Swift 3 - Saving images to Core Data

Question

For some reason I can't figure out how to save images to core data and fetch them again. I have a feeling it's something about my types but have a look:

I get my data from an api call to my server. It returns a base64 string. Here is where I get the data:

updateAccessTokenOnly(newAccessToken: aToken!)
saveImageToDB(brandName: imageBrandName, image: data! )

Here I save it to my DB:

func saveImageToDB(brandName: String, image: Data) {
    dropImages(){tableDropped in
        let managedContext = getContext()
        let entity = NSEntityDescription.entity(forEntityName: "CoffeeShopImage", in: managedContext)!
        let CSI = NSManagedObject(entity: entity, insertInto: managedContext)

        CSI.setValue(image, forKey: "image")
        CSI.setValue(brandName, forKey: "brandName")

        do {
            try managedContext.save()
            print("saved!")
        } catch let error as NSError {
            print("Could not save. \(error), \(error.userInfo)")
        }
    }
}

then to fetch it:

    func getImageFromDB(callback: @escaping (_ image: UIImage)-> ()) {

    let fetchRequest: NSFetchRequest<NSManagedObject> = NSFetchRequest(entityName: "CoffeeShopImage")

    do {
        let searchResults = try getContext().fetch(fetchRequest)

        for images in searchResults {
            print("vi når her ned i get image")
            if (images.value(forKey: "brandName")! as! String == "Baresso"){
                print(images.value(forKey: "brandName")! as! String)

                let image: Data = images.value(forKey: "image")! as! Data
                let decodedimage = UIImage(data: image)

                callback(decodedimage!)

            }
        }
    } catch {
        print("Error with request: \(error)")
    }
}

Full error log:

https://docs.google.com/document/d/1gSXE64Sxtzo81eBSjv4bnBjBnnmG4MX2tuvNtnuJDIM/edit?usp=sharing

Hope someone can help. Thanks in advance!

UPDATED

So I uninstalled the app and then the code above worked. However the pictures come out blue? (yes I've checked that the pictures sent from the database are correct).

Any solution?

Answer 1

replace

let image: Data = images.value(forKey: "image")! as! Data
let dataDecoded : Data = Data(base64Encoded: image, options: [])!
let decodedimage = UIImage(data: dataDecoded)

with

let image: Data = images.value(forKey: "image")! as! Data
let decodedimage = UIImage(data: image)

Base64 is a way to to convert data to a string. There is no reason to use it here. You already have the data from the database you just want to convert it to a UIImage.

also change

let image = data?.base64EncodedData()
saveImageToDB(brandName: imageBrandName, image: image!)

to

saveImageToDB(brandName: imageBrandName, image: data!)

base64EncodedData is turning the data from image data into a utf-8 encoded based64encoded string. There is no reason for that.

You should get the base64 encoded string from server, convert it to data and then you never need base64 again. Read and write data to your database, and after you read it convert it to a UIImage. Base64 is an encoding method to transfer data. If you are not talking to the server there is no reason to use base64.

Answer 2

After the suggested corrections from Jon Rose all I needed was to add

.withRenderingMode(.alwaysOriginal)

to where I was showing my picture and the code worked.

Answer 3

Saving Image:

 guard let managedObjectContext = managedObjectContext else { return }

    // Create User
    let user = User(context: managedObjectContext)

    // Configure User
    user.name = "name"
    user.about = "about"
    user.address = "Address"
    user.age = 30
    if let img = UIImage(named: "dog.png") {
        let data = img.pngData() as NSData?
        user.image = data
    }

Fetching Image:

// Create Fetch Request
    let fetchRequest: NSFetchRequest<User> = User.fetchRequest()

    // Configure Fetch Request
    fetchRequest.sortDescriptors = [NSSortDescriptor(key: "name", ascending: true)]
    let users = try! managedContext.fetch(fetchRequest)
    let user: User = users.first as! User
    if let imageData = user?.image {
            imgView.image = UIImage(data: imageData as Data)
    }