SDWebImage NSURLRequests failing intermittently - ios

Question

I'm loading images from a remote server using SDWebImage into a UICollectionView using the following code:
[myCell.imageView setImageWithURL:imgURL placeholderImage:nil options:SDWebImageRetryFailed success:^(UIImage *image)
{
[_imageCache storeImage:image forKey:[imgURL absoluteString] toDisk:YES];
} failure:^(NSError *error){
NSLog(#"ERROR: %#", error);
}];
For most cells, this code works fine - it loads the images and saves them to my local disk. However, after several (it seems random?) images, they stop loading. I then get the following error:
ERROR: Error Domain=NSURLErrorDomain Code=-1001 "The request timed out." UserInfo=0x1d33fdc0 {NSErrorFailingURLStringKey=http://path/to/image.jpg, NSErrorFailingURLKey=http://path/to/image.jpg, NSLocalizedDescription=The request timed out., NSUnderlyingError=0x1d34c0f0 "The request timed out."}
When this happens, my app seems to stop sending NSURLRequests altogether. After a period of time, probably about 20-30 seconds, I can refresh the table and the failed images will load in correctly and the app will resume responding to all NSURLRequests perfectly fine.
I find that this tends to happen more often if I scroll down my collection view fast. Could it be trying to download too many at once? Is there a way to limit the number of concurrent downloads? This method appears to be deprecated in the latest SDWebImage code.

Answer 1

Figured it out. I was using MWPhotoBrowser in another part of my app. MWPhotoBrowser comes with an older/modified version of SDWebImage. I downloaded the latest version of SDWebImage from Github, renamed/refactored all of the files, and imported my newly updated and modified SDWebImage alongside the one MWPhotoBrowser relies on.
The new version of SDWebImage has solved my problem completely!

Answer 2

It's better if use asynchronous download by share manager and display when finish download with SDWebImage. Now, you can scroll fast to test.
- (UICollectionViewCell *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
MyCell *myCell = (MyCell *)[cv dequeueReusableCellWithReuseIdentifier:#"MyCell" forIndexPath:indexPath];
//Set placeholder
myCell.imageView.image = [UIImage imageNamed:#"placeholder.png"];
NSURL *cellImageURL = [NSURL URLWithString:[NSString stringWithFormat:#"%#",[self.collectionData objectAtIndex:indexPath.row]]];
[myCell.cellIndicator startAnimating];
SDWebImageManager *manager = [SDWebImageManager sharedManager];
[manager downloadWithURL:cellImageURL
delegate:self
options:0
success:^(UIImage *image, BOOL cached)
{
//Display when finish download
myCell.imageView.image = image;
[myCell.cellIndicator stopAnimating];
} failure:nil];
return cell;
}
*EDIT:
If problem still not solve on device: try to separate download and display
#interface ViewController ()
#property (retain , nonatomic) NSMutableArray *linksArray;
#property (retain , nonatomic) NSMutableArray *imagesArray;
#end
- (void)viewDidLoad
{
[super viewDidLoad];
[self initLinksArray];
//Add placehoder.png to your imagesArray
[self initImagesArray];
//Download to NSMultableArray
[self performSelectorInBackground:#selector(downloadImages) withObject:nil];
}
- (void)initImagesArray{
self.imagesArray = [[[NSMutableArray alloc] init] autorelease];
for (NSInteger i = 0; i < self.linksArray.count; i++) {
[self.imagesArray addObject:[UIImage imageNamed:#"placeholder.png"]];
}
}
- (void)downloadImages{
for (NSInteger i = 0; i < self.linksArray.count; i++) {
NSURL *cellImageURL = [NSURL URLWithString:[self.linksArray objectAtIndex:i]];
SDWebImageManager *manager = [SDWebImageManager sharedManager];
[manager downloadWithURL:cellImageURL
delegate:self
options:0
success:^(UIImage *image, BOOL cached)
{
[self.imagesArray replaceObjectAtIndex:i withObject:image];
} failure:nil];
}
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return [self.imagesArray count];;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
SDCell *cell = (SDCell *)[cv dequeueReusableCellWithReuseIdentifier:#"SDCell" forIndexPath:indexPath];
cell.cellImageView.image = [self.imagesArray objectAtIndex:indexPath.row];
return cell;
}