(Ruby) IMAP Download and Verify Signed MIME

Downloads the unmodified MIME of a digitally signed email, saves the .p7s signature (and other MIME parts), then loads the email into a Chilkat email object (which unwraps the S/MIME and verifies the signature) and then saves attachments (if the MIME parts were not already saved).

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

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

imap = Chilkat::CkImap.new()

# Connect to an IMAP server.
# Use TLS
imap.put_Ssl(true)
imap.put_Port(993)
success = imap.Connect("imap.someMailServer.com")
if (success != true)
    print imap.lastErrorText() + "\n";
    exit
end

success = imap.Login("myLogin","myPassword")
if (success != true)
    print imap.lastErrorText() + "\n";
    exit
end

# Select an IMAP mailbox
success = imap.SelectMailbox("Inbox")
if (success != true)
    print imap.lastErrorText() + "\n";
    exit
end

# Download the 1st email (as MIME) in the Inbox by sequence number.
sbMime = Chilkat::CkStringBuilder.new()
success = imap.FetchSingleAsMimeSb(1,false,sbMime)
if (success != true)
    print imap.lastErrorText() + "\n";
    exit
end

# Load it into a MIME object and check to see if it is signed
mime = Chilkat::CkMime.new()
mime.LoadMimeSb(sbMime)
alreadySavedParts = false
if (mime.ContainsSignedParts() == true)

    # This will save the .p7s and other parts...
    # sa is a CkStringArray
    sa = mime.ExtractPartsToFiles("qa_output")
    if (mime.get_LastMethodSuccess() == true)
        numFiles = sa.get_Count()
        i = 0
        while i < numFiles
            print "Created: " + sa.getString(i) + "\n";
            i = i + 1
        end

        alreadySavedParts = true
    end

end

# Load the MIME into an Email object.  This unwraps the security layers and verifies signatures.
email = Chilkat::CkEmail.new()
email.SetFromMimeSb(sbMime)

if (email.get_ReceivedSigned() == true)

    print "This email was signed." + "\n";

    # Check to see if the signatures were verified.
    if (email.get_SignaturesValid() == true)
        print "Digital signature(s) verified." + "\n";

        print "Signer: " + email.signedBy() + "\n";

        # The certificate used for signing may be obtained
        # by calling email.GetSignedByCert.
        # cert is a CkCert
        cert = email.GetSignedByCert()
        if (email.get_LastMethodSuccess() != true)
            print "Failed to get signing certificate object." + "\n";
        else
            print "Signing cert: " + cert.subjectCN() + "\n";

        end

    end

else
    print "Digital signature verification failed." + "\n";
end

if (alreadySavedParts != true)
    email.SaveAllAttachments("qa_output")
end