JSONDecoder failed to decode nested dictionaries - ios

Question

I'm using JSONDecoder to decode from a JSON file which has nested dictionaries. It fails to decode from the json data to my customized model.
This is what I have tried in my code.
The JSONDecoder looks like this:
let netWorkManager = NetWorkManager(URL: url, httpMethodType: .GET)
netWorkManager.callAPI { (data, status, error) in
guard let data = data else {
onFail(NetWorkError.otherError)
return
}
switch status {
case 200:
do{
if let responseModel = try JSONDecoder().decode(ResonseModel?.self, from: data) {
onSuccess(responseModel)
}
}catch {
onFail(NetWorkError.otherError)
}
default:
onFail(NetWorkError.otherError)
}
}
The model looks like this:
struct ResonseModel: Codable {
let type : String
let format: String
let data: [String: Champion]
struct Champion: Codable {
let version: String
let id: String
let key: Int
let name: String
let title: String
let blurb: String
}
}
The JSON structure looks like this:
{
"type": "champion",
"format": "standAloneComplex",
"version": "9.3.1",
"data": {
"Aatrox": {
"version": "9.3.1",
"id": "Aatrox",
"key": "266",
"name": "Aatrox",
"title": "the Darkin Blade",
"blurb": "Once honored defenders of Shurima against the Void, Aatrox and his brethren would eventually become an even greater threat to Runeterra, and were defeated only by cunning mortal sorcery. But after centuries of imprisonment, Aatrox was the first to find...",
"info": {
"attack": 8,
"defense": 4,
"magic": 3,
"difficulty": 4
},
"tags": [
"Fighter",
"Tank"
],
"partype": "Blood Well",
},
"Ahri": {
"version": "9.3.1",
"id": "Ahri",
"key": "103",
"name": "Ahri",
"title": "the Nine-Tailed Fox",
"blurb": "Innately connected to the latent power of Runeterra, Ahri is a vastaya who can reshape magic into orbs of raw energy. She revels in toying with her prey by manipulating their emotions before devouring their life essence. Despite her predatory nature...",
"info": {
"attack": 3,
"defense": 4,
"magic": 8,
"difficulty": 5
},
"tags": [
"Mage",
"Assassin"
],
"partype": "Mana",
},
...
this is the link for the JSON if you want to look into it: http://ddragon.leagueoflegends.com/cdn/9.3.1/data/en_US/champion.json
I want to decode the "data" property as a dictionary whose key is the name of the champion and value is the champion. But the jsonDecoder seems doesn't recognize my model structure. It ends up catch the error.

Answer 1

The JSON-parameter "key" is not an Integer.
Change it to String and it will work:
struct ResonseModel: Codable {
let type : String
let format: String
let data: [String: Champion]
struct Champion: Codable {
let version: String
let id: String
let key: String
let name: String
let title: String
let blurb: String
}
}

Answer 2

You can switch to manually decoding Champion in order to clean up the data.
struct ResonseModel: Decodable {
let type : String
let format: String
let data: [String: Champion]
struct Champion: Decodable {
let version: String
let id: String
let key: Int
let name: String
let title: String
let blurb: String
enum CodingKeys: String, CodingKey {
case version, id, key, name, title, blurb
}
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
self.version = try container.decode(String.self, forKey: .version)
self.id = try container.decode(String.self, forKey: .id)
guard let key = Int(try container.decode(String.self, forKey: .key)) else {
throw DecodingError.valueNotFound(Int.self,
.init(codingPath: decoder.codingPath,
debugDescription: "Bad value for id"))
}
self.key = key
self.name = try container.decode(String.self, forKey: .name)
self.title = try container.decode(String.self, forKey: .title)
self.blurb = try container.decode(String.self, forKey: .blurb)
}
}
}
This is basically the code that the compiler writes for you; it just converts the string into an int because that's what you really wanted.