SwiftUI解码报错No value associated with key CodingKeys问题求助

问题原因 #

• 字段归属层级错误：object和has_more都是JSON根层级的字段，并不存在于data数组的子元素中，你在RequestData的自定义解码逻辑里尝试从data子元素中解码这两个不存在的字段，直接触发了keyNotFound错误。
• 类型不匹配：has_more字段是布尔类型，你代码里写成了String类型，就算字段存在也会解码失败。
• 通用设计逻辑错误：通用Request的设计应该是根据根节点的object字段判断data数组的元素类型，而非从data元素内部读取类型标识。

修正后可运行代码 #

let json = """
{
    "object": "bottle",
    "has_more": false,
    "data": [
        {
          "id": "5ffa81e7-1d91-43b5-83cc-9ee1ab634c7b",
          "name": "14 Hands Hot to Trot White Blend",
          "price": "$8.99",
          "image": "https://cdn11.bigcommerce.com/s-7a906/images/stencil/1000x1000/products/8186/10996/14-Hands-Hot-to-Trot-White-Blend__56901.1488985626.jpg?c=2",
          "sku": "088586004490",
          "size": "750ML",
          "origination": "USA, Washington",
          "varietal": "White Wine",
          "information": "14 Hands Hot to Trot White Blend",
          "proof": 121.5,
          "brand_id": "1",
          "rating": 1,
          "review_count": 5
        }
    ]
}
"""

// 通用请求返回枚举，后续新增类型直接加case即可
enum Request: Decodable {
    case bottle(hasMore: Bool, data: [Bottle])
    // 后续扩展其他类型示例：case user(hasMore: Bool, data: [User])
    
    enum CodingKeys: String, CodingKey {
        case object, hasMore = "has_more", data
    }
    
    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        let objectType = try container.decode(String.self, forKey: .object)
        let hasMore = try container.decode(Bool.self, forKey: .hasMore)
        switch objectType {
        case "bottle":
            let data = try container.decode([Bottle].self, forKey: .data)
            self = .bottle(hasMore: hasMore, data: data)
        default:
            throw DecodingError.dataCorrupted(.init(codingPath: decoder.codingPath, debugDescription: "未知的object类型: \(objectType)"))
        }
    }
}

struct Bottle: Decodable {
    let id: String
    let name: String
    let price: String
    let image: String
    let sku: String
    let size: String
    let origination: String
    let varietal: String
    let information: String
    let proof: Float
    let brand_id: String
    let rating: Int
    let review_count: Int
}

// 解码调用
let decoder = JSONDecoder()
let requestResult = try decoder.decode(Request.self, from: json.data(using: .utf8)!)

switch requestResult {
case .bottle(_, let bottles):
    bottles.forEach { print($0.name) }
}

内容的提问来源于stack exchange，提问作者Trenton