(Go) IMAP Download and Verify Signed MIME

Downloads the original MIME of a digitally signed email and saves the .p7s signature along with other MIME parts. It then imports the email into a Chilkat email object to unwrap the S/MIME and verify the signature, and subsequently saves the attachments if they haven't been saved already.

Note: This example requires Chilkat v11.0.0 or greater.

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

    success := false

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

    imap := Imap_Ref.html">chilkat.NewImap()

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

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

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

    // Download the 1st email (as MIME) in the Inbox by sequence number.
    sbMime := StringBuilder_Ref.html">chilkat.NewStringBuilder()
    success = imap.FetchSingleAsMimeSb(1,false,sbMime)
    if success == false {
        fmt.Println(imap.LastErrorText())
        imap.DisposeImap()
        sbMime.DisposeStringBuilder()
        return
    }

    // Load it into a MIME object and check to see if it is signed
    mime := Mime_Ref.html">chilkat.NewMime()
    mime.LoadMimeSb(sbMime)
    alreadySavedParts := false
    if mime.ContainsSignedParts() == true {

        // This will save the .p7s and other parts...
        st := StringTable_Ref.html">chilkat.NewStringTable()
        success = mime.PartsToFiles("c:/temp/qa_output",st)
        if success == true {
            numFiles := st.Count()
            i := 0
            for i < numFiles {
                fmt.Println("Created: ", *st.StringAt(i))
                i = i + 1
            }

            alreadySavedParts = true
        }

    }

    // Load the MIME into an Email_Ref.html">Email object.  This unwraps the security layers and verifies signatures.
    email := Email_Ref.html">chilkat.NewEmail()
    email.SetFromMimeSb(sbMime)

    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 := Cert_Ref.html">chilkat.NewCert()
            success = email.LastSignerCert(i,cert)
            if success == false {
                fmt.Println("Failed to get signing certificate object.")
            } else {
                fmt.Println("Signing cert: ", cert.SubjectCN())
            }

        }

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

    if alreadySavedParts != true {
        email.SaveAllAttachments("c:/temp/qa_output")
    }


    imap.DisposeImap()
    sbMime.DisposeStringBuilder()
    mime.DisposeMime()
    st.DisposeStringTable()
    email.DisposeEmail()
    cert.DisposeCert()