Using cryptography with ObjectMapper

Question

I have a class which it is being mapped with ObjectMapper. In the past the mapping worked fine, but a change in the project Architecture made the webservice return fields that were Double to a String with Cryptographed value.

is it possible to decryptograph and cast the webservice field into my class variable during the mapping?

This is what I have today:

class PosicaoConsolidada: Mappable {
    var portifolioBalance: Double!
    var families: [Family]!

    required init?(map: Map) {}

    public func mapping(map: Map) {
        portifolioBalance <- map["pointsBalance"]
        families <- map["fam"]
    }
}

This is what I imagine to do:

class PosicaoConsolidada: Mappable {
    var portifolioBalance: Double!
    var families: [Family]!

    required init?(map: Map) {}

    public func mapping(map: Map) {
        portifolioBalance <- Double(Decryptor.decrypt(map["pointsBalance"]))
        families <- map["fam"]
    }
}

Answer 1

There are several ways to accomplish the data decryption. ObjectMapper provides the protocol TransformType to deal with data transformations while mapping (reference).

Transformer:

import ObjectMapper

class PointsTransform: TransformType {
    typealias Object = Double
    typealias JSON = String

    func transformFromJSON(_ value: Any?) -> Object? {
        guard let encoded = value as? String
            else { return nil }

        // TODO: Replace with decoding logic
        return 239_584.938
    }

    func transformToJSON(_ value: Object?) -> JSON? {
        guard let decoded = value
            else { return nil }

        return "\(decoded)"
    }
}

Model:

class PosicaoConsolidada: Mappable {
    var portifolioBalance: Double!
    var families: [Family]!

    required init?(map: Map) {}

    public func mapping(map: Map) {
        portifolioBalance <- (map["pointsBalance"], PointsTransform())
        families <- map["fam"]
    }

}