I have data as below:
data =
[
"\u65b0\u5317\u5e02\u4e09\u91cd\u5340","\u65b0\u5317\u5e02\u6c38\u548c\u5340",
"\u53f0\u5317\u5e02\u4e2d\u5c71\u5340","\u53f0\u5317\u5e02\u4e2d\u6b63\u5340",
"\u53f0\u5317\u5e02\u4fe1\u7fa9\u5340","\u53f0\u5317\u5e02\u5357\u6e2f\u5340",
"\u53f0\u5317\u5e02\u5927\u540c\u5340","\u53f0\u5317\u5e02\u5927\u5b89\u5340",
"\u53f0\u5317\u5e02\u6587\u5c71\u5340","\u53f0\u5317\u5e02\u677e\u5c71\u5340",
"\u53f0\u5317\u5e02\u842c\u83ef\u5340"
]
but when I want to convert it to array, I use the code:
data.array
it always give me nil, what can I do?
I've also tried data.arrayValue and data.arrayValue.map {$0.stringValue}
Assume your data construct is
[
{
"data": [
"\u65b0\u5317\u5e02\u4e09\u91cd\u5340",
"\u65b0\u5317\u5e02\u6c38\u548c\u5340",
"\u53f0\u5317\u5e02\u4e2d\u5c71\u5340",
"\u53f0\u5317\u5e02\u4e2d\u6b63\u5340",
"\u53f0\u5317\u5e02\u4fe1\u7fa9\u5340",
"\u53f0\u5317\u5e02\u5357\u6e2f\u5340",
"\u53f0\u5317\u5e02\u5927\u540c\u5340",
"\u53f0\u5317\u5e02\u5927\u5b89\u5340",
"\u53f0\u5317\u5e02\u6587\u5c71\u5340",
"\u53f0\u5317\u5e02\u677e\u5c71\u5340",
"\u53f0\u5317\u5e02\u842c\u83ef\u5340"
]
}
]
Convert JSON into entity meanwhile conform Codable Protocol
typealias DistEntity = [Dist]
struct Dist: Codable {
let data: [String]
}
Implementation model layer
protocol JSONFetcher: AnyObject {
func distParser(forResource fileName: String, completionHandler handler: #escaping((Result<DistEntity, Error>) -> ()))
}
class ModelLayer: JSONFetcher {
enum ParserError: Error {
case PathNotFound
case ConvertsObjectError
case DecoderError
}
func distParser(forResource fileName: String, completionHandler handler: #escaping((Result<DistEntity, Error>) -> ())) {
guard let url = Bundle.main.url(forResource: fileName, withExtension: "json") else { return handler(.failure(ParserError.PathNotFound)) }
guard let jsonData = try? Data(contentsOf: url) else { return handler(.failure(ParserError.ConvertsObjectError)) }
let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .iso8601
guard let distEntity: DistEntity = try? decoder.decode(DistEntity.self, from: jsonData) else { return handler(.failure(ParserError.DecoderError)) }
handler(.success(distEntity))
}
}
Preliminary parse in the interface of business logic layer
final class viewModel {
private var fetcher: JSONFetcher
init(fetcher: JSONFetcher = ModelLayer()) {
self.fetcher = fetcher
}
private func distParser() {
self.fetcher.distParser(forResource: "YourJSONFileName") { (result) in
switch result {
case .success(let entity):
print("[Dist Entity]: \(entity)")
case .failure(let error):
print(error.localizedDescription)
}
}
}
}
Can't make sure that's useful for your scenario,
If no solve, may you should provide more detail info.
Related
Goals
Accessing the Dictionaries within an array
Some how get all 1957 Dictionaries decoded without hand coding each ticker name.
The below image is data from https://rapidapi.com/Glavier/api/binance43/ to replicate the below image get Symbol Price Ticker needs to be selected.
With the help of another question which was answered here I have included code below which I am trying to change to accomplish the above goals.
