Question 68940 in IOS Swift Question posted in
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working with similar json objects, casting int to string – Ios swift

i am working with a service that have both a websocket for live data and a api for historical data

the JSON looks similar and i would like to decode it to the same object
the only difference is that in the live one variable is a number but as a string and with the historical data the number is an int.

and preferably i would like to not have to create 2 almost identical decodable objects.

have anyone tried something similar.

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2

Answers


  1. 0

    I think you need a wrapper for that case of some sort. To make it as convenient as possible you could use a property wrapper for this

    @propertyWrapper
struct NormalOrStringyInt: Decodable {
    var wrappedValue: Int?

    init(from decoder: Decoder) throws {
        let container = try decoder.singleValueContainer()
        if let value = try? container.decode(Int.self) {
            wrappedValue = value
        } else if
            let string = try? container.decode(String.self),
            let value = Int(string)
        {
            wrappedValue = value
        } else {
            wrappedValue = nil // default value
        }
    }
}

struct Model: Codable { 
    @NormalOrStringyInt var id: Int? 
    var someInt: Int
    var someString: String
    ...
}

let model = try! JSONDecoder().decode(Model, from: data)
let id: Int? = model.id.wrappedValue
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  2. 0

    You have to define a single type (Int or String) for your data structure and use init with Decoder to make a custom parsing.

    struct MyData: Decodable {
    let value: Int // Could be Int or String from different services
}

extension MyData {
    enum CodingKeys: String, CodingKey {
        case value
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)

        do {
            value = try container.decode(Int.self, forKey: .value)
        } catch {
            let stringValue = try container.decode(String.self, forKey: .value)

            if let valueInt = Int(stringValue) {
                value = valueInt
            } else {
                var codingPath = container.codingPath
                codingPath.append(CodingKeys.value)
                let debugDescription = "Could not create Int from String (stringValue) of field (CodingKeys.value.rawValue)"
                let context = DecodingError.Context(codingPath: codingPath, debugDescription: debugDescription)
                throw DecodingError.dataCorrupted(context)
            }
        }
    }
}
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