refactor: 채팅방 파일 다운로드 리펙토링

src/main/java/com/dku/council/global/config/webclient/WebClientConfig.java

@@ -29,6 +29,7 @@ public WebClient plainWebClient() {
 
         return WebClient.builder()
                 .clientConnector(new ReactorClientHttpConnector(client))
+                .codecs(configurer -> configurer.defaultCodecs().maxInMemorySize(10 * 1024 * 1024))
                 .build();
     }
 

src/main/java/com/dku/council/infra/nhn/s3/service/ObjectDownloadService.java

@@ -2,38 +2,33 @@
 
 import com.dku.council.infra.nhn.global.service.service.NHNAuthService;
 import lombok.RequiredArgsConstructor;
+import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.http.*;
 import org.springframework.stereotype.Service;
-import org.springframework.web.client.RestTemplate;
+import org.springframework.web.reactive.function.client.WebClient;
 
-import java.io.ByteArrayInputStream;
-import java.io.InputStream;
 import java.util.List;
-import java.util.Objects;
 
 @Service
 @RequiredArgsConstructor
 public class ObjectDownloadService {
 
+    private final WebClient webClient;
     private final NHNAuthService nhnAuthService;
 
     public ResponseEntity<byte[]> downloadObject(String fileName, String fileUrl) {
-
-        // RestTemplate 생성
-        RestTemplate restTemplate = new RestTemplate();
-
         // 헤더 생성
         HttpHeaders headers = new HttpHeaders();
         headers.add("X-Auth-Token", nhnAuthService.requestToken());
         headers.setAccept(List.of(MediaType.APPLICATION_OCTET_STREAM));
         headers.setContentDispositionFormData("attachment", fileName);
 
-        HttpEntity<String> requestHttpEntity = new HttpEntity<String>(null, headers);
-
-        // API 호출, 데이터를 바이트 배열로 받음
-        ResponseEntity<byte[]> response = restTemplate.exchange(fileUrl, HttpMethod.GET, requestHttpEntity, byte[].class);
-
-        return response;
+        return webClient.get()
+                .uri(fileUrl)
+                .headers(httpHeaders -> httpHeaders.addAll(headers))
+                .exchangeToMono(value -> value.toEntity(new ParameterizedTypeReference<byte[]>() {
+                }))
+                .block();
     }
 
 }