Swift Combine Memory Leak from CFNetwork - swift

Question

I am trying to plug a memory leak. I have the following class that fetches API requests:
public struct Service {
public let baseURL: URL
public let session: URLSession
public init (baseURL: URL, session: URLSession) {
self.baseURL = baseURL
self.session = session
}
public struct Response {
public let data: Data
public let response: URLResponse
}
public enum ServiceError: Error {
case api(title: String, messages: [String])
case other(Error)
}
struct ServiceErrorResponse: Decodable {
let response: ErrorResponse
enum CodingKeys: String, CodingKey {
case response = "error"
}
}
struct ErrorResponse: Decodable {
let title: String
let messages: [String]
}
public enum HTTPMethod: String {
case get = "GET"
case put = "PUT"
case post = "POST"
case patch = "PATCH"
case delete = "DELETE"
}
public func run(_ request: URLRequest) -> AnyPublisher<Response, ServiceError> {
return session
.dataTaskPublisher(for: request)
.tryMap { data, response in
guard let httpResponse = response as? HTTPURLResponse, httpResponse.statusCode == 200 else {
let error = try JSONDecoder().decode(ServiceErrorResponse.self, from: data)
let title = error.response.title
let messages = error.response.messages
print(error.response)
throw ServiceError.api(title: title, messages: messages)
}
return Response(data: data, response: response)
}
.mapError { err in
let error = err is ServiceError ? err : ServiceError.other(err)
return error as! Service.ServiceError
}
.eraseToAnyPublisher()
}
public func fetch(
_ path: String,
method: HTTPMethod = .get,
params: Data? = nil
) -> AnyPublisher<Response, ServiceError> {
let url: URL
if let params = params, method == .get {
url = buildGetURLWithParams(path: path, params: params)!
}
else {
url = baseURL.appendingPathComponent(path)
}
var request = URLRequest(url: url)
request.httpMethod = method.rawValue
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
if let params = params, method != .get {
request.httpBody = params
}
return run(request)
}
private func buildGetURLWithParams(path: String, params: Data) -> URL? {
if let json = try? JSONSerialization.jsonObject(with: params, options: []) as? [String: String] {
var urlComponents = URLComponents(
url: baseURL.appendingPathComponent(path),
resolvingAgainstBaseURL: false
)
urlComponents?.queryItems = json.map { URLQueryItem(name: $0, value: $1) }
return urlComponents?.url
}
else { return nil }
}
}
I then make requests from the app using the following:
typealias ServiceResponse = Service.Response
typealias ServiceError = Service.ServiceError
typealias ServiceMethod = Service.HTTPMethod
enum MyAPI {
static let service = Service(
baseURL: URL(string: "http://127.0.0.1:3000/api")!,
session: URLSession(configuration: URLSessionConfiguration.default)
)
static func login(email: String, password: String) -> AnyPublisher<ServiceResponse, ServiceError> {
let params = ["email": email, "password": password]
let json = try! JSONEncoder().encode(params)
return service.fetch("/login", method: .post, params: json)
}
}
The login function fetches a response and returns an AnyPublisher which is consumed as follows:
enum UserAction {
case login
case loginSuccess(UserResponse)
case loginFailure
case logout
static func login(email: String, password: String) -> Dispatch<AppAction> {
return { dispatch in
dispatch(.userAction(action: .login))
return MyAPI.login(email: email, password: password)
.map(\.data)
.decode(type: UserResponse.self, decoder: JSONDecoder())
.receive(on: DispatchQueue.main)
.sink(
receiveCompletion: { completion in
if case .failure(let err) = completion {
print("--------------------------")
print("Retrieving data failed with error \(err)")
}
},
receiveValue: { result in
dispatch(.userAction(action: .loginSuccess(result))) // Here I have a memory leak
}
)
}
}
}
I am mimicking something like Redux where a dispatch actions to change state, so I return an 'effect' from the UserAction login that gets the dispatch function. Everything works nicely but at the receiveValue line I get a memory leak with the following description:
Any ideas what could be causing it or how I can find out? Im fairly new to Xcode and Swift.