CallApi.swift - this file calls the API and models it to PriceApiModel
import UIKit
class ViewController: UIViewController {
let headers = [
"X-RapidAPI-Key": "Sorry I cannot include this",
"X-RapidAPI-Host": "binance43.p.rapidapi.com"
]
let request = NSMutableURLRequest(url: NSURL(string: "https://binance43.p.rapidapi.com/ticker/price")! as URL,
cachePolicy: .useProtocolCachePolicy,
timeoutInterval: 10.0)
func getData() {
request.httpMethod = "GET"
request.allHTTPHeaderFields = headers
let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
if (error != nil) {
print("error")
} else {
let httpResponse = response as? HTTPURLResponse
do {
//let dictionary = try JSONSerialization.jsonObject(with: data!, options: [])
let model = try JSONDecoder().decode(PriceApiModel.self, from: data!)
//print(String(model.symbol) + "name") // please see output below
//print(dictionary)
} catch {
print("NOT WORKING ")
}
}
})
dataTask.resume()
}
}
PriceApiModel.swift - I am trying to find a way for this file to be a model for decoding the data
struct PriceApiModel: Hashable, Codable {
//changed the String type to Decimal
var price: String
// every property you are interested to decode needs a CodingKey.
// You can omit values you are not interested in
enum CodingKeys: CodingKey{
case askPrice
}
// here you decode your data into the struct
init(from decoder: Decoder) throws {
// get the container
let container = try decoder.container(keyedBy: CodingKeys.self)
// decode the askPrice into a String and cast it into a Decimal
let askPrice = String(try container.decode(String.self, forKey: .askPrice))
// check if casting was succesfull else throw
guard let askPrice = askPrice else{
throw CustomError.decodingError
}
// assign it
self.askPrice = askPrice
}
}
So I just tried out what you want to achieve here. First of all, you declared a service class (fetching data) as ViewController, by inheritance a UIViewController. It seems to me a bit odd just having this in a class because the UIViewController is not used. Secondly, I would recommend you to watch or read something about Codable for example Hackingforswift. It helped at least me :)
However, here is a Code that shows you a way how it could work:
OptionalObject is needed because of the data structure, holding everything within an array.
struct OptionalObject<Base: Decodable>: Decodable {
public let value: Base?
public init(from decoder: Decoder) throws {
do {
let container = try decoder.singleValueContainer()
self.value = try container.decode(Base.self)
} catch {
self.value = nil
}
}
}
struct PriceApiModel: Codable {
let price: String
let symbol: String
}
enum ServiceError: Error {
case failureAtDecoding
}
// MVVM Pattern https://www.hackingwithswift.com/books/ios-swiftui/introducing-mvvm-into-your-swiftui-project
class ServiceViewModel: ObservableObject {
// Publisher you can subscribe to it.
// Every time the Publisher changes view will re-render.
#Published var priceModel: [PriceApiModel] = []
let headers = [
"X-RapidAPI-Key": "",
"X-RapidAPI-Host": "binance43.p.rapidapi.com"
]
var request = URLRequest(
url: URL(string: "https://binance43.p.rapidapi.com/ticker/price")!,
cachePolicy: .useProtocolCachePolicy,
timeoutInterval: 5.0
)
init() {
self.getData { priceModel in
// As DocC says:
/// A value that represents either a success or a failure, including an
// So you have to "unwrap" it to handle success or failure
switch priceModel {
case let .success(result):
DispatchQueue.main.async {
self.priceModel = result
}
case let .failure(failure):
print(failure)
}
}
}
func getData(priceModel: #escaping (Result<[PriceApiModel], Error>) -> Void) {
request.httpMethod = "GET"
request.allHTTPHeaderFields = headers
let session = URLSession.shared
let dataTask = session.dataTask(with: request) { (data, response, error) -> Void in
if let error = error {
priceModel(.failure(error))
} else if let data = data {
let model = try? JSONDecoder().decode([OptionalObject<PriceApiModel>].self, from: data)
let editModel = model?.compactMap {
PriceApiModel(price: $0.value?.price ?? "nil", symbol: $0.value?.symbol ?? "nil")
}
if let editModel = editModel {
priceModel(.success(editModel))
} else {
priceModel(.failure(ServiceError.failureAtDecoding))
}
}
}
dataTask.resume()
}
}
struct ContentView: View {
// Initialize the ServiceViewModel as StateObject
#StateObject var viewModel: ServiceViewModel = .init()
var body: some View {
NavigationView {
List {
ForEach(viewModel.priceModel, id: \.symbol) { model in
HStack {
Text(model.symbol)
Spacer()
Text(model.price)
}
}
}
}
}
}
Hope I could help.
