Swift

Get a Header Attribute of an Attached Message

Demonstrates the Chilkat Email.GetAttachedMessageAttr method, which returns a header-field attribute value for the Nth attached (embedded) email. The first argument is the zero-based attached-message index, the second is the header field name, and the third is the attribute name. This example attaches an email and reads the filename attribute of its Content-Disposition header.

Background: MIME header fields can carry named attributes (parameters) after the main value — for example Content-Disposition: attachment; filename="report.eml", where filename is an attribute. Rather than parsing the raw header yourself, this method extracts a single named attribute from a chosen header of a specific embedded message, which is convenient when a message forwards other emails as nested message/rfc822 parts.

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Swift


func chilkatTest() {
    var success: Bool = false

    //  Demonstrates the GetAttachedMessageAttr method, which returns a header-field attribute
    //  value for the Nth attached (embedded) email.  The first argument is the zero-based
    //  attached-message index, the second is the header field name, and the third is the attribute name.

    //  Build an inner email to attach.
    let innerEmail = CkoEmail()!
    innerEmail.subject = "Embedded message"
    innerEmail.from = "alice@example.com"
    innerEmail.add(to: "Bob", emailAddress: "bob@example.com")

    //  Attach it to an outer email as a message/rfc822 part.
    let email = CkoEmail()!
    email.subject = "Has an attached message"
    success = email.attach(email: innerEmail)
    if success == false {
        print("\(email.lastErrorText!)")
        return
    }

    //  Get the "filename" attribute of the "Content-Disposition" header of the first
    //  attached message (index 0).
    var fname: String? = email.getAttachedMessageAttr(index: 0, fieldName: "Content-Disposition", attrName: "filename")
    print("Attached message filename attribute: \(fname!)")

}