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Sieve Working GroupP. Saint-Andre
Internet-DraftXSF
Expires: August 5, 2007A. Melnikov
 Isode Limited
 February 1, 2007


Sieve Notification Mechanism: xmpp
draft-ietf-sieve-notify-xmpp-03

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Copyright Notice

Copyright © The IETF Trust (2007).

Abstract

This document describes a profile of the Sieve extension for notifications, to allow notifications to be sent over the Extensible Messaging and Presence Protocol (XMPP), also known as Jabber.



Table of Contents

1.  Introduction
    1.1.  Overview
    1.2.  Terminology
2.  Definition
    2.1.  Notify parameter ":method"
    2.2.  Notify tag ":from"
    2.3.  Notify tag ":options"
    2.4.  Notify tag ":importance"
    2.5.  Notify tag ":message"
3.  Examples
4.  Internationalization Considerations
5.  Security Considerations
6.  References
    6.1.  Normative References
    6.2.  Informative References
§  Authors' Addresses
§  Intellectual Property and Copyright Statements




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1.  Introduction



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1.1.  Overview

The [NOTIFY] (Melnikov, A., Leiba, B., Segmuller, W., and T. Martin, “Sieve Extension: Notifications,” January 2007.) extension to the [SIEVE] (Showalter, T. and P. Guenther, “Sieve: An Email Filtering Language,” August 2006.) mail filtering language is a framework for providing notifications by employing URIs to specify the notification mechanism. This document defines how xmpp URIs (see [XMPP‑URI] (Saint-Andre, P., “Internationalized Resource Identifiers (IRIs) and Uniform Resource Identifiers (URIs) for the Extensible Messaging and Presence Protocol (XMPP),” August 2006.)) are used to generate notifications via the Extensible Messaging and Presence Protocol (see [XMPP] (Saint-Andre, P., “Extensible Messaging and Presence Protocol (XMPP): Core,” October 2004.)), which is widely implemented in Jabber instant messaging technologies.



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1.2.  Terminology

This document inherits terminology from [NOTIFY] (Melnikov, A., Leiba, B., Segmuller, W., and T. Martin, “Sieve Extension: Notifications,” January 2007.), [SIEVE] (Showalter, T. and P. Guenther, “Sieve: An Email Filtering Language,” August 2006.), and [XMPP] (Saint-Andre, P., “Extensible Messaging and Presence Protocol (XMPP): Core,” October 2004.).

The capitalized key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 (Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” March 1997.) [TERMS].



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2.  Definition

The xmpp mechanism results in the sending of an XMPP message to notify a recipient about an email message. The general XMPP syntax is as follows:

The recommended mapping of the Sieve notify action into XMPP syntax is described in the following sections.



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2.1.  Notify parameter ":method"

The ":method" parameter MUST be a URI that conforms to the xmpp URI scheme (as specified in [XMPP‑URI] (Saint-Andre, P., “Internationalized Resource Identifiers (IRIs) and Uniform Resource Identifiers (URIs) for the Extensible Messaging and Presence Protocol (XMPP),” August 2006.)) and that identifies an XMPP account associated with the email inbox. The URI MAY include the resource identifier portion of an XMPP address but SHOULD NOT include an authority component, query component, or fragment identifier component. The processing application MUST extract an XMPP address from the URI in accordance with the processing rules specified in [XMPP‑URI] (Saint-Andre, P., “Internationalized Resource Identifiers (IRIs) and Uniform Resource Identifiers (URIs) for the Extensible Messaging and Presence Protocol (XMPP),” August 2006.). The resulting XMPP address MUST be encapsulated in XMPP syntax as the value of the XMPP 'to' attribute.



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2.2.  Notify tag ":from"

The ":from" tag has no special meaning for this notification mechanism, and this specification puts no restriction on its use. As noted, the value of the XMPP 'from' attribute specified in the XMPP notification message MUST be the XMPP address of the notification service itself. The value of the ":from" tag MAY be transformed into XMPP syntax; if so, it SHOULD be encapsulated as the value of an [XEP‑0131] (Saint-Andre, P. and J. Hildebrand, “Stanza Headers and Internet Metadata,” August 2005.) header named "Reply-To".



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2.3.  Notify tag ":options"

The ":options" tag has no special meaning for this notification mechanism. Any handling of this tag is the responsibility of an implementation.



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2.4.  Notify tag ":importance"

The ":importance" tag has no special meaning for this notification mechanism, and this specification puts no restriction on its use. The value of the ":importance" tag MAY be transformed into XMPP syntax (in addition to or instead of including in the default message); if so, it MUST be encapsulated as the value of an [XEP‑0131] (Saint-Andre, P. and J. Hildebrand, “Stanza Headers and Internet Metadata,” August 2005.) header named "Urgency", and the XML character of that header MUST be "high" if the value of the ":importance" tag is "1", "medium" if the value of the ":importance" tag is "2", or "low" if the value of the ":importance" tag is "3".



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2.5.  Notify tag ":message"

If included, the ":message" tag SHOULD be transformed into the XML character data of an XMPP <body/> element. If not included, the rule specified in [NOTIFY] (Melnikov, A., Leiba, B., Segmuller, W., and T. Martin, “Sieve Extension: Notifications,” January 2007.) SHOULD be followed, as shown in the examples below.



