I'm new to Rxswift Here is my View Model code:
let test = reloadRelay
.asObservable()
//2
.flatMapLatest({ apiClient.requestData(type: rankingType) })
.map({ $0.results })
.asDriver { (error) -> Driver<[ArticleResult]> in
errorRelay.accept((error as? ErrorResult)?.localizedDescription ?? error.localizedDescription)
return Driver.just([])
}
This is very typical and simple ViewModel with logics to get data and send the View layer.
However, when I initialise the ViewModel. The networking call (2) never happened.
Here is my networking code:
func requestData(type: ArticlesRankingType) -> Observable<Articles> {
let urlString = "https://api.nytimes.com/svc/mostpopular/v2/\(type.rawValue)/7.json?api-key=dylOnQnYUzEF1B9MTYYHM0MyffMPBZRi"
let urlRequest = URLRequest(url: URL(string: urlString)!, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 10)
return Observable.create { observer in
let task = URLSession.shared.dataTask(with: urlRequest) { data, response, error in
if let error = error {
observer.onError(error)
return
}
if let data = data ,let responseCode = response as? HTTPURLResponse {
do {
let decoder = JSONDecoder()
if responseCode.statusCode == 200 {
let value = try decoder.decode(Articles.self, from: data)
return observer.onNext(value)
}
}
catch let parseJSONError {
observer.onError(error!)
print("error on parsing request to JSON : \(parseJSONError)")
}
}
}
task.resume()
return Disposables.create {
task.cancel()
}
}
}
Here is how I call my output in View:
articlesViewModel.output
.articles.asDriver(onErrorJustReturn: [])
.drive(tableView.rx.items(cellIdentifier: "aCell", cellType: ArticlesCell.self))
articlesViewModel
.input
.reload
.asDriver(onErrorJustReturn: ())
.drive()
Can someone tell what's wrong with my code? Thanks
Related
I am learning about API's and decided to practice using them by writing a simple function to call an api and print the response. The issues I am having is that the response is not printing to the console. I am also new to Swift but watched a couple of tutorials, which lead me to write this basic skeleton code.
import Foundation
struct Posts: Codable {
let userId: Int
let id: Int
let title: String
let body: String
}
func fetch() {
guard let url = URL(string: "https://jsonplaceholder.typicode.com/posts") else {
return
}
let task = URLSession.shared.dataTask(with: url) { data, response, error in
guard let data = data, error == nil else {
return
}
do {
let posts = try JSONDecoder().decode(Posts.self, from: data)
print(posts) //Doesn't print the response
}
catch {
print(error)
}
}
task.resume()
}
fetch()
func fetch() {
guard let url = URL(string: "https://jsonplaceholder.typicode.com/posts") else {
return
}
let task = URLSession.shared.dataTask(with: url) { data, response, error in
guard let data = data, error == nil else {
return
}
do {
let posts = try JSONDecoder().decode([Posts].self, from: data)
print(posts)
}
catch {
print(error)
}
}
task.resume()
}
Hi i am a beginner studying swift and would like to know what to use when making an api request. What is the modern and professional way?
is it using an escaping closure like so:
func getTrendingMovies(completion: #escaping (Result< [Movie], Error >) -> Void) {
guard let url = URL(string: "\(Constants.baseUrl)/trending/all/day?api_key=\.(Constants.API_KEY)") else {return}
let task = URLSession.shared.dataTask(with: URLRequest(url: url)) { data, _,
error in
guard let data = data, error == nil else {
return
}
do {
let results = try JSONDecoder().decode(TrendingMoviesResponse.self, from:
data)
completion(.success(results.results))
} catch {
completion(.failure(error))
}
}
task.resume()
}
or should i make an api request without escaping closure while using a sort of delegate like so:
func performRequest(with urlString: String){
if let url = URL(string: urlString){
let session = URLSession(configuration: .default)
let task = session.dataTask(with: url) { data, response, error in
if error != nil {
delegate?.didFailWithError(error: error!)
return
}
if let safeData = data{
// created parseJson func
if let weather = parseJSON(safeData){
delegate?.didUpdateWeather(self,weather: weather)
}
}
}
task.resume()
} else {
print("url is nil")
}
}
I agree with matt, the modern and professional way is async/await
func getTrendingMovies() async throws -> [Movie] {
let url = URL(string: "\(Constants.baseUrl)/trending/all/day?api_key=\(Constants.API_KEY)")!
let (data, _) = try await URLSession.shared.data(from: url)
return try JSONDecoder().decode(TrendingMoviesResponse.self, from: data).results
}
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)
}
I have the following JSON that is formatted like this:
{
"error":false
}
I understand that is not an array because it does not include square brackets on both sides, but I cannot seem to understand how to properly get Swift to interpret this correctly.
This is the structure I am using:
struct CheckStruct: Decodable {
let error: String?
}
And the following is the function that should read the JSON:
private func JSONFunc() {
guard let url = URL(string: "https://example.com/example/example.php"),
let value = name.addingPercentEncoding(withAllowedCharacters: .urlQueryValueAllowed)
else { return }
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.httpBody = "number=\(number)".data(using: .utf8)
URLSession.shared.dataTask(with: request) { data, _, error in
guard let data = data else { return }
do {
self.CheckRecord = try JSONDecoder().decode(Array<CheckStruct>.self,from:data)
DispatchQueue.main.async {
// Do something
}
}
catch {
print(error)
}
}.resume()
}
UPDATE:
If I were to use the results of the function to create an if else statement, how would this look?
For example if results are true do this..
else do this...
Your model should be like this:
struct CheckStruct: Codable {
let error: Bool?
}
And your function should be like this:
private func JSONFunc() {
guard let url = URL(string: "https://example.com/example/example.php"),
let value = name.addingPercentEncoding(withAllowedCharacters: .urlQueryValueAllowed)
else { return }
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.httpBody = "number=\(number)".data(using: .utf8)
URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data else { return }
do {
let myData= try JSONDecoder().decode(CheckStruct.self, from:data)
print(myData.error)
} catch {
print(error)
}
}.resume()
}
BONUS
//Create Typealias
typealias BoolHandler = ((Bool?) -> Void)
//Create Function with Completion
private func fetchData(_ completion: #escaping BoolHandler) {
guard let url = URL(string: "https://example.com/example/example.php"),
let value = name.addingPercentEncoding(withAllowedCharacters: .urlQueryValueAllowed)
else { return }
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.httpBody = "number=\(number)".data(using: .utf8)
URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data else { return }
do {
let myData= try JSONDecoder().decode(CheckStruct.self, from:data)
DispatchQueue.main.async {
completion(myData.error)
}
} catch {
DispatchQueue.main.async {
completion(nil)
}
}
}.resume()
}
//Call Method
fetchData { isSuccess in
if isSuccess {
// Do something
} else {
// Do something
}
}
I hope it will work for you.
Enjoy.
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
}
}