feat: add presigned upload support for recruit files

src/main/java/inha/gdgoc/domain/recruit/core/dto/response/RecruitCoreApplicantDetailResponse.java

@@ -22,6 +22,10 @@ public record RecruitCoreApplicantDetailResponse(
 ) {
 
     public static RecruitCoreApplicantDetailResponse from(RecruitCoreApplication entity) {
+        return from(entity, entity.getFileUrls());
+    }
+
+    public static RecruitCoreApplicantDetailResponse from(RecruitCoreApplication entity, List<String> fileUrls) {
         return new RecruitCoreApplicantDetailResponse(
             entity.getId(),
             entity.getSession(),
@@ -31,7 +35,7 @@ public static RecruitCoreApplicantDetailResponse from(RecruitCoreApplication ent
             entity.getWish(),
             entity.getStrengths(),
             entity.getPledge(),
-            entity.getFileUrls(),
+            fileUrls,
             entity.getResultStatus(),
             RecruitCoreApplicationReviewResponse.from(entity),
             entity.getCreatedAt(),

src/main/java/inha/gdgoc/domain/recruit/core/service/RecruitCoreApplicationService.java

@@ -13,6 +13,7 @@
 import inha.gdgoc.domain.recruit.core.exception.RecruitCoreApplicationNotFoundException;
 import inha.gdgoc.domain.recruit.core.exception.RecruitCoreClosedException;
 import inha.gdgoc.domain.recruit.core.repository.RecruitCoreApplicationRepository;
+import inha.gdgoc.domain.resource.service.S3Service;
 import inha.gdgoc.domain.user.entity.User;
 import inha.gdgoc.domain.user.enums.UserRole;
 import inha.gdgoc.domain.user.repository.UserRepository;
@@ -35,11 +36,12 @@ public class RecruitCoreApplicationService {
     private final UserRepository userRepository;
     private final RecruitCoreSessionResolver recruitCoreSessionResolver;
     private final MajorNormalizer majorNormalizer;
+    private final S3Service s3Service;
 
     @Transactional(readOnly = true)
     public RecruitCoreApplicantDetailResponse getApplicantDetail(Long id) {
         RecruitCoreApplication app = getApplication(id);
-        return RecruitCoreApplicantDetailResponse.from(app);
+        return RecruitCoreApplicantDetailResponse.from(app, toS3FileUrls(app.getFileUrls()));
     }
 
     @Transactional(readOnly = true)
@@ -119,7 +121,23 @@ public RecruitCoreApplicantDetailResponse getApplicantDetailForViewer(
         if (!privileged && !application.isOwnedBy(viewerId)) {
             throw new BusinessException(GlobalErrorCode.FORBIDDEN_USER);
         }
-        return RecruitCoreApplicantDetailResponse.from(application);
+        return RecruitCoreApplicantDetailResponse.from(application, toS3FileUrls(application.getFileUrls()));
+    }
+
+    private List<String> toS3FileUrls(List<String> fileKeys) {
+        if (fileKeys == null || fileKeys.isEmpty()) {
+            return List.of();
+        }
+        return fileKeys.stream()
+            .map(this::toS3FileUrl)
+            .toList();
+    }
+
+    private String toS3FileUrl(String fileKey) {
+        if (fileKey.startsWith("http://") || fileKey.startsWith("https://")) {
+            return fileKey;
+        }
+        return s3Service.getS3FileUrl(fileKey);
     }
 
     private RecruitCoreApplication getApplication(Long id) {

src/main/java/inha/gdgoc/domain/recruit/member/controller/RecruitMemberController.java

@@ -20,6 +20,7 @@
 import inha.gdgoc.domain.recruit.member.dto.response.CheckStudentIdResponse;
 import inha.gdgoc.domain.recruit.member.dto.response.RecruitMemberSummaryResponse;
 import inha.gdgoc.domain.recruit.member.dto.response.SpecifiedMemberResponse;
+import inha.gdgoc.domain.resource.dto.response.PresignedUploadResponse;
 import inha.gdgoc.domain.recruit.member.entity.RecruitMember;
 import inha.gdgoc.domain.recruit.member.service.RecruitMemberService;
 import inha.gdgoc.global.dto.response.ApiResponse;
@@ -29,6 +30,9 @@
 import io.swagger.v3.oas.annotations.security.SecurityRequirement;
 import io.swagger.v3.oas.annotations.tags.Tag;
 import jakarta.validation.Valid;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.PositiveOrZero;
 import java.util.List;
 import lombok.RequiredArgsConstructor;
 import org.springframework.data.domain.Page;
@@ -67,6 +71,13 @@ public class RecruitMemberController {
 
     private final RecruitMemberService recruitMemberService;
 
