post json request in swift

Question

I know how to post simple json:

 // Compose a query string
 let postString = “firstName=James&lastName=Bond”;
 request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding);

Now the server side require the json format like:

{ 
"name": "testuser123", 
"pass": "testuser123", 
"field_shouji": 
  { "und": 
    [{ 
      "value": "15652344931" 
    }] 
  }
}

and the content type should be: application/json. I have googled the whole day, still could find the right way.

Answer 1

You need to send a valid format of JSON.
“firstName=James&lastName=Bond”; is not JSON format.

Swift 4

Since Swift 3 and 4 Apple is starting to remove NS* stuff (even that many of them are just aliases to NS*) we'll use more Swift way

//Method just to execute request, assuming the response type is string (and not file)
func HTTPsendRequest(request: URLRequest,
                     callback: @escaping (Error?, String?) -> Void) {
    let task = URLSession.shared.dataTask(with: request) { (data, res, err) in
        if (err != nil) {
            callback(err,nil)
        } else {
            callback(nil, String(data: data!, encoding: String.Encoding.utf8))
        }
    }
    task.resume()
}

// post JSON
func HTTPPostJSON(url: String,  data: Data,
                  callback: @escaping (Error?, String?) -> Void) {
    
    var request = URLRequest(url: URL(string: url)!)
    
    request.httpMethod = "POST"
    request.addValue("application/json",forHTTPHeaderField: "Content-Type")
    request.addValue("application/json",forHTTPHeaderField: "Accept")
    request.httpBody = data
    HTTPsendRequest(request: request, callback: callback)
}

Usage example

var dict = Dictionary<String, Any>()

dict["username"] = "hello"
dict["password"] = "swift"
let data = try JSONSerialization.data(withJSONObject: dict, options: [])

HTTPPostJSON(url: "http://example.com/login", data: data) { (err, result) in
    if(err != nil){
        print(err!.localizedDescription)
        return
    }
    print(result ?? "")
}

---

Swift < 4

func HTTPsendRequest(request: NSMutableURLRequest,
    callback: (String, String?) -> Void) {
        let task = NSURLSession.sharedSession()
            .dataTaskWithRequest(request) {
                (data, response, error) -> Void in
                if (error != nil) {
                    callback("", error.localizedDescription)
                } else {
                    callback(NSString(data: data,
                        encoding: NSUTF8StringEncoding)! as String, nil)
                }
        }
        
        task.resume()
}

func HTTPPostJSON(url: String,  data: NSData,
    callback: (String, String?) -> Void) {
        
        var request = NSMutableURLRequest(URL: NSURL(string: url)!)
        
        request.HTTPMethod = "POST"
        request.addValue("application/json",forHTTPHeaderField: "Content-Type")
        request.addValue("application/json",forHTTPHeaderField: "Accept")
        request.HTTPBody = data
        HTTPsendRequest(request, callback: callback)
}

Usage example

we'll set NSMutableDictionary and convert it to JSON

var json = NSMutableDictionary()
json.setValue("testuser123", forKey: "name"); //set all your values..

let data = NSJSONSerialization.dataWithJSONObject(json, options: NSJSONWritingOptions(0), error: nil);
HTTPPostJSON("http;..", data:data!) { (response, error) -> Void in
    println(response);
}