Can Swift convert a class / struct data into dictionary? - swift

For example:
class Test {
var name: String;
var age: Int;
var height: Double;
func convertToDict() -> [String: AnyObject] { ..... }
}
let test = Test();
test.name = "Alex";
test.age = 30;
test.height = 170;
let dict = test.convertToDict();
dict will have content:
{"name": "Alex", "age": 30, height: 170}
Is this possible in Swift?
And can I access a class like a dictionary, for example probably using:
test.value(forKey: "name");
Or something like that?

You can just add a computed property to your struct to return a Dictionary with your values. Note that Swift native dictionary type doesn't have any method called value(forKey:). You would need to cast your Dictionary to NSDictionary:
struct Test {
let name: String
let age: Int
let height: Double
var dictionary: [String: Any] {
return ["name": name,
"age": age,
"height": height]
}
var nsDictionary: NSDictionary {
return dictionary as NSDictionary
}
}
You can also extend Encodable protocol as suggested at the linked answer posted by #ColGraff to make it universal to all Encodable structs:
struct JSON {
static let encoder = JSONEncoder()
}
extension Encodable {
subscript(key: String) -> Any? {
return dictionary[key]
}
var dictionary: [String: Any] {
return (try? JSONSerialization.jsonObject(with: JSON.encoder.encode(self))) as? [String: Any] ?? [:]
}
}
struct Test: Codable {
let name: String
let age: Int
let height: Double
}
let test = Test(name: "Alex", age: 30, height: 170)
test["name"] // Alex
test["age"] // 30
test["height"] // 170

You could use Reflection and Mirror like this to make it more dynamic and ensure you do not forget a property.
struct Person {
var name:String
var position:Int
var good : Bool
var car : String
var asDictionary : [String:Any] {
let mirror = Mirror(reflecting: self)
let dict = Dictionary(uniqueKeysWithValues: mirror.children.lazy.map({ (label:String?, value:Any) -> (String, Any)? in
guard let label = label else { return nil }
return (label, value)
}).compactMap { $0 })
return dict
}
}
let p1 = Person(name: "Ryan", position: 2, good : true, car:"Ford")
print(p1.asDictionary)
["name": "Ryan", "position": 2, "good": true, "car": "Ford"]

A bit late to the party, but I think this is great opportunity for JSONEncoder and JSONSerialization.
The accepted answer does touch on this, this solution saves us calling JSONSerialization every time we access a key, but same idea!
extension Encodable {
/// Encode into JSON and return `Data`
func jsonData() throws -> Data {
let encoder = JSONEncoder()
encoder.outputFormatting = .prettyPrinted
encoder.dateEncodingStrategy = .iso8601
return try encoder.encode(self)
}
}
You can then use JSONSerialization to create a Dictionary if the Encodable should be represented as an object in JSON (e.g. Swift Array would be a JSON array)
Here's an example:
struct Car: Encodable {
var name: String
var numberOfDoors: Int
var cost: Double
var isCompanyCar: Bool
var datePurchased: Date
var ownerName: String? // Optional
}
let car = Car(
name: "Mazda 2",
numberOfDoors: 5,
cost: 1234.56,
isCompanyCar: true,
datePurchased: Date(),
ownerName: nil
)
let jsonData = try car.jsonData()
// To get dictionary from `Data`
let json = try JSONSerialization.jsonObject(with: jsonData, options: [])
guard let dictionary = json as? [String : Any] else {
return
}
// Use dictionary
guard let jsonString = String(data: jsonData, encoding: .utf8) else {
return
}
// Print jsonString
print(jsonString)
Output:
{
"numberOfDoors" : 5,
"datePurchased" : "2020-03-04T16:04:13Z",
"name" : "Mazda 2",
"cost" : 1234.5599999999999,
"isCompanyCar" : true
}

Use protocol, it is an elegant solution. 1. encode struct or class to data 2. decode data and transfer to dictionary.
/// define protocol convert Struct or Class to Dictionary
protocol Convertable: Codable {
}
extension Convertable {
/// implement convert Struct or Class to Dictionary
func convertToDict() -> Dictionary<String, Any>? {
var dict: Dictionary<String, Any>? = nil
do {
print("init student")
let encoder = JSONEncoder()
let data = try encoder.encode(self)
print("struct convert to data")
dict = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as? Dictionary<String, Any>
} catch {
print(error)
}
return dict
}
}
struct Student: Convertable {
var name: String
var age: Int
var classRoom: String
init(_ name: String, age: Int, classRoom: String) {
self.name = name
self.age = age
self.classRoom = classRoom
}
}
let student = Student("zgpeace", age: 18, classRoom: "class one")
print(student.convertToDict() ?? "nil")
ref: https://a1049145827.github.io/2018/03/02/Swift-%E4%BB%8E%E9%9B%B6%E5%AE%9E%E7%8E%B0%E4%B8%80%E4%B8%AAStruct%E6%88%96Class%E8%BD%ACDictionary%E7%9A%84%E9%9C%80%E6%B1%82/