+    public record ProofFilePresignedUploadRequest(
+            @NotBlank String fileName,
+            @NotBlank String contentType,
+            @NotNull @PositiveOrZero Long fileSize
+    ) {
+    }
+
     @PostMapping(value = "/apply", consumes = MediaType.APPLICATION_JSON_VALUE)
     public ResponseEntity<ApiResponse<Void, Void>> recruitMemberAdd(
             @RequestBody Map<String, Object> applicationRequest
@@ -86,6 +97,19 @@ public ResponseEntity<ApiResponse<Void, Void>> recruitMemberAddMultipart(
         return ResponseEntity.ok(ApiResponse.ok(MEMBER_SAVE_SUCCESS));
     }
 
+    @PostMapping("/apply/proof-file/presigned-upload")
+    public ResponseEntity<ApiResponse<PresignedUploadResponse, Void>> createProofFilePresignedUpload(
+            @Valid @RequestBody ProofFilePresignedUploadRequest request
+    ) {
+        PresignedUploadResponse response = recruitMemberService.createProofFilePresignedUpload(
+                request.fileName(),
+                request.contentType(),
+                request.fileSize()
+        );
+
+        return ResponseEntity.ok(ApiResponse.ok("증빙 파일 업로드 URL을 발급했습니다.", response));
+    }
+
     @PostMapping("/memo")
     public ResponseEntity<ApiResponse<Void, Void>> recruitMemberMemoAdd(
             @Valid @RequestBody RecruitMemberMemoRequest recruitMemberMemoRequest

src/main/java/inha/gdgoc/domain/recruit/member/service/RecruitMemberService.java

@@ -5,6 +5,9 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import inha.gdgoc.domain.resource.enums.S3KeyType;
+import inha.gdgoc.domain.resource.dto.response.PresignedUploadResponse;
+import inha.gdgoc.domain.resource.exception.ResourceErrorCode;
+import inha.gdgoc.domain.resource.exception.ResourceException;
 import inha.gdgoc.domain.resource.service.S3Service;
 import inha.gdgoc.domain.recruit.member.dto.request.ApplicationRequest;
 import inha.gdgoc.domain.recruit.member.dto.request.RecruitMemberMemoRequest;
@@ -36,6 +39,8 @@
 @RequiredArgsConstructor
 @Service
 public class RecruitMemberService {
+    private static final long MAX_PROOF_FILE_SIZE = 10 * 1024 * 1024;
+
     private final RecruitMemberRepository recruitMemberRepository;
     private final RecruitMemberMemoRepository recruitMemberMemoRepository;
     private final AnswerRepository answerRepository;
@@ -63,6 +68,7 @@ public void addRecruitMember(Map<String, Object> requestPayload, MultipartFile f
             String proofFileUrl = s3Service.getS3FileUrl(key);
             answers.put("proofFileUrl", proofFileUrl);
         }
+        normalizeProofFileUrl(answers);
 
         RecruitMember member = memberRequest
                 .toEntity(semesterCalculator.currentSemester(), majorNormalizer);
@@ -86,12 +92,30 @@ public void addRecruitMember(Map<String, Object> requestPayload, MultipartFile f
 
     private String uploadProofFile(MultipartFile file) {
         try {
-            return s3Service.upload(0L, S3KeyType.study, file);
+            return s3Service.upload(0L, S3KeyType.recruitMember, file);
         } catch (Exception e) {
             throw new RuntimeException("증빙 파일 업로드 중 오류가 발생했습니다.", e);
         }
     }
 
+    public PresignedUploadResponse createProofFilePresignedUpload(
+            String fileName,
+            String contentType,
+            Long fileSize
+    ) {
+        if (fileSize == null || fileSize > MAX_PROOF_FILE_SIZE) {
+            throw new ResourceException(ResourceErrorCode.INVALID_BIG_FILE);
+        }
+
+        S3Service.PresignedUpload presignedUpload = s3Service.createPresignedUpload(
+                0L,
+                S3KeyType.recruitMember,
+                fileName,
+                contentType
+        );
+        return new PresignedUploadResponse(presignedUpload.key(), presignedUpload.uploadUrl());
+    }
+
     @Transactional
     public void addRecruitMemberMemo(RecruitMemberMemoRequest recruitMemberMemoRequest) {
         String cleanPhone = normalizePhoneNumber(recruitMemberMemoRequest.getPhoneNumber());
@@ -187,6 +211,7 @@ private Map<String, Object> buildAnswersFromNumberedPayload(Map<String, Object>
         putIfPresent(answers, "gdgInterest", step6.get("gdgInterest"));
         putIfPresent(answers, "gdgWish", step6.get("gdgWish"));
         putIfPresent(answers, "gdgFeedback", step6.get("gdgFeedback"));
+        putIfPresent(answers, "proofFileUrl", step6.get("proofFileUrl"));
 
         return answers;
     }
@@ -213,7 +238,19 @@ private Map<String, Object> normalizeAnswers(Map<String, Object> rawAnswers) {
         putIfPresent(answers, "gdgInterest", rawAnswers.get("gdgInterest"));
         putIfPresent(answers, "gdgWish", rawAnswers.get("gdgWish"));
         putIfPresent(answers, "gdgFeedback", rawAnswers.get("gdgFeedback"));
+        putIfPresent(answers, "proofFileUrl", rawAnswers.get("proofFileUrl"));
         return answers;
     }
 
