I am trying to use the open weathermap.org api to return the "main" key in JSON. For some reason I keep getting caught up in my error around "failed to convert". I'm not exactly sure why I am failing to convert the JSON anyone have any ideas? Thank you.
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
let url = "https://api.openweathermap.org/data/2.5/weather?zip=10514&appid=#####################"
getData(from: url)
}
struct Response: Codable {
let weather: MyResult
}
struct MyResult: Codable {
let main: String
}
Below is the function being called to change access the JSON.
private func getData(from url:String) {
URLSession.shared.dataTask(with: URL(string:url)!, completionHandler: {
data, response, error in
guard let data = data, error == nil else {
print("Something went wrong")
return
}
// have data
var result: Response?
do {
result = try JSONDecoder().decode(Response.self, from: data)
} catch {
print("failed to convert")
}
guard let json = result else {
return
}
print(json.weather.main)
}).resume()
}
EDIT: This is what the json pulls up. Am I creating the structs incorrectly? if so how should I do it properly? thank you
{"coord":{"lon":-73.73,"lat":41.2},"weather":[{"id":802,"main":"Clouds","description":"scattered clouds","icon":"03n"}],"base":"stations","main":{"temp":291.67,"feels_like":288.73,"temp_min":290.93,"temp_max":292.59,"pressure":1024,"humidity":72},"visibility":10000,"wind":{"speed":5.7,"deg":130},"clouds":{"all":40},"dt":1594956028,"sys":{"type":1,"id":4403,"country":"US","sunrise":1594892168,"sunset":1594945530},"timezone":-14400,"id":0,"name":"Mount Kisco","cod":200}
In the JSON response, the property weather is an array:
{..., weather: [{...}] }
but in your model it expects a MyResult type. Change it to expect an array of [MyResult]:
struct Response: Codable {
let weather: [MyResult]
}
Related
I'm receiving response data from an API, when I'm trying to decode it by using json decoder, the nested json data won't be decoded because it returns null.
json data as follow:
{
"token": "string",
"details": {
"ID": "string",
"Name": "string",
"Message": null
}
}
Decoding model is:
struct response: Codable {
let token: String?
let usrData: userData?
}
struct userData:Codable{
let ID,Name,Message: String?
}
URLSession.shared.dataTask(with: request) { (data, response, error) in
guard let data = data, error == nil else {
completion(.failure(.custom(errorMessage: "Please check internet connection")))
return
}
guard let loginResponse = try? JSONDecoder().decode(response.self, from:data) else
{
completion(.failure(.invalidCredentials))
return
}
print(loginResponse.userData?.userID as Any) //returns nil
print(loginResponse.token) //token printed
guard let token = loginResponse.token else {
completion(.failure(.invalidCredentials))
return
}
completion(.success(token))
}.resume()
The token from the response will be successfully decoded, but the userData returns null.
Your model's property name and decoded json property name must be equal if your are not mapping , so change your struct with :
struct response: Codable {
let token: String?
let details: userDto?
}
That certainly can not work, first, in your response struct you have a let variable that says usrData that can not be identified as details. Second you write usrData: userDto what is userDto you clearly did a mistake or forgot to mention it. However, do it like that for example:
struct Response: Codable {
let token: String?
let details: UserData?
}
struct UserData: Codable {
let ID,Name,Message: String?
}
let filePath = Bundle.main.path(forResource:"test", ofType: "json")
let data = try Data(contentsOf: URL(fileURLWithPath: filePath!))
if let loginResponse = try? JSONDecoder().decode(Response.self, from: data) {
loginResponse
}
The example is not completely correct, because fileURLWithPath is deprecated but you should get the idea from it.
I also recommend following some basic roles, like writing Structs with an uppercase letter.
here is the string(my whole response is string) which i get after api call .
"{'result': {'ip':'49.36.183.40','id':'T1199','Date':'2022-7-24','Time':'20:58:36','Temp':38.94,'PM25':117.00,'lux':7.00,'VOC':586.00,'CO':0.97,'CO2':828.00,'O3':118.00,'RH':48.88,'Pres':989.00}}",,,
I tried this since I was receiving the string back :
#Published var singleData : [iotData] = []
func loadSingleData() {
if let url = URL(string: urlString) {
URLSession.shared.dataTask(with: url) { [weak self ] data , response, error in
DispatchQueue.main.async {
let decoder = JSONDecoder()
if let data = data {
if let users = try? decoder.decode([String : iotData].self, from: data) {
print(users)
} else {
print("failed to decode the data")
}
} else {
print("Failed to load the data")
}
}
}.resume()
} else {
print("wrong url")
}
}
but my output is failed to decode the data
also there are commas outside json string how do i take care of those .
