Add S3Client objectExists support in S3Template (#978)

Author: Ziemowit

spring-cloud-aws-s3-parent/spring-cloud-aws-s3/src/main/java/io/awspring/cloud/s3/S3Operations.java

@@ -28,6 +28,7 @@
  * {@link S3Template}.
  *
  * @author Maciej Walkowiak
+ * @author Ziemowit Stolarczyk
  * @since 3.0
  */
 public interface S3Operations {
@@ -70,6 +71,15 @@ public interface S3Operations {
 	 */
 	void deleteObject(String s3Url);
 
+	/**
+	 * Checks if an S3 object exists.
+	 *
+	 * @param bucketName - the bucket name
+	 * @param key - the object key
+	 * @return true if object exists; false otherwise
+	 */
+	boolean objectExists(String bucketName, String key);
+
 	/**
 	 * Returns some or all (up to 1,000) of the objects in a bucket. Does not handle pagination. If you need pagination
 	 * you should use {@link S3PathMatchingResourcePatternResolver} or {@link S3Client}

spring-cloud-aws-s3-parent/spring-cloud-aws-s3/src/main/java/io/awspring/cloud/s3/S3Template.java

@@ -28,6 +28,7 @@
 import software.amazon.awssdk.services.s3.model.ListObjectsV2Request;
 import software.amazon.awssdk.services.s3.model.ListObjectsV2Response;
 import software.amazon.awssdk.services.s3.model.NoSuchBucketException;
+import software.amazon.awssdk.services.s3.model.NoSuchKeyException;
 import software.amazon.awssdk.services.s3.model.PutObjectRequest;
 import software.amazon.awssdk.services.s3.presigner.S3Presigner;
 import software.amazon.awssdk.services.s3.presigner.model.GetObjectPresignRequest;
@@ -39,6 +40,7 @@
  * Higher level abstraction over {@link S3Client} providing methods for the most common use cases.
  *
  * @author Maciej Walkowiak
+ * @author Ziemowit Stolarczyk
  * @since 3.0
  */
 public class S3Template implements S3Operations {
@@ -101,6 +103,19 @@ public void deleteObject(String s3Url) {
 		this.deleteObject(location.getBucket(), location.getObject());
 	}
 
+	@Override
+	public boolean objectExists(String bucketName, String key) {
+		Assert.notNull(bucketName, "bucketName is required");
+		Assert.notNull(key, "key is required");
+		try {
+			s3Client.headObject(request -> request.bucket(bucketName).key(key));
+		}
+		catch (NoSuchBucketException | NoSuchKeyException e) {
+			return false;
+		}
+		return true;
+	}
+
 	@Override
 	public List<S3Resource> listObjects(String bucketName, String prefix) {
 		Assert.notNull(bucketName, "bucketName is required");

spring-cloud-aws-s3-parent/spring-cloud-aws-s3/src/test/java/io/awspring/cloud/s3/S3TemplateIntegrationTests.java

@@ -61,6 +61,7 @@
  *
  * @author Maciej Walkowiak
  * @author Yuki Yoshida
+ * @author Ziemowit Stolarczyk
  */
 @Testcontainers
 class S3TemplateIntegrationTests {
@@ -164,6 +165,26 @@ void deletesObjectByS3Url() {
 				.isThrownBy(() -> client.headObject(r -> r.bucket(BUCKET_NAME).key("key.txt")));
 	}
 
+	@Test
+	void whenObjectExistsShouldReturnTrue() {
+		client.putObject(r -> r.bucket(BUCKET_NAME).key("key.txt"), RequestBody.fromString("hello"));
+
+		final boolean existsObject = s3Template.objectExists(BUCKET_NAME, "key.txt");
+
+		assertThat(existsObject).isTrue();
+	}
+
+	@Test
+	void whenObjectNotExistsShouldReturnFalse() {
+		client.putObject(r -> r.bucket(BUCKET_NAME).key("key.txt"), RequestBody.fromString("hello"));
+
+		final boolean existsObject1 = s3Template.objectExists(BUCKET_NAME, "other-key.txt");
+		final boolean existsObject2 = s3Template.objectExists("other-bucket", "key.txt");
+
+		assertThat(existsObject1).isFalse();
+		assertThat(existsObject2).isFalse();
+	}
+
 	@Test
 	void listObjects() throws IOException {
 		client.putObject(r -> r.bucket(BUCKET_NAME).key("hello-en.txt"), RequestBody.fromString("hello"));