Sieve Working Group A. Melnikov Internet-Draft Isode Limited Intended status: Standards Track November 20, 2008 Expires: May 24, 2009 The SIEVE mail filtering language - extension for accessing mailbox metadata draft-melnikov-sieve-imapext-metadata-05 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of 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 May 24, 2009. Abstract This memo defines an extension to the SIEVE mail filtering language (RFC 5228) for accessing mailbox and server annotations (variables). Melnikov Expires May 24, 2009 [Page 1]
Internet-Draft Sieve METADATA November 2008 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Implementation note . . . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . 3 3. mailbox and mboxmetadata Sieve extensions . . . . . . . . . 3 3.1. Test mailbox_exists . . . . . . . . . . . . . . . . . . . . 3 3.2. ':create' argument to 'fileinto' command . . . . . . . . . . 4 3.3. Test metadata . . . . . . . . . . . . . . . . . . . . . . . 4 3.4. Test metadata_exists . . . . . . . . . . . . . . . . . . . . 5 4. servermetadata Sieve extension . . . . . . . . . . . . . . . 5 4.1. Test server_metadata . . . . . . . . . . . . . . . . . . . . 5 4.2. Test server_metadata_exists . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . 7 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 8.1. Normative References . . . . . . . . . . . . . . . . . . . . 8 8.2. Informative References . . . . . . . . . . . . . . . . . . . 8 Author's Address . . . . . . . . . . . . . . . . . . . . . . 9 Intellectual Property and Copyright Statements . . . . . . . 10 Melnikov Expires May 24, 2009 [Page 2]
Internet-Draft Sieve METADATA November 2008 1. Introduction This memo defines an extension to the SIEVE mail filtering language (RFC 5228) for accessing mailbox and server annotations (variables). This allows to customize Sieve engine behaviour based on variables set using [METADATA]. 1.1. Implementation note An implementation of this extension doesn't need to implement [METADATA] or even [IMAP], however it has to use the same data model as described in Section 3 of [METADATA]. For example, it should be possible to implement the "servermetadata" extension defined in this document by making Sieve engine read values from user's [LDAP] or [ACAP] entry. But note that defining LDAP/ACAP schema is out of scope for this document. 2. Conventions used in this document 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 [Kwds]. Conventions for notations are as in [SIEVE] section 1.1, including the use of [ABNF]. This document is written with an assumption that readers are familiar with data model and terms defined in Section 3 of [METADATA]. 3. mailbox and mboxmetadata Sieve extensions 3.1. Test mailbox_exists Usage: mailbox_exists <mailbox-names: string-list> The "mailbox_exists" test is true if all mailboxes listed in the mailbox-names argument exist in the mailstore and each allows the "fileinto" action for the user in whose context the Sieve script runs. The capability string for use with the require command is "mailbox". Example: The following example assumes that the Sieve engine also supports "reject" [REJECT] and "fileinto" [SIEVE]. However these extensions are not required in order to implement the "mailbox". Melnikov Expires May 24, 2009 [Page 3]
Internet-Draft Sieve METADATA November 2008 require ["fileinto", "reject", "mailbox"]; if mailbox_exists "Partners" { fileinto "Partners"; } else { reject "This message was not accepted by the Mailstore"; } 3.2. ':create' argument to 'fileinto' command Usage: fileinto [:create] <mailbox: string> If the optional :create argument is specified with "fileinto" it instructs Sieve interpreter to create the specified mailbox before attempting to deliver the message into the specified mailbox. If the mailbox already exists, this argument is ignored. Failure to create the specified mailbox is considered to be an error. The capability string for use with the :create parameter is "mailbox". 3.3. Test metadata Usage: metadata [MATCH-TYPE] [COMPARATOR] <mailbox: string> <annotation-name: string> <key-list: string-list> This test retrieves the value of the mailbox annotation "annotation- name" for the mailbox "mailbox" [METADATA]. The retrieved value is compared to the "key-list". The test returns true if the annotation (of the specified type) exists and its value matches any of the keys. The default match type is ":is". The default comparator is "i;ascii- casemap". The capability string for use with the require command is "mboxmetadata". Note that access to annotations starting with the /private prefix MUST only be done as the user in whose context the Sieve script runs. Example: The following example assumes that the Sieve engine also supports the "vacation" [VACATION] extension. However this extension is not required in order to implement the "mboxmetadata" extension. Melnikov Expires May 24, 2009 [Page 4]
