refactor: 이메일 로그인 코드 가독성 개선

Author: nayonsoso

src/main/java/com/example/solidconnection/auth/service/EmailSignInService.java

@@ -1,21 +1,18 @@
 package com.example.solidconnection.auth.service;
 
-import static com.example.solidconnection.common.exception.ErrorCode.USER_NOT_FOUND;
+import static com.example.solidconnection.common.exception.ErrorCode.SIGN_IN_FAILED;
 
 import com.example.solidconnection.auth.dto.EmailSignInRequest;
 import com.example.solidconnection.auth.dto.SignInResponse;
 import com.example.solidconnection.common.exception.CustomException;
 import com.example.solidconnection.siteuser.domain.AuthType;
 import com.example.solidconnection.siteuser.domain.SiteUser;
 import com.example.solidconnection.siteuser.repository.SiteUserRepository;
-import java.util.Optional;
 import lombok.RequiredArgsConstructor;
 import org.springframework.security.crypto.password.PasswordEncoder;
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 
-/*
- * 보안을 위해 이메일과 비밀번호 중 무엇이 틀렸는지 구체적으로 응답하지 않는다.
- * */
 @Service
 @RequiredArgsConstructor
 public class EmailSignInService {
@@ -24,19 +21,21 @@ public class EmailSignInService {
     private final SiteUserRepository siteUserRepository;
     private final PasswordEncoder passwordEncoder;
 
+    @Transactional(readOnly = true)
     public SignInResponse signIn(EmailSignInRequest signInRequest) {
-        Optional<SiteUser> optionalSiteUser = siteUserRepository.findByEmailAndAuthType(signInRequest.email(), AuthType.EMAIL);
-        if (optionalSiteUser.isPresent()) {
-            SiteUser siteUser = optionalSiteUser.get();
-            validatePassword(signInRequest.password(), siteUser.getPassword());
-            return signInService.signIn(siteUser);
-        }
-        throw new CustomException(USER_NOT_FOUND, "이메일과 비밀번호를 확인해주세요.");
+        SiteUser siteUser = getEmailMatchingUserOrThrow(signInRequest.email());
+        validatePassword(signInRequest.password(), siteUser.getPassword());
+        return signInService.signIn(siteUser);
+    }
+
+    private SiteUser getEmailMatchingUserOrThrow(String email) {
+        return siteUserRepository.findByEmailAndAuthType(email, AuthType.EMAIL)
+                .orElseThrow(() -> new CustomException(SIGN_IN_FAILED));
     }
 
     private void validatePassword(String rawPassword, String encodedPassword) {
         if (!passwordEncoder.matches(rawPassword, encodedPassword)) {
-            throw new CustomException(USER_NOT_FOUND, "이메일과 비밀번호를 확인해주세요.");
+            throw new CustomException(SIGN_IN_FAILED);
         }
     }
 }

src/main/java/com/example/solidconnection/common/exception/ErrorCode.java

@@ -56,6 +56,7 @@ public enum ErrorCode {
     ACCESS_TOKEN_EXPIRED(HttpStatus.UNAUTHORIZED.value(), "액세스 토큰이 만료되었습니다. 재발급 api를 호출해주세요."),
     REFRESH_TOKEN_EXPIRED(HttpStatus.UNAUTHORIZED.value(), "리프레시 토큰이 만료되었습니다. 다시 로그인을 진행해주세요."),
     ACCESS_DENIED(HttpStatus.FORBIDDEN.value(), "접근 권한이 없습니다."),
+    SIGN_IN_FAILED(HttpStatus.UNAUTHORIZED.value(), "로그인에 실패했습니다. 이메일과 비밀번호를 확인해주세요."),
 
     // s3
     S3_SERVICE_EXCEPTION(HttpStatus.BAD_REQUEST.value(), "S3 서비스 에러 발생"),

src/test/java/com/example/solidconnection/auth/service/EmailSignInServiceTest.java

@@ -55,7 +55,7 @@ class 로그인에_실패한다 {
             // when & then
             assertThatCode(() -> emailSignInService.signIn(signInRequest))
                     .isInstanceOf(CustomException.class)
-                    .hasMessageContaining(ErrorCode.USER_NOT_FOUND.getMessage());
+                    .hasMessageContaining(ErrorCode.SIGN_IN_FAILED.getMessage());
         }
 
         @Test
@@ -68,7 +68,7 @@ class 로그인에_실패한다 {
             // when & then
             assertThatCode(() -> emailSignInService.signIn(signInRequest))
                     .isInstanceOf(CustomException.class)
-                    .hasMessageContaining(ErrorCode.USER_NOT_FOUND.getMessage());
+                    .hasMessageContaining(ErrorCode.SIGN_IN_FAILED.getMessage());
         }
     }
 }