Use HeadObject with an AWS SDK or CLI - AWS SDK Code Examples

There are more AWS SDK examples available in the AWS Doc SDK Examples GitHub repo.

Use HeadObject with an AWS SDK or CLI

The following code examples show how to use HeadObject.

CLI
AWS CLI

The following command retrieves metadata for an object in a bucket named my-bucket:

aws s3api head-object --bucket my-bucket --key index.html

Output:

{ "AcceptRanges": "bytes", "ContentType": "text/html", "LastModified": "Thu, 16 Apr 2015 18:19:14 GMT", "ContentLength": 77, "VersionId": "null", "ETag": "\"30a6ec7e1a9ad79c203d05a589c8b400\"", "Metadata": {} }
  • For API details, see HeadObject in AWS CLI Command Reference.

Java
SDK for Java 2.x
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

Determine the content type of an object.

import software.amazon.awssdk.regions.Region; import software.amazon.awssdk.services.s3.S3Client; import software.amazon.awssdk.services.s3.model.HeadObjectRequest; import software.amazon.awssdk.services.s3.model.HeadObjectResponse; import software.amazon.awssdk.services.s3.model.S3Exception; /** * Before running this Java V2 code example, set up your development * environment, including your credentials. * <p> * For more information, see the following documentation topic: * <p> * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html */ public class GetObjectContentType { public static void main(String[] args) { final String usage = """ Usage: <bucketName> <keyName> Where: bucketName - The Amazon S3 bucket name.\s keyName - The key name.\s """; if (args.length != 2) { System.out.println(usage); System.exit(1); } String bucketName = args[0]; String keyName = args[1]; Region region = Region.US_EAST_1; S3Client s3 = S3Client.builder() .region(region) .build(); getContentType(s3, bucketName, keyName); s3.close(); } /** * Retrieves the content type of an object stored in an Amazon S3 bucket. * * @param s3 an instance of the {@link S3Client} class, which is used to interact with the Amazon S3 service * @param bucketName the name of the S3 bucket where the object is stored * @param keyName the key (file name) of the object in the S3 bucket */ public static void getContentType(S3Client s3, String bucketName, String keyName) { try { HeadObjectRequest objectRequest = HeadObjectRequest.builder() .key(keyName) .bucket(bucketName) .build(); HeadObjectResponse objectHead = s3.headObject(objectRequest); String type = objectHead.contentType(); System.out.println("The object content type is " + type); } catch (S3Exception e) { System.err.println(e.awsErrorDetails().errorMessage()); System.exit(1); } } }

Get the restore status of an object.

import software.amazon.awssdk.regions.Region; import software.amazon.awssdk.services.s3.S3Client; import software.amazon.awssdk.services.s3.model.HeadObjectRequest; import software.amazon.awssdk.services.s3.model.HeadObjectResponse; import software.amazon.awssdk.services.s3.model.S3Exception; public class GetObjectRestoreStatus { public static void main(String[] args) { final String usage = """ Usage: <bucketName> <keyName>\s Where: bucketName - The Amazon S3 bucket name.\s keyName - A key name that represents the object.\s """; if (args.length != 2) { System.out.println(usage); System.exit(1); } String bucketName = args[0]; String keyName = args[1]; Region region = Region.US_EAST_1; S3Client s3 = S3Client.builder() .region(region) .build(); checkStatus(s3, bucketName, keyName); s3.close(); } /** * Checks the restoration status of an Amazon S3 object. * * @param s3 an instance of the {@link S3Client} class used to interact with the Amazon S3 service * @param bucketName the name of the Amazon S3 bucket where the object is stored * @param keyName the name of the Amazon S3 object to be checked * @throws S3Exception if an error occurs while interacting with the Amazon S3 service */ public static void checkStatus(S3Client s3, String bucketName, String keyName) { try { HeadObjectRequest headObjectRequest = HeadObjectRequest.builder() .bucket(bucketName) .key(keyName) .build(); HeadObjectResponse response = s3.headObject(headObjectRequest); System.out.println("The Amazon S3 object restoration status is " + response.restore()); } catch (S3Exception e) { System.err.println(e.awsErrorDetails().errorMessage()); System.exit(1); } } }
  • For API details, see HeadObject in AWS SDK for Java 2.x API Reference.

Ruby
SDK for Ruby
Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

require 'aws-sdk-s3' # Wraps Amazon S3 object actions. class ObjectExistsWrapper attr_reader :object # @param object [Aws::S3::Object] An Amazon S3 object. def initialize(object) @object = object end # Checks whether the object exists. # # @return [Boolean] True if the object exists; otherwise false. def exists? @object.exists? rescue Aws::Errors::ServiceError => e puts "Couldn't check existence of object #{@object.bucket.name}:#{@object.key}. Here's why: #{e.message}" false end end # Example usage: def run_demo bucket_name = "amzn-s3-demo-bucket" object_key = "my-object.txt" wrapper = ObjectExistsWrapper.new(Aws::S3::Object.new(bucket_name, object_key)) exists = wrapper.exists? puts "Object #{object_key} #{exists ? 'does' : 'does not'} exist." end run_demo if $PROGRAM_NAME == __FILE__
  • For API details, see HeadObject in AWS SDK for Ruby API Reference.