How to download file in swift?
Example downloader class without Alamofire:
class Downloader {
class func load(URL: NSURL) {
let sessionConfig = NSURLSessionConfiguration.defaultSessionConfiguration()
let session = NSURLSession(configuration: sessionConfig, delegate: nil, delegateQueue: nil)
let request = NSMutableURLRequest(URL: URL)
request.HTTPMethod = "GET"
let task = session.dataTaskWithRequest(request, completionHandler: { (data: NSData!, response: NSURLResponse!, error: NSError!) -> Void in
if (error == nil) {
// Success
let statusCode = (response as NSHTTPURLResponse).statusCode
println("Success: \(statusCode)")
// This is your file-variable:
// data
}
else {
// Failure
println("Failure: %@", error.localizedDescription);
}
})
task.resume()
}
}
This is how to use it in your own code:
class Foo {
func bar() {
if var URL = NSURL(string: "http://www.mywebsite.com/myfile.pdf") {
Downloader.load(URL)
}
}
}
Swift 3 Version
Also note to download large files on disk instead instead in memory. see `downloadTask:
class Downloader {
class func load(url: URL, to localUrl: URL, completion: @escaping () -> ()) {
let sessionConfig = URLSessionConfiguration.default
let session = URLSession(configuration: sessionConfig)
let request = try! URLRequest(url: url, method: .get)
let task = session.downloadTask(with: request) { (tempLocalUrl, response, error) in
if let tempLocalUrl = tempLocalUrl, error == nil {
// Success
if let statusCode = (response as? HTTPURLResponse)?.statusCode {
print("Success: \(statusCode)")
}
do {
try FileManager.default.copyItem(at: tempLocalUrl, to: localUrl)
completion()
} catch (let writeError) {
print("error writing file \(localUrl) : \(writeError)")
}
} else {
print("Failure: %@", error?.localizedDescription);
}
}
task.resume()
}
}
Swift 4 and Swift 5 Version if Anyone still needs this
import Foundation
class FileDownloader {
static func loadFileSync(url: URL, completion: @escaping (String?, Error?) -> Void)
{
let documentsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let destinationUrl = documentsUrl.appendingPathComponent(url.lastPathComponent)
if FileManager().fileExists(atPath: destinationUrl.path)
{
print("File already exists [\(destinationUrl.path)]")
completion(destinationUrl.path, nil)
}
else if let dataFromURL = NSData(contentsOf: url)
{
if dataFromURL.write(to: destinationUrl, atomically: true)
{
print("file saved [\(destinationUrl.path)]")
completion(destinationUrl.path, nil)
}
else
{
print("error saving file")
let error = NSError(domain:"Error saving file", code:1001, userInfo:nil)
completion(destinationUrl.path, error)
}
}
else
{
let error = NSError(domain:"Error downloading file", code:1002, userInfo:nil)
completion(destinationUrl.path, error)
}
}
static func loadFileAsync(url: URL, completion: @escaping (String?, Error?) -> Void)
{
let documentsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let destinationUrl = documentsUrl.appendingPathComponent(url.lastPathComponent)
if FileManager().fileExists(atPath: destinationUrl.path)
{
print("File already exists [\(destinationUrl.path)]")
completion(destinationUrl.path, nil)
}
else
{
let session = URLSession(configuration: URLSessionConfiguration.default, delegate: nil, delegateQueue: nil)
var request = URLRequest(url: url)
request.httpMethod = "GET"
let task = session.dataTask(with: request, completionHandler:
{
data, response, error in
if error == nil
{
if let response = response as? HTTPURLResponse
{
if response.statusCode == 200
{
if let data = data
{
if let _ = try? data.write(to: destinationUrl, options: Data.WritingOptions.atomic)
{
completion(destinationUrl.path, error)
}
else
{
completion(destinationUrl.path, error)
}
}
else
{
completion(destinationUrl.path, error)
}
}
}
}
else
{
completion(destinationUrl.path, error)
}
})
task.resume()
}
}
}
Here is how to call this method :-
let url = URL(string: "http://www.filedownloader.com/mydemofile.pdf")
FileDownloader.loadFileAsync(url: url!) { (path, error) in
print("PDF File downloaded to : \(path!)")
}