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I got a problem: Until today, I sent HTML mails with PHP using a header which contains
Content-type: text/html;
Now, I added functionality to add attachments. For this, I had to change this line to
Content-Type: multipart/mixed;
Now, with multipart/mixed, the rest of the mail, so the normal text, gets shown just as text/plain. How can I realize that attachments work and the mailtext is still HTML?
898
Each line should be separated with an LF (\n). Lines should not exceed 70 characters (We will use wordwrap() function to achieve this.) This contains additional headers, like From, Cc, Mime Version, and Bcc.
If you really want to learn how to format an Internet Message then you should refer its Request For Comments (aka RFC). The one that defines "Multipurpose Internet Mail Extensions - Format of Internet Message Bodies" is RFC2045 issued on November 1996.
The format is somehow very strict and must be followed as-is.
Basically the message contains a header and the body. The header defines the type of the message, the way it's formated, some other fields which differ from one type to another.
The body is formed by different entities. An entity can be for instance just a plain-text like "Hello there!" but also can be an image, an attachment, whatever.
NOTE In the following examples everything enclosed into brackets (eg. {hello}) should be replaced with your real value. Any newline is in reality CRLF (ie. ASCII 13 + ASCII 10). Where you see two CRLF stick to it. It would be the worst moment to show how creative you are.
Basically for an email message that has attachments the header should look like this:
MIME-Version: 1.0
To: {email@domain}
Subject: {email-subject}
X-Priority: {2 (High)}
Content-Type: multipart/mixed; boundary="{mixed-boudary}"
In the above example the {mixed-boudary} may be any unique hash value, like 000008050800060107020705. The others are self-explanatory.
Now, anytime we want to append a new entity to the message (like the message body, an image, an attachment) we have to tell the email agent that a new section is coming, ie. to prefix that entity with the {mixed-boundary} value. We call this "open the boundary". Note that by opening a boundary we don't insert that boundary as was defined initially, we use 2 more minus signs in front, like --{mixed-boudary}. When we close a boundary we proceed likewise, except that we have to use other 2 minus signs at the end, like --{mixed-boudary}--
--{mixed-boudary}
the entity content
--{mixed-boudary}--
Because the email agent should understand what type has the content of our new inserted entity we have to declare that right after the opening of boundary. The declaration is just a header which contains only those parameters/values that are compatible with the entity.
For a HTML body content my entity header would look like:
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: 7bit
so the whole body (enclosed into boundaries) will finally look like:
--{mixed-boudary}
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: 7bit
<html>
<head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head>
<body bgcolor="#FFFFFF" text="#000000">
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Pellentesque vel
dapibus arcu. Duis quam dui, ornare non mi nec, luctus faucibus massa. Vivamus
quis purus in erat euismod ullamcorper vitae eget dolor. Aliquam tempor erat
accumsan, consectetur ex et, rhoncus risus.
</body>
</html>
If another entity has to be inserted we proceed exactly like above. When there is no more data to add to the message we close the mixed-boundary, ie. CRLF + --{mixed-boudary}--.
If for any reason an entity has to be inserted with an alternative representation (eg. a body message is inserted both as plain-text format and also as HTML format), then the entity content has to be declared with content-type multipart/alternative (although the global multipart/mixed header still remains!). Each alternative representation will be enclosed by this new boundary.
A complete example below:
MIME-Version: 1.0
To: {email@domain}
Subject: {email-subject}
X-Priority: {2 (High)}
Content-Type: multipart/mixed; boundary="{mixed-boudary}"
--{mixed-boudary}
Content-Type: multipart/alternative; boundary="{alternative-boudary}"
--{alternative-boudary}
Content-Type: text/plain; charset=utf-8;
Content-Transfer-Encoding: 7bit
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Pellentesque vel
dapibus arcu. Duis quam dui, ornare non mi nec, luctus faucibus massa. Vivamus
quis purus in erat euismod ullamcorper vitae eget dolor. Aliquam tempor erat
accumsan, consectetur ex et, rhoncus risus.
--{alternative-boudary}
Content-Type: text/html; charset=utf-8;
Content-Transfer-Encoding: 7bit
<html>
<head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head>
<body bgcolor="#FFFFFF" text="#000000">
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Pellentesque vel
dapibus arcu. Duis quam dui, ornare non mi nec, luctus faucibus massa. Vivamus
quis purus in erat euismod ullamcorper vitae eget dolor. Aliquam tempor erat
accumsan, consectetur ex et, rhoncus risus.
