itchan

README

Itchan Imageboard

A modern, high-performance imageboard built with Go, featuring a clean three-layer architecture, advanced authentication, and comprehensive rate limiting. Designed for privacy-conscious communities with domain-based board access control.

Table of Contents

• Features
• Architecture
• Tech Stack
• Getting Started
  • Prerequisites
  • Quick Start with Docker
  • Local Development
• Project Structure
• Backend Architecture
• Database Schema
• Configuration
• API Endpoints
• Frontend
• Testing
• Security Features
• Deployment
• Monitoring
• CI/CD
• Contributing
• License

Features

Core Functionality

• Boards & Threads: Create boards with custom names, organize discussions in threads
• Messages & Replies: Post messages with cross-thread reply support
• File Attachments: Upload images (JPEG, PNG, GIF) and videos (MP4, WebM, OGG) with automatic thumbnail generation
• Attachments-Only Messages: Post messages with only attachments (text is optional)
• Markdown Support: Rich text formatting using a custom markdown parser
• Thread Bumping: Automatic bump-to-top with configurable bump limits
• Pinned Threads: Pin important threads to the top of boards
• Pagination: Efficient board browsing with configurable threads per page
• Disable Media Mode: Cookie-based toggle to replace all images and videos with text placeholders

Authentication & Authorization

• User Registration: Email-based registration with confirmation codes
• Invite System: Registered users can generate invite codes to bring in friends without corporate email
• JWT Authentication: Secure, stateless authentication using JWT tokens
• Dual Auth Methods: Cookie-based (browsers) and Bearer token (API/mobile clients) support
• Admin Roles: Special privileges for board and content moderation
• User Blacklist: Admin-managed user blacklist with cached validation for banned users
• Board Permissions: Domain-based access control (restrict boards to specific email domains)
• CSRF Protection: Token-based CSRF protection for state-changing requests

Performance & Security

• Nginx Reverse Proxy: TLS termination, HTTP/2, connection limits, slowloris protection
• Two-Layer Rate Limiting: Nginx (per-IP, connection limits) + Go (per-user, token bucket)
• Media Sanitization: Automatic EXIF/metadata stripping from images and videos using ffmpeg
• Email Encryption: AES-256-GCM encryption of email addresses at the application level
• Database Partitioning: Automatic table partitioning by board for optimal performance
• Materialized Views: Fast board previews with configurable refresh intervals
• Security Headers: HSTS, CSP, X-Frame-Options, X-Content-Type-Options
• Gzip Compression: Automatic response compression
• CORS Support: Configured for secure cross-origin requests
• Graceful Shutdown: Proper cleanup and connection handling

Developer Experience

• Clean Architecture: Three-layer backend (Storage → Service → Handler)
• Comprehensive Testing: Unit and integration tests for all layers
• Docker Deployment: Full containerization with Docker Compose
• Type Safety: Strong domain types and validation
• Middleware Chain: Composable authentication, authorization, and rate limiting

Architecture

    Web Browsers   Mobile Apps    API Clients
    (Cookies)      (Bearer)       (Bearer)
        │              │              │
        └──────────────┼──────────────┘
                       ▼
┌─────────────────────────────────────────────────────────────┐
│                      Docker Compose                          │
├──────────────────────────────────────────────────────────────┤
│   Nginx (Reverse Proxy)                                      │
│   TLS termination, rate limiting, HTTP/2                     │
│   Ports 80/443                                               │
├──────────────┬──────────────────────┬──────────────────────┤
│   Frontend   │   Backend API        │   PostgreSQL 17.6    │
│   (Go HTML)  │   (REST Service)     │   (Partitioned DB)   │
│   Port 8081  │   Port 8080          │      Port 5432       │
│   (internal) │   (internal)         │      (internal)      │
└──────────────┴──────────────────────┴──────────────────────┘

Backend Layers:
  Handler    ← HTTP routing, JSON I/O, validation
     ↓
  Service    ← Business logic, authentication, file processing
     ↓
  Storage    ← PostgreSQL operations, partitioning, queries