This answer is like the above which uses Mirror. But consider the nested class/struct case.
extension Encodable {
func dictionary() -> [String:Any] {
var dict = [String:Any]()
let mirror = Mirror(reflecting: self)
for child in mirror.children {
guard let key = child.label else { continue }
let childMirror = Mirror(reflecting: child.value)
switch childMirror.displayStyle {
case .struct, .class:
let childDict = (child.value as! Encodable).dictionary()
dict[key] = childDict
case .collection:
let childArray = (child.value as! [Encodable]).map({ $0.dictionary() })
dict[key] = childArray
case .set:
let childArray = (child.value as! Set<AnyHashable>).map({ ($0 as! Encodable).dictionary() })
dict[key] = childArray
default:
dict[key] = child.value
}
}
return dict
}
}

Related

Skipping empty string with JSONEncoders swift

I a codable serialization extension which I use to turn my Codable struct to dictionaries, the problem I am facing is strings. I get string value from my UITextField at at times this value could be empty and as a result an empty string is decoded. How can I return nil if the value is an empty string.
extension Encodable {
var requestDictionary: [String: Any]? {
let encoder = JSONEncoder()
encoder.keyEncodingStrategy = .convertToSnakeCase
guard let data = try? encoder.encode(self) else { return nil }
return (try? JSONSerialization.jsonObject(with: data, options: .allowFragments)).flatMap { $0 as? [String: Any] }
}
}
if I have a Struct
let example = Exa(age: 10, name: "")
let dict = example.requestDictionary
print(dict)
I want it to just print ["age": 10] and return nil for the empty string
You can implement your own String encoding method extending KeyedEncodingContainer:
extension KeyedEncodingContainer {
mutating func encode(_ value: String, forKey key: K) throws {
guard !value.isEmpty else { return }
try encodeIfPresent(value, forKey: key)
}
}
Btw your request dictionary can be simplified as:
extension Encodable {
var dictionary: [String: Any]? {
let encoder = JSONEncoder()
encoder.keyEncodingStrategy = .convertToSnakeCase
return try? JSONSerialization.jsonObject(with: encoder.encode(self)) as? [String: Any]
}
}
Playground testing:
struct Exa: Encodable {
let age: Int
let name: String
}
let example = Exa(age: 10, name: "")
let dict = example.dictionary!
print(dict) // "["age": 10]\n"
I'll just another approach using a property wrapper to mark which properties could be skipped.
#propertyWrapper
struct SkipEmpty {
var wrappedValue: String
}
extension SkipEmpty: Codable {
init(from decoder: Decoder) throws {
let container = try decoder.singleValueContainer()
self.wrappedValue = try container.decode(String.self)
}
func encode(to encoder: Encoder) throws {
// nothing to do here, see below
}
}
But to actually skip, you'd also need to create a overload for the KeyedEncodingContainer.encode method for the SkipEmpty type:
extension KeyedEncodingContainer {
mutating func encode(_ value: SkipEmpty, forKey key: K) throws {
if !value.wrappedValue.isEmpty {
try encode(value.wrappedValue, forKey: key) // encode the value here
}
}
}
You could possibly try to make it more generic, e.g. SkipEmpty<T: Codable> and provide another argument for the value to skip or a predicate, etc...
The usage is:
struct Exa: Encodable {
var age: Int
#SkipEmpty var name: String
}

Firebase - How do I read this map via embedded structs?

