使用decodable捕获单行中的嵌套对象数组

Question

下面是我的json响应和我需要构造的结构。

条件:我不想创建任何其他结构除了响应，媒体，并希望在单行解析如下所指定的。

{
     "name": "xxxx",
     "title": "xxxxxxx",
     "assets": [
        {
          "items": [
            {
              "id": "eeee",
              "desc": "rrrrrr"
            },            {
              "id": "eeee",
            },            {
              "desc": "rrrrrr"
            }]
        }]
}



struct Response {
    let name  : String
    let title : string
    let items : [Media]

    private enum codingKeys : String, CodingKey {
        case name = "name"
        case title = "title"
        case items = "assets.items"
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: codingKeys.self)
        name = try container.decode(String.self, forKey: .name)
        title = try container.decode(TrayLayout.self, forKey: .title)
        items = try container.decode([Media].self, forKey: .items)
    }
}

Answer 1

找到了一种新的方法：

struct Media: Codable {
    let id,desc: String?
    enum CodingKeys: String, CodingKey {
        case id,desc
    }
}
struct Response: Decodable, CustomStringConvertible {
    let name,title: String?
    @NestedKey
    let items: [Media]?
    enum CodingKeys: String,NestableCodingKey {
        case name,title,
        case items = "assets/items"
    }

}

Answer 2

我设法为你的问题找到了解决方案。

考虑以下是示例json

let jsonString = """
{
     "name": "xxxx",
     "title": "xxxxxxx",
     "assets": [
        {
          "items": [
            {
              "id": "id11",
              "desc": "desc11"
            },            {
              "id": "id12",
            },            {
              "desc": "desc13"
            }]
        },{
          "items": [
            {
              "id": "id21",
              "desc": "desc21"
            },            {
              "id": "id22",
            },            {
              "desc": "desc23"
            }]
        }]
}
"""

您的结构将如下所示

struct Media: Codable {
    let id,desc: String?
    enum CodingKeys: String, CodingKey {
        case id,desc
    }
}

struct Response: Decodable {
    let name,title: String?
    let items: [Media]?
    enum CodingKeys: String, CodingKey {
        case name,title,items
        case assets = "assets"
    }
    // Decoding
    init(from decoder: Decoder) throws {

        let container = try decoder.container(keyedBy: CodingKeys.self)
        name = try container.decode(String.self, forKey: .name)
        title = try container.decode(String.self, forKey: .title)

        // Here as the assets contains array of object which has a key as items and then again consist of a array of Media we need to decode as below
        let assets = try container.decode([[String:[Media]]].self, forKey: .assets)

        // At this stage will get assets with a array of array so we first map and retrive the items and then reduce them to one single array
        items = assets.compactMap{$0[CodingKeys.items.rawValue]}.reduce([], +)
    }
}

最后，我们可以按如下方式使用它

let data = jsonString.data(using: .utf8)!
let myResponse = try! JSONDecoder().decode(Response.self, from: data)

现在您可以访问数据，如下所示

myResponse.name
myResponse.title
myResponse.items

希望这段基本代码能帮助你实现你想做的事情。然后，您可以继续进行更多的嵌套解析。

我要感谢Nic Laughter的such a detailed article；通过参考，我设法提出了上面的解决方案。

Answer 3

您可以尝试这样做：

struct Response: Decodable {
  let name, title: String
  let assets: [Assets]
}

struct Assets: Decodable {
 let items: [Items]
}

struct Items: Decodable {
  let id, desc: String
}

然后你可以像这样解码它：

guard let response = try? JSONDecoder().decode(Response.self, from: data) else { print("Response not parsed"); return }