PromiseKit - 带有重新加载第一个承诺的可选承诺

Posted 2023-02-24

【中文标题】PromiseKit - 带有重新加载第一个承诺的可选承诺

【英文标题】：PromiseKit - Optional promise with reload first promise

【发布时间】：2018-02-09 22:17:16

【问题描述】：

我阅读了所有文档，但没有成功回答我的问题。 我有这种情况

我调用认证的api点

如果响应是 200 到 299，我会填写 如果响应是 401，我调用 api 来刷新令牌

如果我刷新了 API 令牌，我需要重新调用第一个 api 点（以恢复所需的数据）。 你能帮我解决这个问题吗？ 谢谢

【参考方案1】：

根据需要使用递归。使用 PromiseKit 你可以做一些很棒的事情。请参阅下面的刷新令牌请求流程。我希望下面的代码是自记录的。

// Define here your errors 
enum MyErrors: Swift.Error 
    case unauthorized
    case unknown


// Here is your primary function for retrieving remote data    
func fetchRemoteData() 
    self.primaryRequest()
        .then  data in
            return self.parsePrimaryRequest(response: data)
        
        .done  parsedResult in
            // do something here if all chaining is success
        
        .recover  primaryRequestError in // this is your case for refresh token
            if case MyErrors.unauthorized = primaryRequestError  // if not authorized
                self.refreshTokenRequest()
                    .then  data in
                        return self.parseRefreshToken(data: data)
                    
                    .done  token in
                        // do someting with token, save it in secure store (keychain)
                        self.fetchRemoteData()
                    
                    .catch  refreshTokenError in
                    // refresh token request has failed
                
            
            else 
                throw primaryRequestError
            
        
        .catch  primaryRequestError in
            // here if error during request
    


func primaryRequest() -> Promise<Data> 
    return Promise  seal in
        // here you execure the request
        // ...
        // ...
        let responseData = Data() // here you get data from URLSessionTask etc
        let yourRequestStatusCode = 401 // take status code


        let successCodes = Array(200...299) // define success codes
        let authorizationErrorCode = 401 // define status code which requires performing refresh token request
        if successCodes.contains(yourRequestStatusCode) 
            return seal.fulfill(responseData)
         else if yourRequestStatusCode == authorizationErrorCode 
            throw MyErrors.unauthorized
         else 
            throw MyErrors.unknown
        
    


func parsePrimaryRequest(response: Data) -> Promise<String> 
    return Promise  seal in
        // here you parse response
        // ...
        // ...

        let parsedObject = "Awesome result"
        seal.fulfill(parsedObject)
    


func refreshTokenRequest() -> Promise<Data> 
    return Promise  seal in
        // here you execure the request to refresh token
        // ...
        // ...
        let responseData = Data() // here you get data from URLSessionTask etc
        let yourRequestStatusCode = 401 // take status code


        let successCodes = Array(200...299) // define success codes for refresh token request
        if successCodes.contains(yourRequestStatusCode) 
            return seal.fulfill(responseData)
         else 
            throw MyErrors.unknown
        
    


func parseRefreshToken(data: Data) -> Promise<String> 
    return Promise  seal in
        // here you parse response
        // ...
        // ...

        let parsedObject = "00000000-00000000-00000000-00000000"
        seal.fulfill(parsedObject)