I am reading data from Firestore to be able to populate into expanding tableview cells. I have a really simple struct:
protocol PlanSerializable {
init?(dictionary:[String:Any])
}
struct Plan{
var menuItemName: String
var menuItemQuantity: Int
var menuItemPrice: Double
var dictionary: [String: Any] {
return [
"menuItemName": menuItemName,
"menuItemQuantity": menuItemQuantity,
"menuItemPrice": menuItemPrice
]
}
}
extension Plan : PlanSerializable {
init?(dictionary: [String : Any]) {
guard let menuItemName = dictionary["menuItemName"] as? String,
let menuItemQuantity = dictionary["menuItemQuantity"] as? Int,
let menuItemPrice = dictionary["menuItemPrice"] as? Double
else { return nil }
self.init(menuItemName: menuItemName, menuItemQuantity: menuItemQuantity, menuItemPrice: menuItemPrice)
}
}
And this is embedded in this struct:
protocol ComplainSerializable {
init?(dictionary:[String:Any])
}
struct Complain{
var status: Bool
var header: String
var message: String
var timeStamp: Timestamp
var email: String
var planDetails: Plan
var dictionary: [String: Any] {
return [
"status": status,
"E-mail": header,
"Message": message,
"Time_Stamp": timeStamp,
"User_Email": email,
"planDetails": planDetails
]
}
}
extension Complain : ComplainSerializable {
init?(dictionary: [String : Any]) {
guard let status = dictionary["status"] as? Bool,
let header = dictionary["E-mail"] as? String,
let message = dictionary["Message"] as? String,
let timeStamp = dictionary["Time_Stamp"] as? Timestamp,
let email = dictionary["User_Email"] as? String,
let planDetails = dictionary["planDetails"] as? Plan
else { return nil }
self.init(status: status, header: header, message: message, timeStamp: timeStamp, email: email, planDetails: planDetails)
}
}
However, I am not able to query any data from Firestore which looks like this:
Here is my query, although I am just reading all the files:
let db = Firestore.firestore()
var messageArray = [Complain]()
func loadMenu() {
db.collection("Feedback_Message").getDocuments() { documentSnapshot, error in
if let error = error {
print("error:\(error.localizedDescription)")
} else {
self.messageArray = documentSnapshot!.documents.compactMap({Complain(dictionary: $0.data())})
for plan in self.messageArray {
print("\(plan.email)")
}
DispatchQueue.main.async {
self.testTable.reloadData()
}
}
}
}
What am I doing wrong?
EDIT:
As suggested, here is the updated embedded struct:
import Foundation
// MARK: - Complain
struct Complain: Codable {
let eMail, message, timeStamp, userEmail: String
let status: Bool
let planDetails: PlanDetails
enum CodingKeys: String, CodingKey {
case eMail = "E-mail"
case message = "Message"
case timeStamp = "Time_Stamp"
case userEmail = "User_Email"
case status, planDetails
}
}
// MARK: - PlanDetails
struct PlanDetails: Codable {
let menuItemName: String
let menuItemQuantity: Int
let menuItemPrice: Double
}
Using quicktype.io, you can generate the struct. From there, all you need to do is run this tiny fragment of code within your response handler.
var compainArray = [Complain]()
func loadMenu() {
db.collection("Feedback_Message").getDocuments() { documentSnapshot, error in
if let error = error {
print("error:\(error.localizedDescription)")
} else {
guard let snapshot = documentSnapshot else {return}
for document in snapshot.documents {
if let jsonData = try? JSONSerialization.data(withJSONObject: document.data()){
if let converted = try? JSONDecoder().decode(Complain.self, from: jsonData){
self.compainArray.append(converted)
}
}
}
DispatchQueue.main.async {
self.testTable.reloadData()
}
}
}
}
Which will handle the looping, and mapping of certain variables. Let me know if you have any trouble with this.

