Installation

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System requirements

• Python: 3.9 or higher
• Operating system: Linux, macOS, or Windows
• Network: Access to YSFlight server
• Memory: ~50MB per proxy instance

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Installation

python --version
# or
python3 --version

git clone https://github.com/the-indian-dev/sakuya-ac.git
cd sakuya-ac

pip install -r requirements.txt

python -m venv venv
source venv/bin/activate  # Linux/macOS
# or
venv\Scripts\activate  # Windows
pip install -r requirements.txt

aiohttp==3.11.12        # Async HTTP for Discord
uvloop==0.21.0          # Fast I/O loop (Linux/macOS)
# ... and supporting libraries

from logging import DEBUG, WARN, INFO, CRITICAL

# Logging Level
LOGGING_LEVEL = INFO  # Use DEBUG for troubleshooting

# Server Configuration
SERVER_HOST = "127.0.0.1"  # YSFlight server IP
SERVER_PORT = 7915          # YSFlight server port
PROXY_PORT = 9000           # Proxy listening port

# YSFlight Server Version
YSF_VERSION = 20150425      # CRITICAL: Must match server

# Enable ViaVersion
VIA_VERSION = True          # Allow newer clients

# G-Limiter
G_LIM = 4                   # Kill at |g| >= 4

# Welcome message
WELCOME_MESSAGE = "Welcome {username} to the server!"

# Command prefix
PREFIX = "/"

# Health hack detection message
HEALTH_HACK_MESSAGE = "Detected for health hack"

# Smoke on damage
SMOKE_PLANE = True
SMOKE_LIFE = 5              # Smoke when life < 5

# Discord integration (optional)
DISCORD_ENABLED = False
DISCORD_TOKEN = "DISCORD_BOT_TOKEN"
CHANNEL_ID = 0

python proxy.py

INFO: Welcome to Sakuya AC
INFO: Perfect and Elegant Proxy for your YSFlight Server
INFO: Licensed under GPLv3
INFO: Press CTRL+C to stop the proxy
INFO: uvloop found! Using uvloop for fast I/O  # Linux only
INFO [proxy.py:371]: Proxy server listening on port 9000

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Configuration options

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Logging

from logging import DEBUG, INFO, WARN, CRITICAL

LOGGING_LEVEL = INFO

• DEBUG: Verbose packet-level logging (use for bug reports)
• INFO: Standard operational logging
• WARN: Warnings and errors only
• CRITICAL: Critical errors only

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Server connection

SERVER_HOST = "127.0.0.1"  # YSFlight server IP or hostname
SERVER_PORT = 7915          # YSFlight server port
PROXY_PORT = 9000           # Port for proxy to listen on

• SERVER_HOST: IP address of your YSFlight server
• SERVER_PORT: Port your YSFlight server listens on
• PROXY_PORT: Port clients connect to (change if 9000 conflicts)

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Version compatibility

YSF_VERSION = 20150425  # Server version
VIA_VERSION = True      # Allow different client versions

• YSF_VERSION: Must match your YSFlight server version
• VIA_VERSION: When True, allows post-20150425 clients to connect

# In proxy.py:172-175
if player.version != YSF_VERSION and VIA_VERSION:
    info(f"ViaVersion enabled : Porting {player.username} from {player.version} to {YSF_VERSION}")
    message_to_client.append(YSchat.message(f"Porting you to YSFlight {YSF_VERSION}, This is currently Experimental"))

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G-limiter

G_LIM = 4  # Kill player when |g| >= 4

• Set to 100 to effectively disable
• Typical values: 4-8 for realism
• Checked in proxy.py:186 via FSNETCMD_AIRPLANESTATE packets

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Damage mechanics

SMOKE_PLANE = True   # Enable smoke on damage
SMOKE_LIFE = 5       # Smoke when life < 5

• Black smoke emitted from aircraft
• Engine breakdown (no afterburner)
• Missiles disabled

addSmoke = FSNETCMD_WEAPONCONFIG.addSmoke(player.aircraft.id)
message_to_server.append(addSmoke)

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Welcome message

WELCOME_MESSAGE = "Welcome {username} to the server!"

• Use {username} placeholder for player name
• Sent when player joins (proxy.py:265)

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Commands

PREFIX = "/"

if msg.message.startswith(PREFIX):
    command = msg.message.split(" ")[0][1:]
    asyncio.create_task(triggerCommand.triggerCommand(command, msg.message, player, message_to_client, message_to_server, plugin_manager))

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Anti-cheat

HEALTH_HACK_MESSAGE = "Detected for health hack"

if player.aircraft.prev_life < player.aircraft.life and player.aircraft.prev_life != -1:
    cheatingMsg = YSchat.message(f"{HEALTH_HACK_MESSAGE} by {player.username}")
    warning(f"Health hack detected for {player.username}, Connected from {player.ip}")

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Discord integration

DISCORD_ENABLED = False
DISCORD_TOKEN = "DISCORD_BOT_TOKEN"
CHANNEL_ID = 0  # Discord channel ID as integer

• In-game chat syncs to Discord channel
• Join/leave notifications sent to Discord
• Discord messages forwarded to game

1. Create Discord bot at discord.com/developers
2. Enable “Message Content Intent” in bot settings
3. Copy bot token to DISCORD_TOKEN
4. Get channel ID (right-click channel → Copy ID) and set CHANNEL_ID
5. Invite bot to server with “Read Messages” and “Send Messages” permissions

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Running in production

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As a service (Linux)

[Unit]
Description=Sakuya AC Proxy Server
After=network.target

[Service]
Type=simple
User=your-user
WorkingDirectory=/path/to/sakuya-ac
ExecStart=/usr/bin/python3 proxy.py
Restart=always

[Install]
WantedBy=multi-user.target

sudo systemctl enable sakuya-ac
sudo systemctl start sakuya-ac
sudo systemctl status sakuya-ac

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With Docker

FROM python:3.9-slim
WORKDIR /app
COPY requirements.txt .
RUN pip install -r requirements.txt
COPY . .
CMD ["python", "proxy.py"]

docker build -t sakuya-ac .
docker run -d -p 9000:9000 --name sakuya-ac sakuya-ac

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Troubleshooting

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Connection refused

• Check firewall allows PROXY_PORT
• Verify proxy is listening on 0.0.0.0 (all interfaces)
• Ensure no other service uses the port: netstat -tulpn | grep 9000

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Version mismatch

• Set YSF_VERSION exactly to your server version
• Enable VIA_VERSION = True for mixed versions
• Check logs for version info: LOGGING_LEVEL = DEBUG

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Health hack false positives

• This is tracked with player.aircraft.just_repaired flag (proxy.py:198)
• Check plugin compatibility
• Report with DEBUG logs and .yfs replay file

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High CPU usage

• Install uvloop on Linux: pip install uvloop
• Reduce LOGGING_LEVEL to WARN or INFO
• Check for packet loop issues in plugins

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Next steps