(Go) IMAP Download and Verify Signed (S/MIME) Email

Demonstrates how to download and verify digitally signed S/MIME email.

Chilkat Go Downloads Go Package for Windows, MacOS, Linux, Alpine Linux, Solaris

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

    imap := chilkat.NewImap()

    // Connect to an IMAP server.
    // Use TLS
    imap.SetSsl(true)
    imap.SetPort(993)
    success := imap.Connect("imap.someMailServer.com")
    if success != true {
        fmt.Println(imap.LastErrorText())
        imap.DisposeImap()
        return
    }

    success = imap.Login("myLogin","myPassword")
    if success != true {
        fmt.Println(imap.LastErrorText())
        imap.DisposeImap()
        return
    }

    // Select an IMAP mailbox
    success = imap.SelectMailbox("Inbox")
    if success != true {
        fmt.Println(imap.LastErrorText())
        imap.DisposeImap()
        return
    }

    // We can choose to fetch UIDs or sequence numbers.
    fetchUids := true

    // Get the message IDs of all the emails in the mailbox
    messageSet := imap.Search("ALL",fetchUids)
    if imap.LastMethodSuccess() != true {
        fmt.Println(imap.LastErrorText())
        imap.DisposeImap()
        return
    }

    // Scan for emails with attachments, and save the attachments
    // to a sub-directory.
    i := 0
    for i < messageSet.Count() {

        uid := messageSet.GetId(i)
        fmt.Println("uid: ", *uid)

        email := imap.FetchSingle(*uid,true)

        // The security layers of signed and/or encrypted emails
        // are automatically "unwrapped" when loaded into
        // a Chilkat email object.
        // An application only needs to check to see if an email
        // was received signed or encrypted, and then examine
        // the success/failure.  For example:
        if email.ReceivedSigned() == true {

            fmt.Println("This email was signed.")

            // Check to see if the signatures were verified.
            if email.SignaturesValid() == true {
                fmt.Println("Digital signature(s) verified.")

                fmt.Println("Signer: ", email.SignedBy())

                // The certificate used for signing may be obtained
                // by calling email.GetSignedByCert.
                cert := email.GetSignedByCert()
                if email.LastMethodSuccess() != true {
                    fmt.Println("Failed to get signing certificate object.")
                }
                else {
                    fmt.Println("Signing cert: ", cert.SubjectCN())
                    cert.DisposeCert()
                }

            }
            else {
                fmt.Println("Digital signature verification failed.")
            }

        }

        email.DisposeEmail()

        i = i + 1
    }

    // Disconnect from the IMAP server.
    success = imap.Disconnect()

    messageSet.DisposeMessageSet()

    imap.DisposeImap()