feat(storage): add object existence validation option to get presigned url

aws-storage-s3/api/aws-storage-s3.api

@@ -176,6 +176,7 @@ public final class com/amplifyframework/storage/s3/options/AWSS3StorageGetPresig
 	public static fun defaultInstance ()Lcom/amplifyframework/storage/s3/options/AWSS3StorageGetPresignedUrlOptions;
 	public fun equals (Ljava/lang/Object;)Z
 	public static fun from (Lcom/amplifyframework/storage/s3/options/AWSS3StorageGetPresignedUrlOptions;)Lcom/amplifyframework/storage/s3/options/AWSS3StorageGetPresignedUrlOptions$Builder;
+	public fun getValidateObjectExistence ()Z
 	public fun hashCode ()I
 	public fun toString ()Ljava/lang/String;
 	public fun useAccelerateEndpoint ()Z
@@ -187,6 +188,7 @@ public final class com/amplifyframework/storage/s3/options/AWSS3StorageGetPresig
 	public synthetic fun build ()Lcom/amplifyframework/storage/options/StorageOptions;
 	public fun build ()Lcom/amplifyframework/storage/s3/options/AWSS3StorageGetPresignedUrlOptions;
 	public fun setUseAccelerateEndpoint (Z)Lcom/amplifyframework/storage/s3/options/AWSS3StorageGetPresignedUrlOptions$Builder;
+	public fun setValidateObjectExistence (Z)Lcom/amplifyframework/storage/s3/options/AWSS3StorageGetPresignedUrlOptions$Builder;
 }
 
 public final class com/amplifyframework/storage/s3/options/AWSS3StorageListOptions : com/amplifyframework/storage/options/StorageListOptions {
@@ -283,11 +285,13 @@ public final class com/amplifyframework/storage/s3/request/AWSS3StorageDownloadF
 
 public final class com/amplifyframework/storage/s3/request/AWSS3StorageGetPresignedUrlRequest {
 	public fun <init> (Ljava/lang/String;Lcom/amplifyframework/storage/StorageAccessLevel;Ljava/lang/String;IZ)V
+	public fun <init> (Ljava/lang/String;Lcom/amplifyframework/storage/StorageAccessLevel;Ljava/lang/String;IZZ)V
 	public fun getAccessLevel ()Lcom/amplifyframework/storage/StorageAccessLevel;
 	public fun getExpires ()I
 	public fun getKey ()Ljava/lang/String;
 	public fun getTargetIdentityId ()Ljava/lang/String;
 	public fun useAccelerateEndpoint ()Z
+	public fun validateObjectExistence ()Z
 }
 
 public final class com/amplifyframework/storage/s3/request/AWSS3StorageListRequest {
@@ -331,6 +335,7 @@ public abstract interface class com/amplifyframework/storage/s3/service/StorageS
 	public abstract fun resumeTransfer (Lcom/amplifyframework/storage/s3/transfer/TransferObserver;)V
 	public abstract fun uploadFile (Ljava/lang/String;Ljava/lang/String;Ljava/io/File;Lcom/amplifyframework/storage/ObjectMetadata;Z)Lcom/amplifyframework/storage/s3/transfer/TransferObserver;
 	public abstract fun uploadInputStream (Ljava/lang/String;Ljava/lang/String;Ljava/io/InputStream;Lcom/amplifyframework/storage/ObjectMetadata;Z)Lcom/amplifyframework/storage/s3/transfer/TransferObserver;
+	public abstract fun validateObjectExists (Ljava/lang/String;)V
 }
 
 public abstract interface class com/amplifyframework/storage/s3/service/StorageService$Factory {

aws-storage-s3/src/androidTest/java/com/amplifyframework/storage/s3/AWSS3StoragePathGetUrlTest.kt

