What's the best way to pass a custom Codable Model into a firebase function? Here's what I have right now, but I get the error: Unsupported type: __SwiftValue for value
struct ExampleStruct: Codable {
var hi: String
var world: Int
var last: [String]
}
let myModel = ExampleStruct(hi: "World", world: 1, last: ["hi world"])
functions.httpsCallable(FirebaseFunctionsNames.exampleName).call(["data":myModel]) { [weak self] (result, error) in
print(result)
print(error)
}
The following ended up solving my question (note: I wouldn't recommend the force unwraps and casts but it's easier to consume in StackOverflow this way :)
struct ExampleStruct: Codable {
var hi: String
var world: Int
var last: [String]
}
let myModel = ExampleStruct(hi: "World", world: 1, last: ["hi world"])
func hiWorld(input: myModel) {
let jsonEncoder = JSONEncoder()
let jsonData = try! jsonEncoder.encode(input)
let json = String(data: jsonData, encoding: .utf8)!
functions.httpsCallable(FirebaseFunctionsNames.exampleName).call(["data":json]) { [weak self] (result, error) in
print(result)
print(error)
}
}
And then on the backend (Typescript):
const myModel = JSON.parse(data.data) as ExampleStruct;
Related
I am using the following struct that conforms to Codable to represent my data within a Set, I then take this set encode it into a JSON Array that looks like the following [{"myexample":"Example5","id":3}]
Struct and Encoding:
struct Model : Codable, Hashable {
var myexample: String?
var id: Int?
}
var mySet: Set<Model> = []
mySet.insert(Model(myexample: "Example4", id: 3))
do {
let json = try JSONEncoder().encode(mySet)
print(String(data: json, encoding: .utf8)!)
} catch {
print(error)
}
How can I inversely decode this array using the following function?
Currently getting this error:
Value of type 'Set' has no member 'utf8'
func processArray(array:Set<Model> = []) {
do{
let mydata = Data(array.utf8.data)
let decoded = try JSONDecoder().decode([Model].self,from: mydata)
print(decoded)
}catch let jsonErr {
print(jsonErr)
}
}
JSON is a string format so a JSON array is also string
func processJSON(_ json: String) {
do{
let mydata = Data(json.utf8)
let decoded = try JSONDecoder().decode(Set<Model>.self,from: mydata)
print(decoded)
} catch {
print(error)
}
}
Here I want to be able to use the value returned from an array. It returns as a type from a struct. I'm unsure of how to use the value as an integer.
struct Item: Codable {
let data: [String : Datum]
}
struct Datum: Codable {
let value: Int
}
var array = Item(data: ["1" : Datum(value: 1),"2": Datum(value: 2), "3":Datum(value: 3)])
var keyArray = ["1", "2", "3"]
print(array.data[keyArray[0]]!)
// Prints Datum(value: 1)
print(array.data[keyArray[0]]! + 1)
//This produces an error "Cannot convert value of type 'Datum' to expected argument type 'Int'"
//Expected result should be 2
My use case is when I get returned a decoded JSON it normally comes back as a dictionary. I'm wanting to use the values returned with a key but I feel like I'm one step short.
Context
Full JSON Link
I'm going to retrieve values from this JSON. (Example from large JSON file)
{"data":{"2":{"high":179,"highTime":1628182107,"low":177,"lowTime":1628182102},"6":{"high":189987,"highTime":1628179815,"low":184107,"lowTime":1628182100},"8":{"high":190800,"highTime":1628181435,"low":188100,"lowTime":1628182095}
}}
The string in front refers to an item ID.
The struct that I came up to decode goes like this.
// MARK: - Single
struct Single: Codable {
let data: [String: Datum]
}
// MARK: - Datum
struct Datum: Codable {
let high, highTime: Int
let low, lowTime: Int?
}
From there I'm planning to iterate through the JSON response to retrieve the item prices I'd want.
#available(iOS 15.0, *)
struct ContentView: View {
#State var dataFromURL: Single = Single(data: [:])
var body: some View {
VStack {
Text("Hello, world!")
.padding()
}
.onAppear {
async {
try await decode()
}
}
}
func decode() async throws -> Single {
let decoder = JSONDecoder()
let urlString = "https://prices.runescape.wiki/api/v1/osrs/latest"
guard let url = URL(string: urlString) else { throw APIError.invalidURL }
let (data, response) = try await URLSession.shared.data(from: url)
guard let response = response as? HTTPURLResponse, response.statusCode == 200 else { throw APIError.invalidServerResponse }
guard let result = try? decoder.decode(Single.self, from: data) else { throw APIError.invalidData }
//We copy our result to an existing variable
dataFromURL = result
return result
}
}
enum APIError: Error {
case invalidURL
case invalidServerResponse
case invalidData
}
extension APIError: CustomStringConvertible {
public var description: String {
switch self {
case.invalidURL:
return "Bad URL"
case .invalidServerResponse:
return "The server did not return 200"
case .invalidData:
return "Their server returned bad data"
}
}
}
I haven't gotten further than grabbing the response from the URL. That is why once I start manipulating the data I'd like to use the response to find other things like what would a profit/loss with another item become. Which isn't the goal of this question at the moment.
