How to update metadata using Amazon S3 SDK

Question

I am using the PHP version of Amazon's AWS SDK. I have a bunch of files with an Expires header; I want to delete that header and add a Cache-control header instead. The update_object function lets me add headers but not remove them.

The answers on this question suggest you can update a file's metadata when you copy it, but I have tried it and it doesn't work. Here is what I used:

$response = $s3->copy_object(
    array(
        'bucket' => $bucket,
        'filename' => $file,
    ),
    array(
        'bucket' => $bucket,
        'filename' => $file2,
    ),
    array(
        'acl' => AmazonS3::ACL_PUBLIC,
        'headers' => array(
            'Content-Type' => 'image/jpeg',
            'Cache-Control' => 'public,max-age=30240000',
        ),
        'meta' => array(
            'x-fake-header' => 'something awesome is happening',
        ),
    )
);

However, the copied object has the exact same headers as the original object (Expires and Content-Type only). I've tried all manner of combinations of the above (with and without Content-Type, Cache-control, meta, etc) and get the same result.

How do I reset the metadata?

Answer 1

I've just found that copying to object to itself actually does change the headers properly. I was copying it to a second file for testing purposes to avoid overwriting the original.

But for some strange reason copying to a different file doesn't change the headers, but copying to the same file does.

Answer 2

Based on Jeffin P S's answer (which works great), I'm proposing a version that creates the new metadata object by cloning the original one. This way, the AWS-specific (non-user) metadata do not get converted into user metadata. Not sure if that would be a real issue, but seems more legit this way.

ObjectMetadata metadataCopy = amazonS3Client.getObjectMetadata(bucketName, fileKey).clone();
metadataCopy.addUserMetadata("yourKey", "updateValue");
metadataCopy.addUserMetadata("otherKey", "newValue");

CopyObjectRequest request = new CopyObjectRequest(bucketName, fileKey, bucketName, fileKey)
      .withSourceBucketName(bucketName)
      .withSourceKey(fileKey)
      .withNewObjectMetadata(metadataCopy);

amazonS3Client.copyObject(request);