AFNetworking get image if it is modified - ios

Question

I am using AFNetworking and download image if it is new image.
After I read though stackoverflow, currently, I am doing like this.
If the image is not modified, there will be cache in http header and I use that fact to check whether image is modified or not.
It is working well for most iOS. But, on iPhone 6s iOS 9.2.1, it always assume as new image.
How shall I detect whether image in server is modified already by using AFNetworking or may be NSUrlConnection?
- (void)downloadSplashScreenFromURL:(NSString *)urlStr
{
BOOL __block responseFromCache = YES; // yes by default
void (^requestSuccessBlock)(AFHTTPRequestOperation *operation, id responseObject) = ^(AFHTTPRequestOperation *operation, id responseObject) {
// response was returned from the server, not from cache
NSString *assestName = [urlStr lastPathComponent];
////WRITE TO FILEPATH
NSString *filePath = [splashDirectory() stringByAppendingString:
[NSString stringWithFormat:#"/%#", assestName]];
if (![[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
DLog(#"Splash : Splash image is empty");
NSData *pngData = UIImagePNGRepresentation(responseObject);
[pngData writeToFile:filePath atomically:YES];
return ;
}
if (responseFromCache) {
// response was returned from cache
DLog(#"SPLASH - RESPONSE FROM CACHE: %#", responseObject);
}
else {
DLog(#"SPLASH - NEW IMAGES FROM SERVER \n Response: %#", responseObject);
NSData *pngData = UIImagePNGRepresentation(responseObject);
[pngData writeToFile:filePath atomically:YES];
[[NSUserDefaults standardUserDefaults] removeObjectForKey:USERDEFAULTS_SPLASH_SCREEN];
[[SplashHelper sharedInstance] showSplash:YES inWindow:[AppDelegate instance].window andSuccessBlock:^{
[[AppDelegate instance] startRunning];
}];
}
};
void (^requestFailureBlock)(AFHTTPRequestOperation *operation, NSError *error) = ^(AFHTTPRequestOperation *operation, NSError *error) {
NSInteger statusCode = operation.response.statusCode;
DLog(#"SPLASH - status code: %lu \nERROR: %#", (long)statusCode, [error localizedDescription]);
DLog(#"SPLASH - ERROR: %#", error);
};
DLog(#"Splash : CALL SPLASH SCREEN HELPER");
AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
AFHTTPRequestOperation *operation = [manager GET:urlStr
parameters:nil
success:requestSuccessBlock
failure:requestFailureBlock];
[manager.requestSerializer setTimeoutInterval:3.0f];
operation.responseSerializer = [AFImageResponseSerializer serializer];
[operation setCacheResponseBlock:^NSCachedURLResponse *(NSURLConnection *connection, NSCachedURLResponse *cachedResponse) {
// this will be called whenever server returns status code 200, not 304
responseFromCache = NO;
DLog(#"Splash : cachedResponse = %#", cachedResponse);
return cachedResponse;
}];
}

Answer 1

I'm using #import "UIImageView+AFNetworking.h" category in my app to load an image from my server to app. Its working great, whenever an an update made for images on server, it'll generate new URLs, thus when I request with new URLs, AFNetworking will not find a cached image and will load new images from server.
And you should also check this, How do I get cached image stored by AFNetworking's UIImageView category? - there comes requirement when you needs to look after for an image inside your app's cache area.