i am beginner in ios development so i don't have any clue how to decode this json string and use it.how can i get past this
here is my model for this
struct iotData : Codable {
var result : Result
}
struct Result: Codable {
let ip, id, Date, Time: String
let Temp: Double
let PM25, lux, VOC: Int
let CO: Double
let CO2, O3: Int
let RH: Double
let Pres: Int
}
Use:
decoder.decode(iotData.self, from: data) { }
Instead of
decoder.decode(iotData, from: data) { }
Also make sure 'data' is actually 'Data' object
I have a JSON response from an api call. The problem is I get different JSON responses depending on whether the user has entered the correct credentials or not. My question is how do I read and decode these responses to a useable struct and what is the best way to go about decoding these different responses. one thing I noticed is both response have a common "isSuccess" that may be useful. I have little to no experience with swift or reading JSON so this is all a learning experience for me.
This is the response for successful login
{"result":{"login":{"isAuthorized":true,"isEmpty":false,"userName":{"isEmpty":false,"name":{"firstName":"Jason","lastName":"Test","displayName":"Test, Jason","isEmpty":false,"fullName":"Jason Test"},"canDelete":false,"id":5793,"canModify":false},"username":"test#testable.com"},"parameters":{"isEmpty":false,"keep_logged_in_indicator":false,"username":"test#testable.com"}},"isAuthorized":true,"version":{"major":"2021","minor":"004","fix":"04","display":"2021.004.04","isEmpty":false},"isSystemDown":false,"timestamp":"2021-07-28T02:47:33Z","isSuccess":true}
This is the response for failure
{"isAuthorized":true,"version":{"major":"2021","minor":"004","fix":"04","display":"2021.004.04","isEmpty":false},"isSystemDown":false,"errors":[{"password":"Unable to login as 'test#testable.com'"}],"timestamp":"2021-07-28T02:47:05Z","isSuccess":false}
This is the code I have written for my api calls
func request<T: Decodable>(endPoint: EndPoint, method: Method, parameters: [String: Any]? = nil, completion: #escaping(Result<T, Error>) -> Void) {
// Creates a urlRequest
guard let request = createRequest(endPoint: endPoint, method: method, parameters: parameters) else {
completion(.failure(AppError.invalidUrl))
return
}
let session = URLSession.shared
session.dataTask(with: request) { data, response, error in
var results: Result<Data, Error>?
guard let httpResponse = response as? HTTPURLResponse, httpResponse.statusCode == 200 else {
completion(.failure(AppError.badStatusCode))
return
}
if let response = response {
// Gets the JSESSIONID
let cookieName = "JSESSIONID"
if let cookie = HTTPCookieStorage.shared.cookies?.first(where: { $0.name == cookieName }) {
debugPrint("\(cookieName): \(cookie.value)")
}
print(response)
}
if let data = data {
results = .success(data)
// Converts data to readable String
let responseString = String(data: data, encoding: .utf8) ?? "unable to convert to readable String"
print("Server Response: \(responseString.description)")
} else if let error = error {
results = .failure(error)
print("Server Error: \(error.localizedDescription)")
}
DispatchQueue.main.async {
self.handleResponse(result: results, completion: completion)
}
}.resume()
}
private func handleResponse<T: Decodable>(result: Result<Data, Error>?, completion: (Result<T, Error>) -> Void) {
guard let result = result else {
completion(.failure(AppError.unknownError))
return
}
switch result {
case .success(let data):
do {
let json = try JSONSerialization.jsonObject(with: data, options: [])
print("Server JsonObject response: \(json)")
} catch {
completion(.failure(AppError.errorDecoding))
}
let decoder = JSONDecoder()
// Decodes that json data
do {
} catch {
}
case .failure(let error):
completion(.failure(error))
}
}
Im mostly interesting in being able to display the json error that occurs when credentials are incorrect. The deadline for my project Is slowing approaching and any help or suggestions would be much appreciated.
You can use Swift's Result type to differentiate a successful result from a failed result.
