[ новости /+++ | форум | теги | ]

Archive-Name: mail/mime-faq/mime0
Version: $Id: mime0,v 1.10 1997/02/08 00:32:20 jsweet Rel $
Posting-Frequency: monthly
X-Comment: since this is a meta-FAQ, and not part of the FAQ, 
   the archive-name is in a separate name space (mime0 instead of
   part0).

--
=======================
comp.mail.mime meta-FAQ
=======================
Help for MIME problems
~~~~~~
--

Contents
~~~~~~~~
  1)  Explanation
  2)  About the MIME FAQ
  3)  Conventions
  4)  Sample Problem Scenarios
  5)  Where else to find the MIME FAQ

--

1) Explanation
--------------
This is the comp.mail.mime meta-FAQ.  It's for those who have
unusually bad problems in dealing with MIME, and thus are unable to
read the comp.mail.mime FAQ articles, even though they're essentially
plain text.

This meta-FAQ also offers some general help for those who have 
various kinds of problems reading MIME messages.

Please note:
  
    Questions about mail systems, how to decode MIME parts on your
    computer, and other such issues, if not already answered in the
    FAQ, should be posted to comp.mail.mime or to the info-mime mailing
    list.

    Correspondence sent to the MIME FAQ maintainer primarily should 
    address information in the MIME FAQ---corrections, additions, or
    suggestions for improvement.
  
Also: neither the MIME meta-FAQ nor the MIME FAQ are intended to solve
every possible problem that you might have with your mail system.  If
you have general difficulties with your mail system, difficulties that
are _not_ specific to MIME, you should consider the possibility that a
more correct forum for your questions lies elsewhere, such as any of
these newsgroups:

     comp.mail.elm                      comp.mail.pine
     comp.mail.eudora.mac               comp.mail.sendmail
     comp.mail.eudora.ms-windows        comp.mail.zmail
     comp.mail.mh                       
     comp.mail.misc                     
     comp.mail.mush

--

2) About the MIME FAQ
---------------------
The comp.mail.mime FAQ itself, aka the MIME FAQ, attempts to answer
frequently asked questions about MIME, the multipurpose and
multi-media standard for Internet mail.

The MIME FAQ is divided into nine parts, using the MIME type
"message/partial".  That usually means nothing to MIME-challenged news
readers and mail user agents, which is usually just fine.  The MIME
FAQ is really just like an ordinary multipart FAQ---it uses plain
US-ASCII text and can be read like any other ordinary USENET article.

So ordinarily, the MIME FAQ is rendered as ordinary plain-text news or
mail, which is fine.  However, with mis-installed, incomplete, or
broken software, there are sometimes special problems encountered with
MIME messages.  While this meta-FAQ can't deal with all possible
problems, this meta-FAQ does enumerate some general scenarios that may
help you to understand whatever difficulties you're having.

Once again, for emphasis: the MIME FAQ is really just plain US-ASCII
text.  You should be able to read it one way or another.  The best
way, of course, is to get yourself some _working_ MIME-capable
software.  The MIME FAQ is a good source of information for finding
such software---assuming that you're able to read the MIME FAQ!

If not, read on...
--

3) Conventions
--------------
In this note, pointers to resources available via the Internet, such
as references to FTPable goodies, appear in WWW URL format.  URLs
beginning with "ftp:" refer to FTP sites.  For example:

ftp://domain.name/path/to/package

Those with FTP access, but without WWW access, may treat such
references as follows:

1. Log into host domain.name using anonymous FTP
2. Look for /path/to/package

An FTP reference usually lists only the distribution site; please
try your nearest FTP archive first.  Archie may be of some help
here.

URLs beginning with "http:" refer to WWW servers.  URLs beginning
with "gopher:" refer to gopher servers.

Internet browsing tools, such as Mosaic, know about URLs.
--

4) Sample Problem Scenarios
---------------------------
If you have problems reading a message in MIME format, it might be for
any of the reasons presented in the scenarios below.  In the case of
the MIME FAQ in particular, Scenario 7 may be especially meaningful.