Shared Modules:
  • domain/       - Domain types and models
  • middleware/   - Auth, rate limiting, board access control
  • config/       - Configuration management
  • jwt/          - JWT token handling
  • validation/   - Input validation and file handling

Tech Stack

• Backend: Go 1.24+ (frontend-agnostic JSON REST API)
• Frontend: Go templates (html/template) - replaceable with any client
• Database: PostgreSQL 17.6 with partitioning
• Reverse Proxy: Nginx (TLS termination, rate limiting, HTTP/2)
• Router: Chi (go-chi/chi)
• Auth: JWT (golang-jwt/jwt) with dual-mode support (Cookie + Bearer)
• TLS: Let's Encrypt (automatic renewal via certbot)
• Markdown: Custom parser
• Media Processing: ffmpeg (for metadata sanitization)
• Monitoring: Prometheus + Grafana (optional)
• Container: Docker & Docker Compose
• CI/CD: GitHub Actions
• Email: SMTP support for confirmations

Getting Started

Prerequisites

• Docker 20.10+ and Docker Compose 2.0+
• Go 1.24+ (for local development)
• PostgreSQL 17.6+ (if running without Docker)
• ffmpeg (for media sanitization - automatically included in Docker image)

Production Deployment

See SETUP.md for full production setup guide with HTTPS and nginx.

git clone https://github.com/itchan-dev/itchan.git
cd itchan
chmod +x scripts/*.sh
./scripts/setup.sh yourdomain.com your-email@example.com
# Configure email in config/private.yaml
make deploy

Quick Start (Development)

For local development without nginx/HTTPS:

git clone https://github.com/itchan-dev/itchan.git
cd itchan
docker-compose up --build

# Frontend UI: http://localhost:8081
# Backend API: http://localhost:8080/v1

The database will be automatically initialized with the schema from backend/internal/storage/pg/migrations/init.sql.

Local Development

For development without Docker:

# 1. Start PostgreSQL (adjust connection settings in config/private.yaml)
# Make sure PostgreSQL is running on localhost:5432

# 2. Run database migrations
psql -U itchan -d itchan -f backend/internal/storage/pg/migrations/init.sql

# 3. Configure your environment
cp config/private.yaml.example config/private.yaml
# Edit config/private.yaml with your database and email settings

