swift - AWS API Gateway 生成的 iOS SDK 缺少必需的 'defaultClient' 成员

Question

我已针对调用 AWS Lambda 的两个不同 REST API 学习了两个 API Gateway 教程。这是link Calc API，这是本文的主题。

在每种情况下，通过 AWS 控制台进行的测试调用都能完美运行。但是，当我从部署阶段的“SDK Generation”选项卡生成 iOS Swift SDK 时，解压缩并导入到我的 Xcode 项目中，defaultClient <API-Name>Client.swift 中缺少成员.

每种情况下的 README.md 文件都表明它应该存在:

# Use the SDK in your project

1. Grab the `defaultClient` from your code

        let client = <API-Name>Client.defaultClient()

1. You can now call your method using the client SDK

但是没有defaultClient在<API-Name>Client.swift .

更新没有defaultClient ，但是有一个default (用反引号括起来，因为 default 是 Swift 中的保留字)。所以我在 REST API 调用中替换了它......并且它起作用了!我不知道为什么......我不知道反引号在 Swift 中意味着什么......如果有人可以向我解释这一点，那就太好了。但我通过API Gateway验证API调用成功；我通过 Cloudwatch 验证了 Lambda 函数返回了正确的值。

这是我调用 API 的代码:

@IBAction func userInvokeApi(_ sender: UIButton) {
    print("You clicked invoke api...")
    let client = SVTLambdaGateClient.default()
    client.calcGet(operand2: "3", _operator: "+", operand1: "5").continueWith{ (task: AWSTask?) -> AnyObject? in
        if let error = task?.error {
            print("Error occurred: \(error)")
            return nil
        }

        if let result = task?.result {
            // Do something with result
            print("The result is... \(result)")
        }

        return nil
    }
}

但是，我还不明白客户端返回的数据结构。这是我得到的:

You clicked invoke api...
The result is... <AmplifyRestApiTest.Empty: 0x600002020770> {
}

以下是生成的 <API-Name>Client.swift 的完整内容文件(删除了一些注释)。我认为 README 可能不再与 SDK 生成同步。

import AWSCore
import AWSAPIGateway

public class SVTLambdaGateClient: AWSAPIGatewayClient {

    static let AWSInfoClientKey = "SVTLambdaGateClient"

    private static let _serviceClients = AWSSynchronizedMutableDictionary()
    private static let _defaultClient:SVTLambdaGateClient = {
        var serviceConfiguration: AWSServiceConfiguration? = nil
        let serviceInfo = AWSInfo.default().defaultServiceInfo(AWSInfoClientKey)
        if let serviceInfo = serviceInfo {
            serviceConfiguration = AWSServiceConfiguration(region: serviceInfo.region, credentialsProvider: serviceInfo.cognitoCredentialsProvider)
        } else if (AWSServiceManager.default().defaultServiceConfiguration != nil) {
            serviceConfiguration = AWSServiceManager.default().defaultServiceConfiguration
        } else {
            serviceConfiguration = AWSServiceConfiguration(region: .Unknown, credentialsProvider: nil)
        }

        return SVTLambdaGateClient(configuration: serviceConfiguration!)
    }()

    /**
     Returns the singleton service client. If the singleton object does not exist, the SDK instantiates the default service client with `defaultServiceConfiguration` from `AWSServiceManager.defaultServiceManager()`. The reference to this object is maintained by the SDK, and you do not need to retain it manually.
     @return The default service client.
     */ 

    public class func `default`() -> SVTLambdaGateClient{
        return _defaultClient
    }

    /**
     Creates a service client with the given service configuration and registers it for the key.
     @param configuration A service configuration object.
     @param key           A string to identify the service client.
     */

    public class func registerClient(withConfiguration configuration: AWSServiceConfiguration, forKey key: String){
        _serviceClients.setObject(SVTLambdaGateClient(configuration: configuration), forKey: key  as NSString);
    }

    /**
     Retrieves the service client associated with the key. You need to call `registerClient(withConfiguration:configuration, forKey:)` before invoking this method or alternatively, set the configuration in your application's `info.plist` file. If `registerClientWithConfiguration(configuration, forKey:)` has not been called in advance or if a configuration is not present in the `info.plist` file of the app, this method returns `nil`.
     Then call the following to get the service client:

        let serviceClient = SVTLambdaGateClient.client(forKey: "USWest2SVTLambdaGateClient")

