json - How to decode this JSON with the new decodable protocol?

问题描述

Problem

I tried to decode my JSON file so it will be casted to native struct types. Apparently it does not work and I have no idea why. I replicated all the JSON objects in structs so the decodable protocol can do its work.

The JSON File

The JSON file can be found here: https://pastebin.com/hZxmDMue

The models (structs)

These are the models that reflect the exact same objects in the JSON file.

 struct Appstructure: Decodable {
  var data: [Subdata]
}

struct Subdata: Decodable {
  var favourites: Items
  var cart: Items
}

struct Items: Decodable {
  var items: [Item]
}

struct Item: Decodable {
  var type: String
  var content: Content
}

struct Content: Decodable {
  var productLines: [String]
  var productImage: String
}

The JSON Parsing

I am using the provided JSONDecoder by apple like so:

func fetchAppStructure() -> Appstructure? {
    guard let path = Bundle.main.path(forResource: "iMessage-test-version-3", ofType: "json") else { return nil }

    guard let data = try? Data(contentsOf: URL(fileURLWithPath: path), options: []) else { return nil }

    do {
      try JSONDecoder().decode(Appstructure.self, from: data)
    } catch  {
      print(error.localizedDescription)
    }

    return nil
  }

Error

However I receive the following decoding error.

 DecodingError
  ▿ keyNotFound : 2 elements
    - .0 : CodingKeys(stringValue: "cart", intValue: nil)
    ▿ .1 : Context
      ▿ codingPath : 2 elements
        - 0 : CodingKeys(stringValue: "data", intValue: nil)
        ▿ 1 : _JSONKey(stringValue: "Index 0", intValue: 0)
          - stringValue : "Index 0"
          ▿ intValue : Optional<Int>
            - some : 0
      - debugDescription : "No value associated with key CodingKeys(stringValue: \"cart\", intValue: nil) (\"cart\")."
      - underlyingError : nil

If anything else is needed to reproduce this bug please ask. It is probably something small in logical thinking. Hopefully somebody sees the issue! Thanks in advance.

标签： jsonswiftdecodable

你的结构是错误的。

子数据有一个favourites或cart，而不是两者。

制作favourites和cart可选。

struct Subdata: Decodable {
  var favourites: Items?
  var cart: Items?
}