Objective-C

Fetch an IMAP Attachment into a BinData

Demonstrates the Chilkat Imap.FetchAttachmentBd method, which stores one attachment's bytes in a BinData object. The first argument is the Email, the second is the zero-based attachment index, and the third is the BinData, which is cleared before the operation. This example fetches the first attachment and prints its byte count.

Background: A BinData holds raw bytes, so it works for any attachment type — image, PDF, zip, and so on. From there you can save it, hash it, or hand it to another API expecting a byte buffer, all without touching the filesystem. Use the string/StringBuilder variants only when the attachment is known to be text.

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Objective-C

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

BOOL success = NO;

//  Demonstrates the Imap.FetchAttachmentBd method, which downloads one attachment's bytes into
//  a BinData object.  The 1st argument is the Email, the 2nd is the zero-based attachment
//  index, and the 3rd is the BinData (which is cleared first).
//  
//  The message is fetched headers-only, then the attachment is downloaded on demand.

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;
}

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

//  Fetch only the message headers.  Attachment bodies are NOT downloaded, but the ckx-imap-*
//  metadata describing the attachments is present, so the attachment info methods still work.
BOOL headersOnly = YES;
BOOL useUid = NO;
int seqNum = 1;
CkoEmail *email = [[CkoEmail alloc] init];
success = [imap FetchEmail: headersOnly msgId: seqNum bUid: useUid email: email];
if (success == NO) {
    NSLog(@"%@",imap.LastErrorText);
    return;
}

int numAttach = [[imap GetMailNumAttach: email] intValue];
if (numAttach > 0) {
    //  Download just the first attachment's bytes from the server into a BinData.
    CkoBinData *bd = [[CkoBinData alloc] init];
    success = [imap FetchAttachmentBd: email attachmentIndex: [NSNumber numberWithInt: 0] binData: bd];
    if (success == NO) {
        NSLog(@"%@",imap.LastErrorText);
        return;
    }

    NSLog(@"%@%d%@",@"Attachment size: ",[bd.NumBytes intValue],@" bytes");
}

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