Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

当文書はインターネットコミュニティに役立つであらうインターネット標準プロトコルを提供するものであり、改良の為の議論や提案を求めてゐる。このプロトコル標準化の状況と現状については"Internet Official Protocol Standards"(STD1)の最新版を参照のこと。当文書は配布に関しての制限を設けてゐない。

Copyright Notice

   Copyright (C) The Internet Society (1998).  All Rights Reserved.


   This document defines the format of Uniform Resource Locators (URL)
   for designating electronic mail addresses. It is one of a suite of
   documents which replace RFC 1738, 'Uniform Resource Locators', and
   RFC 1808, 'Relative Uniform Resource Locators'. The syntax of
   'mailto' URLs from RFC 1738 is extended to allow creation of more RFC
   822 messages by allowing the URL to express additional header and
   body fields.

当文書は、電子メールアドレスを示すURLの形式を定義してゐる。当文書は、RFC1738(Uniform Resource Locators)、RFC1808(Relative Uniform Resource Locators)を書き換へる文書の一つである。RFC1738で定義されてゐるURLに於けるmailto構文は、URLで追加ヘッダと本文を表すことを認められた為、より多くの表現を可能とするやうRFC822を拡張したものである。

1. Introduction

   The mailto URL scheme is used to designate the Internet mailing
   address of an individual or service. In its simplest form, a mailto
   URL contains an Internet mail address.

mailtoスキームは、個人又は法人の電子メールアドレスを指定する為に使はれる。最も簡単な形式では、mailto URLは電子メールアドレスを含むこととなる。

   For greater functionality, because interaction with some resources
   may require message headers or message bodies to be specified as well
   as the mail address, the mailto URL scheme is extended to allow
   setting mail header fields and the message body.


2. Syntax of a mailto URL

   Following the syntax conventions of RFC 1738 [RFC1738], a "mailto"
   URL has the form:
     mailtoURL  =  "mailto:" [ to ] [ headers ]
     to         =  #mailbox
     headers    =  "?" header *( "&" header )
     header     =  hname "=" hvalue
     hname      =  *urlc
     hvalue     =  *urlc

RFC1738の構文規約に従ふとmailto URLの記述は以下のやうになる。


   "#mailbox" is as specified in RFC 822 [RFC822]. This means that it
   consists of zero or more comma-separated mail addresses, possibly
   including "phrase" and "comment" components. Note that all URL
   reserved characters in "to" must be encoded: in particular,
   parentheses, commas, and the percent sign ("%"), which commonly occur
   in the "mailbox" syntax.


   "hname" and "hvalue" are encodings of an RFC 822 header name and
   value, respectively. As with "to", all URL reserved characters must
   be encoded.


   The special hname "body" indicates that the associated hvalue is the
   body of the message. The "body" hname should contain the content for
   the first text/plain body part of the message. The mailto URL is
   primarily intended for generation of short text messages that are
   actually the content of automatic processing (such as "subscribe"
   messages for mailing lists), not general MIME bodies.

特別な"hname"である"body"は、"hvalue"と対になりメッセージ本文を表す。"body hname"はメッセージの一行目である"text/plain"本文の内容を含むべきである。mailto URLは一般的なMIME文としてではなく、実際には自動処理の内容である短いテキストメッセージ――例へば、メーリングリストのsubscribeメッセージのやうな――を生成する為に用意されてゐる。

   Within mailto URLs, the characters "?", "=", "&" are reserved.

mailto URLでは、"?"と"="、"&"は予約されてゐる。

   Because the "&" (ampersand) character is reserved in HTML, any mailto
   URL which contains an ampersand must be spelled differently in HTML
   than in other contexts.  A mailto URL which appears in an HTML
   document must use "&" instead of "&".