The object model to parse that JSON would be:
struct Price: Decodable {
let high: Int?
let highTime: Date?
let low: Int?
let lowTime: Date?
}
struct ResponseObject: Decodable {
let prices: [String: Price]
enum CodingKeys: String, CodingKey {
case prices = "data"
}
}
(Note, the documentation says that either high or low might be missing, so we have to make them all optionals.)
Now, the id number is being passed as a string in the JSON/ResponseObject. But that is a number (look at mapping). So, I would remap that dictionary so that the key was an integer, e.g.
enum ApiError: Error {
case unknownError(Data?, URLResponse?)
}
func fetchLatestPrices(completion: #escaping (Result<[Int: Price], Error>) -> Void) {
let url = URL(string: "https://prices.runescape.wiki/api/v1/osrs/latest")!
let task = URLSession.shared.dataTask(with: url) { data, response, error in
guard
error == nil,
let responseData = data,
let httpResponse = response as? HTTPURLResponse,
200..<300 ~= httpResponse.statusCode
else {
completion(.failure(error ?? ApiError.unknownError(data, response)))
return
}
let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .secondsSince1970
do {
let responseObject = try decoder.decode(ResponseObject.self, from: responseData)
let keysAndValues = responseObject.prices.map { (Int($0.key)!, $0.value) }
let prices = Dictionary(uniqueKeysWithValues: keysAndValues)
completion(.success(prices))
} catch {
completion(.failure(error))
}
}
task.resume()
}
The code that converts that [String: Price] to a [Int: Price] is this:
let keysAndValues = responseObject.prices.map { (Int($0.key)!, $0.value) }
let prices = Dictionary(uniqueKeysWithValues: keysAndValues)
I must say that this is a questionable API design, to have keys returned as integers in one endpoint and as strings as another. But it is what it is. So, the above is how you handle that.
Anyway, now that you have a dictionary of prices, keyed by the id numbers, you can use that in your code, e.g.
var prices: [Int: Price] = [:]
var products: [Product] = []
let group = DispatchGroup()
group.enter()
fetchLatestPrices { result in
defer { group.leave() }
switch result {
case .failure(let error):
print(error)
case .success(let values):
prices = values
}
}
group.enter()
fetchProducts { result in
defer { group.leave() }
switch result {
case .failure(let error):
print(error)
case .success(let values):
products = values }
}
group.notify(queue: .main) {
for product in products {
print(product.name, prices[product.id] ?? "no price found")
}
}
Where
func fetchProducts(completion: #escaping (Result<[Product], Error>) -> Void) {
let url = URL(string: "https://prices.runescape.wiki/api/v1/osrs/mapping")!
let task = URLSession.shared.dataTask(with: url) { data, response, error in
guard
error == nil,
let responseData = data,
let httpResponse = response as? HTTPURLResponse,
200..<300 ~= httpResponse.statusCode
else {
completion(.failure(error ?? ApiError.unknownError(data, response)))
return
}
do {
let products = try JSONDecoder().decode([Product].self, from: responseData)
completion(.success(products))
} catch {
completion(.failure(error))
}
}
task.resume()
}
And
struct Product: Decodable {
let id: Int
let name: String
let examine: String
let members: Bool
let lowalch: Int?
let limit: Int?
let value: Int
let highalch: Int?
let icon: String
}
(As an aside, I do not know if some of these other properties should be optionals or not. I just used optionals where I empirically discovered that they are occasionally missing.)
I tried to directly get the data recieved from a URLsession updated into the instance variables. Tried the code below in playgroud, I can see until the self.cityName = weatherdecoded.name the code seems working fine, but the self.cityName which intended to be the instance's variable didn't got updated. The results are nils. Hope to understand the reason, what is the mistake i made. Thanks!
import UIKit
class WeatherManager {
var cityName: String?
var conditionID: Int?
var temp: Double?
func fetchData(cityName: String) {
let session = URLSession(configuration: .default)
let urlStr = "https://api.openweathermap.org/data/2.5/weather?units=metric&appid=8da179fa1c83749056ec6a5385cabb04&q=" + cityName.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
print(urlStr)
let url = URL(string: urlStr)!
let weatherDataSession = session.dataTask(with: url, completionHandler: getdata(data:response:error:))
weatherDataSession.resume()
}
func getdata(data: Data?, response: URLResponse?, error: Error?) {
if error != nil {
print(error!)
