Simple class to generate AWS STS GetcallerIdentity presigned url

stspresigner.java

import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
import software.amazon.awssdk.auth.signer.Aws4Signer;
import software.amazon.awssdk.auth.signer.params.Aws4PresignerParams;
import software.amazon.awssdk.http.SdkHttpFullRequest;
import software.amazon.awssdk.http.SdkHttpMethod;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.sts.StsClient;
import software.amazon.awssdk.services.sts.endpoints.StsEndpointParams;
import software.amazon.awssdk.services.sts.endpoints.StsEndpointProvider;

import java.net.URI;
import java.time.Instant;
import java.time.temporal.ChronoUnit;

public class StsPreSigner {
    public static final String GET_CALLER_IDENTITY_ACTION = "GetCallerIdentity";
    public static final String GET_CALLER_IDENTITY_VERSION = "2011-06-15";

    private static final Aws4Signer signer = Aws4Signer.create();

    private final SdkHttpFullRequest getCallerIdentityRequest;
    private final AwsCredentialsProvider clientCredentialsProvider;
    private final Region region;

    public StsPreSigner(StsClient stsClient) {
        this.clientCredentialsProvider = (AwsCredentialsProvider) stsClient.serviceClientConfiguration()
                .credentialsProvider();
        StsEndpointProvider endPointProvider = (StsEndpointProvider) stsClient.serviceClientConfiguration()
                .endpointProvider().get();
        StsEndpointParams stsEndpointParams = StsEndpointParams.builder()
                .region(stsClient.serviceClientConfiguration().region()).build();
        URI endpoint = endPointProvider.resolveEndpoint(stsEndpointParams).getNow(null).url();
        region = stsClient.serviceClientConfiguration().region();
        getCallerIdentityRequest = SdkHttpFullRequest.builder().method(SdkHttpMethod.GET).protocol(endpoint.getScheme())
                .host(endpoint.getHost()).encodedPath("/").appendRawQueryParameter("Action", GET_CALLER_IDENTITY_ACTION)
                .appendRawQueryParameter("Version", GET_CALLER_IDENTITY_VERSION).build();
    }

    public String getCallerIdentity() {
        Aws4PresignerParams params = Aws4PresignerParams.builder()
                .awsCredentials(this.clientCredentialsProvider.resolveCredentials())
                .expirationTime(Instant.now().plus(10, ChronoUnit.MINUTES)).signingRegion(this.region)
                .signingName(StsClient.SERVICE_NAME).build();

        return signer.presign(getCallerIdentityRequest, params).getUri().toString();
    }
}

This is not supported by the SDK, and it's not so easy :(