Download a file using AFNetworking

BJMWebService.m

/*
 * Downloading files using AFNetworking is not a 1-step process, but it's still pretty easy.  
 * 
 * NOTE: If you're downloading a file from S3, make sure to set the proper Content-Type.  For example,
 *       a zip file should ideally have the content type of application/zip.  
 * 
 * Inspired by various sources online.
 */

#pragma mark - Downloading Files

- (void)downloadFileAtPath:(NSString *)path andOnCompletion:(void (^)(NSURL *fileURL, NSError *error))completionBlock {
    NSURL *fileURL = [NSURL URLWithString:path];
    if( fileURL ) {
        NSURLRequest *request = [NSURLRequest requestWithURL:fileURL];
        AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];

        NSString *fullPath = [NSTemporaryDirectory() stringByAppendingPathComponent:[fileURL lastPathComponent]];
        [operation setOutputStream:[NSOutputStream outputStreamToFileAtPath:fullPath append:NO]];

        [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
            NSError *error = nil;
            [[NSFileManager defaultManager] attributesOfItemAtPath:fullPath error:&error];

            if (error) {
                DLog(@"Error: Couldn't download file at path: %@. Details: %@", path, error );
            } else {
                if( completionBlock ) {
                    NSURL *downloadedFileURL = [NSURL fileURLWithPath:fullPath];
                    completionBlock( downloadedFileURL, error );
                }
            }
        } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
            DLog( @"Error: Couldn't download file. Details: %@", error );

            if( completionBlock ) {
                completionBlock( nil, error );
            }
        }];

        [operation start];
    }
}