return
}
if let safedata = data {
let decoder = JSONDecoder()
do {
let weatherdecoded = try decoder.decode(Weatherdata.self, from: safedata)
self.cityName = weatherdecoded.name
self.conditionID = weatherdecoded.weather[0].id
self.temp = weatherdecoded.main.temp
} catch {
print(error)
}
}
}
}
struct Weatherdata: Decodable {
let weather : [Weather]
let main: Main
let name: String
}
struct Weather: Decodable {
let id: Int
let description: String
}
struct Main: Decodable {
let temp: Double
}
let weathermanager = WeatherManager()
weathermanager.fetchData(cityName: "beijing")
print(weathermanager.cityName)
print(weathermanager.conditionID)
print(weathermanager.temp)
The simple reason is the fact that you are printing the values before the request actually completes. You have to use a completion handler:
class WeatherManager {
func fetchObject<T: Decodable>(urlPath: String, onCompletion: #escaping (Result<T, Error>) -> Void) {
let session = URLSession(configuration: .default)
let url = URL(string: urlPath)!
let task = session.dataTask(with: url) { data, _, error in
if let error = error {
onCompletion(.failure(error))
return
}
let decoder = JSONDecoder()
do {
let decoded = try decoder.decode(T.self, from: data ?? Data())
onCompletion(.success(decoded))
} catch {
onCompletion(.failure(error))
}
}
task.resume()
}
func fetchWeather(cityName: String, onCompletion: #escaping (Result<Weatherdata, Error>) -> Void) {
let urlPath = "https://api.openweathermap.org/data/2.5/weather?units=metric&appid=8da179fa1c83749056ec6a5385cabb04&q=" + cityName.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
fetchObject(urlPath: urlPath, onCompletion: onCompletion)
}
}
struct Weatherdata: Decodable {
let weather : [Weather]
let main: Main
let name: String
}
struct Weather: Decodable {
let id: Int
let description: String
}
struct Main: Decodable {
let temp: Double
}
let weathermanager = WeatherManager()
weathermanager.fetchWeather(cityName: "beijing") { result in
switch result {
case .success(let weatherData):
print(weatherData.name)
print(weatherData.weather[0].id)
print(weatherData.main.temp)
case .failure(let error):
print(error)
}
}
I am trying to post 2 parameters (email: and password) to get a response from the server with detailed user information, I build API to handle this and get a good response using Postman, but when I tried to implement this with Swift4 new urlsession JSON decode and encode, it keeps failing and I got error on decoding the response data.
this my JSON response when using Postman:
{
"error": "false",
"message": "downloaded",
"UserInfo": {
"id": 5,
"email": "abc#hotmail.com",
"lastname": "Bence",
"name": "Mark",
"phone": "1234567",
"add1": "333",
"add2": "444",
"city": "ott",
"postalcode": "tttttt"
}
}
My struct file:
import UIKit
struct loginPost: Encodable {
let email: String
let password: String
}
struct User: Decodable {
let error: String?
let message: String?
let UserInfo: [UserData]
}
struct UserData: Codable {
let id: Int?
let email: String?
let lastname: String?
let name: String?
let phone: String?
let add1: String?
let add2: String?
let city: String
let postalcode: String?
}
My Function
func downloadJson() {
let url = URL(string: http://192.168.0.10/api/login_hashed.php)
guard let downloadURL = url else { return }
//POST Req
var request = URLRequest(url: downloadURL)
request.httpMethod = "POST"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
let newpost = loginPost(email: "abc#hotmail.com", password: "123456")
do {
let jsonBody = try JSONEncoder().encode(newpost)
request.httpBody = jsonBody
print(jsonBody)
}catch{
print("some error")
}
URLSession.shared.dataTask(with: request) { data, urlResponse, error in
guard let data = data, error == nil, urlResponse != nil else {
print("something is wrong with url")
return
}
print("downloaded..")
do
{
let decoder = JSONDecoder()
let downloaduser = try decoder.decode(User.self, from: data)
self.logmessage = downloaduser.message!
print(self.logmessage)
DispatchQueue.main.async {
// self.tableView.reloadData()
}
} catch {
print("something wrong with decode")
}
}.resume()
}
I have figured it out finally, thanks,.
I just want to mention the cause of this error and share my experience.
The main cause is the way you send JSON and receive the incoming response. you should know exactly how the data look in order to create your struct the acceptable way.
My return data is just simple 2 line of text and array of text, my struct was:
import UIKit
struct loginPost: Encodable {
let email: String
let password: String
}
struct User: Decodable {
let error: String?
let message: String?
let UserInfo: [UserData]
}
struct UserData: Codable {
let id: Int?
let email: String?
let lastname: String?
let name: String?
let phone: String?
let add1: String?
let add2: String?
let city: String
let postalcode: String?