Scenario 1:

You have mis-installed, incomplete, or broken software, and it
absolutely refuses to deal properly with a MIME message of any sort.

You're not necessarily entirely out of luck.  Your choices are to fix
or to replace your software.  There are many options available for
doing this, some of which are covered in the scenarios that follow.

To overcome the immediate problem, you might try to bypass your
software entirely, and look at the message in its "raw" state.

To read a raw message, save the message to a text file any way you
can, and use your favorite text editor (emacs, vi, or whatever) to
read the text file.


Scenario 2:

Your mail system outsmarted itself--it can handle some MIME stuff,
but not whatever it is you received.  

For this, you'll either need a smarter mail system, or you'll need to
tell the mail system how to handle whatever's in the message, or
you'll need to defeat the mail system entirely, and look at the
message in its "raw" state, as described in Scenario 1.  Scenario 4,
below, may offer some help too.


Scenario 3:

You received a "MIME-like" message that's almost, but not quite,
entirely unlike a real MIME message.  It looks similar enough to a
real MIME message that it breaks your mail software.  The SunOS
"mailtool" is notorious for sending such MIME-like messages.  Early
versions of Netscape (1.0? --aka "Mozilla") are also thought to be
guilty of this.

Conversion tools do exist for certain situations, e.g. sun2mime or
sun-to-mime.  Some work, some don't.  Whatever you find, it's probably
worth a try.  Otherwise, you'll either have to read the message with
the same mail program that generated such a thing, or content yourself
with the raw message.

    [ Steinar Bang <sb@metis.no> 2-Feb-1996 ]

    Q: How to make the Solaris [>=2.4?] OW Mailtool send attachments
       using MIME?
    
    A: Set "send rfc" in your .mailrc.


Scenario 4:

Your mail system doesn't understand MIME stuff at all.  

For this, you must either content yourself with the "raw" message, or
you can try to track down some tools to help you.  From John Gardiner
Myers <jgm+@CMU.EDU>, we have this advice:

    A minimalist MIME-reading program, munpack, is available from
    this URL:
  
      ftp://ftp.andrew.cmu.edu/pub/mpack/
  
    (i.e. use anonymous FTP to site ftp.andrew.cmu.edu, and look
    in the directory /pub/mpack.)
  
    The munpack program reads MIME messages and writes the decoded
    parts out to files.  Versions are available for Unix, MS-DOS,
    Macintosh, and Amiga platforms.

    In short, munpack is the MIME equivalent of uudecode/binhex.  

    { See appendix B.3 of the MIME FAQ for additional information
      about the mpack tool suite. }

    To decode a MIME message, first save it to a text file.  If
    possible, save it with all headers included.  Munpack can decode
    some MIME files when the headers are missing or incomplete, other
    files it cannot decode without having the information in the
    headers.  In general, messages which have a statement at the
    beginning that they are in MIME format can be decoded without the
    headers.  Messages which have been split into multiple parts
    generally require all headers in order to be reassembled and
    decoded.

    Some LAN-based mail systems and some mail providers (including
    America Online, as of the writing of this document) place the mail
    headers at the bottom of the message, instead of at the top of the
    message.  If you are having problems decoding a MIME message on
    such a system, you need to convert the mail back into the standard
    format by removing the system's nonstandard headers and moving the
    standard Internet headers to the top of the message (separated
    from the message body with a blank line).

    There must be exactly one message per file.  Munpack cannot deal
    with multiple messages in a single file, to decode things
    correctly it must know when one message ends and the next one
    begins.

See also Scenario 7, below.


Scenario 5:

You don't have all the necessary equipment to listen to an audio part,
or to view a graphical part, or to read text written in a foreign
character set.  

You're out of luck here; you can handle a lot of MIME stuff on a plain
old 24x80 ASCII terminal, but let's face it: if you're stuck with
something like that, YOU LOSE.  If someone asks you how to listen to
an audio message on a 24x80 ASCII terminal, cruel laughter may help to
enlighten the penitent.  ;-)


Scenario 6:

You _do_ have the necessary equipment to listen to an audio part, or
to view a graphical part, such as an audio capable workstation or an
X terminal, but your software doesn't know how to deal with whatever
those kinds of MIME contents are.

