Swift

Get the Content-ID of an Attachment

Demonstrates the Chilkat Email.GetAttachmentContentID method, which returns the Content-ID header field for the Nth attachment. The index is zero-based, so the first attachment is 0. This example adds an attachment and reads its Content-ID (which may be empty when none was assigned).

Background: A Content-ID is a unique identifier for a MIME part. It is essential for inline "related" resources, where HTML references an image by cid:, but ordinary file attachments usually have none. Reading it is useful when inspecting how a message is assembled, or when distinguishing parts that are referenced from the body versus those meant purely as downloadable attachments.

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Swift


func chilkatTest() {
    //  Demonstrates the GetAttachmentContentID method, which returns the Content-ID header
    //  field for the Nth attachment.  The index is zero-based (the first attachment is 0).

    let email = CkoEmail()!
    email.subject = "Attachment Content-ID"

    email.addStringAttachment(fileName: "notes.txt", str: "Some notes.")

    //  Get the Content-ID of the first attachment (may be empty if none was assigned).
    var cid: String? = email.getAttachmentContentID(index: 0)
    print("Attachment 0 Content-ID: \(cid!)")

}