Pasto

A Crystal-based pastebin application with live syntax highlighting, SSH access, user accounts, and extensive theme support.

Features

Core Features

• 🚀 Fast & Lightweight: Built with Crystal for excellent performance
• 🎨 Live Preview: Real-time syntax highlighting as you type
• 🌈 Extensive Theming: 321+ syntax highlighting themes from Tartrazine
• 🎭 Smart Language Detection: Auto-detects language with Hansa classification
• 📱 Responsive Design: Works beautifully on desktop and mobile
• 🔒 Built-in Security: Rate limiting and size validation

SSH Access

• 🔑 SSH Paste Creation: Create pastes directly via SSH (cat file | ssh pasto.example.com)
• 👤 SSH Key Authentication: Your SSH key becomes your identity
• 🔗 Automatic Account Linking: SSH keys automatically linked to user accounts

User Accounts & Profiles

• 📋 User Profiles: View and manage all your pastes in one place
• ✏️ Editable Display Names: Personalize your profile
• 🎨 Theme Preferences: UI and syntax theme preferences saved per user
• 🔐 Session Management: Secure web sessions with cookie-based auth

Paste Management

• 📝 Paste Titles: Add optional titles or auto-generate from content
• 📜 Version History: Full edit history with Sepia versioning
• 🕐 View Past Versions: Browse and compare previous versions
• ✏️ Edit Your Pastes: Modify pastes you own
• 🗑️ Delete Pastes: Remove pastes from your profile

Modern UI

• 🎯 Clean Interface: Modern design with Pico CSS and Lucide icons
• 📐 Collapsible Sidebar: Theme controls in a space-saving sidebar
• ⌨️ CodeJar Editor: Lightweight code editor with syntax highlighting
• 🔄 Live Preview Pane: See rendered output as you type

Quick Start

Docker (Recommended)

The easiest way to run Pasto is with Docker Compose:

# Clone the repository
git clone https://github.com/ralsina/pasto.git
cd pasto

# Start Pasto (web + SSH server)
docker compose up -d

# View logs
docker compose logs -f

# Stop Pasto
docker compose down

The services will be available at:

• Web interface: http://localhost:3000
• SSH access: ssh -p 2222 localhost

Docker Configuration

The docker-compose.yml file includes:

• pasto service: Web interface on port 3000
• pasto-ssh service: SSH server on port 2222
• Persistent volumes for data, sessions, cache, and SSH keys

To customize, edit the environment variables in docker-compose.yml:

environment:
  PASTO_PORT: 3000
  PASTO_MAX_PASTE_SIZE: 1048576  # 1MB
  PASTO_THEME: monokai
  PASTO_RATE_LIMIT: 10
  PASTO_SESSION_SECRET: "your-secret-here"  # Change in production!

Volumes

Backup

# Backup all data
docker compose exec pasto tar -czf - /app/data > pasto-backup.tar.gz

# Or copy volumes
docker run --rm -v pasto-data:/data -v $(pwd):/backup alpine \
  tar -czf /backup/pasto-data-backup.tar.gz /data

Manual Installation

# Clone the repository
git clone https://github.com/ralsina/pasto.git
cd pasto

# Install dependencies
shards install

# Build the application
shards build --release

# Run the server
./bin/pasto

SSH Usage

Create a paste via SSH:

# Simplest form - just pipe content
cat myfile.py | ssh -p 2222 pasto.example.com

# Or use echo
echo "Hello, World!" | ssh -p 2222 pasto.example.com

# Redirect from file
ssh -p 2222 pasto.example.com < myfile.py

# Explicit paste command (also works)
cat myfile.py | ssh -p 2222 pasto.example.com paste

The server returns the URL of your new paste.