You may need additional software, such as xv, or audiotool, or
whatever.  If that software came with neither your hardware nor your
MIME-capable mail user agent or news reader, then you need to go
treasure hunting on the Internet, or get it from some commercial
source.  After finding and installing that software, you may also have
to do some additional configuration of your mail system or news
readers so that they know where to find these additional programs and
how to invoke them.

Note: the MIME FAQ itself has no graphics or audio in it; it's really
just plain text.


Scenario 7:

Your mail system doesn't want to show a "message/partial" (like the
comp.mail.mime FAQ articles).  

For this, you may need to assemble all the parts of the message
together.  Here is specific advice for various types of mailers:


Metamail and other mailcap-based mail user agents:

  The mailcap file needs an entry for message/partial.  One entry,
  contributed by Tim Goodwin, is this:

      message/partial; showpartial %s %{id} %{number} %{total}

  The showpartial command is part of the metamail distribution.
  Metamail is available from these URLs:

  ftp://ftp.bellcore.com/pub/nsb/mm2.7.tar.Z
        [The core metamail software]

  ftp://ftp.bellcore.com/pub/nsb/contrib2.7.tar.Z
        [Contributed software]

  ftp://ftp.bellcore.com/pub/nsb/mm2.7.dos.zip
        [MS-DOS binaries]


MH:

  You can assemble the message together using this command:

    mhn -store cur:9

  Alternatively, you can view the "raw" message by using this
  MH command:

    show -noshowproc


{ Brief advice for other specific mail systems is welcome. }


Scenario 8:

You've saved some MIME messages into files, and you have no idea
how to read them.

Here is specific advice for various types of mailers:

Metamail:

    [ Susan Gruber <sgruber@netcom.com> 13-Dec-1994 ]
  
    This is the command that I used to read my files:

      metamail -y filename

MH:

  mhn -show -file filename

Pine:

    [ "Mark H. Wood" <MWOOD@indyvax.iupui.edu> 18-Mar-1996 ]

    pine -F file


{ Brief advice for other specific mail systems welcome. }



Scenario 9:

Your mail system has automatically introduced MIME constructs that
your recipient cannot handle.

This is a tough problem.  Ned Freed correctly points out that some
kind of transformation of your message may be required in order to get
the message delivered at all.  This may occur because the message
contains 8-bit characters, which won't necessarily get through an
arbitrary mail system.  For another example, your message may have
been too large and had to be fragmented into smaller messages.

Other possibilities:

  - Your message went through a misdesigned or misconfigured mail
    system somewhere along the way. For example, Microsoft Exchange's
    SMTP component incorrectly uses quoted-printable encoding in an
    attempt to control message formatting.

  - MIME may not be involved at all; the message may be a "MIME-like"
    message (see Scenario 3, above) that is produced by a broken
    mail user agent.

It may be the case that you and your recipient cannot find a way to
exchange data via e-mail at all.  This is the kind of interoperability
problem that MIME can help to solve, but of course, compatible tools
are required on both ends.

Some individuals may try to fall back on uuencode, and that may work
in some cases, but there are many cases in which uuencode simply won't
work (see the MIME FAQ for details).

The best solution is for both parties to use correctly implemented
MIME-aware mail systems, or for both parties to have interoperating
tools for encoding and decoding data that use base64 or some other
format that will survive transport through problematic mail gateways.
The MIME FAQ contains references to many such tools.

--


5) Where else to find the MIME FAQ
----------------------------------

 - Many sites archive news.answers postings, including these:
   
   ftp://ftp.uu.net/usenet/news.answers/mail/mime-faq/
   ftp://rtfm.mit.edu/pub/usenet-by-group/news.answers/mail/mime-faq/
   
   If possible, please try to find a closer site; for example, by
   asking archie for "mime-faq".
   
 
 - This site makes an HTML version of the MIME FAQ available:
 
   http://www.cs.ruu.nl/wais/html/na-dir/mail/mime-faq/.html

 
========================================================================

[ end of MIME meta-FAQ ]

Партнёры:

Хостинг: