Decoding the same object with different keys

[VillSkog]

I am currently working with an API that gives me exactly the same JSON on several endpoints (either as part of a bigger object, an array, ...) but they don't always have the same keys ...
I asked the backend developer to make those uniform but he told me that the Android app already uses the API so it won't happen anytime soon.

Thus, I was wondering if there was any way to decode the exact same json (+/- some optionals) but with different keys, without making a whole new class ..

Just to make sure I'm clear, here's an exemple:

json A:

{
    "name" : "Awesome shop",
    "id" : "42"
}

json B

{
    "shop_name" : "Awesome shop",
    "shop_id" : "42"
}

As of now, I use a bridge class ShopB (subclass of Shop) to decode jsonB into a Shop model. Also note that the keys are not always in the form "var" / "shop_var" like in my exemple, they are just completely unrelated.

[gfontenot]

Yep, it's actually pretty easy with Argo. We supply an Alternative operator (<|>) for exactly this use case:

struct Shop {
  let id: String
  let name: String
}

extension Shop: Argo.Decodable {
  static func decode(_ j: JSON) -> Decoded<Shop> {
    return curry(Shop.init)
      <^> j <| "id"
      <*> (j <| "name") <|> (j <| "shop_name")
  }
}

[VillSkog]

Oh crap, I didn't see the notification before. That's awesome, thank you.

[VillSkog]

Actually, it doesn't seem to work so well for optionals. Is there a workaround this ?

struct Shop {
  let id: String
  let name: String
  let images: [String]
}

extension Shop: Argo.Decodable {
  static func decode(_ j: JSON) -> Decoded<Shop> {
    return curry(Shop.init)
      <^> j <| "id"
      <*> j <| "name"
      <*> (json <||? "shop_images" <|> json <||? "images")
  }
}     

The Alternative operator doesn't try to parse the second key since the first one is allowed to be nil (I guess ?).

[gfontenot]

yep, the trick is to not use the failable operators, and to instead wrap the whole thing in .optional:

<*> .optional(json <|| "shop_images" <|> json <|| "images")

[VillSkog]

That did the trick indeed. Thank you very much, my code will get much lighter.

[gfontenot]

Spectacular! Glad I could help. I'm going to go ahead and close this now, but feel free to re-open if you have any additional questions.