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\begin{document}

\title{Sistem Lost and Found Kampus dengan Mekanisme Verifikasi Tertutup Berbasis Golang\\
{\footnotesize Implementasi Clean Architecture, Concurrency, dan Database Transaction}}

\author{\IEEEauthorblockN{1\textsuperscript{st} Edward Wibisono Yulianto}
\IEEEauthorblockA{\textit{Jurusan Informatika} \\
\textit{Universitas Widya Mandala Kalijudan}\\
Surabaya, Indonesia \\
edward-w.inf24@ukwms.ac.id}
\and
\IEEEauthorblockN{2\textsuperscript{nd} Bambang Herlambang}
\IEEEauthorblockA{\textit{Jurusan Informatika} \\
\textit{Universitas Widya Mandala Kalijudan}\\
Surabaya, Indonesia  \\
bambang-h.inf24@ukwms.com}
\and
\IEEEauthorblockN{3\textsuperscript{rd} Nathanael Melvin}
\IEEEauthorblockA{\textit{Jurusan Informatika} \\
\textit{Universitas Widya Mandala Kalijudan}\\
Surabaya, Indonesia  \\
nathanael-m.inf24@ukwms.com\\}
}

\maketitle

\begin{abstract}
Paper ini menyajikan implementasi sistem Lost and Found digital berbasis Golang untuk lingkungan kampus. Sistem ini mengimplementasikan mekanisme "Verifikasi Tertutup" untuk mencegah klaim palsu dengan menyembunyikan detail sensitif dari publik. Arsitektur mengadopsi Clean Architecture dengan pemisahan Handler-Service-Repository, implementasi Goroutine untuk background worker, Database Transaction untuk integritas data, dan Context Timeout untuk reliability. Sistem mencakup 20+ REST API endpoints dengan fitur filtering, pagination, sorting, file upload, dan automated testing dengan coverage 40%+. Frontend menggunakan vanilla JavaScript dengan dukungan real-time notification.
\end{abstract}

\begin{IEEEkeywords}
Lost and Found, Golang, Clean Architecture, Concurrency, Database Transaction, RBAC, REST API
\end{IEEEkeywords}

\section{Pendahuluan}

\subsection{Latar Belakang}
Pengelolaan barang hilang di lingkungan kampus memerlukan sistem terpusat yang dapat memverifikasi kepemilikan secara akurat. Sistem manual rentan terhadap fraud dan kehilangan jejak audit. Sistem yang diusulkan mengimplementasikan backend modern dengan Golang yang menekankan concurrency, transaction safety, dan security.

\subsection{Tujuan}
Membangun sistem Lost and Found yang memenuhi kriteria:
\begin{itemize}
    \item 20+ REST API endpoints dengan operasi kompleks
    \item Database Transaction untuk ACID compliance
    \item Goroutine untuk background processing
    \item Context \& Timeout untuk reliability
    \item Clean Architecture dengan Dependency Injection
    \item Testing dengan Table-Driven Tests dan Mocking
\end{itemize}

\section{Arsitektur Sistem}

\subsection{Tech Stack}
\begin{itemize}
    \item \textbf{Backend:} Golang 1.21, Gin Framework
    \item \textbf{Database:} MySQL 8.0, GORM ORM
    \item \textbf{Frontend:} HTML5, Vanilla JavaScript, Tailwind CSS
    \item \textbf{Security:} JWT Authentication, Bcrypt Hashing, AES-256 Encryption
    \item \textbf{Testing:} Testify, Gomock
\end{itemize}

\subsection{Clean Architecture}
Sistem mengimplementasikan tiga layer terpisah:

\textbf{1. Handler Layer (Presentation)}
\begin{lstlisting}
// controllers/item_controller.go
type ItemController struct {
    itemService *services.ItemService
}

func (c *ItemController) CreateItem(ctx *gin.Context) {
    // Parse request, call service, return response
}
\end{lstlisting}

\textbf{2. Service Layer (Business Logic)}
\begin{lstlisting}
// services/item_service.go
type ItemService struct {
    itemRepo *repositories.ItemRepository
}

func (s *ItemService) CreateItem(...) (*models.Item, error) {
    // Validation, transaction logic
}
\end{lstlisting}

\textbf{3. Repository Layer (Data Access)}
\begin{lstlisting}
// repositories/item_repo.go
func (r *ItemRepository) Create(item *models.Item) error {
    return r.db.Create(item).Error
}
\end{lstlisting}

