Perl

Add a Custom Header to a Related Item

Demonstrates the Chilkat Email.AddRelatedHeader method, which adds a custom MIME header field to an existing related item identified by its zero-based index. This example first adds a related style sheet (which becomes index 0) and captures its generated Content-ID, builds an HTML body that references the style sheet by that cid:, then attaches an extra header field to the related item and prints the resulting MIME.

Background: Like attachments, each related item (an inline image, style sheet, etc.) is a MIME part with its own small header block describing that part — Content-Type, Content-ID, Content-Location, and so on. AddRelatedHeader lets you insert additional fields into that per-part block, which is occasionally required for interoperability with clients that look for specific custom headers on embedded resources.

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Perl

use chilkat();

#  Demonstrates the AddRelatedHeader method, which adds a custom MIME header field to an
#  existing related item, identified by its zero-based index.

$email = chilkat::CkEmail->new();
$email->put_Subject("Related item with a custom header");

#  Add a related item first (a style sheet); capture its generated Content-ID.  It becomes
#  related-item index 0.
$cid = $email->addRelatedString("styles.css","body { color: black; }","utf-8");
if ($email->get_LastMethodSuccess() == 0) {
    print $email->lastErrorText() . "\r\n";
    exit;
}

#  Build the HTML body, referencing the related style sheet by its Content-ID.  A
#  placeholder is used and then replaced with the actual Content-ID.
$sbHtml = chilkat::CkStringBuilder->new();
$sbHtml->Append("<html><head><link rel=\"stylesheet\" href=\"cid:PLACEHOLDER_CID\"/></head><body>Styled content.</body></html>");
$numReplaced = $sbHtml->Replace("PLACEHOLDER_CID",$cid);
$email->SetHtmlBody($sbHtml->getAsString());

#  Add a custom header field to the first related item (index 0).
$email->AddRelatedHeader(0,"X-Custom-Related-Header","some value");

#  The custom header now appears in the related item's MIME part.
print $email->getMime() . "\r\n";