Swift-未调用Combine订阅

Question

最近，我尝试使用freshOS/Networking swift包。

我读了好几遍README文件，但我无法使用它。我正在尝试获取使用公共API服务的国家的列表，下面是我所做的：

型号

import Foundation
import Networking
struct CountryModel: Codable {
let error: Bool
let msg: String
let data: [Country]
}
struct Country: Codable {
let name: String
let Iso3: String
}
extension Country: NetworkingJSONDecodable {}
extension CountryModel: NetworkingJSONDecodable {}
/* 
Output
{
"error":false,
"msg":"countries and ISO codes retrieved",
"data":[
{
"name":"Afghanistan",
"Iso2":"AF",
"Iso3":"AFG"
}
]
}
*/

查看控制器+callAPI()功能中的打印(数据(不打印

override func viewDidLoad() {
super.viewDidLoad()

configureUI()
callAPI()

}
fileprivate func configureUI() {
title = "Choose Country"

view.addSubview(tableView)
tableView.delegate = self
tableView.dataSource = self
tableView.frame = view.bounds
}
fileprivate func callAPI() {
let countriesService = CountriesApi()
var cancellable = Set<AnyCancellable>()

countriesService.countries().sink(receiveCompletion: { completion in
switch completion {
case .finished:
print("finished") // not printing
break
case .failure(let error):
print(error.localizedDescription)
}
}) { data in
print(data) // not printing
self.countriesData = data
}.store(in: &cancellable)
}

国家API((

struct CountriesApi: NetworkingService {

let network = NetworkingClient(baseURL: "https://countriesnow.space/api/v0.1")

// Create
func create(country c: Country) -> AnyPublisher<Country, Error> {
post("/countries/create", params: ["name" : c.name, "Iso3" : c.Iso3])
}

// Read
func fetch(country c: Country) -> AnyPublisher<Country, Error> {
get("/countries/(c.Iso3)")
}

// Update
func update(country c: Country) -> AnyPublisher<Country, Error> {
put("/countries/(c.Iso3)", params: ["name" : c.name, "Iso3" : c.Iso3])
}

// Delete
func delete(country c: Country) -> AnyPublisher<Void, Error> {
delete("/countries/(c.Iso3)")
}

func countries() -> AnyPublisher<[CountryModel], Error> {
get("/countries/iso")
}
}

我希望有人能帮我弥补我所缺少的。

Answer 1

问题在于callAPI()函数，如果您将代码更改为：

fileprivate func callAPI() {
let countriesService = CountriesApi()
var cancellable = Set<AnyCancellable>()

countriesService.countries()
.print("debugging")
.sink(receiveCompletion: { completion in
switch completion {
case .finished:
print("finished") // not printing
break
case .failure(let error):
print(error.localizedDescription)
}
}) { data in
print(data) // not printing
self.countriesData = data
}.store(in: &cancellable)
}

注意，我刚刚添加了print("debugging")行。

如果你运行它，你可以在控制台中看到你的订阅立即被取消。

调试：接收取消

为什么？因为你的"；可取消的"；或"；订阅"；只存在于您的函数范围内，因此，它会立即被释放。

您可以做的是在ViewController中添加设置为属性的可取消项，如下所示：

final class ViewController: UIViewController {

private var cancellable = Set<AnyCancellable>()

fileprivate func callAPI() {
// the code you had without the set
let countriesService = CountriesApi()

countriesService.countries().sink(receiveCompletion: { completion in
switch completion {
case .finished:
print("finished") // not printing
break
case .failure(let error):
print(error.localizedDescription)
}
}) { data in
print(data) // not printing
self.countriesData = data
}.store(in: &cancellable)
}

}