There is an equivalent for URL Session in URLSession.shared.dataTaskPublisher(for:>) and simlairily for handling' error sand decoding But how to go about handling the return type of discardableResult? There is an equivalent for URL Session in URLSession.shared.dataTaskPublisher(for:>) and simlairily for handling' error sand decoding
#discardableResult class func taskForGETRequest<ResponseType: Decodable>(url: URL, responseType: ResponseType.Type, completion: #escaping (ResponseType?, Error?) -> Void) -> URLSessionTask {
let task = URLSession.shared.dataTask(with: url) { data, response, error in
guard let data = data else {
DispatchQueue.main.async {
completion(nil, error)
}
return
}
let decoder = JSONDecoder()
do {
let responseObject = try decoder.decode(ResponseType.self, from: data)
DispatchQueue.main.async {
completion(responseObject, nil)
}
} catch {
do {
let errorResponse = try decoder.decode(TMDBResponse.self, from: data)
completion(nil,errorResponse)
} catch {
DispatchQueue.main.async {
completion(nil, error)
}
}
}
}
task.resume()
return task
}
class func taskForPOSTRequest<RequestType: Encodable, ResponseType: Decodable>(url: URL, responseType: ResponseType.Type, body: RequestType, completion: #escaping (ResponseType?, Error?) -> Void) {
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.httpBody = try! JSONEncoder().encode(body)
let task = URLSession.shared.dataTask(with: request) { (data, response, error) in
guard let data = data else {
completion(nil, error)
return
}
let decoder = JSONDecoder()
do {
let responseObject = try decoder.decode(ResponseType.self, from: data)
completion(responseObject, nil)
} catch {
do {
let errorResponse = try decoder.decode(TMDBResponse.self, from: data)
completion(nil,errorResponse)
} catch {
DispatchQueue.main.async {
completion(nil, error)
}
}
}
}
task.resume()
}
Related
I am starting to use RxSwift to make the service call.
This was my old code:
class Service: GraphQLService {
func graphQL(body: [String: Any?], onSuccess: #escaping (Foundation.Data) throws -> (), onFailure: #escaping (Error) -> ()) {
guard let urlValue = Bundle.main.urlValue else { return }
guard let url = URL(string: urlValue) else { return
print("Error with info.plist")
}
var request = URLRequest(url: url)
let userKey = Bundle.main.userKeyValue
request.httpMethod = "POST"
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.setValue(userKey, forHTTPHeaderField: "userid")
request.httpBody = try? JSONSerialization.data(withJSONObject: body, options: .fragmentsAllowed)
URLSession.shared.dataTask(with: request) { (data, response, error) in
if let error = error {
onFailure(error)
}
if let data = data {
do{
try onSuccess(data)
}
catch{
onFailure(error)
}
}
}.resume()
}
And here I do the function to get time deposits:
final class TimeDepositManager: Service, TimeDepositManagerProtocol {
let timeDepositQuery = Bundle.main.queryValue
func getTimeDeposits(onSuccess: #escaping ([TimeDeposits]) -> (), onFailure: #escaping (Error) -> ()) {
let body = ["query": timeDepositQuery]
Service().graphQL(body: body, onSuccess: { data in
let json = try? JSONDecoder().decode(GraphQLResponse.self, from: data)
onSuccess(json?.data?.account?.timeDeposits ?? [])
}, onFailure: onFailure)
}
And so far this is my code with RxSwift:
class Service: GraphQLService {
func graphQL(body: [String : Any?]) -> Observable<Foundation.Data> {
return Observable.create { observer in
let urlValue = Bundle.main.urlValue
let url = URL(string: urlValue ?? "")
let session = URLSession.shared
var request = URLRequest(url: url!)
let userKey = Bundle.main.userKeyValue
request.httpMethod = "POST"
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.setValue(userKey, forHTTPHeaderField: "userid")
request.httpBody = try? JSONSerialization.data(withJSONObject: body, options: .fragmentsAllowed)
session.dataTask(with: request) { (data, response, error) in
if let error = error {
observer.onError(error)
}
if let data = data {
do{
try onSuccess(data)
observer.onNext(data)
}
catch{
//onFailure(error)
observer.onError(error)
print("Error: \(error.localizedDescription)")
}
}
}.resume()
return Disposables.create {
session.finishTasksAndInvalidate()
}
}
}
This is where I don't understand how in my getTimeDeposits () I can do the deserialization with try? JSONDecoder () ... with RxSwift without using onSuccess?
final class TimeDepositManager: Service, TimeDepositManagerProtocol {
let timeDepositQuery = Bundle.main.queryValue
func getTimeDeposits() -> Observable<[TimeDeposits]> {
let body = ["query": timeDepositQuery]
Service().graphQL(body: body)
}
You can have getTimeDeposits() return an Observable as well and handle the deserialization in a map closure. A couple of other things.
