电子邮件源码分析

Question

Message-ID: <000e01c34d24$2176c8a0$017d7d7d@mistruster>
From: Webmaster <[email protected]>
To: "Webmaster" <[email protected]>
Subject: This is a test.
Date: Fri, 18 Jul 2003 20:00:00 +0800
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="xxxxxxxxxxxxxxxx"This is a multi-part message in MIME format.--xxxxxxxxxxxxxxxx
Content-Type: multipart/related;
type="multipart/alternative";
boundary="yyyyyyyyyyyyyyyy"
--yyyyyyyyyyyyyyyy
Content-Type: multipart/alternative;
boundary="wwwwwwwwwwwwwwww"
--wwwwwwwwwwwwwwww
Content-Type: text/plain;
charset="gb2312"
Content-Transfer-Encoding: base64SGVsbG86DQogIFRoaXMgaXMgYSB0ZXN0Lg0KaHR0cDovL3d3dy5taXN0cnVzdGVyLmNvbS9tYWls
Lw0K--wwwwwwwwwwwwwwww
Content-Type: text/html;
charset="gb2312"
Content-Transfer-Encoding: base64PCFET0NUWVBFIEhUTUwgUFVCTElDICItLy9XM0MvL0RURCBIVE1MIDQuMCBUcmFuc2l0aW9uYWwv
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VE1MPg0K--wwwwwwwwwwwwwwww--

Answer 1

--yyyyyyyyyyyyyyyy
Content-Type: image/gif;
name="club.gif"
Content-Transfer-Encoding: base64
Content-ID: <000801c34d24$215536e0$017d7d7d@mistruster>R0lGODlhRAA8APcAAGF4taTE5PH6/pWYljs8O5Oy2SdKEfX19djb3Mnt/dTx/uT2/rm9uu3u76Km
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dQQQg+vY8qk7AEa3Un2EBiSxpys4AXii04N856uHOoz0dYeqxF7i8Afo/oMBeHJAPBLR3j0FL1Bq
KRQZ9GK+vQjBDM6baTtCMYgKVKd+Y7FFIn5nBycMby1xaEIYZkE+WC1PCOlDgcEAxwwY2OAFESPq
F7CXhjRwohXca0ISxgA+7SqwfHhhsDvUt+L2RcAGaHCAwTB1vezhAQ+wE8KO/TeEJQwBgSU236LS
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huG5Z8itGdwhEkI7xB/gUAZLOPwWloD4LUCxCRhY3CQ32AW0AC7FKXJLtT/IbBbrRIEWrGMdEP9Y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--yyyyyyyyyyyyyyyy----xxxxxxxxxxxxxxxx
Content-Type: text/plain;
name="=?gb2312?B?yc+127rNztIuVFhU?="
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
filename="=?gb2312?B?yc+127rNztIuVFhU?="yc+127j4ztLSu8urvcWjrL3MztLI57rO0tnBorK7tbmjrL/JztLWu9Gnu+HByy0tzNPF3KGjDQrJ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=--xxxxxxxxxxxxxxxx
Content-Type: application/mac-binhex40;
name="=?gb2312?B?yc+127rNztIuemlw?="
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
filename="=?gb2312?B?yc+127rNztIuemlw?="UEsDBBQAAAAIAFyf8i7zotgDIAEAAAACAAAMAAAAyc+127rNztIuVFhUXc9Pb4IwGAbwu4nfRP3O
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76GQVbSuqmF7LmQ14W9318o46R84qTo6tseyow9Px2uXkmxXKrNvr0wiK2O76PwrkcarYRsdHApU
CoHJuoHm6tjNCOPGGW8hHvTYZyPbBFPzC4vfUPhGLIqo5aWmC5R6LR/X5DK8vdTx7gw6lHGIR9NG
dnr0jRO59yi09M6Ek03elRxdfTDOLA1lBNiX09wZxF7P3+dPHYCaMDhqtVo/UEsBAhQAFAAAAAgA
XJ/yLvOi2AMgAQAAAAIAAAwAAAAAAAAAAAAgALaBAAAAAMnPtdu6zc7SLlRYVFBLBQYAAAAAAQAB
ADoAAABKAQAAAAA=--xxxxxxxxxxxxxxxx--