I am trying to parse JSON using Swift, which has dynamic keys. Tried several ways but still did not find the solution. Could you please help me ?
I am trying to parse NativeName, which is dynamic based on which language country name is present.
API: https://restcountries.com/v3.1/all
struct Objects: Codable {
let name: Name
let cca2 : String
let flag: String
}
struct Name: Codable {
let common, official: String
let nativeName: NativeName
}
struct NativeName: Codable {
var deu : Deu
}
struct Deu: Codable {
let official, common: String?
}
and here is JSON Model:
class ParsingService {
static let shared = ParsingService()
func fetchData() {
guard let url = URL(string: "https://restcountries.com/v3.1/all") else {
print("DEBUG: URL is nill")
return}
let session = URLSession.shared
let task = session.dataTask(with: url) { data, _, error in
guard let retrievedData = data, error == nil else {
print("DEBUG: Data is not available")
return}
print("DEBUG: Data is available \(retrievedData)")
guard let decodedData = self.JSONParsing(inputData: retrievedData) else {
print("DEBUG: Missing data")
return}
print("DEBUG: Data is there")
print("DEBUG: \(decodedData[0].cca2)")
print("DEBUG: \(decodedData[0].flag)")
print("DEBUG: \(decodedData[0].name.nativeName.deu.official)")
DispatchQueue.main.async {
print(decodedData.currencies)
}
}
task.resume()
}
func JSONParsing(inputData: Data)-> [Objects]? {
let decoder = JSONDecoder()
do {
let data = try? decoder.decode([Objects].self, from: inputData)
return data
} catch {
print("DEBUG: Cannot get data")
return nil
}
}
}
you could try this approach:
struct ContentView: View {
var body: some View {
Text("testing")
.onAppear {
fetchData() { results in
print("---> results: \(results.count) \n")
for i in 0..<3 {
print("---> results[\(i)]: \(results[i].name.nativeName)")
}
}
}
}
// todo deal with errors
func fetchData(completion: #escaping ([Objects]) -> Void) {
let url = URL(string: "https://restcountries.com/v3.1/all")
guard let url = url else { completion([]); return }
URLSession.shared.dataTask(with: url) { (data, response, error) in
guard let data = data else { completion([]); return }
do {
let results = try JSONDecoder().decode([Objects].self, from: data)
completion(results)
}
catch {
print("Error: \(error)")
completion([])
}
}.resume()
}
}
struct Objects: Codable {
let name: Name
let cca2 : String
let flag: String
}
struct Deu: Codable {
let official, common: String?
}
struct Name: Codable {
let common, official: String
let nativeName: NativeName? // <-- here
}
// -- here
struct NativeName: Codable {
var lang: [String: Deu]
init(from decoder: Decoder) throws {
let container = try decoder.singleValueContainer()
lang = try container.decode([String: Deu].self)
}
func encode(to encoder: Encoder) throws {
// todo
}
}
Note, you could also use a Tuple, such as var lang: (key: String, value: Deu)
I am trying to decode data from a Firebase DataSnapshot so that it can be decoded using JSONDecoder.
I can decode this data fine when I use a URL to access it with a network request (obtaining a Data object).
However, I want to use the Firebase API to directly obtain the data, using observeSingleEvent as described on this page.
But, when I do this, I cannot seem to convert the result into a Data object, which I need to use JSONDecoder.
