MakingRequestsWithFederatedTempCredentials.java

// Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-s3-developer-guide/blob/master/LICENSE-SAMPLECODE.)

import java.io.IOException;

import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicSessionCredentials;
import com.amazonaws.auth.policy.Policy;
import com.amazonaws.auth.policy.Resource;
import com.amazonaws.auth.policy.Statement;
import com.amazonaws.auth.policy.Statement.Effect;
import com.amazonaws.auth.policy.actions.S3Actions;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.securitytoken.AWSSecurityTokenService;
import com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClientBuilder;
import com.amazonaws.services.securitytoken.model.Credentials;
import com.amazonaws.services.securitytoken.model.GetFederationTokenRequest;
import com.amazonaws.services.securitytoken.model.GetFederationTokenResult;
import com.amazonaws.services.s3.model.ObjectListing;

public class MakingRequestsWithFederatedTempCredentials {

    public static void main(String[] args) throws IOException {
        String clientRegion = "*** Client region ***";
        String bucketName = "*** Specify bucket name ***";
        String federatedUser = "*** Federated user name ***";
        String resourceARN = "arn:aws:s3:::" + bucketName;

        try {
            AWSSecurityTokenService stsClient = AWSSecurityTokenServiceClientBuilder
                    .standard()
                    .withCredentials(new ProfileCredentialsProvider())
                    .withRegion(clientRegion)
                    .build();
            
            GetFederationTokenRequest getFederationTokenRequest = new GetFederationTokenRequest();
            getFederationTokenRequest.setDurationSeconds(7200);
            getFederationTokenRequest.setName(federatedUser);
            
            // Define the policy and add it to the request.
            Policy policy = new Policy();
            policy.withStatements(new Statement(Effect.Allow)
                    .withActions(S3Actions.ListObjects)
                    .withResources(new Resource(resourceARN)));
            getFederationTokenRequest.setPolicy(policy.toJson());
            
            // Get the temporary security credentials.
            GetFederationTokenResult federationTokenResult = stsClient.getFederationToken(getFederationTokenRequest);
            Credentials sessionCredentials = federationTokenResult.getCredentials();
    
            // Package the session credentials as a BasicSessionCredentials
            // object for an Amazon S3 client object to use.
            BasicSessionCredentials basicSessionCredentials = new BasicSessionCredentials(
                                                                    sessionCredentials.getAccessKeyId(), 
                                                                    sessionCredentials.getSecretAccessKey(),
                                                                    sessionCredentials.getSessionToken());
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                                    .withCredentials(new AWSStaticCredentialsProvider(basicSessionCredentials))
                                    .withRegion(clientRegion)
                                    .build();
    
            // To verify that the client works, send a listObjects request using 
            // the temporary security credentials.
            ObjectListing objects = s3Client.listObjects(bucketName);
            System.out.println("No. of Objects = " + objects.getObjectSummaries().size());
        }
        catch(AmazonServiceException e) {
            // The call was transmitted successfully, but Amazon S3 couldn't process 
            // it, so it returned an error response.
            e.printStackTrace();
        }
        catch(SdkClientException e) {
            // Amazon S3 couldn't be contacted for a response, or the client
            // couldn't parse the response from Amazon S3.
            e.printStackTrace();
        }
    }
}