Reading Unread POP3 Email

The POP3 protocol does not provide the ability to ask the server which emails are "unread". Furthermore, a pure POP3 server does not even keep this information. Some servers, such as Exchange Server, expose both POP3 and IMAP interfaces. In these cases, information about read/unread status exists on the server, but it is only available via the IMAP protocol. Email clients such as Outlook and Thunderbird keep read/unread information on the client computer. This example demonstrates how UIDLs can be saved to track and read "unread" email.

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#include <C_CkMailMan.h>
#include <C_CkStringArray.h>
#include <C_CkEmailBundle.h>
#include <C_CkEmail.h>

void ChilkatSample(void)
    {
    HCkMailMan mailman;
    BOOL success;
    HCkStringArray saSeenUidls;
    HCkStringArray saUidls;
    HCkStringArray saUnseenUidls;
    long i;
    long n;
    HCkEmailBundle bundle;
    HCkEmail email;

    //  The mailman object is used for receiving (POP3)
    //  and sending (SMTP) email.
    mailman = CkMailMan_Create();

    //  Any string argument automatically begins the 30-day trial.

    success = CkMailMan_UnlockComponent(mailman,"30-day trial");
    if (success != TRUE) {
        printf("Component unlock failed\n");
        return;
    }

    //  Set the POP3 server's hostname
    CkMailMan_putMailHost(mailman,"mail.chilkatsoft.com");

    //  Set the POP3 login/password.
    CkMailMan_putPopUsername(mailman,"***");
    CkMailMan_putPopPassword(mailman,"***");

    //  We're keeping a list of already-seen UIDLs in a text file:
    //  If this is the first time you're running this example,
    //  create an empty text file named "seenUidls.txt"
    saSeenUidls = CkStringArray_Create();
    success = CkStringArray_LoadFromFile(saSeenUidls,"seenUidls.txt");
    if (success != TRUE) {
        printf("failed to load seenUidls.txt\n");
        return;
    }

    //  Get the complete list of UIDLs on the mail server.

    saUidls = CkMailMan_GetUidls(mailman);

    if (saUidls == 0 ) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        return;
    }

    //  We don't have set operators (yet) on the StringArray object,
    //  so create a new string array object (it's an object, not an actual array)
    //  and add the UIDLs from saUidls that aren't already seen.
    saUnseenUidls = CkStringArray_Create();

    n = CkStringArray_getCount(saUidls);
    for (i = 0; i <= n - 1; i++) {
        if (CkStringArray_Contains(saSeenUidls,CkStringArray_getString(saUidls,i)) != TRUE) {
            CkStringArray_Append(saUnseenUidls,CkStringArray_getString(saUidls,i));
        }

    }

    if (CkStringArray_getCount(saUnseenUidls) == 0) {
        printf("No unseen emails!\n");
        CkStringArray_Dispose(saUidls);
        return;
    }

    //  Download in full the unseen emails:

    bundle = CkMailMan_FetchMultiple(mailman,saUnseenUidls);
    if (bundle == 0 ) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkStringArray_Dispose(saUidls);
        return;
    }

    for (i = 0; i <= CkEmailBundle_getMessageCount(bundle) - 1; i++) {
        email = CkEmailBundle_GetEmail(bundle,i);
        printf("%s\n",CkEmail_ck_from(email));
        printf("%s\n",CkEmail_subject(email));
        printf("----\n");
        CkEmail_Dispose(email);
    }

    //  We've seen all the emails, save saUidls to "seenUidls.txt"
    CkStringArray_SaveToFile(saUidls,"seenUidls.txt");

    CkStringArray_Dispose(saUidls);

    CkMailMan_Dispose(mailman);
    CkStringArray_Dispose(saSeenUidls);
    CkStringArray_Dispose(saUnseenUidls);

    }