convert Codable to Json (Dictionary) Swift

How can I convert Codable to Json Dictionay its a nested struct
struct one
struct User: Codable {
var name = "siddhant"
var age = 12
var topInt = ["1","2","3"]
var moreDetails = MoreDetails()
}
struct Two
struct MoreDetails: Codable {
var image = "ImageUrl"
}
I need out put as a Json when I convert this to Json it just convert me the struct one not the 2nd struct
do {
let sid = try JSONEncoder().encode(users)
let dict = try JSONSerialization.jsonObject(with: sid, options: []) as? [String: Any]
print(dict)
}
catch {
print(error)
}
current output which is wrong:
(["name": siddhant, "topInt": <__NSArrayI 0x2831a1c20>(1,2,3),
"moreDetails": {
image = ImageUrl;
}, "age": 12])
I want output like
{
"name": "siddhant",
"topInt": ["1", "2", "3"],
"moreDetails": {
"image": "ImageUrl"
},
"age": 12
}
You can create an extension on Encodable so that you can use it for all elements that conform to Encodable protocol
extension Encodable {
var dictionary: [String: Any]? {
guard let data = try? JSONEncoder().encode(self) else { return nil }
return (try? JSONSerialization.jsonObject(with: data, options: .allowFragments)).flatMap { $0 as? [String: Any] }
}
}
In your case if the model is user of type User
guard let userDict = user.dictionary else { return }
what I did now is
let users = User()
let staticJson = ["name": users.name,
"age": users.age,
"topInt": users.topInt,
"moreDetails": ["image": users.moreDetails.image]] as? [String: Any]
You need to specify what is your desired result. Following your code:
struct User: Codable {
var name = "siddhant"
var age = 12
var topInt = ["1","2","3"]
var moreDetails = MoreDetails()
var dictionaryJson: [String : Any] {
let encoder = JSONEncoder()
return (try? JSONSerialization.jsonObject(with: encoder.encode(self), options: .allowFragments)) as? [String: Any] ?? [:]
}
}
struct MoreDetails: Codable {
var image = "ImageUrl"
}
do {
let users = User()
let jsonData = try JSONEncoder().encode(users)
let jsonString = String(data: jsonData, encoding: .utf8)!
print(jsonString)
print("\n")
print(users.dictionaryJson)
print("\n")
print("Getting the var from dictionary")
print(users.dictionaryJson["moreDetails"])
} catch {
print(error)
}
The output:
{"age":12,"moreDetails":{"image":"ImageUrl"},"name":"siddhant","topInt":["1","2","3"]}
["topInt": <__NSArrayI 0x6000008e8150>(
1,
2,
3
)
, "name": siddhant, "age": 12, "moreDetails": {
image = ImageUrl;
}]
Getting the var from dictionary
Optional({
image = ImageUrl;
})

Get 'NSInvalidArgumentException' 'Attempt to insert non-property list object when saving class type array to UserDefaults [duplicate]