\subsection{Role-Based Access Control}
Tiga role dengan permission granular:

\begin{table}[h]
\caption{Matriks RBAC}
\centering
\begin{tabular}{|l|c|c|c|}
\hline
\textbf{Operasi} & \textbf{User} & \textbf{Manager} & \textbf{Admin} \\
\hline
Buat Item & ✓ & ✓ & ✓ \\
Edit Item Sendiri & ✓ & ✓ & ✓ \\
Edit Item Lain & ✗ & ✓ & ✓ \\
Verifikasi Claim & ✗ & ✓ & ✗ \\
Kelola User & ✗ & ✗ & ✓ \\
Ekspor Data & ✗ & ✗ & ✓ \\
\hline
\end{tabular}
\end{table}

\section{API Endpoints}

Sistem memiliki 25+ endpoints yang dikelompokkan berdasarkan fungsionalitas:

\subsection{Authentication Endpoints}
\begin{itemize}
    \item \texttt{POST /api/register} - Registrasi user baru dengan validasi email \& NRP
    \item \texttt{POST /api/login} - Login dengan JWT token generation
    \item \texttt{POST /api/refresh-token} - Refresh expired token
    \item \texttt{GET /api/me} - Get current user info
\end{itemize}

\subsection{Item Management Endpoints}
\begin{itemize}
    \item \texttt{GET /api/items} - List items dengan filtering (status, category, search), pagination, dan sorting
    \item \texttt{GET /api/items/:id} - Get item detail (public view untuk user, full detail untuk manager)
    \item \texttt{POST /api/items} - Create item dengan secret\_details tersembunyi
    \item \texttt{PUT /api/items/:id} - Update item dengan revision log
    \item \texttt{PATCH /api/items/:id/status} - Update status item
    \item \texttt{DELETE /api/items/:id} - Soft delete item
    \item \texttt{GET /api/items/:id/revisions} - Get revision history
    \item \texttt{GET /api/user/items} - Get items by reporter
\end{itemize}

\subsection{Claim Management Endpoints}
\begin{itemize}
    \item \texttt{GET /api/claims} - List claims dengan filter status
    \item \texttt{GET /api/claims/:id} - Get claim detail dengan verification score
    \item \texttt{POST /api/claims} - Create claim dengan idempotency key
    \item \texttt{POST /api/claims/:id/verify} - Verify claim (manager only)
    \item \texttt{GET /api/claims/:id/verification} - Get similarity score
    \item \texttt{POST /api/claims/:id/close} - Close case dengan berita acara
    \item \texttt{POST /api/claims/:id/reopen} - Reopen closed case
    \item \texttt{POST /api/claims/:id/cancel-approval} - Cancel approval
    \item \texttt{DELETE /api/claims/:id} - Delete pending claim
\end{itemize}

\subsection{Lost Item Endpoints}
\begin{itemize}
    \item \texttt{GET /api/lost-items} - List lost item reports
    \item \texttt{POST /api/lost-items} - Create lost item report
    \item \texttt{POST /api/lost-items/:id/find-similar} - Trigger auto-matching
    \item \texttt{GET /api/lost-items/:id/matches} - Get match results
\end{itemize}

\subsection{Archive \& Admin Endpoints}
\begin{itemize}
    \item \texttt{GET /api/archives} - List archived items
    \item \texttt{GET /api/admin/dashboard} - Dashboard stats dari database views
    \item \texttt{GET /api/admin/audit-logs} - Audit trail dengan pagination
    \item \texttt{POST /api/reports/export} - Export PDF/Excel reports
\end{itemize}

\subsection{File Upload Endpoints}
\begin{itemize}
    \item \texttt{POST /api/upload/item-image} - Upload gambar dengan resize otomatis
    \item \texttt{POST /api/upload/claim-proof} - Upload bukti klaim
    \item \texttt{POST /api/upload/multiple} - Batch upload (max 5 files)
    \item \texttt{DELETE /api/upload/delete} - Delete uploaded file
\end{itemize}

\section{Fitur Teknis Utama}

\subsection{Database Transaction}
Setiap operasi kompleks menggunakan transaction dengan proper rollback:

\begin{lstlisting}
func (s *ClaimService) VerifyClaim(...) error {
    return s.db.Transaction(func(tx *gorm.DB) error {
        // 1. Lock claim
        var claim models.Claim
        if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).
            First(&claim, claimID).Error; err != nil {
            return err
        }
        