RxCocoa already has a method on URLSession so you don't need to write your own.
I suggest reducing the amount of code you have in a function that makes the network request. You want to be able to test your logic for making the request without actually making it.
Something like this:
final class TimeDepositManager: Service, TimeDepositManagerProtocol {
let timeDepositQuery = Bundle.main.queryValue
func getTimeDeposits() -> Observable<[TimeDeposits]> {
let body = ["query": timeDepositQuery]
return Service().graphQL(body: body)
.map { try JSONDecoder().decode(GraphQLResponse.self, from: $0).data?.account?.timeDeposits ?? [] }
}
}
class Service: GraphQLService {
func graphQL(body: [String: Any?]) -> Observable<Data> {
guard let urlValue = Bundle.main.urlValue else { fatalError("Error with info.plist") }
let request = urlRequest(urlValue: urlValue, body: body)
return URLSession.shared.rx.data(request: request) // this is in RxCocoa
}
func urlRequest(urlValue: String, body: [String: Any?]) -> URLRequest {
guard let url = URL(string: urlValue) else { fatalError("Error with urlValue") }
var request = URLRequest(url: url)
let userKey = Bundle.main.userKeyValue
request.httpMethod = "POST"
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.setValue(userKey, forHTTPHeaderField: "userid")
request.httpBody = try? JSONSerialization.data(withJSONObject: body, options: .fragmentsAllowed)
return request
}
}
If you don't want to use RxCocoa for some reason, here is the correct way to wrap the URLSession.dataTask method:
extension URLSession {
func data(request: URLRequest) -> Observable<Data> {
Observable.create { observer in
let task = self.dataTask(with: request, completionHandler: { data, response, error in
guard let response = response as? HTTPURLResponse else {
observer.onError(URLError.notHTTPResponse(data: data, response: response))
return
}
guard 200 <= response.statusCode && response.statusCode < 300 else {
observer.onError(URLError.failedResponse(data: data, response: response))
return
}
guard let data = data else {
observer.onError(error ?? RxError.unknown)
return
}
observer.onNext(data)
observer.onCompleted() // be sure to call `onCompleted()` when you are done emitting values.
// make sure every possible path through the code calls some method on `observer`.
})
return Disposables.create { task.cancel() } // don't forget to handle cancelation properly. You don't want to kill *all* tasks, just this one.
}
}
}
enum URLError: Error {
case notHTTPResponse(data: Data?, response: URLResponse?)
case failedResponse(data: Data?, response: HTTPURLResponse)
}
Here i am extracting data as DataModel. But i want to make this class generic and pass the model myself so that i can use it to parse data from multiple API's. Can Anyone Help?
import Foundation
struct NetworkManager {
func fetchData(url : String, completion : #escaping (DataModel?) -> ()) {
print("Neeraj here")
let sessionURL = URL(string: url)
let session = URLSession(configuration: .default)
let dataTask = session.dataTask(with: sessionURL!) { (data, response, error) in
if error == nil {
if let safeData = data {
if let parsedData = self.parseData(data : safeData) {
print("got data")
completion(parsedData)
}
else {
debugPrint("failed to fetch data")
completion(nil)
}
}
}
else {
print("error in data task is \(String(describing: error))")
completion(nil)
}
}
dataTask.resume()
}
func parseData(data : Data) -> DataModel? {
let decoder = JSONDecoder()
do {
let decodedData = try decoder.decode(DataModel.self, from: data)
return decodedData
} catch {
print("error while parsing data \(error)")
return nil
}
}
}
With the convenient Result type you can write a quite tiny generic method, it returns the decoded type on success and any error on failure
func fetchData<T: Decodable>(urlString: String, completion: #escaping (Result<T,Error>) -> Void) {
guard let url = URL(string: urlString) else { return } // or throw an error
URLSession.shared.dataTask(with: url) { (data, _, error) in
if let error = error { completion(.failure(error)); return }
completion( Result{ try JSONDecoder().decode(T.self, from: data!) })
}.resume()
}
Note: Force unwrapping data! is 100% safe if no error occurs
Be aware that you have to specify the concrete type when you are going to call the method
fetchData(urlString: "https://example.com/api") { (result : Result<MyModel,Error>) in
switch result {
case .success(let model): print(model)
case .failure(let error): print(error)
}
}
You can add a generic type constraint (called Model) which conforms Decodable like below:
struct NetworkManager {
func fetchData<Model: Decodable>(url : String, completion : #escaping (Model?) -> ()) {
let sessionURL = URL(string: url)
let session = URLSession(configuration: .default)
let dataTask = session.dataTask(with: sessionURL!) { (data, response, error) in
if error == nil {
if let safeData = data {
do {
let decodedData = try JSONDecoder().decode(Model.self, from: safeData)
completion(decodedData)
} catch {
print("error while parsing data \(error)")
}