I have a simple object which conforms to the NSCoding protocol.
import Foundation
class JobCategory: NSObject, NSCoding {
var id: Int
var name: String
var URLString: String
init(id: Int, name: String, URLString: String) {
self.id = id
self.name = name
self.URLString = URLString
}
// MARK: - NSCoding
required init(coder aDecoder: NSCoder) {
id = aDecoder.decodeObject(forKey: "id") as? Int ?? aDecoder.decodeInteger(forKey: "id")
name = aDecoder.decodeObject(forKey: "name") as! String
URLString = aDecoder.decodeObject(forKey: "URLString") as! String
}
func encode(with aCoder: NSCoder) {
aCoder.encode(id, forKey: "id")
aCoder.encode(name, forKey: "name")
aCoder.encode(URLString, forKey: "URLString")
}
}
I'm trying to save an instance of it in UserDefaults but it keeps failing with the following error.
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Attempt to insert non-property list object for key jobCategory'
This is the code where I'm saving in UserDefaults.
enum UserDefaultsKeys: String {
case jobCategory
}
class ViewController: UIViewController {
#IBAction func didTapSaveButton(_ sender: UIButton) {
let category = JobCategory(id: 1, name: "Test Category", URLString: "http://www.example-job.com")
let userDefaults = UserDefaults.standard
userDefaults.set(category, forKey: UserDefaultsKeys.jobCategory.rawValue)
userDefaults.synchronize()
}
}
I replaced the enum value to key with a normal string but the same error still occurs. Any idea what's causing this?
You need to create Data instance from your JobCategory model using JSONEncoder and store that Data instance in UserDefaults and later decode using JSONDecoder.
struct JobCategory: Codable {
let id: Int
let name: String
}
// To store in UserDefaults
if let encoded = try? JSONEncoder().encode(category) {
UserDefaults.standard.set(encoded, forKey: UserDefaultsKeys.jobCategory.rawValue)
}
// Retrieve from UserDefaults
if let data = UserDefaults.standard.object(forKey: UserDefaultsKeys.jobCategory.rawValue) as? Data,
let category = try? JSONDecoder().decode(JobCategory.self, from: data) {
print(category.name)
}
Old Answer
You need to create Data instance from your JobCategory instance using archivedData(withRootObject:) and store that Data instance in UserDefaults and later unarchive using unarchiveTopLevelObjectWithData(_:), So try like this.
For Storing data in UserDefaults
let category = JobCategory(id: 1, name: "Test Category", URLString: "http://www.example-job.com")
let encodedData = NSKeyedArchiver.archivedData(withRootObject: category, requiringSecureCoding: false)
let userDefaults = UserDefaults.standard
userDefaults.set(encodedData, forKey: UserDefaultsKeys.jobCategory.rawValue)
For retrieving data from UserDefaults
let decoded = UserDefaults.standard.object(forKey: UserDefaultsKeys.jobCategory.rawValue) as! Data
let decodedTeams = NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(decoded) as! JobCategory
print(decodedTeams.name)
Update Swift 4, Xcode 10
I have written a struct around it for easy access.
//set, get & remove User own profile in cache
struct UserProfileCache {
static let key = "userProfileCache"
static func save(_ value: Profile!) {
UserDefaults.standard.set(try? PropertyListEncoder().encode(value), forKey: key)
}
static func get() -> Profile! {
var userData: Profile!
if let data = UserDefaults.standard.value(forKey: key) as? Data {
userData = try? PropertyListDecoder().decode(Profile.self, from: data)
return userData!
} else {
return userData
}
}
static func remove() {
UserDefaults.standard.removeObject(forKey: key)
}
}
Profile is a Json encoded object.
struct Profile: Codable {
let id: Int!
let firstName: String
let dob: String!
}
Usage:
//save details in user defaults...
UserProfileCache.save(profileDetails)
Hope that helps!!!
Thanks
