I would like to get data from server, but credential (username, password. Not Basi Authentification) is necessary to get it. Therefore, I try to use URLSession with URLCredential as following:
https://developer.apple.com/documentation/foundation/url_loading_system/handling_an_authentication_challenge
However, I could not understand this document...
So could you tell me how to use URLSession with URLCredential?
I tried URLSession like:
func startLoad() {
let url = URL(string: "https://www.abcde-test-url.com/")!
let task = URLSession.shared.dataTask(with: url) { data, response, error in
if let error = error {
print("client error: \(error.localizedDescription) \n")
return
}
guard let data = data, let response = response as? HTTPURLResponse else {
print("no data or no response")
return
}
if response.statusCode == 200 {
print(data)
} else {
print("error status code: \(response.statusCode)\n")
}
}
task.resume()
}
But I couldn't understand the usage with URLCredential.
Related
I'm performing a post request over my rest api that I built in node. Then the data are stored in a mongodb collection.
This is my code that I use to post the request:
// create dataTask using the session object to send data to the server
let task = session.dataTask(with: request) { data, response, error in
if let error = error {
print("Post Request Error: \(error.localizedDescription)")
return
}
// ensure there is valid response code returned from this HTTP response
guard let httpResponse = response as? HTTPURLResponse,
(200...299).contains(httpResponse.statusCode)
else {
print("Invalid Response received from the server")
return
}
// ensure there is data returned
guard let responseData = data else {
print("nil Data received from the server")
return
}
do {
// create json object from data or use JSONDecoder to convert to Model stuct
if let jsonResponse = try JSONSerialization.jsonObject(with: responseData, options: .mutableContainers) as? [String: ErrorHandler] {
print(jsonResponse)
DispatchQueue.main.async {
self?.isLoading = false
self?.signedIn = true
}
} else {
print("data maybe corrupted or in wrong format")
throw URLError(.badServerResponse)
}
} catch let error {
print(error.localizedDescription)
}
}
task.resume()
The problem is that the responseJson is always nil. I tried to perform the same request with postman and I get the response correctly. What is the problem? Also because the data are correctly uploaded everywhere.
This is my postman result of the same post request.
I am use URLSession for POST request and obtain list of players, but sometimes I am obtain error "Error Domain=NSURLErrorDomain Code=-1001", how I can handle it?
How I am get error inside "completion"?
func addPlayer(playerCode: String, completion: #escaping (Error?) -> ()) {
guard let url = URL(string: "\(url)") else { return }
var urlRequest = URLRequest(url: url)
urlRequest.httpMethod = "POST"
let playerCode = [playerCode]
let params = ["players": playerCode]
do {
let data = try JSONSerialization.data(withJSONObject: params, options: .init())
urlRequest.httpBody = data
urlRequest.setValue("application/json", forHTTPHeaderField: "content-type")
let sessionConfig = URLSessionConfiguration.default
sessionConfig.timeoutIntervalForRequest = 5.0
DispatchQueue.global(qos: .background).async {
URLSession(configuration: sessionConfig).dataTask(with: urlRequest) { (data, resp, err) in
guard let data = data else { return }
guard let resp = resp else { return }
print(data)
print(resp)
guard let response = resp as? HTTPURLResponse, (200 ..< 530) ~= response.statusCode else {
print("Error: HTTP request failed")
return
}
if response.statusCode == 200 {
print("Status code is 200")
do {
let json = try JSONDecoder().decode(ListOfPlayers.self, from: data)
// I am do what I am want
} catch let jsonError {
print("Error json serialization \(jsonError)")
}
completion(nil)
} else if response.statusCode == 422 {
print("Status code is 422")
completion(nil)
return
}
}.resume()
}
} catch {
}
}
Also I am try use this code:
guard let err = err else { return }
if (err._code == -1001) {
print("Oops bad connection")
}
but this code don't executed during "Time out"
You can cast your error to URLError type and then use the code property to safely check if it's a session timeout error:
if (err as? URLError)?.code == .timedOut {
// Handle session timeout
}
I'm trying to improve my error handling when I don't get back any data in my JSON. The function below works fine without any issues except if I catch an error. I'm not sure of how to pass the error to prompt the user or is the way to handle the error if googlebusinessinfo is nil I likely have no data and pass a generic error?