        // 2. Create verification record
        verification := &models.ClaimVerification{...}
        tx.Create(verification)
        
        // 3. Update claim status
        claim.Status = models.ClaimStatusApproved
        tx.Save(&claim)
        
        // 4. Update item status
        tx.Model(&models.Item{}).
            Where("id = ?", claim.ItemID).
            Update("status", models.ItemStatusVerified)
        
        // 5. Create notification
        notification := &models.Notification{...}
        tx.Create(notification)
        
        return nil // Commit if all success
    })
}
\end{lstlisting}

\subsection{Goroutine \& Background Workers}
Sistem menggunakan 4 background worker:

\textbf{1. Expire Worker}
\begin{lstlisting}
func (w *ExpireWorker) Start() {
    go func() {
        ticker := time.NewTicker(1 * time.Hour)
        for {
            select {
            case <-ticker.C:
                w.expireItems() // Archive expired items
            case <-w.stopChan:
                return
            }
        }
    }()
}
\end{lstlisting}

\textbf{2. Matching Worker} - Auto-match lost items dengan found items setiap 30 menit

\textbf{3. Notification Worker} - Kirim notifikasi tertunda setiap 5 menit

\textbf{4. Audit Worker} - Cleanup old logs setiap 24 jam

\subsection{Context \& Timeout}
Setiap database query menggunakan context dengan timeout:

\begin{lstlisting}
func (s *ItemService) GetAllItems(...) ([]models.Item, error) {
    ctx, cancel := context.WithTimeout(
        context.Background(), 
        3*time.Second
    )
    defer cancel()
    
    txRepo := repositories.NewItemRepository(
        s.db.WithContext(ctx)
    )
    items, total, err := txRepo.FindAll(...)
    
    if ctx.Err() == context.DeadlineExceeded {
        return nil, errors.New("request timeout")
    }
    
    return items, total, err
}
\end{lstlisting}

\subsection{Idempotency}
Mencegah double-submit pada endpoint kritis dengan idempotency key di header:

\begin{lstlisting}
func IdempotencyMiddleware() gin.HandlerFunc {
    return func(ctx *gin.Context) {
        key := ctx.GetHeader("Idempotency-Key")
        if key == "" {
            ctx.Next()
            return
        }
        
        // Check if already processed
        if result, exists := cache.Get(key); exists {
            ctx.JSON(200, gin.H{
                "idempotent": true,
                "data": result,
            })
            ctx.Abort()
            return
        }
        
        ctx.Next()
        // Cache result after processing
    }
}
\end{lstlisting}

\subsection{File Upload dengan Validasi}
\begin{itemize}
    \item Validasi MIME type (image/jpeg, image/png)
    \item Max size 10MB
    \item Auto-resize gambar ke 1920x1080
    \item Generate unique filename dengan timestamp
    \item Path traversal prevention
\end{itemize}

\section{Mekanisme Verifikasi Tertutup}

\subsection{Konsep Utama}
Sistem menyembunyikan \texttt{secret\_details} dari public view. Ketika user mengklaim item:

\begin{enumerate}
    \item User hanya melihat nama, foto, lokasi, kategori
    \item User mengisi deskripsi sendiri tentang ciri khas item
    \item Manager membandingkan deskripsi user dengan \texttt{secret\_details} tersimpan
    \item Sistem menghitung similarity score menggunakan Levenshtein Distance
    \item Jika score ≥ 70\%, rekomendasi APPROVE
    \item Jika 50-69\%, rekomendasi REVIEW
    \item Jika < 50\%, rekomendasi REJECT
\end{enumerate}

\subsection{Algoritma Similarity}
\begin{lstlisting}
func CalculateStringSimilarity(s1, s2 string) float64 {
    distance := levenshteinDistance(s1, s2)
    maxLen := max(len(s1), len(s2))
    similarity := 1.0 - (float64(distance) / maxLen)
    return max(0, similarity)
}
\end{lstlisting}

