How to make NSURLSession POST request in Swift

Question

Hi I am very beginner for Swift and I am trying to make NSURLSession "Post" request sending some parameter like my below code

According to my below code response not coming from server can some one help me please

BackGroundClass:-

 import UIKit

protocol sampleProtocal{

    func getResponse(result:NSDictionary)
    func getErrorResponse(error:NSString)
}

class BackGroundClass: NSObject {

    var delegate:sampleProtocal?

    func callPostService(url:String,parameters:NSDictionary){


        print("url is===>\(url)")

        let request = NSMutableURLRequest(URL: NSURL(string:url)!)

        let session = NSURLSession.sharedSession()
        request.HTTPMethod = "POST"

        //Note : Add the corresponding "Content-Type" and "Accept" header. In this example I had used the application/json.
        request.addValue("application/json", forHTTPHeaderField: "Content-Type")
        request.addValue("application/json", forHTTPHeaderField: "Accept")

        request.HTTPBody = try! NSJSONSerialization.dataWithJSONObject(parameters, options: [])

        let task = session.dataTaskWithRequest(request) { data, response, error in
            guard data != nil else {
                print("no data found: \(error)")
                return
            }

            do {
                if let json = try NSJSONSerialization.JSONObjectWithData(data!, options: []) as? NSDictionary {
                    print("Response: \(json)")
                    self.mainResponse(json)
                } else {
                    let jsonStr = NSString(data: data!, encoding: NSUTF8StringEncoding)// No error thrown, but not NSDictionary
                    print("Error could not parse JSON: \(jsonStr)")
                    self.eroorResponse(jsonStr!)
                }
            } catch let parseError {
                print(parseError)// Log the error thrown by `JSONObjectWithData`
                let jsonStr = NSString(data: data!, encoding: NSUTF8StringEncoding)
                print("Error could not parse JSON: '\(jsonStr)'")
                self.eroorResponse(jsonStr!)
            }
        }

        task.resume()
    }

    func mainResponse(result:NSDictionary){
        delegate?.getResponse(result)
    }

    func eroorResponse(result:NSString){
        delegate?.getErrorResponse(result)
    }
}

ViewController:-

import UIKit

class ViewController: UIViewController,sampleProtocal {

    override func viewDidLoad() {
        super.viewDidLoad()

        let delegate = BackGroundClass();
        delegate.self;

        let params = ["scancode":"KK03799-008", "UserName":"admin"] as Dictionary<String, String>

        let backGround=BackGroundClass();
        backGround.callPostService("url", parameters: params)
    }

    func getResponse(result: NSDictionary) {
        print("Final response is\(result)");
    }

    func getErrorResponse(error: NSString) {
        print("Final Eroor code is\(error)")
    }
}

Answer 1

Swift 4 post example with json payload-

func postAction(_ sender: Any) {
    let Url = String(format: "your url")
    guard let serviceUrl = URL(string: Url) else { return }
    let parameterDictionary = ["username" : "Test", "password" : "123456"]
    var request = URLRequest(url: serviceUrl)
    request.httpMethod = "POST"
    request.setValue("Application/json", forHTTPHeaderField: "Content-Type")
    guard let httpBody = try? JSONSerialization.data(withJSONObject: parameterDictionary, options: []) else {
        return
    }
    request.httpBody = httpBody
    
    let session = URLSession.shared
    session.dataTask(with: request) { (data, response, error) in
        if let response = response {
            print(response)
        }
        if let data = data {
            do {
                let json = try JSONSerialization.jsonObject(with: data, options: [])
                print(json)
            } catch {
                print(error)
            }
        }
    }.resume()
}