+    private void normalizeProofFileUrl(Map<String, Object> answers) {
+        Object proofFileUrl = answers.get("proofFileUrl");
+        if (!(proofFileUrl instanceof String fileUrl) || fileUrl.isBlank()) {
+            return;
+        }
+        if (fileUrl.startsWith("http://") || fileUrl.startsWith("https://")) {
+            return;
+        }
+        answers.put("proofFileUrl", s3Service.getS3FileUrl(fileUrl));
+    }
+
 }

src/main/java/inha/gdgoc/domain/resource/controller/ResourceController.java

@@ -2,13 +2,17 @@
 
 import static inha.gdgoc.domain.resource.controller.message.ResourceMessage.IMAGE_SAVE_SUCCESS;
 
+import inha.gdgoc.domain.resource.dto.request.PresignedUploadRequest;
+import inha.gdgoc.domain.resource.dto.response.PresignedUploadResponse;
 import inha.gdgoc.domain.resource.dto.response.S3ResultResponse;
 import inha.gdgoc.domain.resource.enums.S3KeyType;
 import inha.gdgoc.domain.resource.service.ResourceService;
 import inha.gdgoc.global.dto.response.ApiResponse;
+import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.Authentication;
+import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
@@ -31,4 +35,13 @@ public ResponseEntity<ApiResponse<S3ResultResponse, Void>> uploadImage(
         S3ResultResponse response = resourceService.uploadImage(authentication, file, s3key);
         return ResponseEntity.ok(ApiResponse.ok(IMAGE_SAVE_SUCCESS, response));
     }
+
+    @PostMapping("/presigned-upload")
+    public ResponseEntity<ApiResponse<PresignedUploadResponse, Void>> createPresignedUpload(
+        Authentication authentication,
+        @Valid @RequestBody PresignedUploadRequest request
+    ) {
+        PresignedUploadResponse response = resourceService.createPresignedUpload(authentication, request);
+        return ResponseEntity.ok(ApiResponse.ok("파일 업로드 URL을 발급했습니다.", response));
+    }
 }

src/main/java/inha/gdgoc/domain/resource/dto/request/PresignedUploadRequest.java

@@ -0,0 +1,14 @@
+package inha.gdgoc.domain.resource.dto.request;
+
+import inha.gdgoc.domain.resource.enums.S3KeyType;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.PositiveOrZero;
+
+public record PresignedUploadRequest(
+    @NotBlank String fileName,
+    @NotBlank String contentType,
+    @NotNull @PositiveOrZero Long fileSize,
+    @NotNull S3KeyType s3key
+) {
+}

src/main/java/inha/gdgoc/domain/resource/dto/response/PresignedUploadResponse.java

@@ -0,0 +1,7 @@
+package inha.gdgoc.domain.resource.dto.response;
+
+public record PresignedUploadResponse(
+    String key,
+    String uploadUrl
+) {
+}

src/main/java/inha/gdgoc/domain/resource/enums/S3KeyType.java

@@ -5,7 +5,9 @@
 @Getter
 public enum S3KeyType {
 
-    study("study");
+    study("study"),
+    recruitCore("recruit/core"),
+    recruitMember("recruit/member");
 
     private final String value;
 

src/main/java/inha/gdgoc/domain/resource/service/ResourceService.java

@@ -1,6 +1,8 @@
 package inha.gdgoc.domain.resource.service;
 
 import inha.gdgoc.domain.auth.service.AuthService;
+import inha.gdgoc.domain.resource.dto.request.PresignedUploadRequest;
+import inha.gdgoc.domain.resource.dto.response.PresignedUploadResponse;
 import inha.gdgoc.domain.resource.dto.response.S3ResultResponse;
 import inha.gdgoc.domain.resource.enums.S3KeyType;
 import inha.gdgoc.domain.resource.exception.ResourceErrorCode;
@@ -35,4 +37,23 @@ public S3ResultResponse uploadImage(Authentication authentication, MultipartFile
             throw new ResourceException(ResourceErrorCode.RESOURCE_UPLOAD_FAILED);
         }
     }
+
+    @Transactional(readOnly = true)
+    public PresignedUploadResponse createPresignedUpload(
+        Authentication authentication,
+        PresignedUploadRequest request
+    ) {
+        if (request.fileSize() > MAX_FILE_SIZE) {
+            throw new ResourceException(ResourceErrorCode.INVALID_BIG_FILE);
+        }
+
+        Long userId = authService.getAuthenticationUserId(authentication);
+        S3Service.PresignedUpload presignedUpload = s3Service.createPresignedUpload(
+            userId,
+            request.s3key(),
+            request.fileName(),
+            request.contentType()
+        );
+        return new PresignedUploadResponse(presignedUpload.key(), presignedUpload.uploadUrl());
+    }
 }

