在 swift 中对动态键和动态对象使用 Codable

Posted 2023-03-15

【中文标题】在 swift 中对动态键和动态对象使用 Codable

【英文标题】：Using Codable on a dynamic key and dynamic object in swift

【发布时间】：2019-11-15 13:41:08

【问题描述】：

我在从服务调用返回的结构中嵌套了以下结构，但我无法对这部分进行编码/解码。我遇到的问题是 customKey 和 customValue 都是动态的。 customValue 可以是数组或字典或字典数组 例如

    "status": "a string value",
    "id": "a string value",
    "property": 
        "customkey1": "customValue1",
        "customKey2": [
            "InnerCustomKey": "InnerCustomValue"
        , 
            "InnerCustomKey": "InnerCustomValue"
        , 
            "InnerCustomKey": "InnerCustomValue"
        ],
        "customkey3": 
            "InnerCustomKey": "InnerCustomValue"
        
    

我尝试了类似 var values: [String:String] 但它在另一个对象中失败。 我按照答案Using Codable on a dynamic type/object 但没有成功

【问题讨论】：

customValue [reasonable] 的选项是有限的吗？

是所有可能的变体（字符串、数组、字典、字典数组）并且都是字符串类型的最内层值吗？

@user28434 customValue 有任何值（字符串、数组、字典、字典数组等）

【参考方案1】：

extension KeyedDecodingContainerProtocol

    func getValueFromAvailableKey(codingKeys:[CodingKey])-> Any?
        for key in codingKeys
            for keyPath in self.allKeys
                if key.stringValue == keyPath.stringValue
                    do
                        if let value = try? self.decodeIfPresent([String].self, forKey:keyPath)
                            return value
                        

                        if let value = try? self.decodeIfPresent([String:String].self, forKey:keyPath)
                            return value
                        

                        if let value = try? self.decodeIfPresent([[String:String]].self, forKey:keyPath)
                            return value
                        

                        if let value = try? self.decodeIfPresent(String.self, forKey:keyPath)
                            return value
                        

                        return nil
                    
                
            
        
        return nil
    


private struct CustomCodingKeys: CodingKey 
    var stringValue: String
    init?(stringValue: String) 
        self.stringValue = stringValue
    
    var intValue: Int?
    init?(intValue: Int) 
        return nil
    


struct CustomModel: Codable 
    var status:String?
    var id: String?
    var property: Property?


    init(from decoder: Decoder)  
        do
            let container = try decoder.container(keyedBy: CustomCodingKeys.self)
            status = try container.decodeIfPresent(String.self, forKey: CustomCodingKeys.init(stringValue: "status")!)
            id = try container.decodeIfPresent(String.self, forKey: CustomCodingKeys.init(stringValue: "id")!)
            property = try container.decodeIfPresent(Property.self, forKey: CustomCodingKeys.init(stringValue: "property")!)


        catch
            print(error.localizedDescription)
        
    

    func encode(to encoder: Encoder) throws 
             var container = encoder.container(keyedBy: CustomCodingKeys.self)
             try? container.encodeIfPresent(self.status, forKey: CustomCodingKeys.init(stringValue: "status")!)
             try? container.encodeIfPresent(self.id, forKey: CustomCodingKeys.init(stringValue: "id")!)
             try? container.encodeIfPresent(self.property, forKey: CustomCodingKeys.init(stringValue: "property")!)
    


// MARK: - Property
struct Property: Codable 
    var customkey:[String:Any?] = [:]

    init(from decoder: Decoder)  
        do
            let container = try decoder.container(keyedBy: CustomCodingKeys.self)
            for key in container.allKeys
                customkey[key.stringValue] = container.getValueFromAvailableKey(codingKeys: [CustomCodingKeys.init(stringValue: key.stringValue)!])
            

        catch
            print(error.localizedDescription)
        
    

    func encode(to encoder: Encoder) throws 
        var container = encoder.container(keyedBy: CustomCodingKeys.self)
        for key in customkey
                 try? container.encodeIfPresent(customkey[key.key] as? String, forKey: CustomCodingKeys.init(stringValue: key.key)!)
                 try? container.encodeIfPresent(customkey[key.key] as? [[String:String]], forKey: CustomCodingKeys.init(stringValue: key.key)!)
                 try? container.encodeIfPresent(customkey[key.key] as? [String:String], forKey: CustomCodingKeys.init(stringValue: key.key)!)
            

    

希望对你有帮助！

【讨论】：

您的示例代码可以很好地解码，但没有编码功能您也请添加编码代码吗？

你想怎么编码？？？你想编码相同的 json 吗？？

是的，我首先解码由您的示例完成的 json 字符串，然后添加一些数据，然后将该数据编码为 json。为此，我必须将属性扩展为编码

@Mahesh 我也重新编辑了编码的答案问候，