Make getUrl return location of bucket if object is empty or null. (#…

…1226)

Back-ported from 3.2.0. Original commit id: a7a07d5

spring-cloud-aws-s3-parent/spring-cloud-aws-s3/src/main/java/io/awspring/cloud/s3/S3Resource.java

@@ -26,6 +26,7 @@
 import org.springframework.core.io.WritableResource;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
 import software.amazon.awssdk.services.s3.S3Client;
 import software.amazon.awssdk.services.s3.model.GetUrlRequest;
 import software.amazon.awssdk.services.s3.model.HeadObjectResponse;
@@ -82,6 +83,9 @@ public S3Resource(Location location, S3Client s3Client, S3OutputStreamProvider s
 
 	@Override
 	public URL getURL() throws IOException {
+		if (!StringUtils.hasText(this.location.getObject())) {
+			return new URL("https", location.getBucket() + ".s3.amazonaws.com", "/");
+		}
 		GetUrlRequest getUrlRequest = GetUrlRequest.builder().bucket(this.getLocation().getBucket())
 				.key(this.location.getObject()).versionId(this.location.getVersion()).build();
 		return s3Client.utilities().getUrl(getUrlRequest);

spring-cloud-aws-s3-parent/spring-cloud-aws-s3/src/test/java/io/awspring/cloud/s3/S3ResourceIntegrationTests.java

@@ -97,6 +97,13 @@ static void beforeAll() {
 		client.createBucket(request -> request.bucket("first-bucket"));
 	}
 
+	@TestAvailableOutputStreamProviders
+	void returnsEmptyUrlToBucketWhenObjectIsEmpty(S3OutputStreamProvider s3OutputStreamProvider) throws IOException {
+		S3Resource resource = s3Resource("s3://first-bucket/", s3OutputStreamProvider);
+		assertThat(resource.getURL().toString())
+			.isEqualTo("https://first-bucket.s3.amazonaws.com/");
+	}
+
 	@TestAvailableOutputStreamProviders
 	void readsFileFromS3(S3OutputStreamProvider s3OutputStreamProvider) throws IOException {
 		client.putObject(PutObjectRequest.builder().bucket("first-bucket").key("test-file.txt").build(),