawei Technologies Updates: 4466 (if approved) A. Melnikov Intended status: Standards Track Isode Limited Expires: January 8, 2010 July 7, 2009 IMAP4 Multimailbox SEARCH Extension draft-ietf-morg-multimailbox-search-01 Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on January 8, 2010. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Abstract The IMAP4 specification allows the searching only of the selected mailbox. A user often wants to search multiple mailboxes, and a Leiba & Melnikov Expires January 8, 2010 [Page 1]
Internet-Draft IMAP4 Multimailbox SEARCH Extension July 2009 client that wishes to support this must issue a series of SELECT and SEARCH commands, waiting for each to complete before moving on to the next. This extension allows a client to search multiple mailboxes with one command, limiting the round-trips and waiting for various searches to complete, and not requiring disruption of the currently selected mailbox. This also uses MAILBOX and TAG fields in ESEARCH responses, allowing a client to pipeline the searches if it chooses. Note A revised version of this draft document will be submitted to the RFC editor as a Proposed Standard for the Internet Community. Discussion and suggestions for improvement are requested, and should be sent to morg@ietf.org. Table of Contents 1. Conventions used in this document . . . . . . . . . . . . . . . 3 2. Extended SEARCH/UID SEARCH command . . . . . . . . . . . . . . 3 3. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 8. Normative References . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 7 Leiba & Melnikov Expires January 8, 2010 [Page 2]
Internet-Draft IMAP4 Multimailbox SEARCH Extension July 2009 1. Conventions used in this document In examples, "C:" indicates lines sent by a client that is connected to a server. "S:" indicates lines sent by the server to the client. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [Kwds]. 2. Extended SEARCH/UID SEARCH command Arguments: OPTIONAL source options OPTIONAL result options OPTIONAL charset specification (see [CHARSET]) searching criteria (one or more) Responses: REQUIRED untagged response: SEARCH or ESEARCH Result: OK - search completed NO - error: cannot search that charset or criteria BAD - command unknown or arguments invalid This section further updates definition of the SEARCH command described in section 2.6.1 of [IMAPABNF] (initially described in section 6.4.4 of [IMAP]. The SEARCH command is extended to allow for optional source and result options. This document does not define any result options. A server that supports this extension includes "MSEARCH" in its IMAP capability string. Unless specified otherwise by a description of a result option, in the presence of a search source option the server MUST return ESEARCH responses instead of the corresponding SEARCH responses. Because message numbers are not useful for mailboxes that are not selected, each ESEARCH response MUST return information about UIDs, not message numbers, regardless of whether it is in response to a SEARCH or a UID SEARCH command. In particular, the responses MUST contain the UID indicator. Presence of a source option in absence of a result option implies the "ALL" result option (see [ESEARCH]). Source options describe which mailboxes must be searched for messages. Note that a SEARCH/UID SEARCH command with source options doesn't affect which mailbox, if any, is currently selected, regardless of which mailboxes are searched. For each mailbox Leiba & Melnikov Expires January 8, 2010 [Page 3]
Internet-Draft IMAP4 Multimailbox SEARCH Extension July 2009 satisfying the source options, a single ESEARCH response MUST be returned if any messages in that mailbox match the search criteria. An ESEARCH respoonse SHOULD NOT be returned for mailboxes that contain no matching messages. Each ESEARCH response MUST contain the MAILBOX, TAG, and UIDVALIDITY correlators. Correlators allow clients to issue several SEARCH/UID SEARCH commands at once (pipelined). The server MAY perform pipelined searches in parallel; or it MAY instead serialize them. The source options, if present, MUST contain a mailbox specifier as defined in the IMAP NOTIFY extension [NOTIFY], section 6 (using the "filter-mailboxes" ABNF item), with the following changes: 1. The "selected-delayed" specifier is not valid here. 2. A "subtree-one" specifier is added. The "subtree" specifier results in a search of the specified mailbox and all selectable mailboxes that are subordinate to it, through an indefinitely deep hierarchy. The "subtree-one" specifier results in a search of the specified mailbox and all selectable child mailboxes, one hierarchy level down. If "subtree" is specified, the server MUST defend against loops in the hierarchy (for example, those caused by recursive file-system links within the message store). The server SHOULD do this by keeping track of the mailboxes that have been searched, and terminating the hierarchy traversal when a repeat is found. If it can not do that, it MAY do it by limiting the hierarchy depth. If the source options are not present, the value "selected" is assumed -- that is, only the currently selected mailbox is searched. If the source options include (or default to) "selected", the IMAP session MUST be in "selected" state. If the source options specify other mailboxes and NOT "selected", then the IMAP session MUST be in "selected" or "authenticated" state. If the session is not in a correct state, the SEARCH command returns a "BAD" result. If the server supports the ACL [ACL] extension, then the logged in user is required to have the 'r' right for each mailbox she wants to search. Mailboxes matching the source options for which the logged in user has no 'r' right MUST be ignored by a multimailbox search. In particular, ESEARCH responses MUST NOT be returned for those mailboxes. [CONTEXT] [NOTIFY] [[anchor3: Interaction with CONTEXT (RFC 5267) needs to be defined. Also, UPDATE option draft-ietf-lemonade-imap-notify might have to be prohibited when both Leiba & Melnikov Expires January 8, 2010 [Page 4]