Internet-Draft Sieve METADATA November 2008 require ["mboxmetadata", "vacation"]; if metadata :is "INBOX" "/private/vendor/vendor.isode/auto-replies" "on" { vacation text: I'm away on holidays till March 2009. Expect a delay. . } 3.4. Test metadata_exists Usage: metadata_exists <mailbox: string> <annotation-names: string- list> The "metadata_exists" test is true if all of the annotations listed in the annotation-names argument exist (have non NIL value) for the specified mailbox. The capability string for use with the require command is "mboxmetadata". 4. servermetadata Sieve extension 4.1. Test server_metadata Usage: server_metadata [MATCH-TYPE] [COMPARATOR] <annotation-name: string> <key-list: string-list> This test retrieves the value of the server annotation "annotation- name" [METADATA]. The retrieved value is compared to the "key-list". The test returns true if the annotation (of the specified type) exists and its value matches any of the keys. The default match type is ":is". The default comparator is "i;ascii- casemap". The capability string for use with the require command is "servermetadata". Note that access to annotations starting with the /private prefix MUST only be done as the user in whose context the Sieve script runs. Example: The following example assumes that the Sieve engine also supports "variables" [Variables] and "enotify" [NOTIFY] and "envelope" [SIEVE] extensions. However these extensions are not Melnikov Expires May 24, 2009 [Page 5]
Internet-Draft Sieve METADATA November 2008 required in order to implement the "servermetadata". require ["enotify", "servermetadata", "variables", "envelope"]; if server_metadata :matches "/private/vendor/vendor.isode/notification-uri" "*" { set "notif_uri" "${0}"; } if not string :is "${notif_uri}" "none" { # :matches is used to get the MAIL FROM address if envelope :all :matches "from" "*" { set "env_from" " [really: ${1}]"; } # :matches is used to get the value of the Subject header if header :matches "Subject" "*" { set "subject" "${1}"; } # :matches is used to get the address from the From header if address :matches :all "from" "*" { set "from_addr" "${1}"; } notify :message "${from_addr}${env_from}: ${subject}" "${notif_uri}"; } 4.2. Test server_metadata_exists Usage: server_metadata_exists <annotation-names: string-list> The "server_metadata_exists" test is true if server annotations with names listed in the annotation-names argument exist. All of the annotations must exist or the test is false. The capability string for use with the require command is "servermetadata". 5. Security Considerations Extensions defined in this document deliberately don't provide a way to modify per-user (per-server) or per-mailbox data. A failure to retrieve data due to server storing annotations being Melnikov Expires May 24, 2009 [Page 6]
Internet-Draft Sieve METADATA November 2008 down or otherwise inaccessible may alter the result of Sieve processing. So implementations SHOULD treat temporary failures to retrieve annotations in the same manner they would treat temporary failures to retrieve the whole Sieve script. Protocols/APIs used to retrieve annotations MUST provide the same level of confidentiality as protocols/APIs used to retrieve Sieve scripts. 6. IANA Considerations IANA is requested to add the following registrations to the list of Sieve extensions: To: iana@iana.org Subject: Registration of new Sieve extension Capability name: mailbox Description: adds test for checking for mailbox existence and a new optional argument to fileinto for creating a mailbox before attempting mail delivery. RFC number: this RFC Contact address: The Sieve discussion list <ietf-mta-filters@imc.org> Capability name: mboxmetadata Description: adds tests for checking for mailbox metadata item existence and for retrieving of a mailbox metadata value. RFC number: this RFC Contact address: The Sieve discussion list <ietf-mta-filters@imc.org> Capability name: servermetadata Description: adds tests for checking for server metadata item existence and for retrieving of a server metadata value. RFC number: this RFC Contact address: The Sieve discussion list <ietf-mta-filters@imc.org> 7. Acknowledgements Thanks to Cyrus Daboo for initial motivation for this draft. The author would also like to thank the OMA MEM working group for providing a set of requirements that made the author realise that they can be partially fulfilled by this document. Melnikov Expires May 24, 2009 [Page 7]
Internet-Draft Sieve METADATA November 2008 8. References 8.1. Normative References [ABNF] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 5234, January 2008. [Kwds] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [METADATA] Daboo, C., "IMAP METADATA Extension", draft-daboo-imap-annotatemore-16 (work in progress), November 2008. [SIEVE] Guenther, P. and T. Showalter, "Sieve: An Email Filtering Language", RFC 5228, January 2008. 8.2. Informative References [ACAP] Newman, C. and J. Myers, "ACAP -- Application Configuration Access Protocol", RFC 2244, November 1997. [IMAP] Homme, K., "Internet Message Access Protocol - Version 4rev1", RFC 3501, March 2003. [LDAP] Zeilenga, K., "Lightweight Directory Access Protocol (LDAP): Technical Specification Road Map", RFC 4510, June 2006. [NOTIFY] Melnikov, A., Leiba, B., Segmuller, W., and T. Martin, "Sieve Extension: Notifications", draft-ietf-sieve-notify-12 (work in progress), January 2008. [REJECT] Stone, A., "The SIEVE mail filtering language - reject extension", draft-ietf-sieve-refuse-reject-09 (work in progress), November 2008. [VACATION] Showalter, T. and N. Freed, "Sieve Email Filtering: Vacation Extension", RFC 5230, January 2008. [Variables] Homme, K., "Sieve: An Email Filtering Language", RFC 5229, January 2008. Melnikov Expires May 24, 2009 [Page 8]
Internet-Draft Sieve METADATA November 2008 Author's Address Alexey Melnikov Isode Limited 5 Castle Business Village 36 Station Road Hampton, Middlesex TW12 2BX UK Email: Alexey.Melnikov@isode.com Melnikov Expires May 24, 2009 [Page 9]
Internet-Draft Sieve METADATA November 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). 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, THE IETF TRUST 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. 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 it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Melnikov Expires May 24, 2009 [Page 10]
