Storing photos locally persistently - ios

Question

I want to store a couple of images locally in my app on the user's device.
What I was using until now (it's still in development):
static func filePath(forKey key: String) -> URL? {
let fileManager = FileManager.default
guard let documentURL = fileManager.urls(for: .documentDirectory,
in: FileManager.SearchPathDomainMask.userDomainMask).first else { return nil }
return documentURL.appendingPathComponent(key + ".png")
}
static func savePhoto(imageKey: String) {
if let filePath = Helpers.filePath(forKey: imageKey) {
do {
try Constants.PHOTO_DATA.write(to: filePath, options: .atomic)
} catch {
print("error")
}
} else {
print(" >>> Error during saving photo. Filepath couldn't be created.")
}
}
static func getPhoto(imageKey: String) -> (image: UIImage, placeholder: Bool) {
if let filePath = Helpers.filePath(forKey: imageKey),
let fileData = FileManager.default.contents(atPath: filePath.path),
let image = UIImage(data: fileData) {
// Retrieve image from device
return (image, false)
}
return (UIImage(named: "placeholder")!, true)
}
Now, during testing I realized that it is not working (but I'm almost 100% sure it was working until now, strange..). It is changing the App's container directory upon every launch.
E.g.
Path:
/var/mobile/Containers/Data/Application/1F3E812E-B128-481C-9724-5E39049D6C81/Documents/D5F14199-CFBF-402A-9894-3487976C4C74.png
Restarting the app, then the path it gives (and where it does not find the image):
/var/mobile/Containers/Data/Application/0A9FCE45-1ED4-46EB-A91B-3ECD56E6A31B/Documents/D5F14199-CFBF-402A-9894-3487976C4C74.png
I read a bit and as far as I see it is 'expected' that it is not working, as the app's directory can change any time the user restarts the app. I should use bookmarkData of the URL class.
My problem is that I couldn't get it working with bookmarkData as I don't really see how should I use it, and couldn't understand its behavior based on some example codes/articles I found. Until now I was simply using URLs to store/retrieve the photo but now I should go with this bookmarkData which is a Data type, which confuses me.

Answer 1

I'm not sure what you want your code means, since both Helper and Constants.PHOTO_DATA are unknown. The code that will definitely will save a UIImage in the documents directory is here:
class ImageSaver {
private let imageStore = FileManager().urls(for: .documentDirectory, in: .userDomainMask).first
//Make this static variable to allow access from all objects without instantiating this class
static var shared : AuxiliaryObjects {
return AuxiliaryObjects()
}
/**
Declaration: save(image : UIImage, with fileName: String, and imageName: String?)
Description: This method saves the received image to the persistent store in the documents directory of the user.
- Parameter image: The UIImage object that must be stored in the documents directory.
- Parameter fileName: A string with the name under which the image must be stored.
- Parameter imageName: The name of the image if needed.
*/
func save(image: UIImage, with fileName: String, and imageName: String?) {
let fileStore = imageStore?.appendingPathComponent(fileName)
let imageData = UIImagePNGRepresentation(image)
do {
try imageData?.write(to: fileStore!)
} catch {
print("Couldn't write the image to disk.")
}
}
/**
Declaration: getImage(with fileName: String, with rectangle: CGRect) -> UIImage?
Description: This method retrieves the image with the specified file name and a given size.
- Parameter fileName: a string with the file name to retrieve.
- Parameter rectangle: the size of the image to return.
- Returns: UIImage?, the image retrieved from the documents directory.
*/
func getImage(with fileName: String, with rectangle: CGRect) -> UIImage? {
var returnImage : UIImage?
var imageRectangle = rectangle
do {
imageStoreArray = try FileManager.default.contentsOfDirectory(at: imageStore!, includingPropertiesForKeys: resourceKeys, options: .skipsHiddenFiles) as [NSURL]
} catch {
return returnImage
}
for url in imageStoreArray {
let urlString = url.lastPathComponent
if urlString == fileName {
let retrievedImage = UIImage(contentsOfFile: url.path!)
//When there is no size set, the original size image is returned
if (rectangle.size.height > 0) || (rectangle.size.width > 0) {
let imageWidth = retrievedImage?.size.width
let imageHeight = retrievedImage?.size.height
if imageWidth! > imageHeight!
{
//The picture is wider than it is high
imageRectangle.size.height *= (imageHeight! / imageWidth!)
} else {
imageRectangle.size.width *= (imageWidth! / imageHeight!)
}
UIGraphicsBeginImageContextWithOptions(imageRectangle.size, false, UIScreen.main.scale)
retrievedImage?.draw(in: imageRectangle)
returnImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
} else {
returnImage = retrievedImage
}
}
}
return returnImage
}
}
Let me know if this works for you.
Kind regards,
MacUserT