Objective-C

Fetch a Chunk of Messages, Tracking Failures

Demonstrates the Chilkat Imap.FetchChunk2 method, which downloads a run of messages by sequence number and reports which succeeded and which failed. The arguments are the starting sequence number, the count, a MessageSet that receives the failed IDs, a MessageSet that receives the successfully-fetched IDs, and the EmailBundle. This example fetches the first chunk of messages and reports the success and failure counts.

Background: When bulk-downloading a large mailbox, individual messages can occasionally fail to fetch (a corrupt message on the server, a transient error) without failing the whole operation. FetchChunk2 is designed for that reality: it returns a partial EmailBundle plus two MessageSet objects so your code can log or retry exactly the messages that did not come through, rather than aborting the entire sync.

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Objective-C

#import <CkoImap.h>
#import <CkoMessageSet.h>
#import <CkoEmailBundle.h>

BOOL success = NO;

//  Demonstrates the Imap.FetchChunk2 method, which downloads a run of messages by sequence
//  number and reports which succeeded and which failed.  The 1st argument is the starting
//  sequence number, the 2nd is the count, the 3rd receives the failed IDs, the 4th receives
//  the successfully-fetched IDs, and the 5th is the EmailBundle.

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

imap.Ssl = YES;
imap.Port = [NSNumber numberWithInt:993];

success = [imap Connect: @"imap.example.com"];
if (success == NO) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

success = [imap Login: @"user@example.com" password: @"myPassword"];
if (success == NO) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

int numMessages = [imap SelectMailbox: @"Inbox"];
if (numMessages < 0) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

//  Fetch messages 1..25 (or fewer if the mailbox is smaller).
int count = 25;
if (count > numMessages) {
    count = numMessages;
}

CkoMessageSet *failedSet = [[CkoMessageSet alloc] init];
CkoMessageSet *fetchedSet = [[CkoMessageSet alloc] init];
CkoEmailBundle *bundle = [[CkoEmailBundle alloc] init];
success = [imap FetchChunk2: [NSNumber numberWithInt: 1] count: [NSNumber numberWithInt: count] failedSet: failedSet fetchedSet: fetchedSet bundle: bundle];
if (success == NO) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

NSLog(@"%@%d",@"Fetched: ",[fetchedSet.Count intValue]);
NSLog(@"%@%d",@"Failed:  ",[failedSet.Count intValue]);

success = [imap Disconnect];
if (success == NO) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}