# 4. Start the backend API
cd backend
go run cmd/itchan-api/main.go -config_folder ../config

# 5. In a new terminal, start the frontend
cd frontend
go run cmd/frontend/main.go -config_folder ../config

Project Structure

itchan/
├── backend/                    # Backend API service
│   ├── cmd/
│   │   ├── itchan-api/        # Main entry point
│   │   │   └── main.go
│   │   └── tools/             # CLI utilities
│   │       └── generate-encryption-key/  # Generate AES-256 encryption key
│   ├── internal/
│   │   ├── handler/           # HTTP handlers (REST endpoints)
│   │   │   ├── auth.go        # Register, login, logout
│   │   │   ├── blacklist.go   # User blacklist management
│   │   │   ├── board.go       # Board CRUD operations
│   │   │   ├── handler.go     # Handler dependencies
│   │   │   ├── health.go      # Health and readiness probes
│   │   │   ├── helpers.go     # Shared handler helpers
│   │   │   ├── invite.go      # Invite code management
│   │   │   ├── message.go     # Message posting and retrieval
│   │   │   ├── thread.go      # Thread operations
│   │   │   └── user_activity.go # User activity tracking
│   │   ├── service/           # Business logic layer
│   │   │   ├── auth.go        # Authentication logic (incl. invites)
│   │   │   ├── board.go       # Board management
│   │   │   ├── gc.go          # Orphaned media cleanup
│   │   │   ├── media_storage.go # File storage service
│   │   │   ├── message.go     # Message processing
│   │   │   ├── thread.go      # Thread management
│   │   │   ├── user_activity.go # User activity tracking
│   │   │   └── utils/         # Service utilities
│   │   │       └── sanitize.go # Media sanitization (EXIF/metadata stripping)
│   │   ├── storage/           # Data access layer
│   │   │   ├── pg/            # PostgreSQL implementation
│   │   │   │   ├── auth.go    # User storage operations
│   │   │   │   ├── blacklist.go # User blacklist operations
│   │   │   │   ├── board.go   # Board storage
│   │   │   │   ├── board_enrichment.go # Board data enrichment
│   │   │   │   ├── board_view.go  # Materialized view management
│   │   │   │   ├── message.go # Message storage
│   │   │   │   ├── message_enrichment.go # Message data enrichment
│   │   │   │   ├── pg.go      # DB connection & partitioning
│   │   │   │   ├── thread.go  # Thread storage
│   │   │   │   ├── user_activity.go # User activity storage
│   │   │   │   ├── migrations/init.sql  # Database schema
│   │   │   │   └── templates/ # SQL templates for partitioning & views
│   │   │   └── fs/            # File system storage
│   │   │       └── fs.go      # File upload/download
│   │   ├── utils/             # Backend utilities
│   │   │   ├── utils.go       # Helper functions
│   │   │   └── email/         # Email sending service
│   │   ├── router/            # Route configuration
│   │   │   └── router.go      # All API routes and middleware
│   │   └── setup/             # Dependency injection
│   │       └── setup.go
│   └── Dockerfile
│
├── frontend/                   # Frontend UI service
│   ├── cmd/frontend/          # Main entry point
│   │   └── main.go
│   ├── internal/
│   │   ├── handler/           # HTTP handlers for pages
│   │   │   ├── account.go     # Account management page
│   │   │   ├── auth.go        # Login/register pages
│   │   │   ├── blacklist.go   # Blacklist management page
│   │   │   ├── board.go       # Board view
│   │   │   ├── faq.go         # FAQ page
│   │   │   ├── handler.go     # Handler dependencies
│   │   │   ├── helpers.go     # Shared handler helpers
│   │   │   ├── index.go       # Homepage
│   │   │   ├── invites.go     # Invite management page
│   │   │   ├── legal.go       # Legal pages (terms, privacy, contacts)
│   │   │   ├── message.go     # Message actions
│   │   │   ├── render.go      # Template rendering
│   │   │   ├── settings.go    # User settings
│   │   │   └── thread.go      # Thread view
│   │   ├── apiclient/         # Backend API client
│   │   │   ├── apiclient.go
│   │   │   ├── auth.go
│   │   │   ├── blacklist.go
│   │   │   ├── board.go
│   │   │   ├── invites.go
│   │   │   ├── message.go
│   │   │   ├── thread.go
│   │   │   └── user_activity.go
│   │   ├── domain/            # Frontend domain models
│   │   │   ├── board.go
│   │   │   ├── common.go      # Common template data
│   │   │   ├── message.go
│   │   │   ├── pages.go       # Page-specific data structs
│   │   │   ├── partials.go    # Partial-specific data structs
│   │   │   └── thread.go
│   │   ├── markdown/          # Markdown processing