@@ -18,16 +18,19 @@ import android.content.Context
 import androidx.test.core.app.ApplicationProvider
 import com.amplifyframework.auth.cognito.AWSCognitoAuthPlugin
 import com.amplifyframework.storage.StorageCategory
+import com.amplifyframework.storage.StorageException
 import com.amplifyframework.storage.StoragePath
 import com.amplifyframework.storage.options.StorageGetUrlOptions
 import com.amplifyframework.storage.options.StorageUploadFileOptions
+import com.amplifyframework.storage.s3.options.AWSS3StorageGetPresignedUrlOptions
 import com.amplifyframework.storage.s3.test.R
 import com.amplifyframework.storage.s3.util.WorkmanagerTestUtils.initializeWorkmanagerTestUtil
 import com.amplifyframework.testutils.random.RandomTempFile
 import com.amplifyframework.testutils.sync.SynchronousAuth
 import com.amplifyframework.testutils.sync.SynchronousStorage
 import java.io.File
 import org.junit.Assert.assertEquals
+import org.junit.Assert.assertThrows
 import org.junit.Assert.assertTrue
 import org.junit.BeforeClass
 import org.junit.Test
@@ -79,4 +82,25 @@ class AWSS3StoragePathGetUrlTest {
         assertEquals("/public/$SMALL_FILE_NAME", result.url.path)
         assertTrue(result.url.query.contains("X-Amz-Expires=30"))
     }
+
+    @Test
+    fun testGetUrlWithObjectExistenceValidationEnabled() {
+        val result = synchronousStorage.getUrl(
+            SMALL_FILE_PATH,
+            AWSS3StorageGetPresignedUrlOptions.builder().setValidateObjectExistence(true).expires(30).build()
+        )
+
+        assertEquals("/public/$SMALL_FILE_NAME", result.url.path)
+        assertTrue(result.url.query.contains("X-Amz-Expires=30"))
+    }
+
+    @Test
+    fun testGetUrlWithStorageExceptionObjectNotFoundThrown() {
+        assertThrows(StorageException::class.java) {
+            synchronousStorage.getUrl(
+                StoragePath.fromString("public/SOME_UNKNOWN_FILE"),
+                AWSS3StorageGetPresignedUrlOptions.builder().setValidateObjectExistence(true).expires(30).build()
+            )
+        }
+    }
 }

aws-storage-s3/src/main/java/com/amplifyframework/storage/s3/AWSS3StoragePlugin.java

@@ -319,6 +319,8 @@ public StorageGetUrlOperation<?> getUrl(
         @NonNull Consumer<StorageException> onError) {
         boolean useAccelerateEndpoint = options instanceof AWSS3StorageGetPresignedUrlOptions &&
             ((AWSS3StorageGetPresignedUrlOptions) options).useAccelerateEndpoint();
+        boolean validateObjectExistence = options instanceof AWSS3StorageGetPresignedUrlOptions &&
+                ((AWSS3StorageGetPresignedUrlOptions) options).getValidateObjectExistence();
         AWSS3StorageGetPresignedUrlRequest request = new AWSS3StorageGetPresignedUrlRequest(
             key,
             options.getAccessLevel() != null
@@ -328,7 +330,8 @@ public StorageGetUrlOperation<?> getUrl(
             options.getExpires() != 0
                 ? options.getExpires()
                 : defaultUrlExpiration,
-            useAccelerateEndpoint
+            useAccelerateEndpoint,
+            validateObjectExistence
         );
 
         AWSS3StorageGetPresignedUrlOperation operation =
@@ -355,10 +358,15 @@ public StorageGetUrlOperation<?> getUrl(
     ) {
         boolean useAccelerateEndpoint = options instanceof AWSS3StorageGetPresignedUrlOptions &&
                 ((AWSS3StorageGetPresignedUrlOptions) options).useAccelerateEndpoint();
+
+        boolean validateObjectExistence = options instanceof AWSS3StorageGetPresignedUrlOptions &&
+                ((AWSS3StorageGetPresignedUrlOptions) options).getValidateObjectExistence();
+
         AWSS3StoragePathGetPresignedUrlRequest request = new AWSS3StoragePathGetPresignedUrlRequest(
                 path,
                 options.getExpires() != 0 ? options.getExpires() : defaultUrlExpiration,
-                useAccelerateEndpoint
+                useAccelerateEndpoint,
+                validateObjectExistence
         );
 
         AWSS3StoragePathGetPresignedUrlOperation operation =

aws-storage-s3/src/main/java/com/amplifyframework/storage/s3/operation/AWSS3StorageGetPresignedUrlOperation.java

@@ -30,14 +30,17 @@
 import java.net.URL;
 import java.util.concurrent.ExecutorService;
 