Swift save Codable object to UserDefault with #propertyWrapper
#propertyWrapper
struct UserDefault<T: Codable> {
let key: String
let defaultValue: T
init(_ key: String, defaultValue: T) {
self.key = key
self.defaultValue = defaultValue
}
var wrappedValue: T {
get {
if let data = UserDefaults.standard.object(forKey: key) as? Data,
let user = try? JSONDecoder().decode(T.self, from: data) {
return user
}
return defaultValue
}
set {
if let encoded = try? JSONEncoder().encode(newValue) {
UserDefaults.standard.set(encoded, forKey: key)
}
}
}
}
enum GlobalSettings {
#UserDefault("user", defaultValue: User(name:"",pass:"")) static var user: User
}
Example User model confirm Codable
struct User:Codable {
let name:String
let pass:String
}
How to use it
//Set value
GlobalSettings.user = User(name: "Ahmed", pass: "Ahmed")
//GetValue
print(GlobalSettings.user)
Save dictionary Into userdefault
let data = NSKeyedArchiver.archivedData(withRootObject: DictionaryData)
UserDefaults.standard.set(data, forKey: kUserData)
Retrieving the dictionary
let outData = UserDefaults.standard.data(forKey: kUserData)
let dict = NSKeyedUnarchiver.unarchiveObject(with: outData!) as! NSDictionary
Based on Harjot Singh answer. I've used like this:
struct AppData {
static var myObject: MyObject? {
get {
if UserDefaults.standard.object(forKey: "UserLocationKey") != nil {
if let data = UserDefaults.standard.value(forKey: "UserLocationKey") as? Data {
let myObject = try? PropertyListDecoder().decode(MyObject.self, from: data)
return myObject!
}
}
return nil
}
set {
UserDefaults.standard.set(try? PropertyListEncoder().encode(newValue), forKey: "UserLocationKey")
}
}
}
Here's a UserDefaults extension to set and get a Codable object, and keep it human-readable in the plist (User Defaults) if you open it as a plain text file:
extension Encodable {
var asDictionary: [String: Any]? {
guard let data = try? JSONEncoder().encode(self) else { return nil }
return try? JSONSerialization.jsonObject(with: data) as? [String : Any]
}
}
extension Decodable {
init?(dictionary: [String: Any]) {
guard let data = try? JSONSerialization.data(withJSONObject: dictionary) else { return nil }
guard let object = try? JSONDecoder().decode(Self.self, from: data) else { return nil }
self = object
}
}
extension UserDefaults {
func setEncodableAsDictionary<T: Encodable>(_ encodable: T, for key: String) {
self.set(encodable.asDictionary, forKey: key)
}
func getDecodableFromDictionary<T: Decodable>(for key: String) -> T? {
guard let dictionary = self.dictionary(forKey: key) else {
return nil
}
return T(dictionary: dictionary)
}
}
If you want to also support array (of codables) to and from plist array, add the following to the extension:
extension UserDefaults {
func setEncodablesAsArrayOfDictionaries<T: Encodable>(_ encodables: Array<T>, for key: String) {
let arrayOfDictionaries = encodables.map({ $0.asDictionary })
self.set(arrayOfDictionaries, forKey: key)
}
func getDecodablesFromArrayOfDictionaries<T: Decodable>(for key: String) -> [T]? {
guard let arrayOfDictionaries = self.array(forKey: key) as? [[String: Any]] else {
return nil
}
return arrayOfDictionaries.compactMap({ T(dictionary: $0) })
}
}
If you don't care about plist being human-readable, it can be simply saved as Data (will look like random string if opened as plain text):
extension UserDefaults {
func setEncodable<T: Encodable>(_ encodable: T, for key: String) throws {
let data = try PropertyListEncoder().encode(encodable)
self.set(data, forKey: key)
}
func getDecodable<T: Decodable>(for key: String) -> T? {
guard
self.object(forKey: key) != nil,
let data = self.value(forKey: key) as? Data
else {
return nil
}
let obj = try? PropertyListDecoder().decode(T.self, from: data)
return obj
}
}
(With this second approach, you don't need the Encodable and Decodable extensions from the top)

