Network Working Group M. Duerst Internet-Draft Aoyama Gakuin University Updates: XXXX (if approved)
February 18, 2008March 9, 2009 Intended status: Experimental Expires: August 21, 2008September 10, 2009 An update to the mailto URI scheme for Email Address Internationalization draft-ietf-eai-mailto-00draft-ietf-eai-mailto-01 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claimsThis Internet-Draft is submitted to IETF in full conformance with the provisions of which heBCP 78 and BCP 79. This document may contain material from IETF Documents or she is aware have beenIETF Contributions published or willmade publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. 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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 August 21, 2008.September 10, 2009. Copyright Notice Copyright (C) The(c) 2009 IETF Trust (2008).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 This document updates the definition of the mailto: URI Scheme for use with internationalized email addresses. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Syntax of a mailto URI . . . . . . . . . . . . . . . . . . . . 3 3. Deployment . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1. Examples Using UTF-8-Based Percent-Encoding . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 7. AcknowledgmentsChange Log . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7.1. Changes between draft 00 and draft 01 . . . . . . . . . . . 5 8. Normative ReferencesAcknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5 Author's Address9. Normative References . . . . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . 6 Intellectual Property and Copyright Statements. . . . . . . . . . 7. . . . . . . 6 1. Introduction [RFCXXXX] defines the mailto URI scheme. It allows for the encoding of non-ASCII characters in arbitrary header fields and in the right- hand side of email addresses, but not in the left-hand side of email addresses. This document experimentally extends the syntax of mailto: URIs to allow the encoding of non-ASCII characters on the left-hand side of email addresses, and the designation of fallback addresses. It also defines the mapping of mailto: URIs to email messages using EAI features. In order to keep this memo short and to reduce accidental differences, where possible this memo does not repeat the provisions in [RFCXXXX]. Whenever this memo does not specify something different, the provisions in [RFCXXXX] MUST be followed. In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in [RFC2119]. Please send comments on this document to the mailing list email@example.com. 2. Syntax of a mailto URI The syntax of the mailto URI given in [RFCXXXX] is changed to use the "mailbox" production in [RFCYYYY][RFC5335] instead of [RFC2822].[RFC5322]. Following the syntax conventions of [STD66], and using the ABNF syntax defined in [RFC5234], a "mailto" URI has the form: mailtoURI = "mailto:" [ to ] [ headers ] to = [ mailbox *("%2C" mailbox ) ] headers = "?" header *( "&" header ) header = hname "=" hvalue hname = *urlc hvalue = *urlc "mailbox" is as specified in [RFCYYYY],[RFC5335], i.e. it is a mail address, possibly including "phrase" and "comment" components. It also possibly includes the alt-address component of angle-addr as specified in [RFCYYYY].[RFC5335]. However, the following changes apply: 1. All characters that can appear in "mailbox" but are reserved or not allowed in URIs have to be percent-encoded. Examples are parentheses, commas, the less-than and greater-than signs ("<" and ">") and the percent sign ("%"), which commonly occur in the "mailbox" syntax. 2. Percent-encoding can be used to denote non-ASCII characters, in order to denote an internationalized email address. Before applying percent-encoding, it has to be made sure that the email address is encoded in UTF-8 [STD63]. This makes the mailto URI directly usable with EAI [RFC4952] and makes it compatible with IRIs [RFC3987]. "hname" is an encoding of an [RFC2822][RFC5322] header name. "hvalue" is an encoding of a [RFCYYYY][RFC5335] header value. As with "to", all URI reserved characters must be encoded. Non-ASCII characters can be encoded in "hvalue" as follows: 1. Non-ASCII characters SHOULD be encoded by first encoing the characters according to UTF-8 [STD63], and then encoding each octet of the corresponding UTF-8 octet sequence using percent- encoding, to result in URI characters. This makes the mailto URI directly usable with EAI [RFC4952] and makes it compatible with IRIs [RFC3987]. 2. MIME encoded words (as defined in [RFC2047]) MAY be used in header values, but MUST NOT be used in an hvalue of a "body" hname. 3. Deployment For the forseeable future, URIs conforming to this memo should only be used in contexts where it can be expected that the recipient can create email messages conforming to the EAI framework [RFC4952]. 4. Examples 4.1. Examples Using UTF-8-Based Percent-Encoding Sending a mail to the user "coffee" (in French, i.e. "cafe" where the final e is an e-acute) at the mailhost "natto".example.org ("natto" is Japanese, written with the two Unicode characters U+7D0D and U+8C46). mailto:%3Ccaf%C3%A9@%E7%B4%8D%E8%B1%86.example.org%3E Please note that if the left-hand side of the mail address contains non-ASCII characters, the less-than and greater-than sign (angle brackets, escaped as %3C and %3E) are mandatory. The above example, with an "alt-address" (see [RFCYYYY])added:[RFC5335])added: mailto:%3Ccaf%C3%A9@%E7%B4%8D%E8%B1%86.example.org%20%3Ccafe@ natto.example.org%3E%3E Please note that at least a space is needed before the "alt-address", and that such a space also has to be percent-encoded. Also, please note that the URI above is separated into two lines to conform to formatting conventions, but that there is no line bleak in actual use. 5. Security Considerations The security considerations of [RFCXXXX], [RFCYYYY],[RFC5335], and [RFC4952] apply, please read them carefully. There are no known security threats specific to this memo alone. 6. IANA Considerations This document updates the definition of the mailto: URI scheme; in the registry of URI schemes, a reference to this memo should be added to the current reference. 7. Change Log Note to RFC Editor: Please completely remove this section before publication. 7.1. Changes between draft 00 and draft 01 o Updated references ([RFC5322], [RFC5335],...). o Changed IPR text to pre5378Trust200902. 8. Acknowledgments This document is the product of the EAI WG of the IETF. We thank all the members of this WG. 8.9. Normative References [RFC2047] Moore, K., "MIME Part Three: Message Header Extensions for Non-ASCII Text", RFC 2047, November 1996. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2822] Resnik, P., "Internet Message Format", RFC 2822, April 2001.[RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource Identifiers (IRIs)", RFC 3987, January 2005. [RFC4952] Klensin, J. and Y. Ko, "Overview and Framework for Internationalized Email", RFC 4952, July 2007. [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, November 1997.January 2008. [RFC5322] Resnik, P., "Internet Message Format", RFC 5322, October 2008. [RFC5335] Abel, Y., "Internationalized Email Headers (work in progress)", September 2008. [RFCXXXX] Duerst, M., Masinter, L., and J. Zawinski, "The 'mailto' URI Scheme (work in progress)", January 2008. [RFCYYYY] Abel, Y., "Internationalized Email Headers (work in progress)", February 2008.March 2009. [STD63] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, November 2003. [STD66] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, April 2004. Author's Address Martin Duerst (Note: Please write "Duerst" with u-umlaut wherever possible, for example as "Dürst" in XML and HTML.) Aoyama Gakuin University 5-10-1 Fuchinobe Sagamihara, Kanagawa 229-8558 Japan Phone: +81 42 759 6329 Fax: +81 42 759 6495 Email: mailto:firstname.lastname@example.org URI: http://www.sw.it.aoyama.ac.jp/D%C3%BCrst/ Full Copyright Statement Copyright (C) The IETF Trust (2008). 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