+import aws.sdk.kotlin.services.s3.model.NotFound;
+
 /**
- *  An operation to retrieve pre-signed object URL from AWS S3.
- *  @deprecated Class should not be public and explicitly cast to. Cast to StorageGetUrlOperation.
- *  Internal usages are moving to AWSS3StoragePathGetPresignedUrlOperation
+ * An operation to retrieve pre-signed object URL from AWS S3.
+ *
+ * @deprecated Class should not be public and explicitly cast to. Cast to StorageGetUrlOperation.
+ * Internal usages are moving to AWSS3StoragePathGetPresignedUrlOperation
  */
 @Deprecated
 public final class AWSS3StorageGetPresignedUrlOperation
-    extends StorageGetUrlOperation<AWSS3StorageGetPresignedUrlRequest> {
+        extends StorageGetUrlOperation<AWSS3StorageGetPresignedUrlRequest> {
     private final StorageService storageService;
     private final ExecutorService executorService;
     private final AuthCredentialsProvider authCredentialsProvider;
@@ -58,13 +61,13 @@ public final class AWSS3StorageGetPresignedUrlOperation
      * @param onError                         Notified upon URL generation error
      */
     public AWSS3StorageGetPresignedUrlOperation(
-        @NonNull StorageService storageService,
-        @NonNull ExecutorService executorService,
-        @NonNull AuthCredentialsProvider authCredentialsProvider,
-        @NonNull AWSS3StorageGetPresignedUrlRequest request,
-        @NonNull AWSS3StoragePluginConfiguration awss3StoragePluginConfiguration,
-        @NonNull Consumer<StorageGetUrlResult> onSuccess,
-        @NonNull Consumer<StorageException> onError
+            @NonNull StorageService storageService,
+            @NonNull ExecutorService executorService,
+            @NonNull AuthCredentialsProvider authCredentialsProvider,
+            @NonNull AWSS3StorageGetPresignedUrlRequest request,
+            @NonNull AWSS3StoragePluginConfiguration awss3StoragePluginConfiguration,
+            @NonNull Consumer<StorageGetUrlResult> onSuccess,
+            @NonNull Consumer<StorageException> onError
     ) {
         super(request);
         this.storageService = storageService;
@@ -79,27 +82,47 @@ public AWSS3StorageGetPresignedUrlOperation(
     @Override
     public void start() {
         executorService.submit(() -> {
-                awsS3StoragePluginConfiguration.getAWSS3PluginPrefixResolver(authCredentialsProvider).
+            awsS3StoragePluginConfiguration.getAWSS3PluginPrefixResolver(authCredentialsProvider).
                     resolvePrefix(getRequest().getAccessLevel(),
                         getRequest().getTargetIdentityId(),
                         prefix -> {
                             try {
                                 String serviceKey = prefix.concat(getRequest().getKey());
+
+                                if (getRequest().validateObjectExistence()) {
+                                    try {
+                                        storageService.validateObjectExists(serviceKey);
+                                    } catch (NotFound nfe) {
+                                        onError.accept(new StorageException(
+                                                "Unable to generate URL for non-existent path: $serviceKey",
+                                                nfe,
+                                                "Please ensure the path is valid or the object has been uploaded."
+                                        ));
+                                        return;
+                                    } catch (Exception exception) {
+                                        onError.accept(new StorageException(
+                                                "Encountered an issue while validating the existence of object",
+                                                exception,
+                                                "See included exception for more details and suggestions to fix."
+                                        ));
+                                        return;
+                                    }
+                                }
+
                                 URL url = storageService.getPresignedUrl(
-                                    serviceKey,
-                                    getRequest().getExpires(),
-                                    getRequest().useAccelerateEndpoint());
+                                        serviceKey,
+                                        getRequest().getExpires(),
+                                        getRequest().useAccelerateEndpoint());
                                 onSuccess.accept(StorageGetUrlResult.fromUrl(url));
                             } catch (Exception exception) {
                                 onError.accept(new StorageException(
-                                    "Encountered an issue while generating pre-signed URL",
-                                    exception,
-                                    "See included exception for more details and suggestions to fix."
+                                        "Encountered an issue while generating pre-signed URL",
+                                        exception,
+                                        "See included exception for more details and suggestions to fix."
                                 ));
                             }
 
-                        },
-                        onError);
+                        }, onError);
             }
         );
     }

aws-storage-s3/src/main/java/com/amplifyframework/storage/s3/operation/AWSS3StoragePathGetPresignedUrlOperation.kt

@@ -14,6 +14,7 @@
  */
 package com.amplifyframework.storage.s3.operation
 
+import aws.sdk.kotlin.services.s3.model.NotFound
 import com.amplifyframework.auth.AuthCredentialsProvider
 import com.amplifyframework.core.Consumer
 import com.amplifyframework.storage.StorageException
@@ -48,6 +49,30 @@ internal class AWSS3StoragePathGetPresignedUrlOperation(
                 return@submit
             }
 
