(Unicode C) 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_CkMailManW.h>
#include <C_CkStringArrayW.h>
#include <C_CkEmailBundleW.h>
#include <C_CkEmailW.h>

void ChilkatSample(void)
    {
    HCkMailManW mailman;
    HCkStringArrayW saSeenUidls;
    BOOL success;
    HCkStringArrayW saUidls;
    HCkStringArrayW saUnseenUidls;
    int i;
    int n;
    HCkEmailBundleW bundle;
    HCkEmailW email;

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

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

    // Set the POP3 server's hostname
    CkMailManW_putMailHost(mailman,L"pop.someMailServer.com");

    // Set the POP3 login/password.
    CkMailManW_putPopUsername(mailman,L"***");
    CkMailManW_putPopPassword(mailman,L"***");

    // You may keep 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 = CkStringArrayW_Create();
    success = CkStringArrayW_LoadFromFile(saSeenUidls,L"seenUidls.txt");
    if (success != TRUE) {
        wprintf(L"failed to load seenUidls.txt\n");
        CkMailManW_Dispose(mailman);
        CkStringArrayW_Dispose(saSeenUidls);
        return;
    }

    // Get the complete list of UIDLs on the mail server.
    saUidls = CkMailManW_GetUidls(mailman);
    if (CkMailManW_getLastMethodSuccess(mailman) == FALSE) {
        wprintf(L"%s\n",CkMailManW_lastErrorText(mailman));
        CkMailManW_Dispose(mailman);
        CkStringArrayW_Dispose(saSeenUidls);
        return;
    }

    // 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 = CkStringArrayW_Create();

    i = 0;
    n = CkStringArrayW_getCount(saUidls);
    while (i < n) {
        if (CkStringArrayW_Contains(saSeenUidls,CkStringArrayW_getString(saUidls,i)) != TRUE) {
            success = CkStringArrayW_Append(saUnseenUidls,CkStringArrayW_getString(saUidls,i));
        }

        i = i + 1;
    }

    if (CkStringArrayW_getCount(saUnseenUidls) == 0) {
        wprintf(L"No unseen emails!\n");
        CkStringArrayW_Dispose(saUidls);
        CkMailManW_Dispose(mailman);
        CkStringArrayW_Dispose(saSeenUidls);
        CkStringArrayW_Dispose(saUnseenUidls);
        return;
    }

    // Download in full the unseen emails:
    bundle = CkMailManW_FetchMultiple(mailman,saUnseenUidls);
    if (CkMailManW_getLastMethodSuccess(mailman) == FALSE) {
        wprintf(L"%s\n",CkMailManW_lastErrorText(mailman));
        CkStringArrayW_Dispose(saUidls);
        CkMailManW_Dispose(mailman);
        CkStringArrayW_Dispose(saSeenUidls);
        CkStringArrayW_Dispose(saUnseenUidls);
        return;
    }

    i = 0;
    while (i < CkEmailBundleW_getMessageCount(bundle)) {
        email = CkEmailBundleW_GetEmail(bundle,i);
        wprintf(L"%s\n",CkEmailW_ck_from(email));
        wprintf(L"%s\n",CkEmailW_subject(email));
        wprintf(L"----\n");
        CkEmailW_Dispose(email);
        i = i + 1;
    }

    // Save saUidls to "seenUidls.txt"
    success = CkStringArrayW_SaveToFile(saUidls,L"seenUidls.txt");

    CkStringArrayW_Dispose(saUidls);


    CkMailManW_Dispose(mailman);
    CkStringArrayW_Dispose(saSeenUidls);
    CkStringArrayW_Dispose(saUnseenUidls);

    }