} else {
debugPrint("failed to fetch data")
completion(nil)
}
}
else {
print("error in data task is \(String(describing: error))")
completion(nil)
}
}
dataTask.resume()
}
}
Usage
struct SampleModel: Decodable {
let name: String
}
NetworkManager().fetchData(url: "") { (data: SampleModel?) in
print(data)
}
You can write a generic function to fetch data like this one :
func fetchGenericData<T: Decodable>(urlString: String, completion: #escaping (T) -> ()) {
let url = URL(string: urlString)
URLSession.shared.dataTask(with: url!) { (data, resp, err) in
if let err = err {
print("Failed to fetch data:", err)
return
}
guard let data = data else { return }
do {
let obj = try JSONDecoder().decode(T.self, from: data)
completion(obj)
} catch let jsonErr {
print("Failed to decode json:", jsonErr)
}
}.resume()
}
}
I suppose that you have a data model, if you have not, you should create for your every object. Also by using a dummy URL i will make a request and fetch the JSON includes some users name and ids with JSON format.
Let`s define a data model for this:
struct StackUser: Decodable {
let id: Int
let name: String
}
fetchGenericData(urlString: "https://api.stackoverexample.com/stackusers") { (stackUsers: [StackUser]) in
stackUsers.forEach({print($0.name)})
}
Finally you will be parse the data and prints like this:
Rob
Matt
Vadian
I'm trying to figure out the best way to unit test a network request. My initial thought was to create a local file with the JSON response for testing purposes but that doesn't seem to be working. See my code below.
I wanna test that I can get a non-nil array back from the completion handler in the function below.
class APIClient {
let downloader = JSONDownloader() // just a class that creates a new data task
// what I want to test
func getArticles(from url: URL?, completion: #escaping([Article]?, Error?) -> ()) {
guard let url = url else { return }
let request = URLRequest(url: url)
let task = downloader.createTask(with: request) { json, error in
DispatchQueue.main.async {
// parse JSON
...
completion(articles, nil)
}
}
task.resume()
}
}
I tried testing as shown below to no avail.
func testArticleResponseIsNotNil() {
let bundle = Bundle(for: APIClientTests.self)
guard let path = Bundle.path(forResource: "response-articles", ofType: "json", inDirectory: bundle.bundlePath) else {
XCTFail("Missing file: response-articles.json")
return
}
let url = URL(fileURLWithPath: path)
var articles: [Article]?
let expectation = self.expectation(description: "Articles")
let client = APIClient()
client.getArticles(from: url) { response, error in
articles = response
expectation.fulfill()
}
wait(for: [expectation], timeout: 5)
XCTAssertNotNil(articles)
}
Any ideas on how exactly I should test this function?
Edit: This is the JSONDownloader class.
class JSONDownloader {
let session: URLSession
init(configuration: URLSessionConfiguration) {
self.session = URLSession(configuration: configuration)
}
convenience init() {
self.init(configuration: .default)
}
typealias JSON = [String: AnyObject]
func createTask(with request: URLRequest, completion: #escaping(JSON?, Error?) -> ()) -> URLSessionDataTask {
let task = session.dataTask(with: request) { data, response, error in
guard let httpResponse = response as? HTTPURLResponse else { return }
if httpResponse.statusCode == 200 {
if let data = data {
do {
let json = try JSONSerialization.jsonObject(with: data, options: []) as? JSON
completion(json, nil)
} catch { completion(nil, error) }
} else { completion(nil, error) }
} else { completion(nil, error) }
}
return task
}
}
I have a json file that looks something like this:
{
"adTitle": "My Title",
"adURL": "https://mylink.com/",
"adImageURL": "http://mywebsite/bannerx#3x.png"
}
I get the JSON value from website: http://mywebsite.com/file.json
The problem is that the ad somehow doesn't load the adImageURL, so when I press the UIImageView, but when I press the area that then UIImageView should be, it open my adURL. This is the code I use for JSON:
var imageURL:String = "http://mywebsite/bannerx#3x.png"
var adURL:String = "https://mylink.com/"
func loadAdvertisement() {
// Set up the URL request
let todoEndpoint: String = "http://mywebsite.com/file.json"
guard let url = URL(string: todoEndpoint) else {
print("Error: cannot create URL")
return
}
let urlRequest = URLRequest(url: url)
// set up the session
let config = URLSessionConfiguration.default
let session = URLSession(configuration: config)
// make the request
let task = session.dataTask(with: urlRequest) {
(data, response, error) in
// 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
}
// parse the result as JSON, since that's what the API provides
do {
guard (try JSONSerialization.jsonObject(with: responseData, options: []) as? [String: AnyObject]) != nil else {
print("error trying to convert data to JSON")
return
}
let json = try JSONSerialization.jsonObject(with: responseData, options:.allowFragments) as! [String:AnyObject]
if (json != nil) {
self.imageURL = (json["adImageURL"] as? String)!
