(Unicode C) Download an IMAP Message Set

Demonstrates how to read a set of IMAP emails.

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

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#include <C_CkImapW.h>
#include <C_CkMessageSetW.h>
#include <C_CkEmailBundleW.h>
#include <C_CkEmailW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkImapW imap;
    BOOL fetchUids;
    HCkMessageSetW messageSet;
    HCkEmailBundleW bundle;
    BOOL headersOnly;
    HCkEmailW email;
    int i;
    int numEmails;

    success = FALSE;

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

    imap = CkImapW_Create();

    // Connect using TLS.
    CkImapW_putSsl(imap,TRUE);
    CkImapW_putPort(imap,993);
    success = CkImapW_Connect(imap,L"imap.example.com");
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkImapW_Dispose(imap);
        return;
    }

    // Authenticate
    success = CkImapW_Login(imap,L"email_account_login",L"email_account_password");
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkImapW_Dispose(imap);
        return;
    }

    // Select an IMAP mailbox
    success = CkImapW_SelectMailbox(imap,L"Inbox");
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkImapW_Dispose(imap);
        return;
    }

    // Search for messages with the word "test" in the subject.
    fetchUids = TRUE;

    messageSet = CkMessageSetW_Create();
    success = CkImapW_QueryMbx(imap,L"Subject test",fetchUids,messageSet);
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkImapW_Dispose(imap);
        CkMessageSetW_Dispose(messageSet);
        return;
    }

    // Download the messages in a single call to FetchMsgSet.
    // 
    // This only makes sense if the number of emails to be downloaded is not too large.  
    // For example, you wouldn't want to download 10000 emails in a single call to FetchMsgSet.
    // Why? For two reasons:  (1) It could potentially cause an out-of-memory condition, and 
    // (2) it would take an extremely large amount of time.  The longer the amount of time,
    // the greater the likelihood of some kind of external networking or server problem occuring,
    // and if it happens, then you would need to re-download everything from the beginning again.
    // For large numbers of emails, it's better to loop over the emails in the message set
    // and download/process one at a time as shown here: Download IMAP Messages One at a Time
    // Downloading one message at a time makes it possible to resume the downloads rather than restart the entire operation all over again.

    // If the message set is reasonable in size, you can download all at once using FetchMsgSet:

    wprintf(L"Number of messages = %d\n",CkMessageSetW_getCount(messageSet));

    bundle = CkEmailBundleW_Create();
    headersOnly = FALSE;
    success = CkImapW_FetchMsgSet(imap,headersOnly,messageSet,bundle);
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkImapW_Dispose(imap);
        CkMessageSetW_Dispose(messageSet);
        CkEmailBundleW_Dispose(bundle);
        return;
    }

    // Display the Subject and From of each email.
    email = CkEmailW_Create();
    i = 0;
    numEmails = CkEmailBundleW_getMessageCount(bundle);
    while (i < numEmails) {
        CkEmailBundleW_EmailAt(bundle,i,email);

        wprintf(L"%s\n",CkEmailW_getHeaderField(email,L"Date"));
        wprintf(L"%s\n",CkEmailW_subject(email));
        wprintf(L"%s\n",CkEmailW_ck_from(email));
        wprintf(L"--\n");
        i = i + 1;
    }



    CkImapW_Dispose(imap);
    CkMessageSetW_Dispose(messageSet);
    CkEmailBundleW_Dispose(bundle);
    CkEmailW_Dispose(email);

    }