Answer 2

我想 From,To,Subject 就不用解释了吧；
MIME-Version: 1.0表示是多功能Internet邮件扩充服务版本1.0。
Content-Type: multipart/mixed;表示本邮件是多部分的，而且是混合排版。
（有可能包含附件）

Answer 3

boundary="xxxxxxxxxxxxxxxx"表示定界符为xxxxxxxxxxxxxxxx
--xxxxxxxxxxxxxxxx  为本邮件定界符开始
Content-Type: multipart/related;
type="multipart/alternative";
boundary="yyyyyyyyyyyyyyyy"  第一部分附件，定界符为yyyyyyyyyyyyyyyy
--yyyyyyyyyyyyyyyy
Content-Type: multipart/alternative;
boundary="wwwwwwwwwwwwwwww"  第一部分附件，定界符为wwwwwwwwwwwwwwww
Content-Transfer-Encoding: base64  编码类型为Base64以下是邮件正文部分，用imap_base64进行解码。
--wwwwwwwwwwwwwwww
Content-Type: text/html;
charset="gb2312"
Content-Transfer-Encoding: base64PCFET0NUWVBFIEhUTUwgUFVCTElDICItLy9XM0MvL0RURCBIVE1MIDQuMCBUcmFuc2l0aW9uYWwv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--wwwwwwwwwwwwwwww--

Answer 4

--wwwwwwwwwwwwwwww--
表示以boundary="wwwwwwwwwwwwwwww"的邮件部分结束。--yyyyyyyyyyyyyyyy 表示boundary="yyyyyyyyyyyyyyyy"的邮件部分开始（邮件附件）
Content-Type: image/gif; 邮件部分类型
name="club.gif" 文件名
Content-Transfer-Encoding: base64
Content-ID: <000801c34d24$215536e0$017d7d7d@mistruster> 
表示该图片在邮件部分内部的ID用于显示在邮件正文上。

Answer 5

--xxxxxxxxxxxxxxxx
Content-Type: text/plain;
name="=?gb2312?B?yc+127rNztIuVFhU?="
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
文本附件

Answer 6

其实每部分都差不多一样的，只是boundary="yyyyyyyyyyyyyyyy"定界符的使用
--yyyyyyyyyyyyyyyy 每一个都表示开始--yyyyyyyyyyyyyyyy-- 为整个boundary="yyyyyyyyyyyyyyyy"部分结束
还有Content-Type:的类型，基本上就是:
application/xxxxx audio/xxxxx image/xxxxx text/xxxxx 几种
Content-Transfer-Encoding:编码类型，基本上就是：
Base64, 7bit, 8bit, binaray几种

Answer 7

如果看了邮件的源码，很容易写收/发电子邮件程序。
一般，要是个图片，就可以直接用base64_decode()来显示出来。

Answer 8

用imap_fetchbody()函数取出邮件各个部分。function get_part (&$stream, &$msg_number, $mime_type, $structure = false, $part_number = false)
{ 
if (!$structure)
{ 
$structure = imap_fetchstructure($stream, $msg_number); 
} 
if($structure)
{ 
if(strtolower ($mime_type) == get_mime_type($structure))
{ 
if(!$part_number)
{ 
$part_number = "1"; 
} 
if ($structure->ifdisposition)
{
if (strtolower ($structure->disposition) == "attachment") return false;
}
$text = imap_fetchbody($stream, $msg_number, $part_number); 
if($structure->encoding == 3)
{ 
return imap_base64($text);
}
else if($structure->encoding == 4)
{ 
return imap_qprint($text); 
}
else
{ 
return $text;
} 
} 
if($structure->type == 1) /* multipart */
{ 
while(list($index, $sub_structure) = each($structure->parts))
{ 
if($part_number)
{ 
$prefix = $part_number . '.'; 
} 
$data = get_part($stream, $msg_number, $mime_type, $sub_structure, $prefix . ($index + 1)); 
if($data)
{ 
return $data; 
} 
} 
} 
} 
return false; 
}

Answer 9

谢谢Mistruster(弱智d)老师~