Add a Detached Signature (Header Placement Control)

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Demonstrates the Chilkat Mime.AddDetachedSignature2 method, which creates the same multipart/signed structure as AddDetachedSignature, with a second argument controlling whether the existing message header fields are transferred to the new outer entity.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Signing wraps the content in a new outer multipart/signed, which raises the question of where the message-level headers (Subject, From, To) should live. This variant lets you choose: transfer them up to the outer entity so the signed message looks like a normal email, or leave them on the inner part. Transferring is typical for email; the finer control matters when the signed entity is embedded in a larger structure.

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    success := false

    mime := chilkat.NewMime()
    success = mime.SetBodyFromPlainText("This message will be signed.")
    if success == false {
        fmt.Println(mime.LastErrorText())
        mime.DisposeMime()
        return
    }

    //  Load the signing certificate (which must have access to its private key) from a PFX file.
    //  The PFX password should come from a secure source rather than being hard-coded.
    pfxPassword := "myPfxPassword"
    cert := chilkat.NewCert()
    success = cert.LoadPfxFile("qa_data/signer.pfx",pfxPassword)
    if success == false {
        fmt.Println(cert.LastErrorText())
        mime.DisposeMime()
        cert.DisposeCert()
        return
    }

    //  AddDetachedSignature2 is the same as AddDetachedSignature, but the 2nd argument controls whether
    //  the existing message header fields are transferred to the new outer multipart/signed entity.
    transferHeaderFields := true
    success = mime.AddDetachedSignature2(cert,transferHeaderFields)
    if success == false {
        fmt.Println(mime.LastErrorText())
        mime.DisposeMime()
        cert.DisposeCert()
        return
    }

    success = mime.SaveMime("qa_output/signed.eml")
    if success == false {
        fmt.Println(mime.LastErrorText())
        mime.DisposeMime()
        cert.DisposeCert()
        return
    }

    fmt.Println("Detached signature added (headers transferred).")

    mime.DisposeMime()
    cert.DisposeCert()