"&"(アンバサンド)はHTMLで予約済みなので、アンバサンドを含むmailto URLでも他の文字とは異なつた記述をしなければならない。HTML文書にmailto URLを記述する場合は、"&"の代わりに"&"と記述しなければならない。

   Also note that it is legal to specify both "to" and an "hname" whose
   value is "to". That is,


     is equivalent to


     is equivalent to



   8-bit characters in mailto URLs are forbidden. MIME encoded words (as
   defined in [RFC2047]) are permitted in header values, but not for any
   part of a "body" hname.

mailto URL中で8bit文字を使用することは禁止されてゐる。MIMEエンコードされた文字列――RFC2047で定義されてゐるやうな――は、ヘッダ内での記述は許可されてゐるが、"body" hnameでは許可されてゐない。

3. Semantics and operations

   A mailto URL designates an "internet resource", which is the mailbox
   specified in the address. When additional headers are supplied, the
   resource designated is the same address, but with an additional
   profile for accessing the resource. While there are Internet
   resources that can only be accessed via electronic mail, the mailto
   URL is not intended as a way of retrieving such objects

mailto URLは、アドレスで指定されたメールボックスとなるインターネットリソースを指定する。追加ヘッダが指定される際は、同じアドレスで指定されるリソースではあるが、リソースに接続するための追加情報が必要となる。電子メールでしか接続出来ないインターネットリソースもあるが、mailto URLはそのやうなリソースを自動的に検索する方法として考へられてゐる訳ではない。

   In current practice, resolving URLs such as those in the "http"
   scheme causes an immediate interaction between client software and a
   host running an interactive server. The "mailto" URL has unusual
   semantics because resolving such a URL does not cause an immediate
   interaction. Instead, the client creates a message to the designated
   address with the various header fields set as default. The user can
   edit the message, send this message unedited, or choose not to send
   the message. The operation of how any URL scheme is resolved is not
   mandated by the URL specifications.

現在の習慣では、httpスキームにあるやうなURLを解決することは、クライアントソフトウェアとサーバとなるホスト間で即時の相互連関を引き起こしてゐる。mailto URLは、解決されたURLが即時の相互連関を引き起こさないので、通常とは違ふ意味を持つ。代わりに、クライアントはデフォルトとして設定された各種ヘッダ情報を基に、指定されたアドレスへのメッセージを生成することとなる。利用者はメッセージを編集することも出来るし、編集せずにそのままメッセージを送信することも出来るし、メッセージを送信しないことも出来る。URLスキームをどのやうにして解決するかの操作方法は、URLの仕様書には明記されてゐない。

4. Unsafe headers

   The user agent interpreting a mailto URL SHOULD choose not to create
   a message if any of the headers are considered dangerous; it may also
   choose to create a message with only a subset of the headers given in
   the URL.  Only the Subject, Keywords, and Body headers are believed
   to be both safe and useful.

mailto URLを解釈するUAは、ヘッダに危険があると思はれるときはメッセージを作るべきではない。ただし、URLで与へられたヘッダ情報だけでメッセージを生成する選択を取つても良い。Subject、Keywords、Bodyヘッダのみが安全で且つ有用であると考へられてゐる。

   The creator of a mailto URL cannot expect the resolver of a URL to
   understand more than the "subject" and "body" headers. Clients that
   resolve mailto URLs into mail messages should be able to correctly
   create RFC 822-compliant mail messages using the "subject" and "body"

mailto URLを記述する者は、"subject"と"body"以外のヘッダが解決されることを期待出来ない。mailto URLをメールメッセージとして解決するクライアントは、"subject"と"body"ヘッダを利用してRFC822に基づくメールメッセージを正しく生成出来るやうにすべきである。

5. Encoding

   RFC 1738 requires that many characters in URLs be encoded. This
   affects the mailto scheme for some common characters that might
   appear in addresses, headers or message contents. One such character
   is space (" ", ASCII hex 20). Note the examples above that use "%20"
   for space in the message body.  Also note that line breaks in the
   body of a message MUST be encoded with "%0D%0A".

RFC1738では、URL中の多くの文字をエンコードすることを要求してゐる。これはmailtoスキーム内のアドレスやヘッダ、本文内に現れると予想される幾つかの一般的な文字に影響を与へる。例へばスペース(" "、ASCII 0x20)が然うである。この例ではメッセージ本文のスペースの記述に"%20"を使用してゐることに注意が必要である。又、メッセージ本文中の改行は"%0D%0A"とエンコードされなければならないことにも注意が必要である。

   People creating mailto URLs must be careful to encode any reserved
   characters that are used in the URLs so that properly-written URL
   interpreters can read them. Also, client software that reads URLs
   must be careful to decode strings before creating the mail message so
   that the mail messages appear in a form that the recipient will
   understand. These strings should be decoded before showing the user
   the message.

