How to generate Signature in AWS from Java

Question

When I invoke API endpoints from REST client, I got error by concerning with Signature.

Request:

Host: https://xxx.execute-ap

Answer 1

The easiest way is to use methods and http-client from Amazon's SDK. I follow the below 3 steps.

Step1: Create basic AWS credentials:

 BasicAWSCredentials awsCreds = new BasicAWSCredentials(ACCESS_KEY,AWS_DATASHOP_SECRET_KEY);

Step2: Create signableRequest:

DefaultRequest signableRequest = new DefaultRequest<>("aws-service-name");
    signableRequest.setHttpMethod(HttpMethodName.GET);
    signableRequest.setResourcePath("fooo");
    signableRequest.setEndpoint(URI.create(baar));
    signableRequest.addParameter("execution_id", executionId);
    signableRequest.addHeader("Content-Type", "application/json");

    signer.sign(signableRequest, awsCreds);

Step3: Execute request using AmazonHttpClient:

new AmazonHttpClient(new ClientConfiguration())
                    .requestExecutionBuilder()
                    .executionContext(new ExecutionContext(true))
                    .request(signableRequest)
                    .errorResponseHandler((new SimpleAwsErrorHandler()))
                    .execute(new MyResponseHandler());

Make sure to implement HttpResponseHandler for SimpleAwsErrorHandler and MyResponseHandler

If you want to use normal http clients, you would have to create a canonical request and calculate signature which most often doesn't match.