Is it possible to do the new style of JSON decoding with a DataSnapshot? How is it possible? I can't seem to figure it out.
I have created a library called CodableFirebase that provides Encoders and Decoders that are designed specifically for Firebase.
So for the example above:
import Firebase
import CodableFirebase
let item: GroceryItem = // here you will create an instance of GroceryItem
let data = try! FirebaseEncoder().encode(item)
Database.database().reference().child("pathToGraceryItem").setValue(data)
And here's how you will read the same data:
Database.database().reference().child("pathToGraceryItem").observeSingleEvent(of: .value, with: { (snapshot) in
guard let value = snapshot.value else { return }
do {
let item = try FirebaseDecoder().decode(GroceryItem.self, from: value)
print(item)
} catch let error {
print(error)
}
})
I've converted Firebase Snapshots using JSONDecoder by converting snapshots back to JSON in Data format. Your struct needs to conform to Decodable or Codable. I've done this with SwiftyJSON but this example is using JSONSerialization and it still works.
JSONSnapshotPotatoes {
"name": "Potatoes",
"price": 5,
}
JSONSnapshotChicken {
"name": "Chicken",
"price": 10,
"onSale": true
}
struct GroceryItem: Decodable {
var name: String
var price: Double
var onSale: Bool? //Use optionals for keys that may or may not exist
}
Database.database().reference().child("grocery_item").observeSingleEvent(of: .value, with: { (snapshot) in
guard let value = snapshot.value as? [String: Any] else { return }
do {
let jsonData = try JSONSerialization.data(withJSONObject: value, options: [])
let groceryItem = try JSONDecoder().decode(GroceryItem.self, from: jsonData)
print(groceryItem)
} catch let error {
print(error)
}
})
Please note that if your JSON keys are not the same as your Decodable struct. You'll need to use CodingKeys. Example:
JSONSnapshotSpinach {
"title": "Spinach",
"price": 10,
"onSale": true
}
struct GroceryItem: Decodable {
var name: String
var price: Double
var onSale: Bool?
enum CodingKeys: String, CodingKey {
case name = "title"
case price
case onSale
}
}
You can find more information on this using Apple Docs here.
No. Firebase returns a FIRDataSnapshot that can't be decodable. You can use this structure however, which is pretty simple and easy to understand:
struct GroceryItem {
let key: String
let name: String
let addedByUser: String
let ref: FIRDatabaseReference?
var completed: Bool
init(name: String, addedByUser: String, completed: Bool, key: String = "") {
self.key = key
self.name = name
self.addedByUser = addedByUser
self.completed = completed
self.ref = nil
}
init(snapshot: FIRDataSnapshot) {
key = snapshot.key
let snapshotValue = snapshot.value as! [String: AnyObject]
name = snapshotValue["name"] as! String
addedByUser = snapshotValue["addedByUser"] as! String
completed = snapshotValue["completed"] as! Bool
ref = snapshot.ref
}
func toAnyObject() -> Any {
return [
"name": name,
"addedByUser": addedByUser,
"completed": completed
]
}
}
And use toAnyObject() to save your item:
let groceryItemRef = ref.child("items")
groceryItemRef.setValue(groceryItem.toAnyObject())
Source: https://www.raywenderlich.com/139322/firebase-tutorial-getting-started-2
Or you can use this solution for children
extension DatabaseReference {
func makeSimpleRequest<U: Decodable>(completion: #escaping (U) -> Void) {
self.observeSingleEvent(of: .value, with: { snapshot in
guard let object = snapshot.children.allObjects as? [DataSnapshot] else { return }
let dict = object.compactMap { $0.value as? [String: Any] }
do {
let jsonData = try JSONSerialization.data(withJSONObject: dict, options: [])
let parsedObjects = try JSONDecoder().decode(U.self, from: jsonData)
completion(parsedObjects)
} catch let error {
print(error)
}
})
}
}
and use
self.refPriceStatistics.child(productId).makeSimpleRequest { (parsedArray: [YourArray]) in
callback(parsedArray)
}
If your data type is Codable you can use the following solution to decode directly. You do not need any plugin. I used the solution for Cloud Firestore.
