PHImageManager requestImageForAsset returns nil sometimes for iCloud photos
IosPhotosframeworkIos Problem Overview
Roughly 10% of the time PHImageManager.defaultManager().requestImageForAsset returns nil instead of a valid UIImage after first returning a valid though "degraded" UIImage. No error or other clue that I can see is returned in the info with the nil.
This seems to happen with photos that need to be downloaded from iCloud, with iCloud Photo Library and Optimize iPad Storage both enabled. I've tried changing the options, size, etc. but nothing seems to matter.
If I retry the requestImageForAsset after the failure it will usually correctly return a UIImage, though sometimes it requires a couple of retries.
Any idea what I might be doing wrong? Or is it just a bug in the Photos framework?
func photoImage(asset: PHAsset, size: CGSize, contentMode: UIViewContentMode, completionBlock:(image: UIImage, isPlaceholder: Bool) -> Void) -> PHImageRequestID? {
let options = PHImageRequestOptions()
options.networkAccessAllowed = true
options.version = .Current
options.deliveryMode = .Opportunistic
options.resizeMode = .Fast
let requestSize = !CGSizeEqualToSize(size, CGSizeZero) ? size : PHImageManagerMaximumSize
let requestContentMode = contentMode == .ScaleAspectFit ? PHImageContentMode.AspectFit : PHImageContentMode.AspectFill
return PHImageManager.defaultManager().requestImageForAsset(asset, targetSize: requestSize, contentMode: requestContentMode, options: options)
{ (image: UIImage!, info: [NSObject : AnyObject]!) in
if let image = image {
let degraded = info[PHImageResultIsDegradedKey] as? Bool ?? false
completionBlock(image: photoBlock.rotatedImage(image), isPlaceholder: degraded)
} else {
let error = info[PHImageErrorKey] as? NSError
NSLog("Nil image error = \(error?.localizedDescription)")
}
}
}
Ios Solutions
Solution 1 - Ios
I just went through this too. By my tests the issue appears on devices that have the "Optimize Storage" option enabled and resides in the difference between the two methods bellow:
[[PHImageManager defaultManager] requestImageForAsset: ...]
This will successfully fetch remote iCloud images if your options are correctly configured.
[[PHImageManager defaultManager] requestImageDataForAsset:...]
This function only works for images that reside on the phones memory or that were recently fetched from iCloud by your app on any other one.
Here's a working snippet I'm using -bear with me the Obj-c :)
PHImageRequestOptions *options = [[PHImageRequestOptions alloc] init];
options.deliveryMode = PHImageRequestOptionsDeliveryModeHighQualityFormat; //I only want the highest possible quality
options.synchronous = NO;
options.networkAccessAllowed = YES;
options.progressHandler = ^(double progress, NSError *error, BOOL *stop, NSDictionary *info) {
NSLog(@"%f", progress); //follow progress + update progress bar
};
[[PHImageManager defaultManager] requestImageForAsset:myPhAsset targetSize:self.view.frame.size contentMode:PHImageContentModeAspectFill options:options resultHandler:^(UIImage *image, NSDictionary *info) {
NSLog(@"reponse %@", info);
NSLog(@"got image %f %f", image.size.width, image.size.height);
}];
Updated for Swift 4:
let options = PHImageRequestOptions()
options.deliveryMode = PHImageRequestOptionsDeliveryMode.highQualityFormat
options.isSynchronous = false
options.isNetworkAccessAllowed = true
options.progressHandler = { (progress, error, stop, info) in
print("progress: \(progress)")
}
PHImageManager.default().requestImage(for: myPHAsset, targetSize: view.frame.size, contentMode: PHImageContentMode.aspectFill, options: options, resultHandler: {
(image, info) in
print("dict: \(String(describing: info))")
print("image size: \(String(describing: image?.size))")
})
Solution 2 - Ios
I found that this had nothing to do with network or iCloud. It occasionally failed, even on images that were completely local. Sometimes it was images from my camera, sometimes it would be from images saved from the web.
I didn't find a fix, but a work around inspired by @Nadzeya that worked 100% of the time for me was to always request a target size equal to the asset size.
Eg.
PHCachingImageManager().requestImage(for: asset,
targetSize: CGSize(width: asset.pixelWidth, height: asset.pixelHeight) ,
contentMode: .aspectFit,
options: options,
resultHandler: { (image, info) in
if (image == nil) {
print("Error loading image")
print("\(info)")
} else {
view.image = image
}
});
I believe the drawbacks to this would be that we're getting the full image back in memory, and then forcing the ImageView to do the scaling, but at least in my use case, there wasn't a noticeable performance issue, and it was much better than loading a blurry or nil image.