     @param key A string to identify the service client.
     @return An instance of the service client.
     */
    public class func client(forKey key: String) -> SVTLambdaGateClient {
        objc_sync_enter(self)
        if let client: SVTLambdaGateClient = _serviceClients.object(forKey: key) as? SVTLambdaGateClient {
            objc_sync_exit(self)
            return client
        }

        let serviceInfo = AWSInfo.default().defaultServiceInfo(AWSInfoClientKey)
        if let serviceInfo = serviceInfo {
            let serviceConfiguration = AWSServiceConfiguration(region: serviceInfo.region, credentialsProvider: serviceInfo.cognitoCredentialsProvider)
            SVTLambdaGateClient.registerClient(withConfiguration: serviceConfiguration!, forKey: key)
        }
        objc_sync_exit(self)
        return _serviceClients.object(forKey: key) as! SVTLambdaGateClient;
    }

    /**
     Removes the service client associated with the key and release it.

     @param key A string to identify the service client.
     */
    public class func removeClient(forKey key: String) -> Void{
        _serviceClients.remove(key)
    }

    init(configuration: AWSServiceConfiguration) {
        super.init()

        self.configuration = configuration.copy() as! AWSServiceConfiguration
        var URLString: String = "https://<my-api-id>.execute-api.us-east-2.amazonaws.com/test"
        if URLString.hasSuffix("/") {
            URLString = URLString.substring(to: URLString.index(before: URLString.endIndex))
        }
        self.configuration.endpoint = AWSEndpoint(region: configuration.regionType, service: .APIGateway, url: URL(string: URLString))
        let signer: AWSSignatureV4Signer = AWSSignatureV4Signer(credentialsProvider: configuration.credentialsProvider, endpoint: self.configuration.endpoint)
        if let endpoint = self.configuration.endpoint {
            self.configuration.baseURL = endpoint.url
        }
        self.configuration.requestInterceptors = [AWSNetworkingRequestInterceptor(), signer]
    }

    /*


     @param operand2 
     @param _operator 
     @param operand1 

     return type: Empty
     */
    public func calcGet(operand2: String, _operator: String, operand1: String) -> AWSTask<Empty> {
        let headerParameters = [
                   "Content-Type": "application/json",
                   "Accept": "application/json",

                ]

        var queryParameters:[String:Any] = [:]
        queryParameters["operand2"] = operand2
        queryParameters["operator"] = _operator
        queryParameters["operand1"] = operand1

        let pathParameters:[String:Any] = [:]

        return self.invokeHTTPRequest("GET", urlString: "/calc", pathParameters: pathParameters, queryParameters: queryParameters, headerParameters: headerParameters, body: nil, responseClass: Empty.self) as! AWSTask<Empty>
    }


    /*


     @param body 

     return type: Empty
     */
    public func calcPost(body: SVTInput) -> AWSTask<Empty> {
        let headerParameters = [
                   "Content-Type": "application/json",
                   "Accept": "application/json",

                ]

        let queryParameters:[String:Any] = [:]

        let pathParameters:[String:Any] = [:]

        return self.invokeHTTPRequest("POST", urlString: "/calc", pathParameters: pathParameters, queryParameters: queryParameters, headerParameters: headerParameters, body: body, responseClass: Empty.self) as! AWSTask<Empty>
    }


    /*


     @param operand2 
     @param _operator 
     @param operand1 

     return type: SVTResult
     */
    public func calcOperand1Operand2OperatorGet(operand2: String, _operator: String, operand1: String) -> AWSTask<SVTResult> {
        let headerParameters = [
                   "Content-Type": "application/json",
                   "Accept": "application/json",

                ]

        let queryParameters:[String:Any] = [:]

        var pathParameters:[String:Any] = [:]
        pathParameters["operand2"] = operand2
        pathParameters["operator"] = _operator
        pathParameters["operand1"] = operand1

        return self.invokeHTTPRequest("GET", urlString: "/calc/{operand1}/{operand2}/{operator}", pathParameters: pathParameters, queryParameters: queryParameters, headerParameters: headerParameters, body: nil, responseClass: SVTResult.self) as! AWSTask<SVTResult>
    }

非常感谢任何帮助!

Answer 1

Amplify 团队(维护和开发 AWS iOS SDK)验证 documentation is incorrect 。它应该引用 default() 而不是 defaultClient()。