Here's my function:
func getBusinessReviews(googleUrl: String, completion: #escaping (WelcomeReview?) -> ()) {
// Create URL
let url = URL(string: googleUrl)
guard let requestUrl = url else { fatalError() }
// Create URL Request
var request = URLRequest(url: requestUrl)
// Specify HTTP Method to use
request.httpMethod = "GET"
//Set HTTP Header
// Send HTTP Request
let task = URLSession.shared.dataTask(with: request) { (data, response, error) in
// Specify HTTP Method to use
request.httpMethod = "GET"
print("(Google)Do we have any data: \(String(describing: data))")
// Check if Error took place
if let error = error {
print("Error took place \(error)")
return
}
// Read HTTP Response Status code
if let response = response as? HTTPURLResponse {
print("(Google)Response HTTP Status code: \(response.statusCode)")
}
// Convert HTTP Response Data to a simple String
if let data = data, let dataString = String(data: data, encoding: .utf8) {
print("Googledata Response data string:\n \(dataString)")
}
if let googlebusinessdata = data {
do {
let googlebusinessinfo = try JSONDecoder().decode(WelcomeReview.self, from: googlebusinessdata)
print("googledata \(googlebusinessinfo)")
completion(googlebusinessinfo)
} catch
{
print("googledata error \(error.localizedDescription)")
let googebusinessinfoerror = error.localizedDescription
}
}
}
task.resume()
}
First of all you can improve the error handling immensely if you print error instead of error.localizedDescription in a Decoding catch block. The former shows the real error, the latter a meaningless generic message.
To answer your question use the generic Result type
func getBusinessReviews(googleUrl: String, completion: #escaping (Result<WelcomeReview,Error>) -> ()) {
// Create URL
let url = URL(string: googleUrl)
guard let requestUrl = url else { fatalError() }
// Create URL Request
var request = URLRequest(url: requestUrl)
// Specify HTTP Method to use
request.httpMethod = "GET"
//Set HTTP Header
// Send HTTP Request
let task = URLSession.shared.dataTask(with: request) { (data, response, error) in
// Specify HTTP Method to use
request.httpMethod = "GET"
print("(Google)Do we have any data: \(String(describing: data))")
// Check if Error took place
if let error = error {
print("Error took place \(error)")
completion(.failure(error))
return
}
// Read HTTP Response Status code
if let response = response as? HTTPURLResponse {
print("(Google)Response HTTP Status code: \(response.statusCode)")
}
// Convert HTTP Response Data to a simple String
if let data = data, let dataString = String(data: data, encoding: .utf8) {
print("Googledata Response data string:\n \(dataString)")
do {
let googlebusinessinfo = try JSONDecoder().decode(WelcomeReview.self, from: data)
print("googledata \(googlebusinessinfo)")
completion(.success(googlebusinessinfo))
} catch
{
print("googledata error:", error)
let googebusinessinfoerror = error.localizedDescription
completion(.failure(error))
}
}
}
task.resume()
}
and call it
getBusinessReviews(googleUrl: "Foo") { result in
switch result {
case .success(let info): print(info)
case .failure(let error): print(error)
}
}
Below line of code is producing the error,
DispatchQueue.main.async {
completion(.success(jsonData), Error as! Error)
}
When print jsonData This code returns perfect result of array but getting this error,
Could not cast value of type 'Swift.String' (0x10fef45c0) to 'Swift.Error' (0x10ff2bd10). (lldb)
As the error says I understand its a cast exception, but I'm not able to modify the code to make it work. I'm kinda new to Swift, so any help would be appreciated. Below is my
import Foundation
class APIService {
private var dataTask: URLSessionDataTask?