}
my mistake on line 18
let UserInfo: [UserData]
it should be
let UserInfo: UserData?
without the square bracket.
one more important point, always try to catch the decode error and it's dicription by implementing }catch let JsonErr {, it will give you exactly why the decode not working.
in my case:
downloaded.. something wrong after downloaded
typeMismatch(Swift.Array, Swift.DecodingError.Context(codingPath:
[h2h.User.(CodingKeys in _E33F61CC43E102744E4EF1B7E9D7EDDE).UserInfo],
debugDescription: "Expected to decode Array but found a
dictionary instead.", underlyingError: nil))
And make sure to make your server API to accept JSON format application/json and
decode what you send in order to receive what you looking for;
php code service API
$UserData = json_decode(file_get_contents("php://input"), true);
Simplest and easy way to decode the json.
MUST TRY
struct Welcome: Codable {
let error, message: String?
let userInfo: UserInfo?
enum CodingKeys: String, CodingKey {
case error, message
case userInfo = "UserInfo"
}
}
// MARK: - UserInfo
struct UserInfo: Codable {
let id: Int?
let email, lastname, name, phone: String?
let add1, add2, city, postalcode: String?
}
After that in your code , when you get response from api then write
let decoder = JSONDecoder()
let obj = try! decoder.decode(Welcome.self, from: jsonData!)
Print(obj)
List item
This Will work Are You Creating Model Is Wrong
struct loginPost: Encodable {
let email: String
let password: String
}
struct Users:Codable {
var error:String?
var message:String?
var UserInfo:UserDetails?
}
struct UserDetails:Codable {
let id: Int?
let email: String?
let lastname: String?
let name: String?
let phone: String?
let add1: String?
let add2: String?
let city: String
let postalcode: String?
}
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
downloadJson()
}
func downloadJson() {
let url = URL(string: "http://192.168.0.10/api/login_hashed.php")
guard let downloadURL = url else { return }
//POST Req
var request = URLRequest(url: downloadURL)
request.httpMethod = "POST"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
let newpost = loginPost(email: "abc#hotmail.com", password: "123456")
do {
let jsonBody = try JSONEncoder().encode(newpost)
request.httpBody = jsonBody
print(jsonBody)
}catch{
print("some error")
}
URLSession.shared.dataTask(with: request) { data, urlResponse, error in
guard let data = data, error == nil, urlResponse != nil else {
print("something is wrong with url")
return
}
print("downloaded..")
do
{
let decoder = JSONDecoder()
let downloaduser = try decoder.decode(Users.self, from: data)
// self.logmessage = downloaduser.message!
// print(self.logmessage)
DispatchQueue.main.async {
// self.tableView.reloadData()
}
} catch {
print("something wrong with decode")
}
}.resume()
}
}
I want to encode Dictionary to json with JSONEncoder.
It seems like a Request, receive a dictionary as parameter and encode it to json as http body.
The code is looks like this:
let dict = ["name": "abcde"]
protocol Request {
var params: [String: Encodable] { get set }
func encode<T>(_ value: T) throws -> Data where T : Encodable
}
extension Request {
func encode<T>(_ value: T) throws -> Data where T : Encodable {
return try JSONEncoder().encode(value)
}
var body: Data? {
if let encoded = try? self.encode(self.params) {
return encoded
}
return nil
}
}
struct BaseRequest: Request {
var params: [String : Encodable]
}
let req = BaseRequest(params: dict)
let body = req.body
But this code occurs error
Fatal error: Dictionary<String, Encodable> does not conform to Encodable because Encodable does not conform to itself. You must use a concrete type to encode or decode.
How could I make this encodable?
You have to introduce type erasure as follows:
struct AnyEncodable: Encodable {
let value: Encodable
init(value: Encodable) {
self.value = value
}
func encode(to encoder: Encoder) throws {
try value.encode(to: encoder)
}
}
struct Model: Encodable {
var params: [String: AnyEncodable]
}
let encoder = JSONEncoder()
encoder.outputFormatting = .prettyPrinted
let json = try! encoder.encode(
Model(
params: [
"hello" : AnyEncodable.init(value: "world")
]
).params
)
print(String(data: json, encoding: .utf8))
If you want to define your struct as conforming to Codable, you can do it like this:
struct Model: Codable {
var param1: String
var param2: Int
}
let model = Model(param1: "test", param2: 0)
let encoded = try? JSONEncoder().encode(model)
let decoded = try? JSONDecoder().decode(Model.self, from: encoded!)
It won't really work if you set params: [String: Any] because the encoders/decoders don't know how to encode/decode Any, but they can do it for the primitive types.
If you want more help, you should read more about the new Codable protocol. I recommend this: https://hackernoon.com/everything-about-codable-in-swift-4-97d0e18a2999