rfc5092.txt

广泛使用的邮件服务器！同时

   imessagepart     = imailbox-ref iuid [isection] [ipartial]

   ipartial         = "/" ipartial-only

   ipartial-only    = ";PARTIAL=" partial-range

   isection         = "/" isection-only

   isection-only    = ";SECTION=" enc-section

   iserver          = [iuserinfo "@"] host [ ":" port ]
                           ; This is the same as "authority" defined
                           ; in [URI-GEN].  See [URI-GEN] for "host"
                           ; and "port" definitions.

   iuid             = "/" iuid-only

   iuid-only        = ";UID=" nz-number
                  ; See [IMAP4] for "nz-number" definition

   iuserinfo        = enc-user [iauth] / [enc-user] iauth
                                ; conforms to the generic syntax of
                                ; "userinfo" as defined in [URI-GEN].

   partial-range    = number ["." nz-number]
                  ; partial FETCH.  The first number is
                           ; the offset of the first byte,
                           ; the second number is the length of
                           ; the fragment.

   uidvalidity      = ";UIDVALIDITY=" nz-number
                       ; See [IMAP4] for "nz-number" definition









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RFC 5092                    IMAP URL Scheme                November 2007


12.  IANA Considerations

   IANA has updated the "imap" definition in the "Uniform Resource
   Identifier scheme registry" to point to this document.

   The registration template (as per [URI-REG]) is specified in Section
   12.1 of this document.

12.1.  IANA Registration of imap: URI Scheme

   This section provides the information required to register the imap:
   URI scheme.

   URI scheme name: imap

   Status: permanent

   URI scheme syntax:

      See Section 11 of [RFC5092].

   URI scheme semantics:

      The imap: URI scheme is used to designate IMAP servers, mailboxes,
      messages, MIME bodies [MIME] and their parts, and search programs
      on Internet hosts accessible using the IMAP protocol.

      There is no MIME type associated with this URI.

   Encoding considerations:

      See Section 8 of [RFC5092].

   Applications/protocols that use this URI scheme name:

      The imap: URI is intended to be used by applications that might
      need access to an IMAP mailstore.  Such applications may include
      (but are not limited to) IMAP-capable web browsers; IMAP clients
      that wish to access a mailbox, message, or edit a message on the
      server using [CATENATE]; [SUBMIT] clients and servers that are
      requested to assemble a complete message on submission using
      [BURL].

   Interoperability considerations:

      A widely deployed IMAP client Netscape Mail (and possibly
      Mozilla/Thunderbird/Seamonkey) uses a different imap: scheme
      internally.



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RFC 5092                    IMAP URL Scheme                November 2007


   Security considerations:

      See Security Considerations (Section 10) of [RFC5092].

   Contact:

      Alexey Melnikov <[e-mail]>

   Author/Change controller:

      IESG

   References:

      [RFC5092] and [IMAP4].

13. References

13.1.  Normative References

   [KEYWORDS]   Bradner, S., "Key words for use in RFCs to Indicate
                Requirement Levels", BCP 14, RFC 2119, March 1997.

   [IMAP4]      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.

   [ABNF]       Crocker, D., Ed., and P. Overell, "Augmented BNF for
                Syntax Specifications: ABNF", RFC 4234, October 2005.

   [MIME]       Freed, N. and N. Borenstein, "Multipurpose Internet Mail
                Extensions (MIME) Part One: Format of Internet Message
                Bodies", RFC 2045, November 1996.

   [URI-GEN]    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.

   [NAMESPACE]  Gahrns, M. and C. Newman, "IMAP4 Namespace", RFC 2342,
                May 1998.

   [LITERAL+]   Myers, J., "IMAP4 non-synchronizing literals", RFC 2088,
                January 1997.



Melnikov & Newman           Standards Track                    [Page 22]

RFC 5092                    IMAP URL Scheme                November 2007


   [ANONYMOUS]  Zeilenga, K., "Anonymous Simple Authentication and
                Security Layer (SASL) Mechanism", RFC 4505, June 2006.

   [DATETIME]   Klyne, G. and C. Newman, "Date and Time on the Internet:
                Timestamps", RFC 3339, July 2002.

   [URLAUTH]    Crispin, M., "Internet Message Access Protocol (IMAP) -
                URLAUTH Extension", RFC 4467, May 2006.

13.2.  Informative References

   [SUBMIT]     Gellens, R. and J. Klensin, "Message Submission for
                Mail", RFC 4409, April 2006.

   [BURL]       Newman, C., "Message Submission BURL Extension", RFC
                4468, May 2006.

   [CATENATE]   Resnick, P., "Internet Message Access Protocol (IMAP)
                CATENATE Extension", RFC 4469, April 2006.

   [SASL]       Melnikov, A., Ed., and K. Zeilenga, Ed., "Simple
                Authentication and Security Layer (SASL)", RFC 4422,
                June 2006.

   [GSSAPI]     Melnikov, A., Ed., "The Kerberos V5 ("GSSAPI") Simple
                Authentication and Security Layer (SASL) Mechanism", RFC
                4752, November 2006.