Other SSH commands:

# Login to link SSH key with web account
ssh -p 2222 pasto.example.com login

# Show help
ssh -p 2222 pasto.example.com help

Web Usage

1. Navigate to http://localhost:3000
2. Type or paste your code in the editor
3. Watch the live preview update
4. Click + to create the paste

Configuration

Pasto supports three configuration methods (in order of priority):

1. Command line arguments
2. Environment variables (prefixed with PASTO_)
3. Configuration file (pasto.yml)

Command Line Options

./bin/pasto \
  --port 3000 \
  --bind 0.0.0.0 \
  --max-paste-size 102400 \
  --theme default-dark \
  --ssh-enabled true \
  --ssh-port 2222 \
  --storage-dir ./data \
  --cache-dir ./public/cache

Environment Variables

export PASTO_PORT=3000
export PASTO_MAX_PASTE_SIZE=102400
export PASTO_THEME=monokai
export PASTO_SSH_ENABLED=true
export PASTO_SSH_PORT=2222
export PASTO_RATE_LIMIT=10

Configuration File (pasto.yml)

port: 3000
bind: "0.0.0.0"
max_paste_size: 102400  # 100KB
theme: default-dark
ssh_enabled: true
ssh_port: 2222
storage_dir: ./data
cache_dir: ./public/cache
rate_limit: 10
rate_window: 60

API Endpoints

Create Paste (Web)

curl -X POST http://localhost:3000 \
  -d "content=print('Hello!')&language=python&title=My%20Paste"

View Paste

# View paste
curl http://localhost:3000/{paste-id}

# View with language override
curl http://localhost:3000/{paste-id}?lang=python

# View with file extension
curl http://localhost:3000/{paste-id}.py

View Paste History

# View all versions (owner only)
curl http://localhost:3000/{paste-id}/history

# View specific version
curl http://localhost:3000/{paste-id}/version/1

Live Highlighting API

curl -X POST http://localhost:3000/highlight \
  -d "content=def hello(): pass&language=python&theme=monokai"

Supported Languages

Pasto supports 35+ programming languages including:

• Popular: Python, JavaScript, TypeScript, Java, C, C++, C#, Go, Rust
• Web: HTML, CSS, SCSS, Sass, JSON, XML, YAML, Markdown
• Systems: Bash, Shell, PowerShell, Dockerfile
• Data: SQL, MySQL, PostgreSQL, CSV
• And more: PHP, Ruby, Perl, Kotlin, Scala, ActionScript...

Only languages with working Tartrazine lexers are available.

Theme Support

UI Themes (Pico CSS)

• 15 color schemes: Slate, Zinc, Gray, Neutral, Stone, Red, Orange, Amber, Yellow, Lime, Green, Emerald, Cyan, Sky, Indigo, Violet, Fuchsia, Pink
• Light/Dark/Auto modes with system preference detection

Syntax Themes (Tartrazine)

• 321+ themes including popular ones like Dracula, Monokai, Nord, Solarized, One Dark, GitHub, VS Code themes, and many more

Project Structure

pasto/
├── src/
│   ├── pasto.cr           # Entry point, configuration
│   ├── server.cr          # Kemal routes and middleware
│   ├── paste.cr           # Paste model, highlighting, themes
│   ├── pasto_ssh.cr       # SSH server entry point
│   └── views/
│       ├── layout.ecr     # Main layout with sidebar
│       ├── index.ecr      # Create paste page
│       ├── show.ecr       # View paste page
│       ├── edit.ecr       # Edit paste page
│       ├── history.ecr    # Version history page
│       └── profile_content.ecr  # User profile
├── data/                  # Sepia storage directory
├── public/cache/          # Cached rendered pastes
├── sessions/              # Session storage
└── pasto.yml              # Configuration file

Development

# Install dependencies
shards install

# Build
shards build

# Build release
shards build --release

# Run tests
crystal spec

# Format code
crystal tool format src/

# Lint
./bin/ameba src/

Security Features

• Rate Limiting: Configurable per-IP rate limits
• Size Validation: Maximum paste size enforcement
• HTML Escaping: All content properly sanitized
• Session Security: Secure cookie-based sessions
• SSH Key Auth: Public key authentication for SSH access

Dependencies

• Kemal: Web framework
• Tartrazine: Syntax highlighting (321+ themes)
• Hansa: Language classification
• Sepia: Object persistence with versioning
• Shirk: SSH server
• Pico CSS: Minimal CSS framework
• Lucide: Icon library
• CodeJar: Code editor

License

MIT License - see LICENSE for details.

Author

Created by Roberto Alsina

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Pasto - Modern pastebin with SSH access and live preview.

Public Instance

A public Pasto instance is available at https://pasto1.ralsina.me.