Networking using JSONDecoder & codable protocol - json

Question

I am wondering what i am doing wrong . I am trying to understand how to use urlsession and codable protocol using JSONDecoder. When i use JSONDecoder i am getting the following error message :
keyNotFound(CodingKeys(stringValue: "name", intValue: nil), my resaponse contain ''name'' . But when i use JSONSerialization, I am able to print the response . If someone can explain me.
Code using JSONDecoder
struct Business:Codable {
let name: String
enum CodingKeys: String, CodingKey {
case name = "name"
}
init(from decoder: Decoder) throws {
let value = try decoder.container(keyedBy: CodingKeys.self)
self.name = try value.decode(String.self, forKey:CodingKeys.name)
}
}
let task = session.dataTask(with: request) { (data, response, error) in
if let response = response as? HTTPURLResponse {
print(response)
} else{
print("error")
}
guard let data = data else {return}
do {
let business = try JSONDecoder().decode(Business.self, from: data)
print(business.name)
} catch {
print("Error parsing JSON: \(error)")
}
}
task.resume()
Code using JSONSerialization
struct Business: Decodable {
let name: String
let displayAddress: String
let categories: String
let imageUrl : String
init(json: [String:Any]) {
name = json["name"] as? String ?? ""
displayAddress = json["location"] as? String ?? ""
categories = json["categories"] as? String ?? ""
imageUrl = json["image_url"] as? String ?? ""
}
}
let task = session.dataTask(with: request) { (data, response, error) in
if let response = response as? HTTPURLResponse {
print(response)
} else{
print("error")
}
guard let data = data else {return}
do {
if let myjson = try JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? Dictionary<String,Any> {
print(myjson)
}
} catch {
print("Error parsing ")
}
}
task.resume()
The response
["region": {
center = {
latitude = "43.67428196976998";
longitude = "-79.39682006835938";
};
}, "businesses": <__NSArrayM 0x60000211cff0>(
{
alias = "pai-northern-thai-kitchen-toronto-5";
categories = (
{
alias = thai;
title = Thai;
}
);
coordinates = {
latitude = "43.647866";
longitude = "-79.38864150000001";
};
"display_phone" = "[phone]";
distance = "3010.095870925626";
id = "r_BrIgzYcwo1NAuG9dLbpg";
"image_url" = "https://s3-media3.fl.yelpcdn.com/bphoto/t-g4d_vCAgZH_6pCqjaYWQ/o.jpg";
"is_closed" = 0;
location = {
address1 = "18 Duncan Street";
address2 = "";
address3 = "";
city = Toronto;
country = CA;
"display_address" = (
"18 Duncan Street",
"Toronto, ON M5H 3G8",
Canada
);
state = ON;
"zip_code" = "M5H 3G8";
};
name = "Pai Northern Thai Kitchen";
phone = "[phone]";
price = "$$";
rating = "4.5";
"review_count" = 2405;
transactions = (
);
url = "https://www.yelp.com/biz/pai-northern-thai-kitchen-toronto-5?adjust_creative=A4ydpSOHv8wBNquTDeh0DQ&utm_campaign=yelp_api_v3&utm_medium=api_v3_business_search&utm_source=A4ydpSOHv8wBNquTDeh0DQ";
},

Answer 1

Business is not the root data object in your JSON. You need something like this:
struct Business: Codable {
let name: String
}
struct RootObject: Codable {
let businesses: [Business]
}
let rootObject = try JSONDecoder().decode(RootObject.self, from: data)
print(rootObject.businesses.first?.name)