feat: presigned url 이미지 업로드 방식 추가

- presigned 이미지 업로드 방식 구현
- 테스트및 검증완료

Author: 7zrv

src/main/java/com/somemore/global/imageupload/usecase/ImageUploadUseCase.java

@@ -4,4 +4,5 @@
 
 public interface ImageUploadUseCase {
     String uploadImage(ImageUploadRequestDto requestDto);
+    String getPresignedUrl(String filename);
 }

src/main/java/com/somemore/global/imageupload/util/ImageUploadUtils.java

@@ -11,9 +11,14 @@ private ImageUploadUtils() {
     }
 
     public static String generateUniqueFileName(String originalFileName) {
+
         String uuid = UUID.randomUUID().toString();
+
         String fileExtension = extractFileExtension(originalFileName);
-        return uuid + fileExtension;
+
+        String fileNameWithoutExtension = originalFileName.substring(0, originalFileName.lastIndexOf("."));
+
+        return uuid + "_" + fileNameWithoutExtension + fileExtension;
     }
 
     private static String extractFileExtension(String fileName) {

src/main/java/com/somemore/global/imageupload/validator/DefaultImageUploadValidator.java

@@ -25,6 +25,11 @@ public void validateFileType(MultipartFile file) {
         }
     }
 
+    @Override
+    public boolean isEmptyFileName(String fileName) {
+        return fileName == null || fileName.isEmpty();
+    }
+
     @Override
     public boolean isEmptyFile(MultipartFile file) {
         return file == null || file.isEmpty();

src/main/java/com/somemore/global/imageupload/validator/ImageUploadValidator.java

@@ -9,4 +9,6 @@ public interface ImageUploadValidator {
     void validateFileType(MultipartFile file);
 
     boolean isEmptyFile(MultipartFile file);
+
+    boolean isEmptyFileName(String fileName);
 }

src/test/java/com/somemore/global/imageupload/service/ImageUploadServiceTest.java

@@ -1,9 +1,7 @@
 package com.somemore.global.imageupload.service;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.*;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.mock;
@@ -17,6 +15,8 @@
 import com.somemore.support.IntegrationTestSupport;
 import java.io.IOException;
 import java.io.InputStream;
+import java.net.URL;
+
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
@@ -28,6 +28,9 @@
 import software.amazon.awssdk.core.sync.RequestBody;
 import software.amazon.awssdk.services.s3.S3Client;
 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;
+import software.amazon.awssdk.services.s3.presigner.model.PresignedGetObjectRequest;
 
 class ImageUploadServiceTest extends IntegrationTestSupport {
 
@@ -99,4 +102,56 @@ void uploadImageWithEmptyFile() {
         // then
         assertThat(imgUrl).isEqualTo(ImageUploadService.DEFAULT_IMAGE_URL);
     }
+
+    @DisplayName("유효한 파일명으로 사전 서명된 URL을 생성할 수 있다.")
+    @Test
+    void getPresignedUrl_success() {
+        // given
+        String filename = "testImage.jpg";
+
+        // Mock the validator to return false (file name is valid)
+        when(imageUploadValidator.isEmptyFileName(filename)).thenReturn(false);
+
+        // Mock the S3Presigner to return a URL
+        S3Presigner mockPresigner = mock(S3Presigner.class);
+        ReflectionTestUtils.setField(imageUploadService, "s3Presigner", mockPresigner);
+
+        PresignedGetObjectRequest mockPresignedRequest = mock(PresignedGetObjectRequest.class);
+        URL mockUrl = mock(URL.class);
+
+        when(mockUrl.toString()).thenReturn("https://test-bucket.s3.amazonaws.com/unique-test-image.jpg");
+        when(mockPresignedRequest.url()).thenReturn(mockUrl);
+        when(mockPresigner.presignGetObject(any(GetObjectPresignRequest.class))).thenReturn(mockPresignedRequest);
+
+        // when
+        String presignedUrl = imageUploadService.getPresignedUrl(filename);
+
+        // then
+        assertNotNull(presignedUrl);
+        assertTrue(presignedUrl.startsWith("https://test-bucket.s3.amazonaws.com/"));
+        assertTrue(presignedUrl.endsWith(".jpg"));
+
+        // Verify interactions
+        verify(imageUploadValidator, times(1)).isEmptyFileName(filename);
+        verify(mockPresigner, times(1)).presignGetObject(any(GetObjectPresignRequest.class));
+    }
+
+    @DisplayName("파일명 검증에 실패하면 null을 반환한다.")
+    @Test
+    void getPresignedUrl_invalidFileName() {
+
+        // given
+        String filename = "";
+
+        when(imageUploadValidator.isEmptyFileName(filename)).thenReturn(true);
+
+        // when
+        String presignedUrl = imageUploadService.getPresignedUrl(filename);
+
+        // then
+        assertNull(presignedUrl);
+
+        // Verify interactions
+        verify(imageUploadValidator, times(1)).isEmptyFileName(filename);
+    }
 }