Ruby

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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require 'chilkat'

success = false

#  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.

email = Chilkat::CkEmail.new()
email.put_Subject("GetRelatedContentID example")

#  Load the image data from a file into a BinData object.
bdImage = Chilkat::CkBinData.new()
success = bdImage.LoadFile("qa_data/images/logo.png")
if (success == false)
    print bdImage.lastErrorText() + "\n";
    exit
end

#  Add the image as a related item from the BinData; capture its generated Content-ID.
cid = email.addRelatedBd("logo.png",bdImage)
if (email.get_LastMethodSuccess() == false)
    print email.lastErrorText() + "\n";
    exit
end

#  Reference the related item in the HTML body by its Content-ID.
sbHtml = Chilkat::CkStringBuilder.new()
sbHtml.Append("<html><body><img src=\"cid:PLACEHOLDER_CID\"/></body></html>")
numReplaced = sbHtml.Replace("PLACEHOLDER_CID",cid)
email.SetHtmlBody(sbHtml.getAsString())

#  Read the Content-ID of the first related item (index 0).
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.