│   │   │   ├── parser.go      # Custom parser with block/inline rules
│   │   │   └── trie.go        # Trie for fast marker matching
│   │   ├── middleware/        # Frontend middleware
│   │   │   ├── auth.go        # Authentication forwarding
│   │   │   └── csrf.go        # CSRF token handling
│   │   ├── router/            # Route configuration
│   │   │   └── router.go
│   │   └── setup/             # Dependency setup
│   │       └── setup.go
│   ├── templates/             # HTML templates
│   │   ├── base.html          # Base layout
│   │   ├── index.html         # Board list
│   │   ├── board.html         # Board view
│   │   ├── thread.html        # Thread view
│   │   ├── login.html         # Login page
│   │   ├── register.html      # Registration page
│   │   ├── register_invite.html # Invite-based registration
│   │   ├── check_confirmation_code.html # Email confirmation
│   │   ├── account.html       # Account management
│   │   ├── admin.html         # Admin panel
│   │   ├── invites.html       # Invite management
│   │   ├── faq.html           # FAQ and rules
│   │   ├── about.html         # About page
│   │   ├── contacts.html      # Contact information
│   │   ├── privacy.html       # Privacy policy
│   │   ├── terms.html         # Terms of service
│   │   └── partials.html      # Reusable components
│   ├── static/                # Static assets
│   │   ├── css/style.css
│   │   ├── js/main.js
│   │   └── favicon.ico
│   └── Dockerfile
│
├── shared/                     # Shared packages
│   ├── api/                   # API request/response types
│   ├── blacklist/             # Blacklist caching
│   ├── config/                # Configuration management
│   ├── crypto/                # Email encryption (AES-256-GCM)
│   ├── csrf/                  # CSRF token protection
│   ├── domain/                # Domain models
│   │   ├── attachments.go     # File attachment models
│   │   ├── auth.go            # User, credentials
│   │   ├── board.go           # Board models
│   │   ├── helpers.go         # Domain helper functions
│   │   ├── message.go         # Message models
│   │   ├── thread.go          # Thread models
│   │   └── types.go           # Custom types and validation
│   ├── errors/                # Error types
│   ├── jwt/                   # JWT utilities
│   ├── logger/                # Structured logging
│   ├── middleware/            # HTTP middleware
│   │   ├── auth.go            # JWT authentication
│   │   ├── security_headers.go # Security headers (HSTS, CSP, etc.)
│   │   ├── board_access/      # Board permission check
│   │   ├── metrics/           # Prometheus metrics
│   │   └── ratelimiter/       # Rate limiting
│   ├── storage/               # Storage interfaces
│   ├── utils/                 # Utility functions
│   │   ├── crypto.go          # Hashing utilities
│   │   └── web.go             # HTTP helpers
│   └── validation/            # Input validation
│       ├── attachment.go      # File validation
│       ├── multipart.go       # Multipart form handling
│       └── errors.go
│
├── nginx/                      # Reverse proxy
│   ├── nginx.conf             # Nginx configuration
│   ├── nginx.conf.explained   # Line-by-line explanation
│   ├── certs/                 # SSL certificates (generated)
│   └── certbot/               # ACME challenge files
│
├── monitoring/                 # Prometheus + Grafana
│   ├── prometheus.yml         # Prometheus configuration
│   └── grafana/               # Grafana dashboards
│
├── scripts/                    # Setup and maintenance
│   ├── setup.sh               # Full initial setup (configs + SSL + cron)
│   ├── gen-configs.sh         # Generate configuration files
│   └── renew-ssl.sh           # SSL certificate renewal (called by cron)
│
├── config/                     # Configuration files
│   ├── public.yaml            # Public configuration (shared with frontend)
│   └── private.yaml           # Private configuration (backend only, generated)
│
├── docker-compose.yml         # Docker orchestration (production)
├── docker-compose.dev.yml     # Docker orchestration (development)
├── docker-compose.monitoring.yml # Monitoring stack
├── Makefile                   # Build and deployment commands
├── SETUP.md                   # Production setup guide
├── CONTRIBUTING.md            # Contribution guidelines
├── SECURITY.md                # Security policy
├── CODE_OF_CONDUCT.md         # Code of conduct
├── go.mod                     # Go module definition
├── go.sum                     # Go module checksums
└── README.md

