动态JSON解码Swift 4
我试图在Swift 4中解码以下JSON:动态JSON解码Swift 4,json,swift,dynamic,decodable,Json,Swift,Dynamic,Decodable,我试图在Swift 4中解码以下JSON: { "token":"RdJY3RuB4BuFdq8pL36w", "permission":"accounts, users", "timout_in":600, "issuer": "Some Corp", "display_name":"John Doe", "device_id":"uuid824fd3c3-0f69-4ee1-979a-e8ab25558421" } 问题是,JSON中的最后2
{
"token":"RdJY3RuB4BuFdq8pL36w",
"permission":"accounts, users",
"timout_in":600,
"issuer": "Some Corp",
"display_name":"John Doe",
"device_id":"uuid824fd3c3-0f69-4ee1-979a-e8ab25558421"
}
问题是,JSON中的最后2个元素(显示\u名称
和设备\u id
)可能存在,也可能不存在,或者这些元素的名称可能完全不同,但仍然未知,即“fred”:“worker”,“hours”:8
因此,我试图实现的是解码已知的内容,即令牌
,权限
,超时
和颁发者
,以及任何其他元素(显示名称
,设备id
等)将它们放入字典中
我的结构如下所示:
struct AccessInfo : Decodable
{
let token: String
let permission: [String]
let timeout: Int
let issuer: String
let additionalData: [String: Any]
private enum CodingKeys: String, CodingKey
{
case token
case permission
case timeout = "timeout_in"
case issuer
}
public init(from decoder: Decoder) throws
{
let container = try decoder.container(keyedBy: CodingKeys.self)
token = container.decode(String.self, forKey: .token)
permission = try container.decodeIfPresent(String.self, forKey: .permission).components(separatedBy: ",")
timeout = try container.decode(Int.self, forKey: . timeout)
issuer = container.decode(String.self, forKey: .issuer)
// This is where I'm stuck, how do I add the remaining
// unknown JSON elements into additionalData?
}
}
// Calling code, breviated for clarity
let decoder = JSONDecoder()
let accessInfo = try decoder.decode(AccessInfo.self, from: data!)
如果有人能提供一些指导的话,能够解码已知结构中JSON也可能包含动态信息的部分就是我的目标
谢谢这个问题实际上是重复的。一旦您了解了构建底层最小CodingKey应用程序结构作为编码密钥的诀窍,就可以将其用于任何字典 在本例中,您将使用键控容器的
allKeys
获取未知的JSON字典键
为了演示,我将仅限于JSON字典中完全未知的部分。想象一下这个JSON:
let j = """
{
"display_name":"John Doe",
"device_id":"uuid824fd3c3-0f69-4ee1-979a-e8ab25558421"
}
"""
let jdata = j.data(using: .utf8)!
假设我们不知道字典里有什么,除了它有字符串键和字符串值之外。所以我们想要解析jdata
,而不知道它的键是什么
因此,我们有一个由一个字典属性组成的结构:
struct S {
let stuff : [String:String]
}
现在的问题是如何将该JSON解析为该结构——即,如何使该结构符合可解码性并处理该JSON
以下是方法:
struct S : Decodable {
let stuff : [String:String]
private struct CK : CodingKey {
var stringValue: String
init?(stringValue: String) {
self.stringValue = stringValue
}
var intValue: Int?
