(C) 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).

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#include <C_CkImap.h>
#include <C_CkStringBuilder.h>
#include <C_CkMime.h>
#include <C_CkStringArray.h>
#include <C_CkEmail.h>
#include <C_CkCert.h>

void ChilkatSample(void)
    {
    HCkImap imap;
    BOOL success;
    HCkStringBuilder sbMime;
    HCkMime mime;
    BOOL alreadySavedParts;
    HCkStringArray sa;
    int numFiles;
    int i;
    HCkEmail email;
    HCkCert cert;

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

    imap = CkImap_Create();

    // Connect to an IMAP server.
    // Use TLS
    CkImap_putSsl(imap,TRUE);
    CkImap_putPort(imap,993);
    success = CkImap_Connect(imap,"imap.someMailServer.com");
    if (success != TRUE) {
        printf("%s\n",CkImap_lastErrorText(imap));
        CkImap_Dispose(imap);
        return;
    }

    success = CkImap_Login(imap,"myLogin","myPassword");
    if (success != TRUE) {
        printf("%s\n",CkImap_lastErrorText(imap));
        CkImap_Dispose(imap);
        return;
    }

    // Select an IMAP mailbox
    success = CkImap_SelectMailbox(imap,"Inbox");
    if (success != TRUE) {
        printf("%s\n",CkImap_lastErrorText(imap));
        CkImap_Dispose(imap);
        return;
    }

    // Download the 1st email (as MIME) in the Inbox by sequence number.
    sbMime = CkStringBuilder_Create();
    success = CkImap_FetchSingleAsMimeSb(imap,1,FALSE,sbMime);
    if (success != TRUE) {
        printf("%s\n",CkImap_lastErrorText(imap));
        CkImap_Dispose(imap);
        CkStringBuilder_Dispose(sbMime);
        return;
    }

    // Load it into a MIME object and check to see if it is signed
    mime = CkMime_Create();
    CkMime_LoadMimeSb(mime,sbMime);
    alreadySavedParts = FALSE;
    if (CkMime_ContainsSignedParts(mime) == TRUE) {

        // This will save the .p7s and other parts...
        sa = CkMime_ExtractPartsToFiles(mime,"qa_output");
        if (CkMime_getLastMethodSuccess(mime) == TRUE) {
            numFiles = CkStringArray_getCount(sa);
            i = 0;
            while (i < numFiles) {
                printf("Created: %s\n",CkStringArray_getString(sa,i));
                i = i + 1;
            }

            CkStringArray_Dispose(sa);
            alreadySavedParts = TRUE;
        }

    }

    // Load the MIME into an Email object.  This unwraps the security layers and verifies signatures.
    email = CkEmail_Create();
    CkEmail_SetFromMimeSb(email,sbMime);

    if (CkEmail_getReceivedSigned(email) == TRUE) {

        printf("This email was signed.\n");

        // Check to see if the signatures were verified.
        if (CkEmail_getSignaturesValid(email) == TRUE) {
            printf("Digital signature(s) verified.\n");

            printf("Signer: %s\n",CkEmail_signedBy(email));

            // The certificate used for signing may be obtained
            // by calling email.GetSignedByCert.
            cert = CkEmail_GetSignedByCert(email);
            if (CkEmail_getLastMethodSuccess(email) != TRUE) {
                printf("Failed to get signing certificate object.\n");
            }
            else {
                printf("Signing cert: %s\n",CkCert_subjectCN(cert));
                CkCert_Dispose(cert);
            }

        }

    }
    else {
        printf("Digital signature verification failed.\n");
    }

    if (alreadySavedParts != TRUE) {
        CkEmail_SaveAllAttachments(email,"qa_output");
    }



    CkImap_Dispose(imap);
    CkStringBuilder_Dispose(sbMime);
    CkMime_Dispose(mime);
    CkEmail_Dispose(email);

    }