loading data object from local file in Swift 3

Question

I'm struggling to get an image file loaded in Swift 3. Here is the code:

do {
    let imageData = try Data(contentsOf: imageUrl2.asURL()) 
} catch { 
    print ("loading image file error") 
}

And the current Url String is:

file:///Users/veikoherne/Library/Developer/CoreSimulator/Devices/889A08D5-B8CC-458C-99FF-643A4BA1A806/data/Containers/Data/Application/F64ED326-7894-4EE7-AA3B-B1BB10DF8259/Documents/img2017-03-23 17:39:24.jpg

and obviously I have checked that this file exists and is valid image. It always ends up telling me "loading image file error". Anyone have experiences loading local data in Swift 3?

The answer mentioned was using NSData object and probably Swift 2. Current Swift 3 refuses to bridge NSData to Data, that's why I have to use Data.

Answer 1

Loading data from local file you should use "contentsOfFile:" method.

Reference link: https://www.hackingwithswift.com/example-code/strings/how-to-load-a-string-from-a-file-in-your-bundle

So in case of reading data you can use:

Data(contentsOf: <URL>, options: <Data.ReadingOptions>)

Reading a plain text as a String, use:

String(contentsOfFile: <LocalFileDirPath>)

Reading an image from document directory, use:

UIImage(contentsOfFile: <LocalFileDirPath>)

Hope this would be helpful!

Answer 2

I experienced the same issue when trying to retrieve a file that I just downloaded. If you have saved a file from some url like I did, this should work:

let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first
let localUrl = documentDirectory.appendingPathComponent("somefile.txt")

if FileManager.default.fileExists(atPath: localUrl.path){
    if let cert = NSData(contentsOfFile: localUrl.path) {
        return cert as Data
    }
}