How to save text file as variable in IOS - ios

Question

I am sending some images via socket and I would like to create text file with information about the images to send over the network as well. I right now I can send the images no problem by creating a variable for the image data like so
let imageData = UIImageJPEGRepresentation(someUIImage, 1.0)
How do create a variable with the data of the text file?
let textData = someTextFileAsData.....

Answer 1

Is this what you want?
let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
// Get the URL to the file. Below is an example
let fileURL = documentsDirectory.appendingPathComponent("test").appendingPathExtension("txt") // Replace "test" with your fileName and "txt" with your fileExtension
var text = ""
do {
text = try String(contentsOf: fileURL)
} catch {
fatalError("error: \(error.localizedDescription)")
}

Answer 2

Expanding a bit on Anthonin C.'s answer:
Each file in iOS is identified by a URL (just like a webpage, but this is a URL referring to the iOS filesystem). There are a few places in the system where you can save files, most of which you can get the URLs for by reading
FileManager.default.urls(for: SearchPathDirectory, in: SearchPathDomainMask)
(FileManager class reference).
For instance, to save in the user's personal "documents" directory, you would do:
let fileName = "socketLog.txt"
if let dir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first {
//build full path to file
let path = dir.appendingPathComponent(fileName)
do {
try text.write(to: path, atomically: false, encoding: String.Encoding.utf8)
}
catch {/* error handling here */}
}
where text would be the string data you want to save.

Answer 3

You should use write(to:​ URL, atomically:​ Bool) or write(to​File:​ String, atomically:​ Bool) of NSData method to write your data in a file.
In your case it would be :
let imageData = UIImageJPEGRepresentation(someUIImage, 1.0)
imageData.writeToFile("imageData.txt", atomically:true)
You can then restore it like that :
var imageData = NSData(contentsOfFile: "imageData.txt")
And to get back the image from data :
let image : UIImage = UIImage(data: imageData)