import Firebase
import FirebaseFirestoreSwift
let db = Firestore.firestore()
let query = db.collection("CollectionName")
.whereField("id", isEqualTo: "123")
guard let documents = snapshot?.documents, error == nil else {
return
}
if let document = documents.first {
do {
let decodedData = try document.data(as: ModelClass.self)
// ModelClass a Codable Class
}
catch let error {
//
}
}
You can convert the value returned by Firebase to Data, and then decode that.
Add this extension to your project:
extension Collection {
//Designed for use with Dictionary and Array types
var jsonData: Data? {
return try? JSONSerialization.data(withJSONObject: self, options: .prettyPrinted)
}
}
Then use it to convert the value of the observed snapshot into data, which can then be decoded:
yourRef.observe(.value) { (snapshot) in
guard snapshot.exists(),
let value = snapshot.value as? [String],
let data = value.jsonData else {
return
}
//cast to expected type
do {
let yourNewObject = try JSONDecoder().decode([YourClass].self, from: data)
} catch let decodeError {
print("decodable error")
}
}
You can use this library CodableFirebase or the following extension can be helpful.
extension JSONDecoder {
func decode<T>(_ type: T.Type, from value: Any) throws -> T where T : Decodable {
do {
let data = try JSONSerialization.data(withJSONObject: value, options: .prettyPrinted)
let decoded = try decode(type, from: data)
return decoded
} catch {
throw error
}
}
I am trying to parse a JSON from an API using Alamofire and SwiftyJSON, but am having trouble trying to access the information in the JSON. I need to simply parse the JSON for an item called "ask_price": and also "time_coinapi" but I am not sure how I manage the response, or if I have to use a different method. here is what I have at the moment:
class CoinAPIManager {
var prices: [String] = []
var times: [String] = []
static let shared = CoinAPIManager()
func getReq() {
let headers: HTTPHeaders = [
"X-CoinAPI-Key": "Key"
]
Alamofire.request("https://rest.coinapi.io/v1/quotes/BITSTAMP_SPOT_BTC_USD/history?time_start=2018-08-21T00:00:00&time_end=2018-08-22T00:00:00&limit=100", headers: headers).responseJSON { response in
debugPrint(response)
if let data = try? String(contentsOf: response) {
let json = JSON(parseJSON: data)
parse(json: json)
}
}
func parse(json: JSON) {
for result in json[].arrayValue {
let price = result["ask_price"].stringValue
}
}
}
}
and I have also tried this:
func getReq() {
let headers: HTTPHeaders = [
"X-CoinAPI-Key": "Key"
]
Alamofire.request("https://rest.coinapi.io/v1/quotes/BITSTAMP_SPOT_BTC_USD/history?time_start=2018-08-21T00:00:00&time_end=2018-08-22T00:00:00&limit=100", headers: headers).responseJSON { response in
debugPrint(response)
switch response.result {
case .failure(let error):
// Do whatever here
return
case .success(let data):
// First make sure you got back a dictionary if that's what you expect
guard let json = data as? [String : AnyObject] else {
print("Failed to get expected response from webserver.")
return
}
// Then make sure you get the actual key/value types you expect
guard var price = json["ask_price"] as? Double else {
print("Failed to get data from webserver")
return
}
}
What am I doing wrong? this is how the JSON looks:
[
{
"symbol_id": "BITSTAMP_SPOT_BTC_USD",
"time_exchange": "2013-09-28T22:40:50.0000000Z",
"time_coinapi": "2017-03-18T22:42:21.3763342Z",
"ask_price": 770.000000000,
"ask_size": 3252,
"bid_price": 760,
"bid_size": 124
},
{
"symbol_id": "BITSTAMP_SPOT_BTC_USD",
"time_exchange": "2013-09-28T22:40:50.0000000",
"time_coinapi": "2017-03-18T22:42:21.3763342",
"ask_price": 770.000000000,
"ask_size": 3252,
"bid_price": 760,
"bid_size": 124
}
]
previous question deleted and reposted due to large mistake
you need to change your response to SwiftyJSON object like this
Alamofire.request("https://rest.coinapi.io/v1/quotes/BITSTAMP_SPOT_BTC_USD/history?time_start=2018-08-21T00:00:00&time_end=2018-08-22T00:00:00&limit=100", headers: headers).responseJSON { response in
debugPrint(response)
switch response.result {
case .failure(let error):
// Do whatever here
return
case .success:
// First make sure you got back a dictionary if that's what you expect
let responseJSON = JSON(response.result.value!)