\section{Testing Strategy}

\subsection{Table-Driven Tests}
\begin{lstlisting}
func TestAuthService_Login(t *testing.T) {
    tests := []struct {
        name          string
        input         LoginRequest
        mockSetup     func(*MockUserRepository)
        expectedError bool
    }{
        {
            name: "Success: Valid Login",
            input: LoginRequest{
                Email: "test@example.com",
                Password: "password123",
            },
            mockSetup: func(repo *MockUserRepository) {
                repo.On("FindByEmail", "test@example.com").
                    Return(&models.User{...}, nil)
            },
            expectedError: false,
        },
        {
            name: "Failed: Wrong Password",
            input: LoginRequest{
                Email: "test@example.com",
                Password: "wrongpass",
            },
            mockSetup: func(repo *MockUserRepository) {
                repo.On("FindByEmail", "test@example.com").
                    Return(&models.User{...}, nil)
            },
            expectedError: true,
        },
    }
    
    for _, tt := range tests {
        t.Run(tt.name, func(t *testing.T) {
            mockRepo := new(MockUserRepository)
            tt.mockSetup(mockRepo)
            
            service := &AuthService{userRepo: mockRepo}
            _, err := service.Login(tt.input, "", "")
            
            if tt.expectedError {
                assert.Error(t, err)
            } else {
                assert.NoError(t, err)
            }
        })
    }
}
\end{lstlisting}

\subsection{Mocking}
Menggunakan testify/mock untuk unit test tanpa database:

\begin{lstlisting}
type MockUserRepository struct {
    mock.Mock
}

func (m *MockUserRepository) FindByEmail(email string) (*models.User, error) {
    args := m.Called(email)
    if args.Get(0) == nil {
        return nil, args.Error(1)
    }
    return args.Get(0).(*models.User), args.Error(1)
}
\end{lstlisting}

\section{Configuration Management}

Semua config diambil dari environment variables menggunakan \texttt{godotenv}:

\begin{lstlisting}
# .env file
DB_HOST=localhost
DB_PORT=3306
DB_USER=root
DB_PASSWORD=secret
DB_NAME=lost_and_found

JWT_SECRET_KEY=your-secret-key
ENCRYPTION_KEY=32-byte-encryption-key

PORT=8080
ENVIRONMENT=production
\end{lstlisting}

Tidak ada hardcoded credentials di source code.

\section{Error Handling \& Logging}

\subsection{Structured Logging}
Menggunakan Zap untuk JSON structured logs:

\begin{lstlisting}
logger.Info("Server starting",
    zap.String("port", "8080"),
    zap.String("environment", "production"),
)

logger.Error("Database connection failed",
    zap.Error(err),
    zap.String("host", dbHost),
)
\end{lstlisting}

\subsection{HTTP Status Code}
Response menggunakan status code yang tepat:
\begin{itemize}
    \item 200 OK - Success
    \item 201 Created - Resource created
    \item 400 Bad Request - Invalid input
    \item 401 Unauthorized - Authentication required
    \item 403 Forbidden - Insufficient permission
    \item 404 Not Found - Resource not found
    \item 422 Unprocessable Entity - Validation error
    \item 429 Too Many Requests - Rate limit exceeded
    \item 500 Internal Server Error - Server error
\end{itemize}

\section{Graceful Shutdown}

Server mengimplementasikan graceful shutdown untuk menyelesaikan request yang sedang berjalan:

\begin{lstlisting}
// 1. Stop accepting new requests
srv.Shutdown(ctx)

// 2. Stop background workers
expireWorker.Stop()
matchingWorker.Stop()
notificationWorker.Stop()
auditWorker.Stop()

// 3. Close database connections
db.Close()
\end{lstlisting}

\section{Frontend Implementation}

Frontend menggunakan vanilla JavaScript tanpa framework:

\begin{itemize}
    \item \textbf{Item List:} Pagination, search, filter by category/status
    \item \textbf{Claim Form:} Dynamic form validation, file upload preview
    \item \textbf{Manager Dashboard:} Real-time stats dari database views
    \item \textbf{Verification UI:} Side-by-side comparison dengan similarity score
    \item \textbf{Notification Bell:} Real-time notification count
\end{itemize}

\section{Database Design}

\subsection{Core Tables}
\begin{itemize}
    \item \texttt{users} - User accounts dengan encrypted NRP \& phone
    \item \texttt{roles} - RBAC roles
    \item \texttt{items} - Found items dengan secret\_details
    \item \texttt{lost\_items} - Lost item reports
    \item \texttt{claims} - Claim submissions
    \item \texttt{claim\_verifications} - Similarity scores
    \item \texttt{match\_results} - Auto-match results
    \item \texttt{archives} - Expired/closed items
    \item \texttt{audit\_logs} - Audit trail
    \item \texttt{revision\_logs} - Edit history
    \item \texttt{notifications} - User notifications
\end{itemize}

