rfc2184.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

   Content-Type: application/x-stuff
    title*1*=us-ascii'en'This%20is%20even%20more%20
    title*2*=%2A%2A%2Afun%2A%2A%2A%20
    title*3="isn't it!"

   Note that:

    (1)   Language and character set information only appear at
          the beginning of a given parameter value.

    (2)   Continuations do not provide a facility for using more
          than one character set or language in the same parameter
          value.

    (3)   A value presented using multiple continuations may
          contain a mixture of encoded and unencoded segments.

    (4)   The first segment of a continuation MUST be encoded if
          language and character set information are given.

    (5)   If the first segment of a continued parameter value is
          encoded the language and character set field delimiters MUST
          be present even when the fields are left blank.




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RFC 2184    MIME Parameter Value and Encoded Word Extensions August 1997


5.  Language specification in Encoded Words

   RFC 2047 provides support for non-US-ASCII character sets in RFC 822
   message header comments, phrases, and any unstructured text field.
   This is done by defining an encoded word construct which can appear
   in any of these places.  Given that these are fields intended for
   display, it is sometimes necessary to associate language information
   with encoded words as well as just the character set.  This
   specification extends the definition of an encoded word to allow the
   inclusion of such information.  This is simply done by suffixing the
   character set specification with an asterisk followed by the language
   tag.  For example:

        From: =?US-ASCII*EN?Q?Keith_Moore?= <[e-mail]>

6.  IMAP4 Handling of Parameter Values

   IMAP4 [RFC-2060] servers SHOULD decode parameter value continuations
   when generating the BODY and BODYSTRUCTURE fetch attributes.

7.  Modifications to MIME ABNF

   The ABNF for MIME parameter values given in RFC 2045 is:

   parameter := attribute "=" value

   attribute := token
                ; Matching of attributes
                ; is ALWAYS case-insensitive.

   This specification changes this ABNF to:

   parameter := regular-parameter / extended-parameter

   regular-parameter := regular-parameter-name "=" value

   regular-parameter-name := attribute [section]

   attribute := 1*attribute-char

   attribute-char := <any (US-ASCII) CHAR except SPACE, CTLs,
                     "*", "'", "%", or tspecials>

   section := initial-section / other-sections

   initial-section := "*1"





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RFC 2184    MIME Parameter Value and Encoded Word Extensions August 1997


   other-sections := "*" (("2" / "3" / "4" / "5" /
                           "6" / "7" / "8" / "9") *DIGIT) /
                          ("1" 1*DIGIT))

   extended-parameter := (extended-initial-name "="
                          extended-value) /
                         (extended-other-names "="
                          extended-other-values)

   extended-initial-name := attribute [initial-section] "*"

   extended-other-names := attribute other-sections "*"

   extended-initial-value := [charset] "'" [language] "'"
                             extended-other-values

   extended-other-values := *(ext-octet / attribute-char)

   ext-octet := "%" 2(DIGIT / "A" / "B" / "C" / "D" / "E" / "F")

   charset := <registered character set name>

   language := <registered language tag [RFC-1766]>

   The ABNF given in RFC 2047 for encoded-words is:

   encoded-word := "=?" charset "?" encoding "?" encoded-text "?="

   This specification changes this ABNF to:

   encoded-word := "=?" charset ["*" language] "?" encoded-text "?="


8.  Character sets which allow specification of language

   In the future it is likely that some character sets will provide
   facilities for inline language labelling. Such facilities are
   inherently more flexible than those defined here as they allow for
   language switching in the middle of a string.

   If and when such facilities are developed they SHOULD be used in
   preference to the language labelling facilities specified here. Note
   that all the mechanisms defined here allow for the omission of
   language labels so as to be able to accomodate this possible future
   usage.






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RFC 2184    MIME Parameter Value and Encoded Word Extensions August 1997


9.  Security Considerations

   This RFC does not discuss security issues and is not believed to
   raise any security issues not already endemic in electronic mail and
   present in fully conforming implementations of MIME.

10.  References

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

   [RFC-1766]
      Alvestrand, H., "Tags for the Identification of Languages", RFC
      1766, March 1995.

   [RFC-2045]
      Freed, N. and Borenstein, N., "Multipurpose Internet Mail
      Extensions (MIME) Part One: Format of Internet Message Bodies",
      RFC 2045, Innosoft, First Virtual Holdings, December 1996.

   [RFC-2046]
      Freed, N. and Borenstein, N., "Multipurpose Internet Mail
      Extensions (MIME) Part Two: Media Types", RFC 2046, Innosoft,
      First Virtual Holdings, December 1996.

   [RFC-2047]
      Moore, K., "Multipurpose Internet Mail Extensions (MIME) Part
      Three: Representation of Non-ASCII Text in Internet Message
      Headers", RFC 2047, University of Tennessee, December 1996.

   [RFC-2048]
      Freed, N., Klensin, J., Postel, J., "Multipurpose Internet Mail
      Extensions (MIME) Part Four: MIME Registration Procedures", RFC
      2048, Innosoft, MCI, ISI, December 1996.

   [RFC-2049]
      Freed, N. and Borenstein, N., "Multipurpose Internet Mail
      Extensions (MIME) Part Five: Conformance Criteria and Examples",
      RFC 2049, Innosoft, FIrst Virtual Holdings, December 1996.

   [RFC-2060]
      Crispin, M., "Internet Message Access Protocol - Version 4rev1",
      RFC 2060, December 1996.

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



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RFC 2184    MIME Parameter Value and Encoded Word Extensions August 1997


   [RFC-2130]
      Weider, C., Preston, C., Simonsen, K., Alvestrand, H., Atkinson,
      R., Crispin, M., Svanberg, P., "Report from the IAB Character Set
      Workshop", RFC 2130, April 1997.

   [RFC-2183]
      Troost, R., Dorner, S., and Moore, K., "Communicating Presentation
      Information in Internet Messages:  The Content-Disposition
      Header", RFC 2183, August 1997.

11.  Authors' Addresses

   Ned Freed
   Innosoft International, Inc.
   1050 East Garvey Avenue South
   West Covina, CA 91790
   USA
    tel: [phone]           fax: [phone]
    email: [e-mail]

   Keith Moore
   Computer Science Dept.
   University of Tennessee
   107 Ayres Hall
   Knoxville, TN 37996-1301
   USA
    email: [e-mail]
























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