Internet-Draft IMAP4 Multimailbox SEARCH Extension July 2009 CONTEXT and this extension are used. We might also have to consider interaction with ESEARCH, RFC 4731.]] 3. Example C: tag1 SEARCH IN ((mailboxes "folder1" subtree "folder2")) unseen C: tag2 SEARCH IN ((mailboxes "folder1" subtree-one "folder2")) subject "chad" S: * ESEARCH (TAG "tag1" MAILBOX "folder1" UIDVALIDITY 1) UID ALL 4001,4003,4005,4007,4009 S: * ESEARCH (TAG "tag2" MAILBOX "folder1" UIDVALIDITY 6789023554) UID ALL 195001:195004,169788 S: * ESEARCH (TAG "tag1" MAILBOX "folder2/banana" UIDVALIDITY 503) UID ALL 3002,4004 S: * ESEARCH (TAG "tag1" MAILBOX "folder2/peach" UIDVALIDITY 3) UID ALL 921691 S: tag1 OK done S: * ESEARCH (TAG "tag2" MAILBOX "folder2/salmon" UIDVALIDITY 1111111) UID ALL 50003,50006,50009,50012 S: tag2 OK done 4. Formal Syntax The following syntax specification uses the augmented Backus-Naur Form (BNF) as described in [ABNF]. Terms not defined here are taken from [IMAP], [NOTIFY], or [IMAPABNF]. filter-mailboxes-other =/ ("subtree-one" SP one-or-more-mailbox) ; Update definition from RFC 5465 [NOTIFY] ; Add new "subtree-one" selector. filter-mailboxes-selected = "selected" ; Update definition from RFC 5465 [NOTIFY] ; We forbid the use of "selected-delayed". one-correlator = ("TAG" SP tag-string) / ("MAILBOX" SP astring) / ("UIDVALIDITY" SP nz-number) ; Each correlator MUST appear exactly once scope-option = scope-option-name [SP scope-option-value] ; No options defined here. Syntax for future extensions. scope-option-name = tagged-ext-label ; No options defined here. Syntax for future extensions. Leiba & Melnikov Expires January 8, 2010 [Page 5]
Internet-Draft IMAP4 Multimailbox SEARCH Extension July 2009 scope-option-value = tagged-ext-val ; No options defined here. Syntax for future extensions. scope-options = scope-option *(SP scope-option) ; A given option may only appear once ; No options defined here. Syntax for future extensions. search = "SEARCH" [SP search-source-opts] [SP search-return-opts] SP search-program ; Updates definition in RFC 4466 [IMAPABNF] search-correlator = SP "(" one-correlator *(SP one-correlator) ")" ; Updates definition in RFC 4466 [IMAPABNF] search-source-opts = "IN" SP "(" source-mbox [SP "(" scope-options ")"] ")" source-mbox = filter-mailboxes *(SP filter-mailboxes) ; filter-mailboxes is defined in RFC 5465 [NOTIFY] ; See updated definition of filter-mailboxes-other, above. ; See updated definition of filter-mailboxes-selected, above. 5. Security Considerations [[anchor5: This needs to be properly written. Notes from minutes of IETF 74, for now...]] Chris suggests shared mailboxes could be used to force spam into search results by owner of shared mailbox. Chris wonders about a parameter that says search only user's own mailboxes (no shared). Cyrus says you can use metadata to tag mailboxes you don't want to search, and use search criteria to exclude them. The "personal" selector may work for this, as well. Suggestions to add EXCLUDE clause (with a nested search criteria) for Trash, e.g. Suggestions to use metadata tags to mark those mailboxes that you want to (not) search 6. IANA Considerations IMAP4 capabilities are registered by publishing a standards track or IESG approved experimental RFC. The registry is currently located here: Leiba & Melnikov Expires January 8, 2010 [Page 6]
Internet-Draft IMAP4 Multimailbox SEARCH Extension July 2009 http://www.iana.org/assignments/imap4-capabilities This document defines the IMAP capability "MSEARCH", and IANA is asked to add it to the registry. 7. Acknowledgements The authors gratefully acknowledge feedback provided by Peter Coates and Arnt Gulbrandsen. 8. Normative References [ABNF] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 5234, January 2008. [ACL] Melnikov, A., "IMAP4 Access Control List (ACL) Extension", RFC 4314, December 2005. [CHARSET] Freed, N. and J. Postel, "IANA Charset Registration Procedures", RFC 2978, October 2000. [CONTEXT] Cridland, D. and C. King, "Contexts for IMAP4", RFC 5267, July 2008. [ESEARCH] Melnikov, A. and D. Cridland, "IMAP4 Extension to SEARCH Command for Controlling What Kind of Information Is Returned", RFC 4731, November 2006. [IMAP] Crispin, M., "Internet Message Access Protocol - Version 4rev1", RFC 3501, March 2003. [IMAPABNF] Melnikov, A. and C. Daboo, "Collected Extensions to IMAP4 ABNF", RFC 4466, April 2006. [Kwds] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [NOTIFY] Gulbrandsen, A., King, C., and A. Melnikov, "The IMAP NOTIFY Extension", RFC 5465, February 2009. Leiba & Melnikov Expires January 8, 2010 [Page 7]
Internet-Draft IMAP4 Multimailbox SEARCH Extension July 2009 Authors' Addresses Barry Leiba Huawei Technologies Phone: +1 646 827 0648 Email: barryleiba@computer.org Alexey Melnikov Isode Limited 5 Castle Business Village 36 Station Road Hampton, Middlesex TW12 2BX UK Email: Alexey.Melnikov@isode.com URI: http://www.melnikov.ca/ Leiba & Melnikov Expires January 8, 2010 [Page 8]