How can I use Swift’s Codable to encode into a dictionary?

I have a struct that implements Swift 4’s Codable. Is there a simple built-in way to encode that struct into a dictionary?
let struct = Foo(a: 1, b: 2)
let dict = something(struct)
// now dict is ["a": 1, "b": 2]
If you don't mind a bit of shifting of data around you could use something like this:
extension Encodable {
func asDictionary() throws -> [String: Any] {
let data = try JSONEncoder().encode(self)
guard let dictionary = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as? [String: Any] else {
throw NSError()
}
return dictionary
}
}
Or an optional variant
extension Encodable {
var dictionary: [String: Any]? {
guard let data = try? JSONEncoder().encode(self) else { return nil }
return (try? JSONSerialization.jsonObject(with: data, options: .allowFragments)).flatMap { $0 as? [String: Any] }
}
}
Assuming Foo conforms to Codable or really Encodable then you can do this.
let struct = Foo(a: 1, b: 2)
let dict = try struct.asDictionary()
let optionalDict = struct.dictionary
If you want to go the other way(init(any)), take a look at this Init an object conforming to Codable with a dictionary/array
Here are simple implementations of DictionaryEncoder / DictionaryDecoder that wrap JSONEncoder, JSONDecoder and JSONSerialization, that also handle encoding / decoding strategies…
class DictionaryEncoder {
private let encoder = JSONEncoder()
var dateEncodingStrategy: JSONEncoder.DateEncodingStrategy {
set { encoder.dateEncodingStrategy = newValue }
get { return encoder.dateEncodingStrategy }
}
var dataEncodingStrategy: JSONEncoder.DataEncodingStrategy {
set { encoder.dataEncodingStrategy = newValue }
get { return encoder.dataEncodingStrategy }
}
var nonConformingFloatEncodingStrategy: JSONEncoder.NonConformingFloatEncodingStrategy {
set { encoder.nonConformingFloatEncodingStrategy = newValue }
get { return encoder.nonConformingFloatEncodingStrategy }
}
var keyEncodingStrategy: JSONEncoder.KeyEncodingStrategy {
set { encoder.keyEncodingStrategy = newValue }
get { return encoder.keyEncodingStrategy }
}
func encode<T>(_ value: T) throws -> [String: Any] where T : Encodable {
let data = try encoder.encode(value)
return try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String: Any]
}
}
class DictionaryDecoder {
private let decoder = JSONDecoder()
var dateDecodingStrategy: JSONDecoder.DateDecodingStrategy {
set { decoder.dateDecodingStrategy = newValue }
get { return decoder.dateDecodingStrategy }
}
var dataDecodingStrategy: JSONDecoder.DataDecodingStrategy {
set { decoder.dataDecodingStrategy = newValue }
get { return decoder.dataDecodingStrategy }
}
var nonConformingFloatDecodingStrategy: JSONDecoder.NonConformingFloatDecodingStrategy {
set { decoder.nonConformingFloatDecodingStrategy = newValue }
get { return decoder.nonConformingFloatDecodingStrategy }
}
var keyDecodingStrategy: JSONDecoder.KeyDecodingStrategy {
set { decoder.keyDecodingStrategy = newValue }
get { return decoder.keyDecodingStrategy }
}
func decode<T>(_ type: T.Type, from dictionary: [String: Any]) throws -> T where T : Decodable {
let data = try JSONSerialization.data(withJSONObject: dictionary, options: [])
return try decoder.decode(type, from: data)
}
}
Usage is similar to JSONEncoder / JSONDecoder…
let dictionary = try DictionaryEncoder().encode(object)
and
let object = try DictionaryDecoder().decode(Object.self, from: dictionary)
For convenience, I've put this all in a repo… https://github.com/ashleymills/SwiftDictionaryCoding
I have create a library called CodableFirebase and it's initial purpose was to use it with Firebase Database, but it does actually what you need: it creates a dictionary or any other type just like in JSONDecoder but you don't need to do the double conversion here like you do in other answers. So it would look something like:
import CodableFirebase
let model = Foo(a: 1, b: 2)
let dict = try! FirebaseEncoder().encode(model)
There is no built in way to do that.
As answered above if you have no performance issues then you can accept the JSONEncoder + JSONSerialization implementation.
But I would rather go the standard library's way to provide an encoder/decoder object.
class DictionaryEncoder {
private let jsonEncoder = JSONEncoder()
/// Encodes given Encodable value into an array or dictionary
func encode<T>(_ value: T) throws -> Any where T: Encodable {
let jsonData = try jsonEncoder.encode(value)
return try JSONSerialization.jsonObject(with: jsonData, options: .allowFragments)
}
}
class DictionaryDecoder {
private let jsonDecoder = JSONDecoder()
/// Decodes given Decodable type from given array or dictionary
func decode<T>(_ type: T.Type, from json: Any) throws -> T where T: Decodable {
let jsonData = try JSONSerialization.data(withJSONObject: json, options: [])
return try jsonDecoder.decode(type, from: jsonData)
}
}
You can try it with following code:
struct Computer: Codable {
var owner: String?
var cpuCores: Int
var ram: Double
}
let computer = Computer(owner: "5keeve", cpuCores: 8, ram: 4)
let dictionary = try! DictionaryEncoder().encode(computer)
let decodedComputer = try! DictionaryDecoder().decode(Computer.self, from: dictionary)
I am force-trying here to make the example shorter. In production code you should handle the errors appropriately.
I'm not sure if it's the best way but you definitely can do something like:
struct Foo: Codable {
var a: Int
var b: Int
init(a: Int, b: Int) {
self.a = a
self.b = b
}
}
let foo = Foo(a: 1, b: 2)
let dict = try JSONDecoder().decode([String: Int].self, from: JSONEncoder().encode(foo))
print(dict)
let dict = try JSONSerialization.jsonObject(with: try JSONEncoder().encode(struct), options: []) as? [String: Any]
I have modified the PropertyListEncoder from the Swift project into a DictionaryEncoder, simply by removing the final serialisation from dictionary into binary format. You can do the same yourself, or you can take my code from here
It can be used like this:
do {
let employeeDictionary: [String: Any] = try DictionaryEncoder().encode(employee)
} catch let error {
// handle error
}
