前言
SwiftyJSON是iOS开发中常用的一个swift版本的解析库，功能对于ObjectMapper之类的库较少，但是代码较少，版本为4.0，解析中对已经废弃的Api进行删减。
代码解析
错误处理
// MARK: - Error
public enum SwiftyJSONError: Int, Swift.Error {
case unsupportedType = 999
case indexOutOfBounds = 900
case elementTooDeep = 902
case wrongType = 901
case notExist = 500
case invalidJSON = 490
}
extension SwiftyJSONError: CustomNSError {
/// return the error domain of SwiftyJSONError
public static var errorDomain: String { return "com.swiftyjson.SwiftyJSON" }
/// return the error code of SwiftyJSONError
public var errorCode: Int { return self.rawValue }
/// return the userInfo of SwiftyJSONError
public var errorUserInfo: [String: Any] {
switch self {
case .unsupportedType:
return [NSLocalizedDescriptionKey: "It is an unsupported type."]
case .indexOutOfBounds:
return [NSLocalizedDescriptionKey: "Array Index is out of bounds."]
case .wrongType:
return [NSLocalizedDescriptionKey: "Couldn't merge, because the JSONs differ in type on top level."]
case .notExist:
return [NSLocalizedDescriptionKey: "Dictionary key does not exist."]
case .invalidJSON:
return [NSLocalizedDescriptionKey: "JSON is invalid."]
case .elementTooDeep:
return [NSLocalizedDescriptionKey: "Element too deep. Increase maxObjectDepth and make sure there is no reference loop."]
}
}
}
在错误处理中，将错误可能出现的错误分为了6种，分别是：
- unsupportedType 不支持的类型
- indexOutOfBounds 索引越界
- elementTooDeep 查找的元素深度过大
- wrongType 错误类型
- notExist 字典的key不存在
- invalidJSON JSON无效
并且在获取errorUserInfo时做了国际化处理。
JSON
类型
public enum Type: Int {
case number
case string
case bool
case array
case dictionary
case null
case unknown
}
JSON类型如同http://www.json.org官网中定义的一样。
初始化
public struct JSON {
/**
使用Data初始化
*/
public init(data: Data, options opt: JSONSerialization.ReadingOptions = []) throws {
let object: Any = try JSONSerialization.jsonObject(with: data, options: opt)
self.init(jsonObject: object)
}
/**
使用任意类型初始化，如果object是Data类型，则使用Data初始化方式，如果不是则当做json对象处理
*/
public init(_ object: Any) {
switch object {
case let object as Data:
do {
try self.init(data: object)
} catch {
self.init(jsonObject: NSNull())
}
default:
self.init(jsonObject: object)
}
}
/**
解析jsonString初始化
*/
public init(parseJSON jsonString: String) {
if let data = jsonString.data(using: .utf8) {
self.init(data)
} else {
self.init(NSNull())
}
}
/**
使用jsonObejct初始化。
jsonObejct中必须确定：
其中所有的对象必须是NSString/String, NSNumber/Int/Float/Double/Bool, NSArray/Array, NSDictionary/Dictionary, or NSNull；
字典的key值是NSStrings/String；
NSNumbers的值不能非空或是无穷。
*/
fileprivate init(jsonObject: Any) {
self.object = jsonObject
}
/**
Merges another JSON into this JSON, whereas primitive values which are not present in this JSON are getting added,
present values getting overwritten, array values getting appended and nested JSONs getting merged the same way.
- parameter other: The JSON which gets merged into this JSON
- throws `ErrorWrongType` if the other JSONs differs in type on the top level.
*/
public mutating func merge(with other: JSON) throws {
try self.merge(with: other, typecheck: true)
}
/**
Merges another JSON into this JSON and returns a new JSON, whereas primitive values which are not present in this JSON are getting added,
present values getting overwritten, array values getting appended and nested JSONS getting merged the same way.
- parameter other: The JSON which gets merged into this JSON
- throws `ErrorWrongType` if the other JSONs differs in type on the top level.
- returns: New merged JSON
*/
public func merged(with other: JSON) throws -> JSON {
var merged = self
try merged.merge(with: other, typecheck: true)
return merged
}
/**
Private woker function which does the actual merging
Typecheck is set to true for the first recursion level to prevent total override of the source JSON
*/
fileprivate mutating func merge(with other: JSON, typecheck: Bool) throws {
if self.type == other.type {
switch self.type {
case .dictionary:
for (key, _) in other {
try self[key].merge(with: other[key], typecheck: false)
}
case .array:
self = JSON(self.arrayValue + other.arrayValue)
default:
self = other
}
} else {
if typecheck {
throw SwiftyJSONError.wrongType
} else {
self = other
}
}
}
/// Private object
fileprivate var rawArray: [Any] = []
fileprivate var rawDictionary: [String: Any] = [:]
fileprivate var rawString: String = ""
fileprivate var rawNumber: NSNumber = 0
fileprivate var rawNull: NSNull = NSNull()
fileprivate var rawBool: Bool = false
/// JSON type, fileprivate setter
public fileprivate(set) var type: Type = .null
/// Error in JSON, fileprivate setter
public fileprivate(set) var error: SwiftyJSONError?
