假设我的Customer数据类型包含一个metadata属性,该属性可以在客户对象中包含任何JSON字典
Customer
metadata
struct Customer { let id: String let email: String let metadata: [String: Any] }
{ "object": "customer", "id": "4yq6txdpfadhbaqnwp3", "email": "john.doe@example.com", "metadata": { "link_id": "linked-id", "buy_count": 4 } }
该metadata属性可以是任何任意的JSON映射对象。
在我可以使用反序列化的JSON(NSJSONDeserialization但使用新的Swift 4 Decodable协议)转换属性之前,我仍然想不出一种方法。
NSJSONDeserialization
Decodable
有谁知道如何在Swift 4中使用Decodable协议实现这一目标?
从我发现的要点中得到一些启发,我为UnkeyedDecodingContainer和编写了一些扩展名KeyedDecodingContainer。您可以在此处找到我的要旨的链接。通过使用以下代码,您现在可以解码任何一种Array<Any>或Dictionary<String, Any>使用熟悉的语法:
UnkeyedDecodingContainer
KeyedDecodingContainer
Array<Any>
Dictionary<String, Any>
let dictionary: [String: Any] = try container.decode([String: Any].self, forKey: key)
要么
let array: [Any] = try container.decode([Any].self, forKey: key)
编辑: 我发现有一个警告,它正在解码字典数组。[[String: Any]]所需的语法如下。您可能想抛出一个错误而不是强制转换:
[[String: Any]]
let items: [[String: Any]] = try container.decode(Array<Any>.self, forKey: .items) as! [[String: Any]]
编辑2: 如果您只是想将整个文件转换为字典,那么最好还是坚持使用JSONSerialization中的api,因为我还没有找到扩展JSONDecoder本身来直接解码字典的方法。
guard let json = try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any] else { // appropriate error handling return }
// Inspired by https://gist.github.com/mbuchetics/c9bc6c22033014aa0c550d3b4324411a struct JSONCodingKeys: CodingKey { var stringValue: String init?(stringValue: String) { self.stringValue = stringValue } var intValue: Int? init?(intValue: Int) { self.init(stringValue: "\(intValue)") self.intValue = intValue } } extension KeyedDecodingContainer { func decode(_ type: Dictionary<String, Any>.Type, forKey key: K) throws -> Dictionary<String, Any> { let container = try self.nestedContainer(keyedBy: JSONCodingKeys.self, forKey: key) return try container.decode(type) } func decodeIfPresent(_ type: Dictionary<String, Any>.Type, forKey key: K) throws -> Dictionary<String, Any>? { guard contains(key) else { return nil } guard try decodeNil(forKey: key) == false else { return nil } return try decode(type, forKey: key) } func decode(_ type: Array<Any>.Type, forKey key: K) throws -> Array<Any> { var container = try self.nestedUnkeyedContainer(forKey: key) return try container.decode(type) } func decodeIfPresent(_ type: Array<Any>.Type, forKey key: K) throws -> Array<Any>? { guard contains(key) else { return nil } guard try decodeNil(forKey: key) == false else { return nil } return try decode(type, forKey: key) } func decode(_ type: Dictionary<String, Any>.Type) throws -> Dictionary<String, Any> { var dictionary = Dictionary<String, Any>() for key in allKeys { if let boolValue = try? decode(Bool.self, forKey: key) { dictionary[key.stringValue] = boolValue } else if let stringValue = try? decode(String.self, forKey: key) { dictionary[key.stringValue] = stringValue } else if let intValue = try? decode(Int.self, forKey: key) { dictionary[key.stringValue] = intValue } else if let doubleValue = try? decode(Double.self, forKey: key) { dictionary[key.stringValue] = doubleValue } else if let nestedDictionary = try? decode(Dictionary<String, Any>.self, forKey: key) { dictionary[key.stringValue] = nestedDictionary } else if let nestedArray = try? decode(Array<Any>.self, forKey: key) { dictionary[key.stringValue] = nestedArray } } return dictionary } } extension UnkeyedDecodingContainer { mutating func decode(_ type: Array<Any>.Type) throws -> Array<Any> { var array: [Any] = [] while isAtEnd == false { // See if the current value in the JSON array is `null` first and prevent infite recursion with nested arrays. if try decodeNil() { continue } else if let value = try? decode(Bool.self) { array.append(value) } else if let value = try? decode(Double.self) { array.append(value) } else if let value = try? decode(String.self) { array.append(value) } else if let nestedDictionary = try? decode(Dictionary<String, Any>.self) { array.append(nestedDictionary) } else if let nestedArray = try? decode(Array<Any>.self) { array.append(nestedArray) } } return array } mutating func decode(_ type: Dictionary<String, Any>.Type) throws -> Dictionary<String, Any> { let nestedContainer = try self.nestedContainer(keyedBy: JSONCodingKeys.self) return try nestedContainer.decode(type) } }