+            if (request.validateObjectExistence) {
+                try {
+                    storageService.validateObjectExists(serviceKey)
+                } catch (nfe: NotFound) {
+                    onError.accept(
+                        StorageException(
+                            "Unable to generate URL for non-existent path: $serviceKey",
+                            nfe,
+                            "Please ensure the path is valid or the object has been uploaded."
+                        )
+                    )
+                    return@submit
+                } catch (exception: Exception) {
+                    onError.accept(
+                        StorageException(
+                            "Encountered an issue while validating the existence of object",
+                            exception,
+                            "See included exception for more details and suggestions to fix."
+                        )
+                    )
+                    return@submit
+                }
+            }
+
             try {
                 val url = storageService.getPresignedUrl(
                     serviceKey,

aws-storage-s3/src/main/java/com/amplifyframework/storage/s3/options/AWSS3StorageGetPresignedUrlOptions.java

@@ -26,10 +26,12 @@
  */
 public final class AWSS3StorageGetPresignedUrlOptions extends StorageGetUrlOptions {
     private final boolean useAccelerationMode;
+    private final boolean validateObjectExistence;
 
     private AWSS3StorageGetPresignedUrlOptions(final Builder builder) {
         super(builder);
         this.useAccelerationMode = builder.useAccelerateEndpoint;
+        this.validateObjectExistence = builder.validateObjectExistence;
     }
 
     /**
@@ -59,6 +61,8 @@ public static Builder from(@NonNull AWSS3StorageGetPresignedUrlOptions options)
         return builder()
             .accessLevel(options.getAccessLevel())
             .targetIdentityId(options.getTargetIdentityId())
+            .expires(options.getExpires())
+            .setValidateObjectExistence(options.getValidateObjectExistence())
             .expires(options.getExpires());
     }
 
@@ -80,6 +84,16 @@ public boolean useAccelerateEndpoint() {
         return useAccelerationMode;
     }
 
+    /**
+     * Gets the flag to determine whether to validate whether an S3 object exists.
+     * Note: Setting this to `true` will result in a latency cost since confirming the existence
+     * of the underlying S3 object will likely require a round-trip network call.
+     * @return boolean flag
+     */
+    public boolean getValidateObjectExistence() {
+        return validateObjectExistence;
+    }
+
     @Override
     @SuppressWarnings("deprecation")
     public boolean equals(Object obj) {
@@ -91,7 +105,8 @@ public boolean equals(Object obj) {
             AWSS3StorageGetPresignedUrlOptions that = (AWSS3StorageGetPresignedUrlOptions) obj;
             return ObjectsCompat.equals(getAccessLevel(), that.getAccessLevel()) &&
                     ObjectsCompat.equals(getTargetIdentityId(), that.getTargetIdentityId()) &&
-                    ObjectsCompat.equals(getExpires(), that.getExpires());
+                    ObjectsCompat.equals(getExpires(), that.getExpires()) &&
+                    ObjectsCompat.equals(getValidateObjectExistence(), that.getValidateObjectExistence());
         }
     }
 
@@ -101,7 +116,8 @@ public int hashCode() {
         return ObjectsCompat.hash(
                 getAccessLevel(),
                 getTargetIdentityId(),
-                getExpires()
+                getExpires(),
+                getValidateObjectExistence()
         );
     }
 
@@ -113,6 +129,7 @@ public String toString() {
                 "accessLevel=" + getAccessLevel() +
                 ", targetIdentityId=" + getTargetIdentityId() +
                 ", expires=" + getExpires() +
+                ", validateObjectExistence=" + getValidateObjectExistence() +
                 '}';
     }
 
@@ -123,6 +140,7 @@ public String toString() {
      */
     public static final class Builder extends StorageGetUrlOptions.Builder<Builder> {
         private boolean useAccelerateEndpoint;
+        private boolean validateObjectExistence;
 
         /**
          * Configure to use acceleration mode on new StorageGetPresignedUrlOptions instances.
@@ -134,6 +152,16 @@ public Builder setUseAccelerateEndpoint(boolean useAccelerateEndpoint) {
             return this;
         }
 
+        /**
+         * Configure to validate object existence flag on new StorageGetPresignedUrlOptions instances.
+         * @param validateObjectExistence boolean flag to represent flag to validate object existence.
+         * @return Current Builder instance for fluent chaining
+         */
+        public Builder setValidateObjectExistence(boolean validateObjectExistence) {
+            this.validateObjectExistence = validateObjectExistence;
+            return this;
+        }
+
         @Override
         @NonNull
         public AWSS3StorageGetPresignedUrlOptions build() {