/// Object in JSON
public var object: Any {
get {
switch self.type {
case .array:
return self.rawArray
case .dictionary:
return self.rawDictionary
case .string:
return self.rawString
case .number:
return self.rawNumber
case .bool:
return self.rawBool
default:
return self.rawNull
}
}
set {
error = nil
switch unwrap(newValue) {
case let number as NSNumber:
if number.isBool {
type = .bool
self.rawBool = number.boolValue
} else {
type = .number
self.rawNumber = number
}
case let string as String:
type = .string
self.rawString = string
case _ as NSNull:
type = .null
case nil:
type = .null
case let array as [Any]:
type = .array
self.rawArray = array
case let dictionary as [String: Any]:
type = .dictionary
self.rawDictionary = dictionary
default:
type = .unknown
error = SwiftyJSONError.unsupportedType
}
}
}
/// The static null JSON
public static var null: JSON { return JSON(NSNull()) }
}
warp
/// Private method to unwarp an object recursively
private func unwrap(_ object: Any) -> Any {
switch object {
case let json as JSON:
return unwrap(json.object)
case let array as [Any]:
return array.map(unwrap)
case let dictionary as [String: Any]:
var unwrappedDic = dictionary
for (k, v) in dictionary {
unwrappedDic[k] = unwrap(v)
}
return unwrappedDic
default:
return object
}
}
递归的方式展开object。
Index
public enum Index: Comparable {
case array(Int)
case dictionary(DictionaryIndex)
case null
static public func == (lhs: Index, rhs: Index) -> Bool {
switch (lhs, rhs) {
case (.array(let left), .array(let right)):
return left == right
case (.dictionary(let left), .dictionary(let right)):
return left == right
case (.null, .null): return true
default:
return false
}
}
static public func < (lhs: Index, rhs: Index) -> Bool {
switch (lhs, rhs) {
case (.array(let left), .array(let right)):
return left < right
case (.dictionary(let left), .dictionary(let right)):
return left < right
default:
return false
}
}
}
建立操作符对数组、字典、与null中的index进行比较。
public typealias JSONIndex = Index
public typealias JSONRawIndex = Index
extension JSON: Swift.Collection {
public typealias Index = JSONRawIndex
public var startIndex: Index {
switch type {
case .array:
return .array(rawArray.startIndex)
case .dictionary:
return .dictionary(rawDictionary.startIndex)
default:
return .null
}
}
public var endIndex: Index {
switch type {
case .array:
return .array(rawArray.endIndex)
case .dictionary:
return .dictionary(rawDictionary.endIndex)
default:
return .null
}
}
public func index(after i: Index) -> Index {
switch i {
case .array(let idx):
return .array(rawArray.index(after: idx))
case .dictionary(let idx):
return .dictionary(rawDictionary.index(after: idx))
default:
return .null
}
}
public subscript (position: Index) -> (String, JSON) {
switch position {
case .array(let idx):
return (String(idx), JSON(self.rawArray[idx]))
case .dictionary(let idx):
let (key, value) = self.rawDictionary[idx]
return (key, JSON(value))
default:
return ("", JSON.null)
}
}
}
通过index直接获取json类型为数组或者字典的值
下标
// MARK: - Subscript
/**
* String和Int类型都能用于下标
*/
public enum JSONKey {
case index(Int)
case key(String)
}
public protocol JSONSubscriptType {
var jsonKey: JSONKey { get }
}
extension Int: JSONSubscriptType {
public var jsonKey: JSONKey {
return JSONKey.index(self)
}
}
extension String: JSONSubscriptType {
public var jsonKey: JSONKey {
return JSONKey.key(self)
}
}
extension JSON {
/// array类型的下标操作
fileprivate subscript(index index: Int) -> JSON {
get {
if self.type != .array {
var r = JSON.null
r.error = self.error ?? SwiftyJSONError.wrongType
return r
} else if self.rawArray.indices.contains(index) {
return JSON(self.rawArray[index])
} else {
var r = JSON.null
r.error = SwiftyJSONError.indexOutOfBounds
return r
}
}
set {
if self.type == .array &&
self.rawArray.indices.contains(index) &&
newValue.error == nil {
self.rawArray[index] = newValue.object
}
}
}
/// dictionary类型的下标操作
fileprivate subscript(key key: String) -> JSON {
get {
var r = JSON.null
if self.type == .dictionary {
if let o = self.rawDictionary[key] {
r = JSON(o)
} else {
r.error = SwiftyJSONError.notExist
}
} else {
r.error = self.error ?? SwiftyJSONError.wrongType
}
return r
}
set {
if self.type == .dictionary && newValue.error == nil {
self.rawDictionary[key] = newValue.object
}
}
}
/// 根据JSONSubscriptType判断使用的方法
fileprivate subscript(sub sub: JSONSubscriptType) -> JSON {
get {
switch sub.jsonKey {
case .index(let index): return self[index: index]
case .key(let key): return self[key: key]
}
}
set {
switch sub.jsonKey {
case .index(let index): self[index: index] = newValue
case .key(let key): self[key: key] = newValue
}
}
}
/**
通过JSONSubscriptType（Int或者JSON）数组的作为路径，获取json中的值
Example:
```
let json = JSON[data]
let path = [9,"list","person","name"]
let name = json[path]
```
*/
public subscript(path: [JSONSubscriptType]) -> JSON {
get {
return path.reduce(self) { $0[sub: $1] }
}
set {
switch path.count {
case 0:
return
case 1:
self[sub:path[0]].object = newValue.object
default:
var aPath = path
aPath.remove(at: 0)
var nextJSON = self[sub: path[0]]
nextJSON[aPath] = newValue
self[sub: path[0]] = nextJSON
}
}
}
public subscript(path: JSONSubscriptType...) -> JSON {
get {
return self[path]
}
set {
self[path] = newValue
}
}
}