Keep Downloaded File (Cache) For The Next Time Application Open - ios

Question

I download external pdf file using this Alamofire way.
The problem is, I would like to keep it for the next time user open the app. So the user does not need to download the pdf again.
I use the following method to download
let destination =
Alamofire.Request.suggestedDownloadDestination(directory: .CachesDirectory,
domain: .UserDomainMask);
Alamofire.download(.GET, urlString, destination: destination)
.progress { bytesRead, totalBytesRead, totalBytesExpectedToRead in
}
.response { request, response, _, error in
print("Downloaded to \(destination(NSURL(string: "")!, response!))");
}
The downloadedFilePath is something like this.
file:///var/mobile/Containers/Data/Application/4957AD15-947A-47D6-A126-EA06A5BCB099/Library/Caches/RewardMe-Presentation-at-NVIDIA-Auditorium.pdf
How do I keep the file for the next time my app launches?
I saved that path into NSUserDefaults the next time the app launches but the file is already gone.

Answer 1

There is a couple of functions add them into you code and call the copyFile where you are showing the path or after that.
func getPath(fileName: String) -> String {
let documentsURL = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0]
let fileURL = documentsURL.URLByAppendingPathComponent(fileName)
print("File Path Is : \(fileURL)")
return fileURL.path!
}
func copyFile(fileName: NSString , filePath : NSString) {
let dPath: String = getPath(fileName as String)
let fileManager = NSFileManager.defaultManager()
if !fileManager.fileExistsAtPath(dPath) {
let fromPath : NSURL = NSURL.fileURLWithPath(filePath);
var error : NSError?
do {
try fileManager.copyItemAtPath(fromPath.path!, toPath: dPath)
} catch let error1 as NSError {
error = error1
}
let alert: UIAlertView = UIAlertView()
if (error != nil) {
alert.title = "Error Occured"
alert.message = error?.localizedDescription
} else {
alert.title = "Successfully Copy"
alert.message = "Your File copy successfully"
}
alert.delegate = nil
alert.addButtonWithTitle("Ok")
alert.show()
}
}
copyFile two parameter one is file name for the file you want to save and second is where the file located.
And for checking what to do next time when application open. First get file path and check the file exist or not. If exist the d'not download the file otherwise download file.
let filePath: String = getPath("testFile.pdf")
let fileManager = NSFileManager.defaultManager()
if fileManager.fileExistsAtPath(dPath) {
//Code for using the file data
}
else {
//Download code for the file
}
Hope it helps :)

Answer 2

HTTP already has a caching mechanism, you could consider using it. Don't re-invent the wheel. Here's a way to do it.