mingw/html/ext/Encode/lib/Encode/MIME/Header.html

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   5 <title>Encode::MIME::Header -- MIME 'B' and 'Q' header encoding</title>
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  13 <big><strong><span class="block">&nbsp;Encode::MIME::Header -- MIME 'B' and 'Q' header encoding</span></strong></big>
  14 </td></tr>
  15 </table>
  16
  17 <p><a name="__index__"></a></p>
  18 <!-- INDEX BEGIN -->
  19
  20 <ul>
  21
  22         <li><a href="#name">NAME</a></li>
  23         <li><a href="#synopsis">SYNOPSIS</a></li>
  24         <li><a href="#abstract">ABSTRACT</a></li>
  25         <li><a href="#description">DESCRIPTION</a></li>
  26         <li><a href="#bugs">BUGS</a></li>
  27         <li><a href="#see_also">SEE ALSO</a></li>
  28 </ul>
  29 <!-- INDEX END -->
  30
  31 <hr />
  32 <p>
  33 </p>
  34 <h1><a name="name">NAME</a></h1>
  35 <p>Encode::MIME::Header -- MIME 'B' and 'Q' header encoding</p>
  36 <p>
  37 </p>
  38 <hr />
  39 <h1><a name="synopsis">SYNOPSIS</a></h1>
  40 <pre>
  41     use Encode qw/encode decode/;
  42     $utf8   = decode('MIME-Header', $header);
  43     $header = encode('MIME-Header', $utf8);</pre>
  44 <p>
  45 </p>
  46 <hr />
  47 <h1><a name="abstract">ABSTRACT</a></h1>
  48 <p>This module implements RFC 2047 Mime Header Encoding.  There are 3
  49 variant encoding names; <code>MIME-Header</code>, <code>MIME-B</code> and <code>MIME-Q</code>.  The
  50 difference is described below</p>
  51 <pre>
  52               decode()          encode()
  53   ----------------------------------------------
  54   MIME-Header Both B and Q      =?UTF-8?B?....?=
  55   MIME-B      B only; Q croaks  =?UTF-8?B?....?=
  56   MIME-Q      Q only; B croaks  =?UTF-8?Q?....?=</pre>
  57 <p>
  58 </p>
  59 <hr />
  60 <h1><a name="description">DESCRIPTION</a></h1>
  61 <p>When you decode(=?<em>encoding</em>?<em>X</em>?<em>ENCODED WORD</em>?=), <em>ENCODED WORD</em>
  62 is extracted and decoded for <em>X</em> encoding (B for Base64, Q for
  63 Quoted-Printable). Then the decoded chunk is fed to
  64 decode(<em>encoding</em>).  So long as <em>encoding</em> is supported by Encode,
  65 any source encoding is fine.</p>
  66 <p>When you encode, it just encodes UTF-8 string with <em>X</em> encoding then
  67 quoted with =?UTF-8?<em>X</em>?....?= .  The parts that RFC 2047 forbids to
  68 encode are left as is and long lines are folded within 76 bytes per
  69 line.</p>
  70 <p>
  71 </p>
  72 <hr />
  73 <h1><a name="bugs">BUGS</a></h1>
  74 <p>It would be nice to support encoding to non-UTF8, such as =?ISO-2022-JP?
  75 and =?ISO-8859-1?= but that makes the implementation too complicated.
  76 These days major mail agents all support =?UTF-8? so I think it is
  77 just good enough.</p>
  78 <p>Due to popular demand, 'MIME-Header-ISO_2022_JP' was introduced by
  79 Makamaka.  Thre are still too many MUAs especially cellular phone
  80 handsets which does not grok UTF-8.</p>
  81 <p>
  82 </p>
  83 <hr />
  84 <h1><a name="see_also">SEE ALSO</a></h1>
  85 <p><a href="file://C|\msysgit\mingw\html/lib/Encode.html">the Encode manpage</a></p>
  86 <p>RFC 2047, <a href="http://www.faqs.org/rfcs/rfc2047.html">http://www.faqs.org/rfcs/rfc2047.html</a> and many other
  87 locations.</p>
  88 <table border="0" width="100%" cellspacing="0" cellpadding="3">
  89 <tr><td class="block" style="background-color: #cccccc" valign="middle">
  90 <big><strong><span class="block">&nbsp;Encode::MIME::Header -- MIME 'B' and 'Q' header encoding</span></strong></big>
  91 </td></tr>
  92 </table>
  93
  94 </body>
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  96 </html>