在完成处理程序中隐藏 http 状态代码上的进度条 - Swift 4

Question

我正在使用完成处理程序从单独的类发出请求，一旦我调用该方法以从另一个类调用 Web 服务，就会显示进度条，现在我需要隐藏进度条如果状态代码不是 200。请检查下面的代码。

API.swift
func getProgramsFromApi(url : String, authToken: String,  
completionBlock : @escaping APICompletionHandlerProgram) -> Void {
var request = URLRequest(url: URL(string: url)!)
request.httpMethod = "GET"
request.setValue("application/json", forHTTPHeaderField: "Accept")
request.setValue(authToken, forHTTPHeaderField: "X-token")
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))")
DispatchQueue.main.async {
SCLAlertView().showError("Error", subTitle: 
(response?.description)!)
}
return
}

if let httpStatus = response as? HTTPURLResponse, 
httpStatus.statusCode != 200 {
//hide progress bar here.
// check for http errors
print("statusCode should be 200, but is  
(httpStatus.statusCode)")
print("response = (String(describing: response))")
}else{

do {
let   jsonResult = try? JSONDecoder().decode(Programs.self, 
from: data)
completionBlock(jsonResult!, error)
}catch let jsonError{
print("some error (jsonError)")
completionBlock(nil!, error)
}
}
}
task.resume()
}

如果状态代码不是 200，我想隐藏以下方法中的进度条。

Program.swift
func fetchDataFromProgramsAPI() {
let apiKEY =  UserDefaults.standard.string(forKey: "API_TOKEN")
apiService.getProgramsFromApi(url: 
Constants.BASE_URL+APIMethod().programs, authToken: apiKEY!){
(success, err) in
Helper.showHUD(hud: self.HUD)
if success.data?.count == 0{
Helper.hideHUD(hud: self.HUD)
return
}

DispatchQueue.main.async {
self.programTable?.reloadData()
}
Helper.hideHUD(hud: self.HUD)
}
}

请帮忙。

Answer 1

一种简单的方法，如果您只对statusCode是否返回200感兴趣，请在完成error块中返回它。

enum NetworkCallError: Error {
case responseUnsuccessful 
//I'd even make a case for all anticipated status codes there for I could handle any status and possibly retry the call based on whatever error is returned. 
case responseUnsuccessful(code: Int) 
}

调整typealias以包含新错误

typealias APICompletionHandlerProgram = (Data?, NetworkCallError?) -> Void

通过completionBlock在不希望statusCode点返回错误情况。

if let httpStatus = response as? HTTPURLResponse, 
httpStatus.statusCode != 200 {
//Hide status bar here < Don't try to manipulate your view from your model. 
//Throw your error in the completion block here.
completionBlock(nil, NetworkCallError.responseUnsuccessful)
//You could move this to a localizedDescription variable for `responseUnsuccessful` but that's out of the scope for this answer.
print("statusCode should be 200, but is  
(httpStatus.statusCode)")
print("response = (String(describing: response))")
}

在呼叫站点：

只需在继续之前检查错误即可。

func fetchDataFromProgramsAPI() {
//{...
apiService.getProgramsFromApi(url: 
Constants.BASE_URL+APIMethod().programs, authToken: apiKEY!){
(success, err) in
Helper.showHUD(hud: self.HUD)
//Don't forget to unwrap the values in the tuple since they may or may not exist. 
guard let success = success,
let err = err else { return } 
switch err {
//Handle your error by retrying call, presenting an alert, whatever. 
case .responseUnsuccessful 
Helper.HideHUD(hud: self.HUD)
//{...} 
return 
}
//...}
}