mailto URLを記述する者は、正確なURLインタプリタが解釈出来るやう、URLで利用される他の予約された文字をエンコードすることに気を付けなければならない。又、URLを読むクライアントソフトウェアは、受信者が理解出来る形式にメールメッセージがなるやうに、メールメッセージを生成する前に文字列をデコードすることに気を付けなければならない。これらの文字列は利用者にメッセージを提示する前にデコードされるべきである。

   The mailto URL scheme is limited in that it does not provide for
   substitution of variables. Thus, a message body that must include a
   user's email address can not be encoded using the mailto URL. This
   limitation also prevents mailto URLs that are signed with public keys
   and other such variable information.

mailto URLスキームは変数の代入を提供しない範囲に限られる。従つて、利用者の電子メールアドレスを含まなければならない本文が、mailto URLを利用してエンコードされることはない。この制限は、mailto URLがpublic keysや他の可変的な情報で署名されることを妨げてゐる。

6. Examples

   URLs for an ordinary individual mailing address:


   A URL for a mail response system that requires the name of the file
   in the subject:


   A mail response system that requires a "send" request in the body:


   A similar URL could have two lines with different "send" requests (in
   this case, "send current-issue" and, on the next line, "send index".)

似たやうなURLで二行の異なる"send"要求を作ることが出来る。当例は"send current-issue"とその次の行に"send index"となつてゐる。


   An interesting use of your mailto URL is when browsing archives of
   messages. Each browsed message might contain a mailto URL like:

メッセージのアーカイブを見る際にmailto URLの興味的な利用方法がある。メッセージはそれぞれ<mailto:foobar@example.com?In-Reply-To=%3c3469A91.D10AF4C@example.com>のやうなmailto URLを含むかも知れない。

   A request to subscribe to a mailing list:


   A URL for a single user which includes a CC of another user:


   Another way of expressing the same thing:


   Note the use of the "&" reserved character, above. The following
   example, by using "?" twice, is incorrect:
     <mailto:joe@example.com?cc=bob@example.com?body=hello>   ; WRONG!



   According to RFC 822, the characters "?", "&", and even "%" may occur
   in addr-specs. The fact that they are reserved characters in this URL
   scheme is not a problem: those characters may appear in mailto URLs,
   they just may not appear in unencoded form. The standard URL encoding
   mechanisms ("%" followed by a two-digit hex number) must be used in
   certain cases.

RFC822に従へば、"?"、"&"、そして"%"でさえアドレス空間に使ふことが出来る。URLスキームでこれらの文字が予約されてゐる事実は問題にならない。エンコードされてゐない形式で使用するから拙いのであり、mailto URLにこれらの文字を使用することは問題とならない。そのやうな場合には標準的なURLをエンコードする仕組み――%に続き2桁の値を16進表記する方法――が使はれなければならない。

   To indicate the address "gorby%kremvax@example.com" one would do:


   To indicate the address "unlikely?address@example.com", and include
   another header, one would do:


   As described above, the "&" (ampersand) character is reserved in HTML
   and must be replacded with "&amp;". Thus, a complex URL that has
   internal ampersands might look like:
     <a href="mailto:?to=joe@xyz.com&amp;cc=bob@xyz.com&amp;body=hello">
     mailto:?to=joe@xyz.com&amp;cc=bob@xyz.com&amp;body=hello</a> to
     send a greeting message to <i>Joe and Bob</i>.


     <a href="mailto:?to=joe@xyz.com&amp;cc=bob@xyz.com&amp;body=hello">
     mailto:?to=joe@xyz.com&amp;cc=bob@xyz.com&amp;body=hello</a> to
     send a greeting message to <i>Joe and Bob</i>.

7. Security Considerations

   The mailto scheme can be used to send a message from one user to
   another, and thus can introduce many security concerns. Mail messages
   can be logged at the originating site, the recipient site, and
   intermediary sites along the delivery path. If the messages are not
   encoded, they can also be read at any of those sites.