In some project, i'm used the swift reflection. But be careful, nested codable objects, are not mapped also there.
let dict = Dictionary(uniqueKeysWithValues: Mirror(reflecting: foo).children.map{ ($0.label!, $0.value) })
I definitely think that there's some value in just being able to use Codable to encode to/from dictionaries, without the intention of ever hitting JSON/Plists/whatever. There are plenty of APIs which just give you back a dictionary, or expect a dictionary, and it's nice to be able to interchange them easily with Swift structs or objects, without having to write endless boilerplate code.
I've been playing round with some code based on the Foundation JSONEncoder.swift source (which actually does implement dictionary encoding/decoding internally, but doesn't export it).
The code can be found here: https://github.com/elegantchaos/DictionaryCoding
It's still quite rough, but I've expanded it a bit so that, for example, it can fill in missing values with defaults when decoding.
Here is a protocol based solution:
protocol DictionaryEncodable {
func encode() throws -> Any
}
extension DictionaryEncodable where Self: Encodable {
func encode() throws -> Any {
let jsonData = try JSONEncoder().encode(self)
return try JSONSerialization.jsonObject(with: jsonData, options: .allowFragments)
}
}
protocol DictionaryDecodable {
static func decode(_ dictionary: Any) throws -> Self
}
extension DictionaryDecodable where Self: Decodable {
static func decode(_ dictionary: Any) throws -> Self {
let jsonData = try JSONSerialization.data(withJSONObject: dictionary, options: [])
return try JSONDecoder().decode(Self.self, from: jsonData)
}
}
typealias DictionaryCodable = DictionaryEncodable & DictionaryDecodable
And here is how to use it:
class AClass: Codable, DictionaryCodable {
var name: String
var age: Int
init(name: String, age: Int) {
self.name = name
self.age = age
}
}
struct AStruct: Codable, DictionaryEncodable, DictionaryDecodable {
var name: String
var age: Int
}
let aClass = AClass(name: "Max", age: 24)
if let dict = try? aClass.encode(), let theClass = try? AClass.decode(dict) {
print("Encoded dictionary: \n\(dict)\n\ndata from decoded dictionary: \"name: \(theClass.name), age: \(theClass.age)\"")
}
let aStruct = AStruct(name: "George", age: 30)
if let dict = try? aStruct.encode(), let theStruct = try? AStruct.decode(dict) {
print("Encoded dictionary: \n\(dict)\n\ndata from decoded dictionary: \"name: \(theStruct.name), age: \(theStruct.age)\"")
}
I wrote a quick gist to handle this (not using the Codable protocol). Be careful, it doesn't type-check any values and doesn't work recursively on values that are encodable.
class DictionaryEncoder {
var result: [String: Any]
init() {
result = [:]
}
func encode(_ encodable: DictionaryEncodable) -> [String: Any] {
encodable.encode(self)
return result
}
func encode<T, K>(_ value: T, key: K) where K: RawRepresentable, K.RawValue == String {
result[key.rawValue] = value
}
}
protocol DictionaryEncodable {
func encode(_ encoder: DictionaryEncoder)
}
There no straight forward way of doing this in Codable. You need to implement Encodable/Decodable protocol for your struct. For your example, you might need to write as below
typealias EventDict = [String:Int]
struct Favorite {
var all:EventDict
init(all: EventDict = [:]) {
self.all = all
}
}
extension Favorite: Encodable {
struct FavoriteKey: CodingKey {
var stringValue: String
init?(stringValue: String) {
self.stringValue = stringValue
}
var intValue: Int? { return nil }
init?(intValue: Int) { return nil }
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: FavoriteKey.self)
for eventId in all {
let nameKey = FavoriteKey(stringValue: eventId.key)!
try container.encode(eventId.value, forKey: nameKey)
}
}
}
extension Favorite: Decodable {
public init(from decoder: Decoder) throws {
var events = EventDict()
let container = try decoder.container(keyedBy: FavoriteKey.self)
for key in container.allKeys {
let fav = try container.decode(Int.self, forKey: key)
events[key.stringValue] = fav
}
self.init(all: events)
}
}
I have made a pod here https://github.com/levantAJ/AnyCodable to facilitate decode and encode [String: Any] and [Any]
pod 'DynamicCodable', '1.0'
And you are able to decode & encode [String: Any] and [Any]
import DynamicCodable
struct YourObject: Codable {
var dict: [String: Any]
var array: [Any]
var optionalDict: [String: Any]?
var optionalArray: [Any]?
enum CodingKeys: String, CodingKey {
case dict
case array
case optionalDict
case optionalArray
}
init(from decoder: Decoder) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
dict = try values.decode([String: Any].self, forKey: .dict)
array = try values.decode([Any].self, forKey: .array)
optionalDict = try values.decodeIfPresent([String: Any].self, forKey: .optionalDict)
optionalArray = try values.decodeIfPresent([Any].self, forKey: .optionalArray)
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(dict, forKey: .dict)
try container.encode(array, forKey: .array)
try container.encodeIfPresent(optionalDict, forKey: .optionalDict)
try container.encodeIfPresent(optionalArray, forKey: .optionalArray)
}
}
After research, we find that if we use the keyword Any in the class which is inherited from the Codable & Decodable it will give the error. So if you want to use a dictionary user with the types of data coming from the server.
For example, the server is sending the dictionary of type [String : Int] then use [String : Int] if you will try [String : Any] it will not work.
Here is dictionary -> object. Swift 5.
extension Dictionary where Key == String, Value: Any {
func object<T: Decodable>() -> T? {
if let data = try? JSONSerialization.data(withJSONObject: self, options: []) {
return try? JSONDecoder().decode(T.self, from: data)
} else {
return nil
}
}
}
Come to think of it, the question does not have an answer in the general case, since the Encodable instance may be something not serializable into a dictionary, such as an array:
let payload = [1, 2, 3]
let encoded = try JSONEncoder().encode(payload) // "[1,2,3]"
Other than that, I have written something similar as a framework.