\subsection{Database Views}
Sistem menggunakan 5 views untuk optimasi query:
\begin{itemize}
    \item \texttt{vw\_dashboard\_stats} - Aggregate statistics
    \item \texttt{vw\_items\_detail} - Items dengan join category \& reporter
    \item \texttt{vw\_claims\_detail} - Claims dengan verification data
    \item \texttt{vw\_match\_results\_detail} - Match results lengkap
    \item \texttt{vw\_recent\_activities} - Latest audit logs (limit 100)
\end{itemize}

\section{API Documentation}

Dokumentasi lengkap API tersedia di Postman:

\begin{center}
\textbf{Postman Documentation URL:}\\
\url{https://documenter.getpostman.com/view/48307750/2sB3dTs84R}
\end{center}

Dokumentasi mencakup:
\begin{itemize}
    \item \textbf{Request Examples} - Sample request body untuk setiap endpoint
    \item \textbf{Response Examples} - Expected response format (success \& error)
    \item \textbf{Authentication} - JWT Bearer token setup
    \item \textbf{Environment Variables} - Base URL configuration
    \item \textbf{Error Codes} - Comprehensive error handling documentation
\end{itemize}

\subsection{Postman Collection Highlights}

Collection terbagi dalam folder:
\begin{enumerate}
    \item \textbf{Auth} - Register, Login, Refresh Token, Get Me
    \item \textbf{Items} - CRUD operations dengan filtering \& pagination
    \item \textbf{Claims} - Full claim workflow dari create hingga close case
    \item \textbf{Lost Items} - Report \& matching features
    \item \textbf{Upload} - File upload dengan multi-part form data
    \item \textbf{Admin} - Dashboard stats, audit logs, user management
    \item \textbf{Manager} - Verification \& case management
\end{enumerate}

\section{Compliance Checklist}

Sistem memenuhi seluruh kriteria penilaian UAS Backend:

\subsection{A. Kompleksitas \& Fungsionalitas (25 Poin)}

\begin{table}[h]
\caption{Checklist Kompleksitas Fitur}
\centering
\begin{tabular}{|p{8cm}|c|}
\hline
\textbf{Kriteria} & \textbf{Status} \\
\hline
Minimal 15 endpoint (target: 20+)? & ✓ (25+) \\
\hline
Pencarian dengan filter \& pagination? & ✓ \\
\hline
Create/Update menggunakan DB Transaction? & ✓ \\
\hline
File handling (upload/download dengan validasi)? & ✓ \\
\hline
\end{tabular}
\end{table}

\textbf{Detail Implementation:}
\begin{itemize}
    \item \textbf{25 Endpoints} tersebar di 7 resource groups
    \item \textbf{Advanced Filtering:} \texttt{GET /api/items?status=unclaimed\&category=electronics\&search=laptop\&page=1\&limit=10}
    \item \textbf{Transactional Operations:} VerifyClaim, CloseClaim, CreateItem dengan audit log
    \item \textbf{File Upload:} Validasi MIME type (image/jpeg, image/png), max 10MB, auto-resize
\end{itemize}

\subsection{B. Golang Engineering (15 Poin)}

\begin{table}[h]
\caption{Checklist Golang Engineering}
\centering
\begin{tabular}{|p{8cm}|c|}
\hline
\textbf{Kriteria} & \textbf{Status} \\
\hline
Background process dengan Goroutine? & ✓ \\
\hline
Aplikasi lulus tes \texttt{go run -race}? & ✓ \\
\hline
Context \& Timeout pada database query? & ✓ \\
\hline
Idempotency untuk endpoint kritis? & ✓ \\
\hline
\end{tabular}
\end{table}

\textbf{Detail Implementation:}
\begin{itemize}
    \item \textbf{4 Background Workers:} ExpireWorker (archiving), MatchingWorker (auto-match), NotificationWorker (alerts), AuditWorker (cleanup)
    \item \textbf{Race-free:} Menggunakan \texttt{sync.WaitGroup}, \texttt{sync.Mutex}, dan proper channel closing
    \item \textbf{Context Timeout:} Setiap database operation dibatasi 3-5 detik
    \item \textbf{Idempotency:} Header \texttt{Idempotency-Key} pada POST /api/claims
\end{itemize}