The Result type is not decodable by default so you will need to write a custom decoder like this:
struct Response: Decodable {
let result: Swift.Result<Result, Errors>
enum CodingKeys: String, CodingKey {
case isSuccess
case errors
case result
}
struct Result: Codable {
let login: Login
struct Login: Codable {
let isAuthorized: Bool
}
}
struct Errors: Error {
let contents: [[String: String]]
}
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
if try container.decode(Bool.self, forKey: .isSuccess) {
result = .success(try container.decode(Result.self, forKey: .result))
} else {
result = .failure(
Errors(contents: try container.decode([[String: String]].self, forKey: .errors))
)
}
}
}
I am trying to decode https://api.exchangeratesapi.io/latest, provided by Exchange Rates API. I'm applying several tutorials I found online, but when I apply my own details, I get an error. My code looks as following:
struct Response: Codable {
var results: [Result]
}
struct Result: Codable {
let base: String
let date: String
let rates: [String:Double]
}
The function to retrieve the data:
func loadData() {
guard let url = URL(string: "https://api.exchangeratesapi.io/latest") else {
print("Invalid URL")
return
}
let request = URLRequest(url: url)
URLSession.shared.dataTask(with: request) { data, response, error in
if let data = data {
if let decodedResponse = try? JSONDecoder().decode(Response.self, from: data) {
// we have good data – go back to the main thread
DispatchQueue.main.async {
// update our UI
self.results = decodedResponse.results
}
// everything is good, so we can exit
return
}
}
// if we're still here it means there was a problem
print("Fetch failed: \(error?.localizedDescription ?? "Unknown error")")
}.resume()
}
And my view:
import SwiftUI
struct ExchangeRateTest: View {
#State private var results = [Result]()
var body: some View {
List(results, id: \.base) { item in
VStack(alignment: .leading) {
Text(item.base)
}
}.onAppear(perform: loadData)
}
}
The error I get is: Fetch Failed: Unknown Error, suggesting that the app is not able to read the online data. What can cause this?
It has nothing to do with my network connection; if I apply another JSON this approach works fine.
Any help would greatly be appreciated.
you can read like this:
struct RateResult: Codable {
let rates: [String: Double]
let base, date: String
}
struct ContentView: View {
#State private var results = RateResult(rates: [:], base: "", date: "")
func loadData() {
guard let url = URL(string: "https://api.exchangeratesapi.io/latest") else {
print("Invalid URL")
return
}
let request = URLRequest(url: url)
URLSession.shared.dataTask(with: request) { data, response, error in
if let data = data {
if let decodedResponse = try? JSONDecoder().decode(RateResult.self, from: data) {
// we have good data – go back to the main thread
DispatchQueue.main.async {
// update our UI
self.results = decodedResponse
}
// everything is good, so we can exit
return
}
}
// if we're still here it means there was a problem
print("Fetch failed: \(error?.localizedDescription ?? "Unknown error")")
}.resume()
}
I think this will be simple I assume I'm just missing something about JSON structure here. I have some code that pulls down some data from an API handle to get a list of country names:
https://restcountries.eu/rest/v2/all?fields=name
Here is a sample of the API data though please feel free to view it using the link above:
[{"name":"Afghanistan"},{"name":"Åland Islands"},{"name":"Albania"},{"name":"Algeria"},{"name":"American Samoa"},{"name":"Andorra"},{"name":"Angola"},{"name":"Anguilla"},{"name":"Antarctica"},{"name":"Antigua and Barbuda"},{"name":"Argentina"}
I created this struct to hold the data
struct CountryList: Codable {
public let country: [Country]
}
struct Country: Codable {
public let name: String
}
I have these two functions that create the URLRequest and then grab the data and return it via a completion handler:
private func setupApiUrlRequest(apiURL: String) throws -> URLRequest {
let urlString = apiURL
guard let url = URL(string: urlString) else {
print("Error setting up URL")
throw CountriesError.invalidURLString
}
var request = URLRequest(url: url)
request.httpMethod = "GET"
return request
}
func getCountries(completion: #escaping (Country?, URLResponse?, Error?) -> Void) {
if let request = try? setupApiUrlRequest(apiURL: "https://restcountries.eu/rest/v2/all?fields=name") {
URLSession.shared.dataTask(with: request) { data,response,error in
guard let data = data else {
completion(nil, response, error)
return
}
do {
let decoder = JSONDecoder()
let downloadedCountries = try decoder.decode(Country.self, from: data)
completion(downloadedCountries, response, nil)
} catch {
print(error.localizedDescription)
completion(nil, response, error)
}
}.resume()
}
}
This gives me an error:
The data couldn’t be read because it isn’t in the correct format.
So it seems like my Struct is not correct somehow but I am just not sure how. Can anyone offer any guidance? I have a few other functions using almost identical code that grab API JSON Data and decode it into structs... just missing something here.
The JSON you've provided is not in the correct format.
Valid JSON:
[{"name":"Afghanistan"},{"name":"Åland Islands"},{"name":"Albania"},{"name":"Algeria"},{"name":"American Samoa"},{"name":"Andorra"},{"name":"Angola"},{"name":"Anguilla"},{"name":"Antarctica"},{"name":"Antigua and Barbuda"},{"name":"Argentina"}]
You need to use the [Country].self instead of just Country.self while parsing, i.e.
do {
let downloadedCountries = try JSONDecoder().decode([Country].self, from: data)
print(downloadedCountries)
} catch {
print(error)
}
Also, there is not requirement of struct CountryList. You can remove that.