java - 在java中的AWS lambda函数中包含访问控制 header

Question

我一直在尝试部署 lambda 函数，然后通过 API 网关访问它。我的 java 函数是用 JAVA 编写的，这是我在 JAVA 中创建一个简单的 AWS lambda 函数所遵循的文档:

https://docs.aws.amazon.com/lambda/latest/dg/java-handler-io-type-pojo.html

这就是我的函数处理程序的样子:

package lambda;

    import com.amazonaws.services.lambda.runtime.Context;
    import com.amazonaws.services.lambda.runtime.RequestHandler;
    import lambda.axon.Path;

    public class shortestPath implements RequestHandler<RequestClass, ResponseClass>{

        public ResponseClass handleRequest(RequestClass request, Context context){
            String inputString = request.inputString;
            int steps = Path.stepsTo(inputString);
            return new ResponseClass(steps);

        }
    }

这是这个请求类:

package lambda;

public class RequestClass {
    String inputString;

    public String getInputString() {
        return inputString;
    }

    public void setInputString(String inputString) {
        this.inputString = inputString;
    }


    public RequestClass(String inputString) {
        this.inputString = inputString;
    }

    public RequestClass() {
    }
}

这是响应类:

package lambda;

public class ResponseClass {
    int steps;

    public ResponseClass(int steps) {
        this.steps = steps;
    }

    public ResponseClass() {
    }
    public int getSteps() {
        return steps;
    }

    public void setSteps(int steps) {
        this.steps = steps;
    }


}

我将其部署在aws上并配置AWS api网关来触发它，当我使用postman( https://www.getpostman.com/ )到达API网关给出的端点时，一切正常

但是通过浏览器尝试相同的操作会出现 CORS 错误:

Access to XMLHttpRequest at 'https://<hash>execute-api.us-east-1.amazonaws.com/dev' from origin 'http://localhost:4200' has been blocked by CORS policy: Request header field access-control-allow-origin is not allowed by Access-Control-Allow-Headers in preflight response.

我尝试在 API 网关控制台中启用 CORS，然后重新部署它:

这篇 Stackoverflow 帖子( Configure CORS response headers on AWS Lambda? )说，如果我使用 lambda 代理，我应该在处理程序响应本身中包含 header ，我不确定代理是什么，但我如何使用当前的实现来做到这一点Lambda 函数，即在我的响应中包含自定义 header

Answer 1

启用cors对于连接到 lambda 函数的 api 网关端点，您必须为 api 端点启用 cors(您已经完成)并配置您的 lambda 函数支持 cors 。

按照我的例子:

// new respose class, replace for your class - ResponseClass
public class Response {

    private int statusCode; // http status code

    private Map<String, String> headers; // headers

    private String body; // body - what you want to return to client

    public Response(int statusCode, Map<String, String> headers, String body) {
        this.statusCode = statusCode;
        this.headers = headers;
        this.body = body;
    }

    public int getStatusCode() {
        return statusCode;
    }

    public Map<String, String> getHeaders() {
        return headers;
    }

    public String getBody() {
        return body;
    }

    public void setStatusCode(int statusCode) {
        this.statusCode = statusCode;
    }

    public void setHeaders(Map<String, String> headers) {
        this.headers = headers;
    }

    public void setBody(String body) {
        this.body = body;
    }

}

/// -------------

package lambda;

    import com.amazonaws.services.lambda.runtime.Context;
    import com.amazonaws.services.lambda.runtime.RequestHandler;
    import lambda.axon.Path;

    public class shortestPath implements RequestHandler<RequestClass, Response>{

        public Response handleRequest(RequestClass request, Context context){
            String inputString = request.inputString;
            int steps = Path.stepsTo(inputString);

            Map<String, String> headers = new HashMap<>();
            headers.put(Access-Control-Allow-Origin, "*"); // cors header, you can add another header fields

            return new Response(200, headers, "" + steps);
            // return new Response(200, headers, "{result: " + steps + "}");
            // simple json response. ex: {result: '3433"}
        }
    }

我的方式只在api gateway使用时有效LAMBDA-PROXY事件配置(默认)