Make REST API call in Swift

Question

I\'m trying to use Swift to make a GET call to a REST API, and have tried to follow numerous tutorials, but can\'t figure it out. Either because I cannot figure out how to

Answer 1

Api Call using Model Class

    let urlString = "http://--.154.--.78/------/index.php?route=api/coupon/all"

    let url = URL(string: urlString)
    var request = URLRequest(url: url!)
    request.httpMethod = "GET"

    URLSession.shared.dataTask(with:request) { (data, response, error) in
        if error != nil {
            print(error)
        } else {
            do {

                let parsedDictionaryArray = try JSONSerialization.jsonObject(with: data!) as! [String:AnyObject]
                print(parsedDictionaryArray)

                if let arry = parsedDictionaryArray["data"] as? [[String:AnyObject]] {
                for dic in arry {
                    let name = dic["name"]
                    let descriptionData = dic["description"]
                    self.modelReference.append(model(name: name as! String, descriptionStr: descriptionData as! String))
                    print(name!)
                }
                }
            } catch let error as NSError {
                print(error)
            }
        }

        }.resume()

create a variable and connect with model class

var modelReference = [model]()

create a model class New -> swift class

import Foundation
class model : NSObject{
var name : String
var descriptionStr: String

init(name : String, descriptionStr: String)
{
    self.name = name
    self.descriptionStr = descriptionStr
}

}

then we can connect with our table view objects

let cell = tableView.dequeueReusableCell(withIdentifier: "TableViewCellID")as! TableViewCell
    cell.listName.text = modelReference[indexPath.row].name

Answer 2

let headers = [
                "cache-control": "no-cache",
                "postman-token": "6f8a-12c6-87a1-ac0f25d6385a"
            ]

            let request = NSMutableURLRequest(url: NSURL(string: "Your url string")! as URL,
                                              cachePolicy: .useProtocolCachePolicy,
                                              timeoutInterval: 10.0)
            request.httpMethod = "GET"
            request.allHTTPHeaderFields = headers

            let session = URLSession.shared
            let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
                if error == nil && data != nil {
                    do {
                        // Convert NSData to Dictionary where keys are of type String, and values are of any type
                        let json = try JSONSerialization.jsonObject(with: data!, options: JSONSerialization.ReadingOptions.mutableContainers) as! [String:AnyObject]
                        print(json)

                        //do your stuff

                      //  completionHandler(true)

                    } catch {
                       // completionHandler(false)
                    }
                }
                else if error != nil
                {
                    //completionHandler(false)
                }
            }).resume()
            }

Answer 3

Swift 5 & 4

let params = ["username":"john", "password":"123456"] as Dictionary<String, String>

var request = URLRequest(url: URL(string: "http://localhost:8080/api/1/login")!)
request.httpMethod = "POST"
request.httpBody = try? JSONSerialization.data(withJSONObject: params, options: [])
request.addValue("application/json", forHTTPHeaderField: "Content-Type")

let session = URLSession.shared
let task = session.dataTask(with: request, completionHandler: { data, response, error -> Void in
    print(response!)
    do {
        let json = try JSONSerialization.jsonObject(with: data!) as! Dictionary<String, AnyObject>
        print(json)
    } catch {
        print("error")
    }
})

task.resume()

Answer 4

edited for swift 2

let url = NSURL(string: "http://www.test.com")

    let task = NSURLSession.sharedSession().dataTaskWithURL(url!) {(data, response, error) in
        print(NSString(data: data!, encoding: NSUTF8StringEncoding))
    }

    task.resume()

Answer 5

If you're working in Swift 3, the syntax changes. The example here worked for me and has a good explanation of the steps: https://grokswift.com/simple-rest-with-swift/

This is the code from that tutorial:

let todoEndpoint: String = "https://jsonplaceholder.typicode.com/todos/1"
guard let url = URL(string: todoEndpoint) else {
  print("Error: cannot create URL")
  return
}
let urlRequest = URLRequest(url: url)

let task = session.dataTask(with: urlRequest) {
  (data, response, error) in
  // check for any errors
  guard error == nil else {
    print("error calling GET on /todos/1")
    print(error!)
    return
  }
  // make sure we got data
  guard let responseData = data else {
    print("Error: did not receive data")
    return
  }
  // parse the result as JSON, since that's what the API provides
  do {
    guard let todo = try JSONSerialization.jsonObject(with: responseData, options: [])
      as? [String: Any] else {
      print("error trying to convert data to JSON")
      return
    }
    // now we have the todo
    // let's just print it to prove we can access it
    print("The todo is: " + todo.description)

    // the todo object is a dictionary
    // so we just access the title using the "title" key
    // so check for a title and print it if we have one
    guard let todoTitle = todo["title"] as? String else {
      print("Could not get todo title from JSON")
      return
    }
    print("The title is: " + todoTitle)
  } catch  {
    print("error trying to convert data to JSON")
    return
  }
}
task.resume()

Answer 6

func getAPICalling(mainUrl:String) {
    //create URL
    guard let url = URL(string: mainUrl) else {
      print("Error: cannot create URL")
      return
    }
    //create request
    let urlRequest = URLRequest(url: url)
    
    // create the session
    let config = URLSessionConfiguration.default
    let session = URLSession(configuration: config)
    
    // make the request
    let task = session.dataTask(with: urlRequest) {
      (data, response, error) in
        
      // check for any errors
      guard error == nil else {
        print("error calling GET")
        print(error!.localizedDescription)
        return
      }
        
      // make sure we got data
      guard let responseData = data else {
        print("error: did not receive data")
        return
      }
        
      // convert Data in JSON && parse the result as JSON, since that's what the API provides
      do {
        guard let object = try JSONSerialization.jsonObject(with: responseData, options: [])
          as? [String: Any] else {
            print("error trying to convert data to JSON")
            return
        }
        //JSON Response
        guard let todoTitle = object["response"] as? NSDictionary else {
          print("Could not get todo title from JSON")
          return
        }
        
        //Get array in response
        let responseList = todoTitle.value(forKey: "radioList") as! NSArray
        
        for item in responseList {
            let dic = item as! NSDictionary
            let str = dic.value(forKey: "radio_des") as! String
            self.arrName.append(str)
            print(item)
        }
        
        DispatchQueue.main.async {
            self.tblView.reloadData()
        }
        
      } catch  {
        print("error trying to convert data to JSON")
        return
      }
    }
    task.resume()
}

Usage:

getAPICalling(mainUrl:"https://dousic.com/api/radiolist?user_id=16")