if responseJSON.count != 0 {
print(responseJSON)
//do whatever you want with your object json
}
}
}
i suggest in your ApiManager you can use completion blocks to manage asyncronous request, check the next code.
class func getRequestWithoutParams(didSuccess:#escaping (_ message: JSON) -> Void, didFail: #escaping (_ alert:UIAlertController)->Void){
Alamofire.request("http://foo.bar"),method: .post,parameters: parameters,encoding: JSONEncoding.default,headers:nil).responseJSON { response in
switch response.result{
case .success:
let res = JSON(response.result.value!)
didSuccess(res)
break
case .failure(let error):
let alert = UIAlertController(title: "Error", message: error.localizedDescription, preferredStyle: .alert)
let done = UIAlertAction(title: "OK", style: .default, handler: nil)
alert.addAction(done)
didFail(alert)
}
}
}
From Swift 4, you should be able to use codable to solve it:
struct YourStructure: Codable {
let symbol_id: String?
let time_exchange: String?
let ask_price: String?
private enum CodingKeys: String, CodingKey {
case symbol_id = "symbol_id"
case time_exchange = "time_exchange"
case ask_price = "ask_price"
}
}
And then parse it with JSONDecoder
let decoder = JSONDecoder()
let parsedData = decoder.decode(YourStructure.self, from: "YourJsonData")
I am trying to decode data from a Firebase DataSnapshot so that it can be decoded using JSONDecoder.
I can decode this data fine when I use a URL to access it with a network request (obtaining a Data object).
However, I want to use the Firebase API to directly obtain the data, using observeSingleEvent as described on this page.
But, when I do this, I cannot seem to convert the result into a Data object, which I need to use JSONDecoder.
Is it possible to do the new style of JSON decoding with a DataSnapshot? How is it possible? I can't seem to figure it out.
I have created a library called CodableFirebase that provides Encoders and Decoders that are designed specifically for Firebase.
So for the example above:
import Firebase
import CodableFirebase
let item: GroceryItem = // here you will create an instance of GroceryItem
let data = try! FirebaseEncoder().encode(item)
Database.database().reference().child("pathToGraceryItem").setValue(data)
And here's how you will read the same data:
Database.database().reference().child("pathToGraceryItem").observeSingleEvent(of: .value, with: { (snapshot) in
guard let value = snapshot.value else { return }
do {
let item = try FirebaseDecoder().decode(GroceryItem.self, from: value)
print(item)
} catch let error {
print(error)
}
})
I've converted Firebase Snapshots using JSONDecoder by converting snapshots back to JSON in Data format. Your struct needs to conform to Decodable or Codable. I've done this with SwiftyJSON but this example is using JSONSerialization and it still works.
JSONSnapshotPotatoes {
"name": "Potatoes",
"price": 5,
}
JSONSnapshotChicken {
"name": "Chicken",
"price": 10,
"onSale": true
}
struct GroceryItem: Decodable {
var name: String
var price: Double
var onSale: Bool? //Use optionals for keys that may or may not exist
}
Database.database().reference().child("grocery_item").observeSingleEvent(of: .value, with: { (snapshot) in
guard let value = snapshot.value as? [String: Any] else { return }
do {
let jsonData = try JSONSerialization.data(withJSONObject: value, options: [])
let groceryItem = try JSONDecoder().decode(GroceryItem.self, from: jsonData)
print(groceryItem)
} catch let error {
print(error)
}
})
Please note that if your JSON keys are not the same as your Decodable struct. You'll need to use CodingKeys. Example:
JSONSnapshotSpinach {
"title": "Spinach",
"price": 10,
"onSale": true
}
struct GroceryItem: Decodable {
var name: String
var price: Double
var onSale: Bool?
enum CodingKeys: String, CodingKey {
case name = "title"
case price
case onSale
}
}
You can find more information on this using Apple Docs here.
