(Objective-C) Fetch Full Email Given Email Header

When email headers are fetched using UIDs (not sequence numbers), then the resultant email object (containing only the header) will include auto-generated ckx-imap-* header fields to record information about the uid, attachments, etc. The IMAP UID of the email will be available in the "ckx-imap-uid" header. There will also be a "ckx-imap-isUid" header field having the value "YES" or "NO". If the email header was downloaded by UID, then "ckx-imap-isUID" will contain the value "YES" and the value of the "ckx-imap-uid" header field is the IMAP UID. If the "ckx-imap-isUID" header has a value of "NO", then the "ckx-imap-uid" header field represents the sequence number. (Sequence numbers of emails on the server can change over time, depending on whether emails are deleted. UIDs must be used to ensure that the correct full email is downloaded.)

The Chilkat Email object provides a GetImapUid method to return the UID from the ckx-imap-uid header. This can then be used to download the full email using the FetchSingle method. Assuming the UID is known, download a single email by UID from an IMAP mail server.

Chilkat Objective-C Library Downloads MAC OS X (Cocoa) Libs iOS Libs

#import <CkoImap.h>
#import <CkoEmail.h>

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

CkoImap *imap = [[CkoImap alloc] init];

// Connect to an IMAP server.
// Use TLS
imap.Ssl = YES;
imap.Port = [NSNumber numberWithInt:993];
BOOL success = [imap Connect: @"imap.someMailServer.com"];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

// Login
success = [imap Login: @"***" password: @"***"];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

// Select an IMAP mailbox
success = [imap SelectMailbox: @"Inbox"];
if (success != YES) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

CkoEmail *emailHeader = 0;
CkoEmail *emailFull = 0;

int uid = 2014;
BOOL isUid = YES;

// Fetch only the email header
emailHeader = [imap FetchSingleHeader: uid bUid: isUid];
if (imap.LastMethodSuccess == YES) {

    // Now fetch the full email
    int uidFromCkxHeader = [emailHeader GetImapUid];
    if (uidFromCkxHeader < 0) {
        // Failed. 

        NSLog(@"%@",@"No ckx-imap-uid header was found.");
        return;
    }

    emailFull = [imap FetchSingle: uidFromCkxHeader bUid: YES];
    if (imap.LastMethodSuccess == YES) {

        // OK, we have the full email, do whatever we want...

    }

}

// Disconnect from the IMAP server.
success = [imap Disconnect];