   A mailto URL gives a template for a message that can be sent by mail
   client software. The contents of that template may be opaque or
   difficult to read by the user at the time of specifying the URL.
   Thus, a mail client should never send a message based on a mailto URL
   without first showing the user the full message that will be sent
   (including all headers that were specified by the mailto URL), fully
   decoded, and asking the user for approval to send the message as
   electronic mail. The mail client should also make it clear that the
   user is about to send an electronic mail message, since the user may
   not be aware that this is the result of a mailto URL.

mailto URLはメールクライアントソフトウェアによつて送ることが出来るメッセージの雛型を提供する。URLを指定する際には、雛型の内容は不透明であるか、利用者にとつて読み辛いものであるかも知れない。従って、メールクライアントは決して、まず最初に送信しやうとしてゐるメッセージの全文――mailto URLによつて指定された全てのヘッダを含む――を複合化して提示し、利用者にそのメッセージを電子メールとして送信しても良いか如何かの同意を得ることなしに、mailto URLに基づくメッセージを送るべきではない。又、mailto URLによつて電子メールメッセージを送信しやうとしてゐる事に利用者が気が付いてゐないかも知れないので、メールクライアントは利用者にはつきりと解るやうにするべきである。

   A mail client should never send anything without complete disclosure
   to the user of what is will be sent; it should disclose not only the
   message destination, but also any headers. Unrecognized headers, or
   headers with values inconsistent with those the mail client would
   normally send should be especially suspect. MIME headers (MIME-
   Version, Content-*) are most likely inappropriate, as are those
   relating to routing (From, Bcc, Apparently-To, etc.)


   Note that some headers are inherently unsafe to include in a message
   generated from a URL. For example, headers such as "From:", "Bcc:",
   and so on, should never be interpreted from a URL. In general, the
   fewer headers interpreted from the URL, the less likely it is that a
   sending agent will create an unsafe message.


   Examples of problems with sending unapproved mail include:
     * mail that breaks laws upon delivery, such as making illegal
     * mail that identifies the sender as someone interested in breaking
     * mail that identifies the sender to an unwanted third party;
     * mail that causes a financial charge to be incurred on the sender;
     * mail that causes an action on the recipient machine that causes
       damage that might be attributed to the sender.


   Programs that interpret mailto URLs should ensure that the SMTP
   "From" address is set and correct.

mailto URLを解釈するプログラムは、SMTPのFromアドレスが定められてゐることと、それが正しいことを保証すべきである。

8. IANA Considerations

   This document changes the definition of the mailto: URI scheme; any
   registry of URI schemes should refer to this document rather than its
   predecessor, RFC 1738.

この文書はmailto: URIスキームの定義を変更するものである。URIスキームの記載には従来のRFC1738ではなく、当文書を参照すべきである。

9. References

   [RFC822] Crocker, D., "Standard for the Format of ARPA Internet Text
            Messages", STD 11, RFC 822, August 1982.

   [RFC1738] Berners-Lee, T., Masinter, L., and M. McCahill, Editors,
             "Uniform Resource Locators (URL)", RFC 1738, December 1994.

   [RFC1808] Fielding, R., "Relative Uniform Resource Locators", RFC
             1808, June 1995.

   [RFC2047] Moore, K., "MIME Part Three: Message Header Extensions for
             Non-ASCII Text", RFC 2047, November 1996.

A. Change from RFC 1738

   RFC 1738 defined only a simple 'mailto' with no headers, just an
   addr-spec (not a full mailbox.)  However, required usage and
   implementation has led to the development of an extended syntax that
   included more header fields.


B. Acknowledgments

   This document was derived from RFC 1738 and RFC 1808 [RFC1808]; the
   acknowledgments from those specifications still applies.


   The following people contributed to this memo or had and discussed
   similar ideas for mailto.

   Harald Alvestrand
   Bryan Costales
   Steve Dorner
   Al Gilman
   Mark Joseph
   Laurence Lundblade
   Keith Moore
   Jacob Palme
   Michael Patton


C. Author Contact Information

   Paul E. Hoffman
   Internet Mail Consortium
   127 Segre Place
   Santa Cruz, CA  95060 USA

   EMail: phoffman@imc.org

   Larry Masinter
   Xerox Corporation
   3333 Coyote Hill Road
   Palo Alto, CA 94304 USA

   EMail: masinter@parc.xerox.com

   Jamie Zawinski
   Netscape Communications Corp.
   501 East Middlefield Road
   Mountain View, CA 94043 USA

   EMail: jwz@netscape.com

D. Full Copyright Statement

   Copyright (C) The Internet Society (2003).  All Rights Reserved.
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   The limited permissions granted above are perpetual and will not be
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   This document and the information contained herein is provided on an



Copyright (C) 2006 七鍵 key@do.ai 初版:2006年04月12日 最終更新:2006年04月14日