init?(intValue: Int) {
return nil
}
}
init(from decoder: Decoder) throws {
let con = try! decoder.container(keyedBy: CK.self)
var d = [String:String]()
for key in con.allKeys {
let value = try! con.decode(String.self, forKey:key)
d[key.stringValue] = value
}
self.stuff = d
}
}
现在我们分析:
let s = try! JSONDecoder().decode(S.self, from: jdata)
我们得到一个S实例,它的stuff
就是这个字典:
["device_id": "uuid824fd3c3-0f69-4ee1-979a-e8ab25558421", "display_name": "John Doe"]
这正是我们想要的结果。受@matt comments的启发,这是我随附的完整示例。我扩展了
KeyedDecodingContainer
来解码未知密钥,并提供一个参数来过滤已知的CodingKeys
示例JSON
{
"token":"RdJY3RuB4BuFdq8pL36w",
"permission":"accounts, users",
"timout_in":600,
"issuer": "Some Corp",
"display_name":"John Doe",
"device_id":"uuid824fd3c3-0f69-4ee1-979a-e8ab25558421"
}
Swift结构
struct AccessInfo : Decodable
{
let token: String
let permission: [String]
let timeout: Int
let issuer: String
let additionalData: [String: Any]
private enum CodingKeys: String, CodingKey
{
case token
case permission
case timeout = "timeout_in"
case issuer
}
public init(from decoder: Decoder) throws
{
let container = try decoder.container(keyedBy: CodingKeys.self)
token = container.decode(String.self, forKey: .token)
permission = try container.decode(String.self, forKey: .permission).components(separatedBy: ",")
timeout = try container.decode(Int.self, forKey: . timeout)
issuer = container.decode(String.self, forKey: .issuer)
// Additional data decoding
let container2 = try decoder.container(keyedBy: AdditionalDataCodingKeys.self)
self.additionalData = container2. decodeUnknownKeyValues(exclude: CodingKeys.self)
}
}
private struct AdditionalDataCodingKeys: CodingKey
{
var stringValue: String
init?(stringValue: String)
{
self.stringValue = stringValue
}
var intValue: Int?
init?(intValue: Int)
{
return nil
}
}
KeyedDecodingContainer扩展
extension KeyedDecodingContainer where Key == AdditionalDataCodingKeys
{
func decodeUnknownKeyValues<T: CodingKey>(exclude keyedBy: T.Type) -> [String: Any]
{
var data = [String: Any]()
for key in allKeys
{
if keyedBy.init(stringValue: key.stringValue) == nil
{
if let value = try? decode(String.self, forKey: key)
{
data[key.stringValue] = value
}
else if let value = try? decode(Bool.self, forKey: key)
{
data[key.stringValue] = value
}
else if let value = try? decode(Int.self, forKey: key)
{
data[key.stringValue] = value
}
else if let value = try? decode(Double.self, forKey: key)
{
data[key.stringValue] = value
}
else if let value = try? decode(Float.self, forKey: key)
{
data[key.stringValue] = value
}
else
{
NSLog("Key %@ type not supported", key.stringValue)
}
}
}
return data
}
}
输出
Token: RdJY3RuB4BuFdq8pL36w
Permission: ["accounts", "users"]
Timeout: 600
Issuer: "Some Corp"
Additional Data: ["display_name":"John Doe", "device_id":"uuid824fd3c3-0f69-4ee1-979a-e8ab25558421"]
您的JSON无效。请提供真实的JSON。重复的,如果未知数据不总是类型为
[String:String]
?这是一个不同的问题,在堆栈溢出问题上也得到了彻底的解决。感谢您的回复。我审阅并编写了@matt works的示例代码。当在单个解析/解码操作中组合已知密钥和未知密钥时,实现变得棘手,因为您希望对容器进行两次解码。。。或者作为一种通用方法进行解码,并手动分配已知键,将剩余的未知键放入字典[String:String]
中。您进入两次,一次使用已知键,正如您已经展示的那样,另一次使用未知键,正如我所做的那样。我需要把整个事情说清楚吗?有人能提供关于已知密钥但未知数据类型的问题的链接吗?经过几个小时的搜索,这终于帮了我的忙!我不明白的一点是下面这行:if keyedBy.init(stringValue:key.stringValue)==nil
。为什么返回零?
Token: RdJY3RuB4BuFdq8pL36w
Permission: ["accounts", "users"]
Timeout: 600
Issuer: "Some Corp"
Additional Data: ["display_name":"John Doe", "device_id":"uuid824fd3c3-0f69-4ee1-979a-e8ab25558421"]