How to decode a JSON with 2 structs that has an array

Question

I'm trying to decode a JSON response but I get an error that says:

The data couldn’t be read because it isn’t in the correct format

The response is in array that went in a ["Product"] node. I get responses but I think the node in ["PictureCollection"] is not properly decoded due to my incorrect format.

Here is the API response. Some API objects are not yet needed. Only the properties I included in Product.swift model.

"RMessage" : "OK",
"RSuccess" : true,
"RValue" : null,
"InputKeyword" : “Soap”,
"ProductSearchMode" : 4,
"Product" : [
{
  "MinPrice" : 2000,
  "Gname" : “Soap Brand 1”,
  "MaxPrice" : 3190,
  "IconFlgList" : [

  ],
  "SoldoutFlg" : null,
  "PictureCollection" : {
    "Count" : 1,
    "URL" : [
      "https:someURL.jpg"
    ]
  },
  "ProgramBroadcastDate" : null,
  "ID" : 107,
  "Icon2OffValue" : “555”,
  "Gcode" : “3333”
},
{
  "Gcode" : “3334”,
  "IconFlgList" : [

  ],
  "PictureCollection" : {
    "Count" : 1,
    "URL" : [
      "https:https:someURL1.jpg"
    ]
  },
  "MaxPrice" : 2100,
  "SoldoutFlg" : null,
  "Icon2OffValue" : “551”,
  "ProgramBroadcastDate" : null,
  "ID" : 108,
  "MinPrice" : 2001,
  "Gname" : "Soap Brand 2”

This is my code:

struct Product: Codable {

var id : Int!
var gcode : String!
var gname : String!
var minPrice : Int!
var maxPrice : Int!
var pictureCollection : PictureCollection

enum CodingKeys : String, CodingKey {
    case id = "ID"
    case gcode = "GCode"
    case gname = "Gname"
    case minPrice = "MinPrice"
    case maxPrice = "MaxPrice"
    case pictureCollection = "PictureCollection"
}


struct PictureCollection : Codable {
var Count : Int!
var URL : String!
}

var product : Product!
var productArray = [Product]()


let jsonResult = JSON(data)

for json in jsonResult["Product"].arrayValue {
        let jsonData = try json.rawData()
        self.product = try JSONDecoder().decode(Product.self,   from: jsonData)
        self.productArray.append(self.product)

    }

Answer 1

The issue is with the struct PictureCollection.

struct PictureCollection : Codable {
   var count : Int!
   var url : String!
}

In the JSON you provided, URL is an array of String. But in the model PictureCollection, you are using URL of type String.

So, your struct PictureCollection should be,

struct PictureCollection : Codable {
   var count : Int
   var url : [String]
}

And, there is no need to use force-unwrapped types (!) here. Avoid using them unnecessarily. It might result in runtime exception.

Also, embed your call to decode(_:from:) in a do-catch block and print the whole error object in the catch block to find the exact reason for the issue, i.e.

do{
    //decode the JSON here...
} catch {
    print(error)
}