Swift Decode JSON - can not decode

Question

I can not decode my JSON File. It works if I decode only a single string but now with my struct it does not work. Is there anything that I do wrong?

My struct that i want to decode:

struct Comment: Decodable, Identifiable {
    var id = UUID()
    var title : String
    var comments : [String]

    private enum Keys: String, CodingKey {
        case response = "Response"
        case commentsArray = "commentsArray"
        case title = "title"
        case comments = "comments"
    }

    init(from decoder: Decoder) throws {
        let values = try decoder.container(keyedBy: Keys.self)
        let response = try values.nestedContainer(keyedBy: Keys.self, forKey: .response)
        let commentsArray = try response.nestedContainer(keyedBy: Keys.self, forKey: .commentsArray)
        title = try commentsArray.decodeIfPresent(String.self, forKey: .title)!
        comments = try commentsArray.decodeIfPresent([String].self, forKey: .comments)!
    }
}

My JSON:

{"Response": {
    "commentsArray":[
      {
        "title": "someTitle",
        "comments": [
          "optionOne",
          "optionTwo"
        ]
      },
      {
        "title": "title",
        "comments": [
          "optionOne",
          "optionTwo"
        ]
      },
      {
        "title": "someto",
        "comments": [
          "optionOne",
          "optionTwo"
        ]
      }
    ]
    }
  }

What error did you get?

Sweeper
– Sweeper

2020-02-11 18:02:13 +00:00
Commented Feb 11, 2020 at 18:02 — Sweeper
– Sweeper, Commented Feb 11, 2020 at 18:02

Jawad Ali · Accepted Answer · 2020-02-11 18:11:18Z

2

use these structs to decode your json

struct Response: Codable {
    var response : Comments

    private enum Keys: String, CodingKey {
      case response = "Response"
    }
}
struct Comments: Codable {
    var commentsArray : [comment]
}
struct comment: Codable {
    let title: String
    let comments: [String]
}

edited Feb 11, 2020 at 18:11

answered Feb 11, 2020 at 18:05

Jawad Ali

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Comments

iamtimmo · Accepted Answer · 2020-02-11 18:59:59Z

I don't think that you want to structure your code this way. You have a hierarchy that you are attempting to capture in a flatter structure.

Response
    CommentsList
        Comments
            Title
            Comment
            Comment
            ...
        Comments
        ...

So, you might want to do something like this:

struct Response: Decodable {
    var commentsArray: [Comments]

    init(from decoder: Decoder) {
        let container = try! decoder.container(keyedBy: ResponseCodingKeys.self)
        let response = try! container.nestedContainer(keyedBy: ListCodingKeys.self, forKey: .response)
        commentsArray = try! response.decode([Comments].self, forKey: .commentsArray)
    }

    enum ResponseCodingKeys: String, CodingKey { case response = "Response" }
    enum ListCodingKeys: String, CodingKey { case commentsArray }
}

struct Comments: Decodable {
    var id = UUID()
    var title: String
    var comments: [String]
}

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