</body>
</html>
--{alternative-boudary}--
--{mixed-boudary}
Content-Type: application/pdf; name="myfile.pdf"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="myfile.pdf"
JVBERi0xLjINOCAwIG9iag08PCAvTGVuZ3RoIDkgMCBSIC9GaWx0ZXIgL0ZsYXRlRGVjb2Rl
ID4+DXN0cmVhbQ1oQ51bbY/cNg7+BfsfhAUO11w3riW/B7gPaZEAAdpcm06RL8EBzoyn68uM
vZ3xZLv//khKsuUxNaMNiiabpUg+pKiHsmxJEcN/UsgiilP4ab2/+XF1I81vszSqclHIOEpj
sdrf/PC2EFVUpmK1vXkZxVKs1uJlJJVYPYrvPra7XVvvxYdIrE7rL83hhVj97+bNyjUoFam7
FnOB+tubGI3FZEkwmhpKXpVRnqJi0PCyjBJ1DjyOYqWBxxXp/1h3X+ov9abZt434pV0feoG/
ars/xU/9/qEZmm7diJ+abmgOr0TGeFNFEuXx5M4B95Idns/QAaJMI1IpKeXi9+ZhaPafm4NQ
cRwzNpK0iirlRvisRBZpVJa+PP51091kkjBWBXrJxUuZRjIXh0Z8FN3MnB5X5st5Kay9355n
--{mixed-boudary}--
TIPS
Use your preferred email client (mine is Thunderbird) and send to yourself one message plain-text only, one HTML only, one mixed, and then each of the earlier but with one file attachment enclosed. When you receive the message just study its source (View -> Message source).
@Edit: a very well documented case study + PHP example can be found at here
168
To send an email with attachment we need to use the multipart/mixed MIME type that specifies that mixed types will be included in the email. Moreover, we want to use multipart/alternative MIME type to send both plain-text and HTML version of the email.Have a look at the example:
<?php
//define the receiver of the email
$to = '[email protected]';
//define the subject of the email
$subject = 'Test email with attachment';
//create a boundary string. It must be unique
//so we use the MD5 algorithm to generate a random hash
$random_hash = md5(date('r', time()));
//define the headers we want passed. Note that they are separated with \r\n
$headers = "From: [email protected]\r\nReply-To: [email protected]";
//add boundary string and mime type specification
$headers .= "\r\nContent-Type: multipart/mixed; boundary=\"PHP-mixed-".$random_hash."\"";
//read the atachment file contents into a string,
//encode it with MIME base64,
//and split it into smaller chunks
$attachment = chunk_split(base64_encode(file_get_contents('attachment.zip')));
//define the body of the message.
ob_start(); //Turn on output buffering
?>
--PHP-mixed-<?php echo $random_hash; ?>
Content-Type: multipart/alternative; boundary="PHP-alt-<?php echo $random_hash; ?>"
--PHP-alt-<?php echo $random_hash; ?>
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Hello World!!!
This is simple text email message.
--PHP-alt-<?php echo $random_hash; ?>
Content-Type: text/html; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
<h2>Hello World!</h2>
<p>This is something with <b>HTML</b> formatting.</p>
--PHP-alt-<?php echo $random_hash; ?>--
--PHP-mixed-<?php echo $random_hash; ?>
Content-Type: application/zip; name="attachment.zip"
Content-Transfer-Encoding: base64
Content-Disposition: attachment
<?php echo $attachment; ?>
--PHP-mixed-<?php echo $random_hash; ?>--
<?php
//copy current buffer contents into $message variable and delete current output buffer
$message = ob_get_clean();
//send the email
$mail_sent = @mail( $to, $subject, $message, $headers );
//if the message is sent successfully print "Mail sent". Otherwise print "Mail failed"
echo $mail_sent ? "Mail sent" : "Mail failed";
?>
As you can see, sending an email with attachment is easy to accomplish. In the preceding example we have multipart/mixed MIME type, and inside it we have multipart/alternative MIME type that specifies two versions of the email. To include an attachment to our message, we read the data from the specified file into a string, encode it with base64, split it in smaller chunks to make sure that it matches the MIME specifications and then include it as an attachment.
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