Backend Architecture

Itchan follows a strict three-layer architecture for maintainability and testability:

1. Handler Layer (internal/handler/)

Responsibility: HTTP request/response handling

• Parse HTTP requests and extract parameters
• Validate input format and types
• Call appropriate service methods
• Convert service responses to HTTP responses
• Handle HTTP-specific errors (404, 401, etc.)

Example: handler/board.go

func (h *Handler) CreateBoard(w http.ResponseWriter, r *http.Request) {
    // Parse request body
    // Validate input
    // Call service.Board.Create()
    // Return JSON response
}

2. Service Layer (internal/service/)

Responsibility: Business logic and orchestration

• Enforce business rules (bump limits, thread counts, etc.)
• Coordinate between multiple storage operations
• Handle file uploads and processing
• Manage transactions
• Authentication and authorization logic

Example: service/thread.go

func (s *Thread) Create(ctx context.Context, data domain.ThreadCreationData) error {
    // Check thread count limits
    // Validate board exists
    // Create thread in storage
    // Trigger GC if needed
}

3. Storage Layer (internal/storage/pg/)

Responsibility: Data persistence

• Execute SQL queries
• Manage database connections
• Handle table partitioning
• Manage materialized views
• Map between database rows and domain models

Example: storage/pg/board.go

func (s *Storage) CreateBoard(ctx context.Context, board *domain.Board) error {
    // Execute INSERT statement
    // Create partition for new board
    // Return database errors
}

Database Schema

The database uses PostgreSQL's table partitioning for scalability. Each board gets its own partition.

Key Tables

• users: User accounts with encrypted email and password hash
• user_blacklist: Blacklisted users with reason and admin reference (cached for JWT validation)
• confirmation_data: Email confirmation codes for registration
• invite_codes: User-generated invite codes for registration
• boards: Board metadata (name, short_name, activity timestamps)
• board_permissions: Domain-based access control (email domain allowlist per board)
• threads: Thread metadata (title, message count, bump time, pinned flag) - partitioned by board
• messages: Individual posts (text, author, timestamps, ordinal) - partitioned by board
• attachments: Links messages to uploaded files - partitioned by board
• files: File metadata with both original and sanitized filenames/MIME types (path, size, dimensions, thumbnail path)
• message_replies: Cross-reference table for reply relationships - partitioned by board

Materialized Views

• board_previews: Pre-computed board views with last N messages per thread
  • Refreshed on configurable intervals (board_preview_refresh_interval)
  • Dramatically improves board page load times

Indexes

Optimized indexes for common queries:

• Thread lookup by board and bump time
• Message lookup by thread
• Reply lookup by receiver message
• Author lookup for moderation

Configuration

Configuration is split into two files:

config/public.yaml (Shared between backend and frontend)

jwt_ttl: 24h                           # JWT token lifetime
threads_per_page: 15                   # Pagination
messages_per_thread_page: 1000         # Messages per thread page (0 = all)
max_thread_count: 100                  # Max threads per board (null = unlimited)
n_last_msg: 3                          # Messages shown in board preview
bump_limit: 500                        # Messages before thread stops bumping
board_preview_refresh_internval: 30s   # Materialized view refresh rate
board_activity_window: 3m              # How far back to check for board activity
blacklist_cache_interval: 300          # Blacklist cache refresh interval (seconds)

# Auth
confirmation_code_ttl: 10m             # Email confirmation code expiration

# Logging
log_level: info                        # debug, info, warn, error
log_format: text                       # text or json

# Security settings
secure_cookies: false                  # Set to true for HTTPS
csrf_enabled: true                     # Enable CSRF protection

# Text length limits (defaults shown, all optional)
board_name_max_len: 10
board_short_name_max_len: 3
thread_title_max_len: 50
message_text_max_len: 10000
message_text_min_len: 1
password_min_len: 8
max_replies_per_message: 50            # Max >>reply links per message

# File upload limits
max_attachments_per_message: 4
max_attachment_size_bytes: 10485760    # 10 MB per file
max_total_attachment_size: 20971520    # 20 MB total
allowed_image_mime_types:
  - image/jpeg
  - image/png
  - image/gif
allowed_video_mime_types:
  - video/mp4
  - video/webm
  - video/ogg

# Invite system
invite_enabled: false
invite_code_length: 12
invite_code_ttl: 720h                  # 30 days
max_invites_per_user: 5                # 0 = unlimited
min_account_age_for_invites: 720h      # 30 days

# User activity page
user_messages_page_limit: 50           # Messages shown on account page

# Caching
static_cache_max_age: 240h             # Static file cache (CSS, JS)
media_cache_max_age: 168h              # User-uploaded media cache

# Media processing
media:
  thumbnail_max_size: 225              # Max dimension (px) for thumbnails
  thumbnail_display_op: 225            # Display size for OP thumbnails
  thumbnail_display_reply: 150         # Display size for reply thumbnails
  jpeg_quality_main: 85               # JPEG quality for main images (0-100)
  jpeg_quality_thumbnail: 75          # JPEG quality for thumbnails (0-100)