No. Firebase returns a FIRDataSnapshot that can't be decodable. You can use this structure however, which is pretty simple and easy to understand:
struct GroceryItem {
let key: String
let name: String
let addedByUser: String
let ref: FIRDatabaseReference?
var completed: Bool
init(name: String, addedByUser: String, completed: Bool, key: String = "") {
self.key = key
self.name = name
self.addedByUser = addedByUser
self.completed = completed
self.ref = nil
}
init(snapshot: FIRDataSnapshot) {
key = snapshot.key
let snapshotValue = snapshot.value as! [String: AnyObject]
name = snapshotValue["name"] as! String
addedByUser = snapshotValue["addedByUser"] as! String
completed = snapshotValue["completed"] as! Bool
ref = snapshot.ref
}
func toAnyObject() -> Any {
return [
"name": name,
"addedByUser": addedByUser,
"completed": completed
]
}
}
And use toAnyObject() to save your item:
let groceryItemRef = ref.child("items")
groceryItemRef.setValue(groceryItem.toAnyObject())
Source: https://www.raywenderlich.com/139322/firebase-tutorial-getting-started-2
Or you can use this solution for children
extension DatabaseReference {
func makeSimpleRequest<U: Decodable>(completion: #escaping (U) -> Void) {
self.observeSingleEvent(of: .value, with: { snapshot in
guard let object = snapshot.children.allObjects as? [DataSnapshot] else { return }
let dict = object.compactMap { $0.value as? [String: Any] }
do {
let jsonData = try JSONSerialization.data(withJSONObject: dict, options: [])
let parsedObjects = try JSONDecoder().decode(U.self, from: jsonData)
completion(parsedObjects)
} catch let error {
print(error)
}
})
}
}
and use
self.refPriceStatistics.child(productId).makeSimpleRequest { (parsedArray: [YourArray]) in
callback(parsedArray)
}
If your data type is Codable you can use the following solution to decode directly. You do not need any plugin. I used the solution for Cloud Firestore.
import Firebase
import FirebaseFirestoreSwift
let db = Firestore.firestore()
let query = db.collection("CollectionName")
.whereField("id", isEqualTo: "123")
guard let documents = snapshot?.documents, error == nil else {
return
}
if let document = documents.first {
do {
let decodedData = try document.data(as: ModelClass.self)
// ModelClass a Codable Class
}
catch let error {
//
}
}
You can convert the value returned by Firebase to Data, and then decode that.
Add this extension to your project:
extension Collection {
//Designed for use with Dictionary and Array types
var jsonData: Data? {
return try? JSONSerialization.data(withJSONObject: self, options: .prettyPrinted)
}
}
Then use it to convert the value of the observed snapshot into data, which can then be decoded:
yourRef.observe(.value) { (snapshot) in
guard snapshot.exists(),
let value = snapshot.value as? [String],
let data = value.jsonData else {
return
}
//cast to expected type
do {
let yourNewObject = try JSONDecoder().decode([YourClass].self, from: data)
} catch let decodeError {
print("decodable error")
}
}
You can use this library CodableFirebase or the following extension can be helpful.
extension JSONDecoder {
func decode<T>(_ type: T.Type, from value: Any) throws -> T where T : Decodable {
do {
let data = try JSONSerialization.data(withJSONObject: value, options: .prettyPrinted)
let decoded = try decode(type, from: data)
return decoded
} catch {
throw error
}
}