src/main/java/inha/gdgoc/domain/resource/service/S3Service.java

@@ -3,6 +3,7 @@
 import inha.gdgoc.domain.resource.enums.S3KeyType;
 import inha.gdgoc.global.config.s3.S3Properties;
 import java.io.IOException;
+import java.time.Duration;
 import java.util.UUID;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
@@ -11,17 +12,20 @@
 import software.amazon.awssdk.services.s3.S3Client;
 import software.amazon.awssdk.services.s3.model.GetUrlRequest;
 import software.amazon.awssdk.services.s3.model.PutObjectRequest;
+import software.amazon.awssdk.services.s3.presigner.S3Presigner;
+import software.amazon.awssdk.services.s3.presigner.model.PresignedPutObjectRequest;
+import software.amazon.awssdk.services.s3.presigner.model.PutObjectPresignRequest;
 
 @Service
 @RequiredArgsConstructor
 public class S3Service {
 
     private final S3Client s3Client;
+    private final S3Presigner s3Presigner;
     private final S3Properties s3Properties;
 
     public String upload(Long userId, S3KeyType s3key, MultipartFile file) throws IOException {
-        String fileName = UUID.randomUUID() + "-" + file.getOriginalFilename();
-        String key = "user/%d/%s/%s".formatted(userId, s3key.getValue(), fileName);
+        String key = buildKey(userId, s3key, file.getOriginalFilename());
 
         PutObjectRequest putReq = PutObjectRequest.builder()
             .bucket(s3Properties.getBucket())
@@ -33,9 +37,43 @@ public String upload(Long userId, S3KeyType s3key, MultipartFile file) throws IO
         return key;
     }
 
+    public PresignedUpload createPresignedUpload(
+        Long userId,
+        S3KeyType s3key,
+        String originalFileName,
+        String contentType
+    ) {
+        String safeContentType = contentType == null || contentType.isBlank()
+            ? "application/octet-stream"
+            : contentType;
+        String key = buildKey(userId, s3key, originalFileName);
+        PutObjectRequest putReq = PutObjectRequest.builder()
+            .bucket(s3Properties.getBucket())
+            .key(key)
+            .contentType(safeContentType)
+            .build();
+        PutObjectPresignRequest presignReq = PutObjectPresignRequest.builder()
+            .signatureDuration(Duration.ofMinutes(5))
+            .putObjectRequest(putReq)
+            .build();
+        PresignedPutObjectRequest presignedReq = s3Presigner.presignPutObject(presignReq);
+        return new PresignedUpload(key, presignedReq.url().toExternalForm());
+    }
+
     public String getS3FileUrl(String key) {
         return s3Client.utilities()
             .getUrl(GetUrlRequest.builder().bucket(s3Properties.getBucket()).key(key).build())
             .toExternalForm();
     }
+
+    private String buildKey(Long userId, S3KeyType s3key, String originalFileName) {
+        String safeFileName = originalFileName == null || originalFileName.isBlank()
+            ? "file"
+            : originalFileName.replaceAll("[\\\\/]", "_");
+        String fileName = UUID.randomUUID() + "-" + safeFileName;
+        return "user/%d/%s/%s".formatted(userId, s3key.getValue(), fileName);
+    }
+
+    public record PresignedUpload(String key, String uploadUrl) {
+    }
 }

src/main/java/inha/gdgoc/global/config/s3/S3Config.java

@@ -7,6 +7,7 @@
 import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
 import software.amazon.awssdk.regions.Region;
 import software.amazon.awssdk.services.s3.S3Client;
+import software.amazon.awssdk.services.s3.presigner.S3Presigner;
 
 @Configuration
 public class S3Config {
@@ -25,4 +26,9 @@ public AwsCredentialsProvider awsCredentialsProvider() {
   public S3Client s3Client(Region region, AwsCredentialsProvider provider) {
     return S3Client.builder().region(region).credentialsProvider(provider).build();
   }
+
+  @Bean
+  public S3Presigner s3Presigner(Region region, AwsCredentialsProvider provider) {
+    return S3Presigner.builder().region(region).credentialsProvider(provider).build();
+  }
 }