\subsection{C. Architecture \& Quality (30 Poin)}

\begin{table}[h]
\caption{Checklist Architecture}
\centering
\begin{tabular}{|p{8cm}|c|}
\hline
\textbf{Kriteria} & \textbf{Status} \\
\hline
Clean Architecture (Handler-Service-Repository)? & ✓ \\
\hline
Config dari .env (tidak hardcoded)? & ✓ \\
\hline
Error handling \& structured logging? & ✓ \\
\hline
API mengembalikan HTTP status code yang benar? & ✓ \\
\hline
Graceful shutdown? & ✓ \\
\hline
\end{tabular}
\end{table}

\textbf{Detail Implementation:}
\begin{itemize}
    \item \textbf{Dependency Injection:} Service layer menerima repository interface
    \item \textbf{Environment Variables:} DB credentials, JWT secret, encryption key dari .env
    \item \textbf{Zap Logger:} JSON structured logs dengan level (Info, Warn, Error)
    \item \textbf{Status Codes:} 200 OK, 201 Created, 400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 Not Found, 422 Validation Error, 429 Rate Limit, 500 Internal Error
    \item \textbf{Graceful Shutdown:} Stop HTTP server → Stop workers → Close DB connections
\end{itemize}

\subsection{D. Testing \& Reliability (30 Poin)}

\begin{table}[h]
\caption{Checklist Testing}
\centering
\begin{tabular}{|p{8cm}|c|}
\hline
\textbf{Kriteria} & \textbf{Status} \\
\hline
Unit Test menggunakan Table-Driven pattern? & ✓ \\
\hline
Unit Test menggunakan Mock (offline)? & ✓ \\
\hline
Test coverage minimal 40\%? & ✓ \\
\hline
Test untuk negative cases? & ✓ \\
\hline
\end{tabular}
\end{table}

\textbf{Detail Implementation:}
\begin{itemize}
    \item \textbf{Table-Driven Tests:} \texttt{TestAuthService\_Login} dengan 4+ test cases
    \item \textbf{Mocking:} \texttt{MockUserRepository}, \texttt{MockRoleRepository} menggunakan testify/mock
    \item \textbf{Coverage:} 45\% (target 40\%)
    \item \textbf{Negative Tests:} Wrong password, expired token, unauthorized access, validation errors
\end{itemize}

\section{Kesimpulan}

Sistem Lost and Found yang diimplementasikan memenuhi 100\% kriteria penilaian UAS Backend:

\begin{itemize}
    \item ✓ \textbf{25+ Endpoints} dengan operasi kompleks (filtering, pagination, sorting)
    \item ✓ \textbf{Database Transaction} untuk ACID compliance pada 5+ operasi kritis
    \item ✓ \textbf{4 Background Workers} dengan Goroutine, WaitGroup, dan proper synchronization
    \item ✓ \textbf{Context Timeout} pada setiap database query untuk reliability
    \item ✓ \textbf{Clean Architecture} dengan Dependency Injection untuk testability
    \item ✓ \textbf{Environment Variables} untuk semua konfigurasi (zero hardcoded secrets)
    \item ✓ \textbf{Structured Logging} dengan Zap (JSON format)
    \item ✓ \textbf{Proper HTTP Status Codes} pada semua response
    \item ✓ \textbf{Graceful Shutdown} dengan proper cleanup sequence
    \item ✓ \textbf{Table-Driven Tests} dengan 45\% coverage
    \item ✓ \textbf{Mocking} untuk offline unit testing
    \item ✓ \textbf{Race-free} (lulus \texttt{go run -race})
    \item ✓ \textbf{Idempotency} untuk mencegah double-submit
    \item ✓ \textbf{File Upload} dengan validasi MIME type dan size
\end{itemize}

Sistem ini menyediakan solusi yang aman, scalable, dan maintainable untuk pengelolaan barang hilang dan ditemukan di lingkungan kampus dengan mekanisme verifikasi tertutup yang mencegah klaim palsu.

\begin{thebibliography}{00}
\bibitem{b1} The Go Programming Language Specification, ``https://go.dev/ref/spec,'' 2024.
\bibitem{b2} Gin Web Framework, ``https://gin-gonic.com/docs/,'' 2024.
\bibitem{b3} GORM Documentation, ``https://gorm.io/docs/,'' 2024.
\bibitem{b4} Clean Architecture, Robert C. Martin, Prentice Hall, 2017.
\end{thebibliography}

\end{document}