Question

as seen as ASIHTTP has been deprecated , for a new project i’m working on i’m trying to learn AFNetworking but i’m facing some problems i’m not able to solve.
i have the need to download many images from my website to save it locally. Unfortunately this images are not server standalone by the server but are incorporated into a plist that , with the image data returns to me some parameters

the php code that serves the image is this

$plist = new CFPropertyList();
$plist->add($maindict = new CFdictionary());
$maindict->add('foldername',new CFString($fol_name));
$file_ext = ($fol_name == "iPhoneRetina") ? "@2x.png" : ".png";
$file_path = "1";
$imgfile = __DIR__.'/documents/'.$file_path.'/'.$fol_name.'/doc_'.$file_path.'_pagina_'.$page_nr.$file_ext;
$imgbinary = fread(fopen($imgfile, "r"), filesize($imgfile));
$maindict->add('image',new CFData($imgbinary));
$maindict->add('page_nr',new CFNumber($page_nr));
$maindict->add('document_id',new CFNumber($doc_id));

to manage the request to this page of the server i’ve used this code

AFHTTPClient *client = [[AFHTTPClient alloc] initWithBaseURL:downloadURL];
    NSDictionary *params;
    AFHTTPRequestOperation *operation;
    for (int x = 0; x < 10; x++) {
        params = @{
            @"page_nr" : [NSNumber numberWithInt:x],
            @"doc_id" : @1,
        };
        NSMutableURLRequest *request = [client requestWithMethod:@"POST" path:@"/getMagazinePage.php" parameters:params];
        operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
        [tempOperations addObject:operation];
    }
    [client enqueueBatchOfHTTPRequestOperations:tempOperations
                                  progressBlock:^(NSUInteger numberOfCompletedOperations, NSUInteger totalNumberOfOperations) {
                                      dispatch_async(dispatch_get_main_queue(), ^{
                                          [cell setDownloadProgress:(float)numberOfCompletedOperations/(float)totalNumberOfOperations];
                                      });

                                  } completionBlock:^(NSArray *operations) {
                                      [cell setDownloaded:YES];
/*                                      for (AFHTTPRequestOperation *ro in operations) {

                                          if (ro.error) {

                                              NSLog(@"++++++++++++++ Operation error");

                                          }else {
                                              //NSLog(@"Operation OK: %@", [ro.responseData description]);
                                          }
                                      }*/

                                  }];

But i’m not able to save the image during the progress block ( as because i have no other parameters to the block ) and iterate trough the operation array may be a little memory consuming, in case images are really heavy or there are a lot of pages.
i’ve read that someone suggest to use the

operation.outputStream = [NSOutputStream outputStreamToFileAtPath:@"download.zip" append:NO];

but in this case i have no direct stream of the image but a value contained in an plist.
Does anyone faced with this problem and how solved it ?

Answer 1

You can set completionBlock on each of the operations to do whatever you need, whether that’s saving the responseData somewhere, or what have you.

Note that there is no guarantee that the completion blocks for all operations will be finished by the time that the batch completes, so don’t depend on that in the batch completion block.