# Registration restrictions
allowed_registration_domains: []       # Empty = allow all domains. Example: ["gmail.com", "company.com"]

config/private.yaml (Backend only - never commit to git!)

jwt_key: "<your-secret-key>"           # JWT signing key (generate random 512+ bit string)
encryption_key: "<your-encryption-key>" # AES-256-GCM key for email encryption (use backend/cmd/tools/generate-encryption-key)

pg:
  host: localhost
  port: 5432
  user: itchan
  password: itchan
  dbname: itchan

email:
  smtp_server: smtp.gmail.com
  smtp_port: 587                          # 587 = STARTTLS, 465 = implicit TLS (Yandex)
  username: your-email@gmail.com
  password: your-app-password
  sender_name: "Itchan Imageboard"
  timeout: 10

API Endpoints

Authentication Methods

The API supports two authentication methods:

1. Cookie-based (automatic for browsers):

   • Login sets an HTTP-only cookie with the JWT
   • Subsequent requests include the cookie automatically
   • Best for browser-based clients

2. Bearer Token (for API/mobile clients):

   • Login returns access_token in response body
   • Include token in requests: Authorization: Bearer <token>
   • Best for mobile apps, CLI tools, third-party integrations

Authentication Endpoints

POST   /v1/auth/register                 - Register new user (rate limited: 1/s per email & IP)
POST   /v1/auth/check_confirmation_code  - Verify email confirmation code (5 attempts per 10 min per email)
POST   /v1/auth/login                    - Login with credentials (returns access_token)
POST   /v1/auth/register_with_invite     - Register with an invite code (rate limited: 1/s per IP)
POST   /v1/auth/logout                   - Logout (clear cookies)

Login Response:

{
  "message": "You logged in",
  "access_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
}

Boards (Authenticated)

GET    /v1/boards                        - List all accessible boards
GET    /v1/{board}                       - Get board with threads (paginated)
GET    /v1/{board}/last_modified         - Get board's last modification timestamp

Example with Bearer Token:

curl -H "Authorization: Bearer <your_token>" \
  http://localhost:8080/v1/boards

Threads (Authenticated)

POST   /v1/{board}                       - Create new thread (rate limited: 1/minute per user)
GET    /v1/{board}/{thread}              - Get thread with all messages
GET    /v1/{board}/{thread}/last_modified - Get thread's last modification timestamp

Messages (Authenticated)

POST   /v1/{board}/{thread}              - Post message to thread (rate limited: 1/second per user)
GET    /v1/{board}/{thread}/{message}    - Get single message

Invites (Authenticated)

GET    /v1/invites/                      - Get user's invite codes
POST   /v1/invites/                      - Generate new invite code (rate limited: 1/minute per user)
DELETE /v1/invites/{codeHash}            - Revoke an invite code

User (Authenticated)

GET    /v1/users/me/activity             - Get current user's activity data
GET    /v1/public_config                 - Get public configuration

Admin (Admin only)

POST   /v1/admin/boards                  - Create new board
DELETE /v1/admin/{board}                 - Delete board
DELETE /v1/admin/{board}/{thread}        - Delete thread
POST   /v1/admin/{board}/{thread}/pin    - Toggle thread pinned status
DELETE /v1/admin/{board}/{thread}/{message} - Delete message
POST   /v1/admin/users/{userId}/blacklist - Blacklist user (with optional reason)
DELETE /v1/admin/users/{userId}/blacklist - Remove user from blacklist
GET    /v1/admin/blacklist               - Get all blacklisted users with details
POST   /v1/admin/blacklist/refresh       - Manually refresh blacklist cache

Health & Monitoring (No auth)

GET    /health                           - Liveness probe (200 if running)
GET    /ready                            - Readiness probe (200 if DB connected)
GET    /metrics                          - Prometheus metrics