   [DIGEST-MD5] Leach, P. and C. Newman, "Using Digest Authentication as
                a SASL Mechanism", RFC 2831, May 2000.

   [URI-REG]    Hansen, T., Hardie, T., and L. Masinter, "Guidelines and
                Registration Procedures for New URI Schemes", BCP 115,
                RFC 4395, February 2006.

















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RFC 5092                    IMAP URL Scheme                November 2007


Appendix A.  Sample Code

   Here is sample C source code to convert between URL paths and IMAP
   mailbox names, taking into account mapping between IMAP's modified
   UTF-7 [IMAP4] and hex-encoded UTF-8, which is more appropriate for
   URLs.  This code has not been rigorously tested nor does it
   necessarily behave reasonably with invalid input, but it should serve
   as a useful example.  This code just converts the mailbox portion of
   the URL and does not deal with parameters, query, or server
   components of the URL.

/* Copyright (C) The IETF Trust (2007).  This version of
   sample C code is part of RFC XXXX; see the RFC itself
   for full legal notices.

   Regarding this sample C code (or any portion of it), the authors
   make no guarantees and are not responsible for any damage
   resulting from its use.  The authors grant irrevocable permission
   to anyone to use, modify, and distribute it in any way that does
   not diminish the rights of anyone else to use, modify, and
   distribute it, provided that redistributed derivative works do
   not contain misleading author or version information.

   Derivative works need not be licensed under similar terms.
 */

#include <stdio.h>
#include <string.h>

/* hexadecimal lookup table */
static const char hex[] = "0123456789ABCDEF";

#define XX 127
/*
 * Table for decoding hexadecimal in %encoding
 */
static const char index_hex[256] = {
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
     0, 1, 2, 3,  4, 5, 6, 7,  8, 9,XX,XX, XX,XX,XX,XX,
    XX,10,11,12, 13,14,15,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,10,11,12, 13,14,15,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,



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RFC 5092                    IMAP URL Scheme                November 2007


    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
};
#define HEXCHAR(c)  (index_hex[(unsigned char)(c)])

/* "gen-delims" excluding "/" but including "%" */
#define GENERAL_DELIMS_NO_SLASH     ":?#[]@" "%"

/* "gen-delims" (excluding "/", but including "%")
   plus subset of "sub-delims" */
#define GENERAL_UNSAFE_NO_SLASH     GENERAL_DELIMS_NO_SLASH ";&=+"
#define OTHER_UNSAFE                " \"<>\\^`{|}"

/* URL unsafe printable characters */
static const char mailbox_url_unsafe[] = GENERAL_UNSAFE_NO_SLASH
                                         OTHER_UNSAFE;

/* UTF7 modified base64 alphabet */
static const char base64chars[] =
  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";

#define UNDEFINED 64

/* UTF16 definitions */
#define UTF16MASK   0x03FFUL
#define UTF16SHIFT  10
#define UTF16BASE   0x10000UL
#define UTF16HIGHSTART   0xD800UL
#define UTF16HIGHEND     0xDBFFUL
#define UTF16LOSTART     0xDC00UL
#define UTF16LOEND  0xDFFFUL

/* Convert an IMAP mailbox to a URL path
 *  dst needs to have roughly 4 times the storage space of src
 *    Hex encoding can triple the size of the input
 *    UTF-7 can be slightly denser than UTF-8
 *     (worst case: 8 octets UTF-7 becomes 9 octets UTF-8)
 */
void MailboxToURL(char *dst, char *src)
{
    unsigned char c, i, bitcount;
    unsigned long ucs4, utf16, bitbuf;
    unsigned char base64[256], utf8[6];

    /* initialize modified base64 decoding table */



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RFC 5092                    IMAP URL Scheme                November 2007


    memset(base64, UNDEFINED, sizeof (base64));
    for (i = 0; i < sizeof (base64chars); ++i) {
     base64[(int) base64chars[i]] = i;
    }

    /* loop until end of string */
    while (*src != '\0') {
     c = *src++;
     /* deal with literal characters and &- */
     if (c != '&' || *src == '-') {
         /* NB: There are no "URL safe" characters after the '~' */
         if (c < ' ' || c > '~' ||
             strchr(mailbox_url_unsafe, c) != NULL) {
          /* hex encode if necessary */
          dst[0] = '%';
          dst[1] = hex[c >> 4];
          dst[2] = hex[c & 0x0f];
          dst += 3;
         } else {
          /* encode literally */
          *dst++ = c;
         }
         /* skip over the '-' if this is an &- sequence */
         if (c == '&') ++src;

     } else {
        /* convert modified UTF-7 -> UTF-16 -> UCS-4 -> UTF-8 -> HEX */
         bitbuf = 0;
         bitcount = 0;
         ucs4 = 0;
         while ((c = base64[(unsigned char) *src]) != UNDEFINED) {
          ++src;
          bitbuf = (bitbuf << 6) | c;
          bitcount += 6;