Swift: JSON Decode fails in some cases - json

Question

I have this struct
struct ProductInfo: Codable {
var code: String
var product_name: String?
var status: Int
enum CodingKeys: String, CodingKey {
case code
case product
case status
enum ProductCodingKeys: String, CodingKey {
case product_name
}
}
init(from decoder: Decoder) throws {
let rootContainer = try! decoder.container(keyedBy: CodingKeys.self)
let productContainer = try! rootContainer.nestedContainer(keyedBy: CodingKeys.ProductCodingKeys.self, forKey: .product)
product_name = try! productContainer.decode(String.self, forKey: .product_name)
code = try! rootContainer.decode(String.self, forKey: .code)
status = try! rootContainer.decode(Int.self, forKey: .status)
}
func encode(to encoder: Encoder) throws {
var rootContainer = encoder.container(keyedBy: CodingKeys.self)
var productContainer = rootContainer.nestedContainer(keyedBy: CodingKeys.ProductCodingKeys.self, forKey: .product)
try rootContainer.encode(code, forKey: .code)
try rootContainer.encode(status, forKey: .status)
try productContainer.encode(product_name, forKey: .product_name)
}
}
Problem is that is the product is not found on the DB, the CodingKey "product" will not exist, only code and status are available.
That means, this line
let productContainer = try! rootContainer.nestedContainer(keyedBy: CodingKeys.ProductCodingKeys.self, forKey: .product)
Will fail because the key is not found in the JSON Response.
My idea was to check the status value (which I have in the Response) but it seems not working
Thanks

Answer 1

You can use contains(_:):
if rootContainer.contains(.product) {
let productContainer = try rootContainer.nestedContainer(keyedBy: CodingKeys.ProductCodingKeys.self, forKey: .product)
product_name = try productContainer.decode(String.self, forKey: .product_name)
}
To test it:
let jsonStr = """
[
{
"code": "8001620004159",
"product": { "_id": "8001620004159", "product_name": "The San Benedetto" },
"status": 1,
"status_verbose": "product found"
},
{
"code": "4007843212122",
"status": 0,
"status_verbose": "product not found"
}
]
"""
let jsonData = Data(jsonStr.utf8)
do {
let decoder = JSONDecoder()
let items = try decoder.decode([ProductInfo].self, from: jsonData)
print(items)
} catch {
print("Error: \(error)")
}
Side note:
I'd avoid try! and replace them with try since the method throws already.