(Go) Send Signed Email using PFX File (long version)

Demonstrates how to send a signed email using a digital certificate w/ private key stored in a PFX file.

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    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // The mailman object is used for sending and receiving email.
    mailman := chilkat.NewMailMan()

    // Set the SMTP server.
    mailman.SetSmtpHost("smtp.mymailserver.com")

    // Create a new email object
    email := chilkat.NewEmail()

    email.SetSubject("This email is signed")
    email.SetBody("This is a digitally signed mail")
    email.SetFrom("Chilkat Admin <admin@chilkatsoft.com>")
    success := email.AddTo("Chilkat Support","support@chilkatsoft.com")

    // Indicate that the email should be sent signed.
    email.SetSendSigned(true)

    // Load a PFX file into a certificate store object.
    // Then locate the certificate matching the  sender's email address,
    // and use it for signing.
    // (a PFX file may contain more than one certificate.)
    certStore := chilkat.NewCertStore()
    // The 1st argument is the path of the PFX file, the 2nd arg is the 
    // PFX file's password:
    success = certStore.LoadPfxFile("/pfx_files/chilkatsoft_secret.pfx","secret")
    if success != true {
        fmt.Println(certStore.LastErrorText())
        mailman.DisposeMailMan()
        email.DisposeEmail()
        certStore.DisposeCertStore()
        return
    }

    cert := certStore.FindCertBySubjectE("admin@chilkatsoft.com")
    if certStore.LastMethodSuccess() == false {
        fmt.Println(certStore.LastErrorText())
        mailman.DisposeMailMan()
        email.DisposeEmail()
        certStore.DisposeCertStore()
        return
    }

    // Alternatively, if a PFX file is known to contain a single certificate,
    // you may load it directly into a Chilkat certificate object.
    // This snippet of source code shows how:
    cert2 := chilkat.NewCert()
    // The 1st argument is the filename, the 2nd arg is the 
    // PFX file's password:
    success = cert2.LoadPfxFile("/pfx_files/chilkatsoft_secret.pfx","secret")
    if success != true {
        fmt.Println(cert2.LastErrorText())
        cert.DisposeCert()
        mailman.DisposeMailMan()
        email.DisposeEmail()
        certStore.DisposeCertStore()
        cert2.DisposeCert()
        return
    }

    // This example will use the cert from the certStore...
    success = email.SetSigningCert(cert)

    // Signed email can be sent in two different ways.  
    // In a multipart/signed email, the signature is attached as a separate MIME part.
    // In an opaque email (signedData) the content of the email is encapsulated within the signature
    // and the email is sent as "application/pkcs7-mime". 
    // Either should be fine, but some receiving systems might require one or the other..
    mailman.SetOpaqueSigning(false)

    // Send a signed email.
    success = mailman.SendEmail(email)
    if success != true {
        fmt.Println(mailman.LastErrorText())
    }
    else {
        // The LastErrorText property provides information
        // even when successful.
        fmt.Println(mailman.LastErrorText())
        fmt.Println("Mail Sent!")
    }

    cert.DisposeCert()

    mailman.DisposeMailMan()
    email.DisposeEmail()
    certStore.DisposeCertStore()
    cert2.DisposeCert()