self.adURL = (json["adURL"] as? String)!
print(self.imageURL)
print(self.adURL)
DispatchQueue.main.async { () -> Void in
self.loadAdImage(self.imageURL)
}
}
} catch {
print("error trying to convert data to JSON")
return
}
}
task.resume()
// let jsonURL = URL(string: "http://mywebsite.com/file.json")
// self.getDataFromUrl(jsonURL!, completion: (data:Data?, response:URLResponse?, error:Error?)) -> Void
}
func loadAdImage(_ url:String) {
getDataFromUrl(URL(string: url)!) { (data, response, error) in
DispatchQueue.main.async { () -> Void in
guard let data = data, error == nil else { return }
print(response?.suggestedFilename ?? "")
print("Download Finished")
self.advertImageView.image = UIImage(data: data)
}
}
}
func getDataFromUrl(_ url:URL, completion: #escaping ((_ data: Data?, _ response: URLResponse?, _ error: NSError? ) -> Void)) {
URLSession.shared.dataTask(with: url) { (data:Data?, response:URLResponse?, error:Error?) in
completion(data, response, error as NSError?)
}.resume()
}
In the event LOG, is prints out both of the print("error trying to convert data to JSON") commands. I have used this code before in my project, and it worked just fine, but I have no idea why it wont work anymore.
Add the message to catch and check what actually error you are getting like this way:
do {
let json = try JSONSerialization.jsonObject(with: responseData, options:.allowFragments) as! [String:AnyObject]
} catch let message {
print("error trying to convert data to JSON" + "\(message)")
return
}
I need to parse JSON from 2 different URL's
let jsonUrlStr1 = "https://123"
let jsonUrlStr2 = "https://325"
guard let url1 = URL(string: jsonUrlStr1) else { return }
guard let url2 = URL(string: jsonUrlStr2) else { return }
Here I'm running session for 1st url:
URLSession.shared.dataTask(with: url1) { (data, response, err) in
if err != nil {
print("Error:\(String(describing: err))")
}
guard let data = data else { return }
do {
let myData1 = try JSONDecoder().decode(SomeJsonModel1.self, from: data)
//Some code
} catch let jsonErr {
print("Error:\(jsonErr)")
}
}.resume()//URLSession
And then again, I'm running another session for 2nd url, using the same way:
URLSession.shared.dataTask(with: url2) { (data, response, err) in
if err != nil {
print("Error:\(String(describing: err))")
}
guard let data = data else { return }
do {
let myData2 = try JSONDecoder().decode(SomeJsonModel2.self, from: data)
//Some code
} catch let jsonErr {
print("Error:\(jsonErr)")
}
}.resume()//URLSession
This code works and I get the result.
But I think there should be a more correct way to parse 2 URLs.
Please advise how to do it correctly. Thanks.
You can try using completion block like this :
func getDataFromJson(url: String, completion: #escaping (_ success: [String : Any]) -> Void) {
let request = URLRequest(url: URL(string: url)!)
let task = URLSession.shared.dataTask(with: request) { Data, response, error in
guard let data = Data, error == nil else { // check for fundamental networking error
print("error=\(String(describing: error))")
return
}
if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 { // check for http errors
print("statusCode should be 200, but is \(httpStatus.statusCode)")
print(response!)
return
}
let responseJSON = try! JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String : Any]
completion(responseJSON)
}
task.resume()
}
and call method like this :
let jsonUrlStr1 = "https://123"
let jsonUrlStr2 = "https://325"
getDataFromJson(url: jsonUrlStr1, completion: { response in
print("JSON response for url1 :: ",response) // once jsonUrlStr1 get it's response call next API
getDataFromJson(url: jsonUrlStr2, completion: { response in
print("JSON response for url2 :: ",response)
})
})