Rate Limits

• Registration: 1/s per email, 1/s per IP, 100 global RPS
• Confirmation Code: 5 attempts per 10 minutes per email, 1/s per IP, 100 global RPS
• Login: 1/s per IP, 1000 global RPS
• Invite Registration: 1/s per IP, 100 global RPS
• Create Thread: 1 per minute per user
• Post Message: 1 per second per user
• Generate Invite: 1 per minute per user
• Get Board: 10 RPS per user
• General authenticated: 100 RPS per user
• Admin: No rate limits

Example Usage

Browser/Frontend (Cookie-based):

// Login - cookie set automatically
await fetch('http://localhost:8080/v1/auth/login', {
  method: 'POST',
  credentials: 'include',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ email: 'user@example.com', password: 'pass' })
});

// Subsequent requests - cookie sent automatically
await fetch('http://localhost:8080/v1/boards', { credentials: 'include' });

API/Mobile Clients (Bearer Token):

# Login and extract token
TOKEN=$(curl -X POST http://localhost:8080/v1/auth/login \
  -H "Content-Type: application/json" \
  -d '{"email":"user@example.com","password":"pass"}' \
  | jq -r '.access_token')

# Use token in requests
curl -H "Authorization: Bearer $TOKEN" http://localhost:8080/v1/boards

Python:

import requests

# Login
response = requests.post('http://localhost:8080/v1/auth/login',
    json={'email': 'user@example.com', 'password': 'pass'})
token = response.json()['access_token']

# Use token
headers = {'Authorization': f'Bearer {token}'}
boards = requests.get('http://localhost:8080/v1/boards', headers=headers)

See BEARER_AUTH_EXAMPLE.md for more examples (React Native, Flutter, Node.js, etc.)

Frontend

The frontend is a server-rendered Go application using html/template.

Templates

• base.html: Common layout (header, footer, navigation)
• index.html: Board listing and creation form
• board.html: Thread list with pagination
• thread.html: Full thread view with all messages and reply form
• login.html / register.html / register_invite.html: Authentication pages
• check_confirmation_code.html: Email confirmation page
• account.html: Account management
• admin.html: Admin panel
• invites.html: Invite code management
• faq.html / about.html / contacts.html: Info pages
• privacy.html / terms.html: Legal pages
• partials.html: Reusable components (message rendering, forms)

Markdown Support

The frontend includes a lightweight custom markdown parser optimized for imageboard use:

• Code blocks (fenced with ```)
• Inline code, bold, italic, strikethrough
• Greentext (lines starting with >)
• Message links (>>threadId#msgId) with hover previews

Interactive Features

• Popup Reply System: Dynamic popup forms for quick replies with intelligent positioning
• Message Preview System: Hover over message links to see inline previews with caching (500 message cache)
• Preview Chains: Navigate through reply chains with automatic cleanup and smart timeout handling
• File Upload Manager: Real-time file preview with thumbnails, size validation, and individual file removal
• Hash-based Reply Links: Support for #reply-{id} URLs to auto-populate reply forms
• Disable Media Mode: Toggle in header to hide all images/videos, showing only filenames and metadata as text links (useful for slow connections, persists via cookie, works without JS)

Static Assets

• CSS: Minimal, responsive stylesheet
• JavaScript: Vanilla JS for dynamic reply forms, message previews, and file upload management
• Favicon: Custom imageboard icon

Testing

Comprehensive test coverage across all layers:

# Backend tests
cd backend

# Unit tests (service layer)
go test ./internal/service/...

# Integration tests (storage layer - requires running PostgreSQL)
go test ./internal/storage/pg/...

# Handler tests
go test ./internal/handler/...

# Frontend tests
cd ../frontend
go test ./internal/handler/...

# Run all tests with coverage
go test -v -coverprofile=coverage.out ./...
go tool cover -html=coverage.out

Test Structure

• Unit tests: Business logic validation (service layer)
• Integration tests: Database operations (storage layer with test DB)
• Handler tests: HTTP endpoint behavior (mocked services)

Integration tests use a separate test database and clean up after execution.