func getPopularPosts(completion: #escaping (Result<Any, Error>, Error) -> Void) {
let popularURL = "URL Here"
guard let url = URL(string: popularURL) else {return}
// Create URL Session - work on the background
dataTask = URLSession.shared.dataTask(with: url) { (data, response, error) in
// Handle Error
if let error = error {
completion(.failure(error), Error.self as! Error)
print("DataTask error: \(error.localizedDescription)")
return
}
guard let response = response as? HTTPURLResponse else {
// Handle Empty Response
print("Empty Response")
return
}
print("Response status code: \(response.statusCode)")
guard let data = data else {
// Handle Empty Data
print("Empty Data")
return
}
do {
// Parse the data
let decoder = JSONDecoder()
let jsonData = try decoder.decode(APIService.self, from: data)
// print(jsonData)
// Back to the main thread
DispatchQueue.main.async {
completion(.success(jsonData), Error as! Error)
}
} catch let error {
completion(.failure(error),error)
}
}
dataTask?.resume()
}
}
Modify the completion block parameters, you already are returning the error inside the Result's .failure(Error) block so no need to repeat it again as another parameter in the completion parameter. Here's how you fix this:
Declaration:
class APIService {
private var dataTask: URLSessionDataTask?
func getPopularPosts(completion: #escaping (Result<CategoriesNewsData, Error>) -> Void) {
let popularURL = "URL Here"
guard let url = URL(string: popularURL) else {return}
// Create URL Session - work on the background
dataTask = URLSession.shared.dataTask(with: url) { (data, response, error) in
// Handle Error
if let error = error {
completion(.failure(error))
print("DataTask error: \(error.localizedDescription)")
return
}
guard let response = response as? HTTPURLResponse else {
// Handle Empty Response
print("Empty Response") // Throw a custom error here too.
return
}
print("Response status code: \(response.statusCode)")
guard let data = data else {
// Handle Empty Data
print("Empty Data") // Throw a custom error here too.
return
}
do {
let decoder = JSONDecoder()
let jsonData = try decoder.decode(CategoriesNewsData.self, from: data)
DispatchQueue.main.async {
completion(.success(jsonData))
}
} catch let error {
completion(.failure(error))
}
}
dataTask?.resume()
}
}
Calling:
service.getPopularPosts { result in
switch result {
case .success(let categoriesNewsData):
print(categoriesNewsData)
case .failure(let error):
print(error)
}
}
I try to make a small command line program in swift 5 to call a Rest Web service
func callRest() {
URLCache.shared = URLCache(memoryCapacity: 0, diskCapacity: 0, diskPath: nil)
let todoEndpoint: String = "http://myURL"
print (todoEndpoint)
guard let url = URL(string: todoEndpoint) else {
print("Error: cannot create URL")
exit(1)
}
// private let apiKey = "my API Key"
let config = URLSessionConfiguration.default
config.httpAdditionalHeaders = [
"Accept": "application/json",
"API-Key": "my API Key"
]
var session = URLSession.shared
session = URLSession(configuration: config)
let urlRequest = URLRequest(url: url)
let task = session.dataTask(with: urlRequest) { (data, response, error) in
print ("task")
// check for any errors
guard error == nil else {
print("error calling GET on /todos/1")
print(error!)
return
}
// make sure we got data
guard let responseData = data else {
print("Error: did not receive data")
return
}
// check the status code
guard let httpResponse = response as? HTTPURLResponse else {
print("Error: It's not a HTTP URL response")
return
}
print (httpResponse)
}
task.resume()
// Response status
}
print ("debut")
callRest()
print("fin")
And I never see a result...
the line print ("task") is never display
Any help appreciate.
I think I don't really understand the task.resume usage...
(same code work in a playground)