Perl

Get the Content-ID of a Related Item

Demonstrates the Chilkat Email.GetRelatedContentID method, which returns the Content-ID of a related item (typically an image or style sheet embedded within an HTML email). The index is zero-based. This example loads an image from a file into a BinData object, adds it as a related item with AddRelatedBd (capturing the generated Content-ID and referencing it from the HTML), then reads that Content-ID back.

Background: The Content-ID is the anchor that ties an inline resource to the HTML that displays it: the body references cid: plus the ID, and the matching related part carries that same Content-ID. Because an image is binary, it is loaded into a BinData object (here from a file) and added with AddRelatedBd. Reading the Content-ID back lets a program verify or rewrite those links — for example when relocating embedded images or converting a message for display outside a mail client.

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use strict;
use warnings;
use Chilkat2;

# Demonstrates the GetRelatedContentID method, which returns the Content-ID of a related
# item.  Related items are typically images and style sheets embedded within HTML emails.
# The index is zero-based.

my $email = Chilkat2::Email->new;
$email->Subject('GetRelatedContentID example');

# Load the image data from a file into a BinData object.
my $bdImage = Chilkat2::BinData->new;
my $success = $bdImage->LoadFile('qa_data/images/logo.png');
if (!$success) {
    print $bdImage->LastErrorText, "\n";
    exit;
}

# Add the image as a related item from the BinData; capture its generated Content-ID.
my $cid = $email->AddRelatedBd('logo.png', $bdImage);
if (!$email->LastMethodSuccess) {
    print $email->LastErrorText, "\n";
    exit;
}

# Reference the related item in the HTML body by its Content-ID.
my $sbHtml = Chilkat2::StringBuilder->new;
$sbHtml->Append('<html><body><img src="cid:PLACEHOLDER_CID"/></body></html>');
my $numReplaced = $sbHtml->Replace('PLACEHOLDER_CID', $cid);
$email->SetHtmlBody($sbHtml->GetAsString());

# Read the Content-ID of the first related item (index 0).
my $cid0 = $email->GetRelatedContentID(0);
print 'Related item 0 Content-ID: ', $cid0, "\n";

# Note: The path "qa_data/images/logo.png" is a relative local filesystem path,
# relative to the current working directory of the running application.