NSURLConnection sendSynchronousReques replacement - ios

Question

I have this chunk of code written in obj-c that I am trying to translate in Swift 3 but I encountered NSURLConnection.sendSynchronousRequest which is both deprecated and for my knowledge bad since it is using a Synchronous operation.
Here is the code :
NSData *responseData = [NSURLConnection sendSynchronousRequest:requestData returningResponse:&response error:&requestError];
NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingAllowFragments error:nil];
Do you have any suggestion in how I may re-write this in a better way and why so?

Answer 1

This is the minimum code you would need to make an async request, if you are replacing a lot of calls you should make an API layer and reuse code rather than copy/pasta everywhere.
let url = URL(string: "http://myURL.com")!;
let request = URLRequest(url: url)
let task = URLSession.shared.dataTask(with: request) { (data, response, error) in
let dictionary = try! JSONSerialization.jsonObject(with: data!, options: .allowFragments)
}
task.resume()

Answer 2

URLSession is a replacement for NSURLConnection introduced in iOS 7. The URLSession class and related classes provide an API for downloading content via HTTP/HTTPS protocols. URLSession API is asynchronous by default.
Below is the simple Get request using URLSession API
public func simpleNetworkRequest(completion: #escaping (_ JSON: [[String: Any]]?, _ error: Error?) -> Void) {
// Set up the URL request
let todoUrl: String = "https://jsonplaceholder.typicode.com/todos/1"
guard let url = URL(string: todoUrl) else {
print("Error: cannot create URL")
return
}
let urlRequest = URLRequest(url: url)
// set up the session
let config = URLSessionConfiguration.default
let session = URLSession(configuration: config)
// make the request
let task = session.dataTask(with: urlRequest) { (data, response, error) in
guard error != nil else {
print(error!.localizedDescription)
completion(nil, error)
return
}
// make sure we got data
guard let responseData = data else {
print("Error: did not receive data")
completion(nil, nil)
return
}
// parse the result as JSON, since that's what the API provides
do {
guard let JSON = try JSONSerialization.jsonObject(with: responseData, options: []) as? [String: AnyObject] else {
print("error trying to convert data to JSON")
completion(nil, nil)
return
}
print("JSON response : \(JSON)")
//code to parse json response and send it back via completion handler
let result = JSON["result"] as? [[String: Any]]
completion(result, nil)
} catch let error {
print(error.localizedDescription)
completion(nil, error)
}
}
task.resume()
}
Below are free resources to get you stated
https://videos.raywenderlich.com/courses/networking-with-nsurlsession/lessons/1
https://www.raywenderlich.com/110458/nsurlsession-tutorial-getting-started
Alternatively you can use Alamofore (recommended) to make network requests
Simple example to make request would be
Alamofire.request("https://httpbin.org/get").responseJSON { response in
print(response.request) // original URL request
print(response.response) // HTTP URL response
print(response.data) // server data
print(response.result) // result of response serialization
if let JSON = response.result.value {
print("JSON: \(JSON)")
}
}

Answer 3

try like this
var request = NSMutableURLRequest(URL: NSURL(string: "request url")!)
var session = NSURLSession.sharedSession()
request.HTTPMethod = "POST"
var params = ["username":"username", "password":"password"] as Dictionary<String, String>
request.HTTPBody = try? NSJSONSerialization.dataWithJSONObject(params, options: [])
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
var task = session.dataTaskWithRequest(request, completionHandler: {data, response, error -> Void in
print("Response: \(response)")})
task.resume()