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3.  Examples

In the following examples, the sender of the email has an address of <mailto:juliet@example.org>, the entity to be notified has an XMPP address of <xmpp:romeo@example.com>, and the notification service has an XMPP address <xmpp:notify.example.com>.

The following is a basic Sieve notify action with only a method:

notify :method "xmpp:romeo@example.com"

The resulting XMPP <message/> stanza might be as follows:

<message from='notify.example.com'
         to='romeo@example.com'
         xml:lang='en'>
  <subject>A Sieve instant notification!</subject>
  <body>&lt;juliet@example.org&gt; Wherefore art thou?</body>
</message>

The following is a more advanced Sieve notify action with a method, importance, subject, and message, as well as a URL pointing to the message:

notify :method "xmpp:romeo@example.com?message;subject=SIEVE"
       :importance "1"
       :message "Contact Juliet immediately!"

The resulting XMPP <message/> stanza might be as follows:

<message from='notify.example.com'
         to='romeo@example.com'
         xml:lang='en'>
  <subject>SIEVE</subject>
  <body>Contact Juliet immediately!</body>
  <headers xmlns='http://jabber.org/protocol/shim'>
    <header name='Urgency'>high</header>
  </headers>
  <x xmlns='jabber:x:oob'>
    <url>
      imap://romeo@example.com/INBOX;UIDVALIDITY=385759045/;UID=20
    </url>
  </x>
</message>


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4.  Internationalization Considerations

Although an XMPP address may contain nearly any [UNICODE] (The Unicode Consortium, “The Unicode Standard, Version 3.2.0,” 2000.) character, the value of the ":method" tag MUST be a Uniform Resource Identifier (see [URI] (Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” January 2005.)) rather than an Internationalized Resource Identifier (see [IRI] (Duerst, M. and M. Suignard, “Internationalized Resource Identifiers (IRIs),” January 2005.)). The rules specified in [XMPP‑URI] (Saint-Andre, P., “Internationalized Resource Identifiers (IRIs) and Uniform Resource Identifiers (URIs) for the Extensible Messaging and Presence Protocol (XMPP),” August 2006.) MUST be followed when generating XMPP URIs.

In accordance with Section 13 of RFC 3920, all data sent over XMPP MUST be encoded in [UTF‑8] (Yergeau, F., “UTF-8, a transformation format of ISO 10646,” November 2003.).



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5.  Security Considerations

Depending on the information included, sending a notification can be comparable to forwarding mail to the notification recipient. Care must be taken when forwarding mail automatically, to ensure that confidential information is not sent into an insecure environment. In particular, implementations MUST conform to the security considerations given in [NOTIFY] (Melnikov, A., Leiba, B., Segmuller, W., and T. Martin, “Sieve Extension: Notifications,” January 2007.), [SIEVE] (Showalter, T. and P. Guenther, “Sieve: An Email Filtering Language,” August 2006.), and [XMPP] (Saint-Andre, P., “Extensible Messaging and Presence Protocol (XMPP): Core,” October 2004.).



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6.  References



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6.1. Normative References

[XEP-0066] Saint-Andre, P., “Out of Band Data,” XSF XEP 0066, January 2006.
[XEP-0131] Saint-Andre, P. and J. Hildebrand, “Stanza Headers and Internet Metadata,” XSF XEP 0131, August 2005.
[NOTIFY] Melnikov, A., Leiba, B., Segmuller, W., and T. Martin, “Sieve Extension: Notifications,” draft-ietf-sieve-notify-06 (work in progress), January 2007.
[SIEVE] Showalter, T. and P. Guenther, “Sieve: An Email Filtering Language,” draft-ietf-sieve-3028bis-09 (work in progress), August 2006.
[TERMS] Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” BCP 14, RFC 2119, March 1997.
[XMPP-URI] Saint-Andre, P., “Internationalized Resource Identifiers (IRIs) and Uniform Resource Identifiers (URIs) for the Extensible Messaging and Presence Protocol (XMPP),” RFC 4622, August 2006.


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6.2. Informative References

[IRI] Duerst, M. and M. Suignard, “Internationalized Resource Identifiers (IRIs),” RFC 3987, January 2005.
[UNICODE] The Unicode Consortium, “The Unicode Standard, Version 3.2.0,” 2000.

The Unicode Standard, Version 3.2.0 is defined by The Unicode Standard, Version 3.0 (Reading, MA, Addison-Wesley, 2000. ISBN 0-201-61633-5), as amended by the Unicode Standard Annex #27: Unicode 3.1 (http://www.unicode.org/reports/tr27/) and by the Unicode Standard Annex #28: Unicode 3.2 (http://www.unicode.org/reports/tr28/).

[URI] Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” STD 66, RFC 3986, January 2005.
[UTF-8] Yergeau, F., “UTF-8, a transformation format of ISO 10646,” STD 63, RFC 3629, November 2003.
[XMPP] Saint-Andre, P., “Extensible Messaging and Presence Protocol (XMPP): Core,” RFC 3920, October 2004.


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Authors' Addresses

  Peter Saint-Andre
  XMPP Standards Foundation
Email:  stpeter@jabber.org
  
  Alexey Melnikov
  Isode Limited
Email:  Alexey.Melnikov@isode.com


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Full Copyright Statement

Intellectual Property

Acknowledgment