A possible optimization here is to re-request the image at it's asset size only if the image comes back as nil.
Solution 3 - Ios
I 've tried many things
- targetSize greater than (400, 400): not work
- targetSize equals to asset size: not work
- Disable
Optimize Storage
in iCloud Photos in Settings: not work - Dispatch
requestImage
to background queue: not work - Use
PHImageManagerMaximumSize
: not work - Use
isNetworkAccessAllowed
: not work - Play with different values in
PHImageRequestOptions
, likeversion
,deliveryMode
,resizeMode
: not work - Add a
progressHandler
: not work - Call
requestImage
again it cases it failed: not work
All I get is nil UIImage
and info with PHImageResultDeliveredImageFormatKey
, like in this radar Photos Frameworks returns no error or image for particular assets
Use aspect fit
What work for me, see https://github.com/hyperoslo/Gallery/blob/master/Sources/Images/Image.swift#L34
- Use
targetSize
with < 200: this is why I can load the thumbnail - Use
aspectFit
: Specify tocontentMode
does the trick for me
Here is the code
let options = PHImageRequestOptions()
options.isSynchronous = true
options.isNetworkAccessAllowed = true
var result: UIImage? = nil
PHImageManager.default().requestImage(
for: asset,
targetSize: size,
contentMode: .aspectFit,
options: options) { (image, _) in
result = image
}
return result
Fetch asynchronously
The above may cause race condition, so make sure you fetch asynchronously, which means no isSynchronous
. Take a look at https://github.com/hyperoslo/Gallery/pull/72
Solution 4 - Ios
I was seeing this as well, and the only thing that worked for me was setting options.isSynchronous = false
. My particular options are:
options.isNetworkAccessAllowed = true
options.deliveryMode = .highQualityFormat
options.version = .current
options.resizeMode = .exact
options.isSynchronous = false
Solution 5 - Ios
Nothing of the above worked for me, but this solution did!
private func getUIImage(asset: PHAsset, retryAttempts: Int = 10) -> UIImage? {
var img: UIImage?
let manager = PHImageManager.default()
let options = PHImageRequestOptions()
options.version = .original
options.isSynchronous = true
options.isNetworkAccessAllowed = true
manager.requestImage(for: asset, targetSize: CGSize(width: asset.pixelWidth, height: asset.pixelHeight), contentMode: .aspectFit, options: options, resultHandler: { image, _ in
img = image
})
if img == nil && retryAttempts > 0 {
return getUIImage(asset: asset, retryAttempts: retryAttempts - 1)
}
return img
}
The difference here is the recursive retries. This works for me 100% of the times.
Solution 6 - Ios
Try to use targetSize greater than (400, 400). It helped me.
Solution 7 - Ios
What it worked for me was letting PHImageManager loading the asset data synchronously, but from an asynchronous background thread. Simplified it looks like this:
DispatchQueue.global(qos: .userInitiated).async {
let requestOptions = PHImageRequestOptions()
requestOptions.isNetworkAccessAllowed = true
requestOptions.version = .current
requestOptions.deliveryMode = .opportunistic
requestOptions.isSynchronous = true
PHImageManager.default().requestImage(for: asset, targetSize: size, contentMode: .aspectFit, options: requestOptions) { image, _ in
DispatchQueue.main.async { /* do something with the image */ }
}
}
Solution 8 - Ios
The following fixed my issue:
let options = PHImageRequestOptions()
options.isSynchronous = false
options.isNetworkAccessAllowed = true
options.deliveryMode = .opportunistic
options.version = .current
options.resizeMode = .exact
Solution 9 - Ios
Starting with iOS 14, this could also happen if the user has not granted permission to use that particular photo using the limited photos picker. For more information, https://developer.apple.com/documentation/photokit/delivering_a_great_privacy_experience_in_your_photos_app
Solution 10 - Ios
I was also getting nil
for iCloud images. It didn't make a difference if I used requestImage
or requestImageData
flavor of the method. My problem, it turns out, was that my device was connected to the network via Charles Proxy since I wanted to monitor requests and responses app made. For some reason device couldn't work with iCloud if connected this way. Once I turned off the proxy app could get iCloud images.
Solution 11 - Ios
The solution for me was setting a targetSize
var image: UIImage?
let options = PHImageRequestOptions()
options.isNetworkAccessAllowed = true
options.isSynchronous = true
options.resizeMode = PHImageRequestOptionsResizeMode.exact
let targetSize = CGSize(width:1200, height:1200)
PHImageManager.default().requestImage(for: self, targetSize: targetSize, contentMode: PHImageContentMode.aspectFit, options: options) { (receivedImage, info) in
if let formAnImage = receivedImage
{
image = formAnImage
}
}
Good coding!