Security Features

Authentication & Authorization

• JWT-based authentication with configurable TTL
• Dual authentication support: Cookie-based (browsers) and Bearer token (API clients)
• Invite system: Users can generate invite codes for registration without corporate email
• Blacklist cache validation: Automatic JWT rejection for blacklisted users with cached validation
• Secure cookie storage with HttpOnly and Secure flags (when enabled)
• Password hashing using bcrypt
• Email encryption: AES-256-GCM encryption of email addresses at the application level
• CSRF protection: Token-based CSRF protection for state-changing requests
• Email confirmation required for registration
• Registration domain restrictions: Optional email domain allowlist for registration
• Admin role for moderation capabilities

Rate Limiting

• Multi-tier rate limiting: Per-user, per-IP, and global limits
• Token bucket algorithm with configurable refill rates
• Admin exemption: Admin users bypass rate limits
• Fingerprinting fallback: Uses request fingerprint if IP unavailable

Board Access Control

• Domain-based permissions: Restrict boards to specific email domains
• Middleware enforcement: Board access checked on every request
• Automatic filtering: Users only see boards they can access

Input Validation & Media Processing

• File type validation: Strict MIME type checking for uploads
• File size limits: Per-file and total attachment size limits
• Media sanitization: Automatic EXIF/metadata stripping from images (decode/encode) and videos (ffmpeg)
• Format normalization: GIF/WebP images converted to JPEG, PNG preserved
• Image dimension extraction: Metadata validation
• SQL injection prevention: Parameterized queries throughout
• XSS prevention: Template auto-escaping, markdown sanitization

Infrastructure

• Nginx reverse proxy: TLS termination, multi-tier rate limiting, connection limits, slowloris protection
• Let's Encrypt: Automatic SSL certificate provisioning and renewal
• Security headers: HSTS, CSP, X-Frame-Options, X-Content-Type-Options, Referrer-Policy
• CORS configuration: Controlled cross-origin access
• Gzip compression: Automatic response compression (nginx)
• Graceful shutdown: Proper connection cleanup
• Database partitioning: Isolation between boards

Deployment

Development

make dev  # or: docker compose up --build

Production

Full setup guide: SETUP.md

make deploy          # Build and start all services (nginx, frontend, api, postgres)

docker compose ps    # View running services
make logs            # View all logs
make logs-api        # View API logs
make logs-frontend   # View frontend logs

Monitoring

Optional Prometheus + Grafana stack for metrics and dashboards.

Enable Monitoring

make deploy-monitoring

Access:

• Grafana: http://localhost:3000 (default: admin/admin)
• Prometheus: http://localhost:9090

Disable Monitoring

make deploy  # Redeploy without monitoring compose file
docker compose stop prometheus grafana  # Stop monitoring services

Available Metrics

• http_requests_total{method, path, status} - Request count
• http_request_duration_seconds{method, path} - Latency histogram
• http_requests_in_flight - Concurrent requests gauge
• Go runtime metrics (goroutines, memory, GC)

Health Endpoints

• GET /health - Liveness probe (200 if running)
• GET /ready - Readiness probe (200 if DB connected)
• GET /metrics - Prometheus metrics (backend only)

CI/CD

Automated testing and deployment via GitHub Actions.

Workflow

1. On Pull Request: Run tests
2. On Push to main: Run tests → Deploy to VPS

Setup

Add these secrets in GitHub (Settings → Secrets → Actions):

• VPS_HOST - Your server IP/hostname
• VPS_USER - SSH username
• VPS_SSH_KEY - Private SSH key content
• VPS_PROJECT_PATH - Path to project on VPS (e.g., /home/user/itchan)

Contributing

Contributions are welcome! Please follow these guidelines:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Write tests for your changes
4. Ensure all tests pass (go test ./...)
5. Format your code (go fmt ./...)
6. Commit your changes (git commit -m 'Add amazing feature')
7. Push to the branch (git push origin feature/amazing-feature)
8. Open a Pull Request

Code Style

• Follow standard Go conventions (gofmt, golint)
• Write descriptive commit messages
• Add comments for complex logic
• Keep functions focused and testable
• Maintain the three-layer architecture separation

License

MIT License - see LICENSE for details.

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Built with ❤️ using Go