Invalid top-level type in JSON write'

Question

I am passing some parameter to api , to done add to cart function. But when i pass the parameter , it showing the crash Invalid top-level type in JSON write' i know there is the problem in my passing parameter . Please help me out!.How to do that.Please help me out !!!

This is the json format of parameter i am passing !!:

{
    "cartType" : "1",
    "cartDetails" : {
        "customerID" : "u",
        "cartAmount" : "6999",  
        "cartShipping" : "1",
        "cartTax1" : "69",
        "cartTax2" : "",
        "cartTax3" : "",
        "cartCouponCode" : "",
        "cartCouponAmount" : "",
        "cartPaymentMethod" : "",
        "cartProductItems" : {
            "productID" : "9",
            "productPrice" : "6999",
            "productQuantity" : "1"
        }
    }
}

My updated solution :

func addtocartapicalling ()
{
    let headers = [
        "cache-control": "no-cache",
        "postman-token": "4c933910-0da0-b199-257b-28fb0b5a89ec"
    ]

    let jsonObj:Dictionary<String, Any> = [
        "cartType" : "1",
        "cartDetails" : [
            "customerID" : "sathish",
            "cartAmount" : "6999",
            "cartShipping" : "1",
            "cartTax1" : "69",
            "cartTax2" : "",
            "cartTax3" : "",
            "cartCouponCode" : "",
            "cartCouponAmount" : "",
            "cartPaymentMethod" : "",
            "cartProductItems" : [
                "productID" : "9",
                "productPrice" : "6999",
                "productQuantity" : "1"
            ]
        ]
    ]

    if (!JSONSerialization.isValidJSONObject(jsonObj)) {
        print("is not a valid json object")
        return
    }

    if let postData = try? JSONSerialization.data(withJSONObject: jsonObj, options: JSONSerialization.WritingOptions.prettyPrinted) {
        let request = NSMutableURLRequest(url: NSURL(string: "http://expapi.php")! as URL,
                                          cachePolicy: .useProtocolCachePolicy,timeoutInterval: 10.0)
        request.httpMethod = "POST"
        request.allHTTPHeaderFields = headers
        request.httpBody = postData

        let session = URLSession.shared
        let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
            if (error != nil) {
                ///print(error)
            } else {

                DispatchQueue.main.async(execute: {

                    if let json = (try? JSONSerialization.jsonObject(with: data!, options: [])) as? Dictionary<String,AnyObject>
                    {
                        let status = json["status"] as? Int;
                        if(status == 1)
                        {
                            print("SUCCESS....")
                            if (json["CartID"] as? Int?) != nil
                            {
                                DispatchQueue.main.async(execute: {

                                    print("INSIDE CATEGORIES")
                                    self.addtocartdata.append(Addtocartmodel(json:CartID))


                                })
                            }

                        }

                    }
                })

            }
        })

        dataTask.resume()
    }
}

last problem in append the values :

In my model data class is look like this :

class Addtocartmodel

{
 var cartid : Int?
init(json:NSDictionary)
    {
         self.cartid = json["CartID"] as? Int
}
}

Answer 1

Your json has some wrong format.Use a dictionary is much clear than json in swift, and use JSONSerialization to convert the dictionary to json string.

The code looks like this:

func addtocartapicalling ()
{
    let headers = [
        "cache-control": "no-cache",
        "postman-token": "4c933910-0da0-b199-257b-28fb0b5a89ec"
    ]

    let jsonObj:Dictionary<String, Any> = [
        "cartType" : "1",
        "cartDetails" : [
            "customerID" : "sathish",
            "cartAmount" : "6999",
            "cartShipping" : "1",
            "cartTax1" : "69",
            "cartTax2" : "",
            "cartTax3" : "",
            "cartCouponCode" : "",
            "cartCouponAmount" : "",
            "cartPaymentMethod" : "",
            "cartProductItems" : [
                "productID" : "9",
                "productPrice" : "6999",
                "productQuantity" : "1"
            ]
        ]
    ]

    if (!JSONSerialization.isValidJSONObject(jsonObj)) {
        print("is not a valid json object")
        return
    }

    if let postData = try? JSONSerialization.data(withJSONObject: jsonObj, options: JSONSerialization.WritingOptions.prettyPrinted) {
        let request = NSMutableURLRequest(url: NSURL(string: "http://expapi.php")! as URL,
                                          cachePolicy: .useProtocolCachePolicy,timeoutInterval: 10.0)
        request.httpMethod = "POST"
        request.allHTTPHeaderFields = headers
        request.httpBody = postData

        let session = URLSession.shared
        let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
            if (error != nil) {
                print(error)
            } else {

                DispatchQueue.main.async(execute: {

                    if let json = (try? JSONSerialization.jsonObject(with: data!, options: [])) as? Dictionary<String,AnyObject>
                    {
                        let status = json["status"] as? Int;
                        if(status == 1)
                        {
                            print("SUCCESS....")
                            print(json)
                            if let CartID = json["CartID"] as? Int {
                                DispatchQueue.main.async(execute: {

                                    print("INSIDE CATEGORIES")
                                    print("CartID:\(CartID)")
                                    self.addtocartdata.append(Addtocartmodel(json:json))
                                })
                            }
                        }
                    }
                })
            }
        })

        dataTask.resume()
    }
}

Answer 2

There is a subtle difference

Try using this

JSONSerialization.jsonObject(with: data, options: []) as? [String:AnyObject] 

instead of

JSONSerialization.data(withJSONObject: data, options: []) as? [String:AnyObject]