VCMI Proxy Server

The purpose of this program is to connect VCMI users together to allow online multiplayer.

Quick start

Following snippet will start proxy server so clients can connect to 0.0.0.0:5002 If server has static IP and/or web address, clients can connect by using this address. Local clients can connect by localhost:5002 or 127.0.0.1:5002

cd proxyServer
python3.8 Server.py &

To stop server

skill python3.8

Note: & symbol in the end runs script in detached mode so it will work even after user session was closed.

Arguments

Program can be started with arguments or without them, full command has following format:

python3.8 server.py logging=info port=5002 capacity=50 healthcheck=30

In example above all arguments have their default values.

Detailed description of arguments

• logging level of logging event to be written into file. Possible options are:
  • debug - if this level activated, debug log events will be written into proxyServer_debug.log file
  • info
  • warning
  • error
  • critical
• port port where clients should connect
• capacity maximum allowed amount of clients to be connected
• healthcheck time in seconds. When is passed, server requests health status of clients (starting form protocol 4)

Lobby protocol description

Packing

Each message has a packet structure, which means that it has infomation about structure size. First 4 bytes stand for structure size (in bytes) then server waits for all bytes to be received.

Handshaking

When first pack is obtained server determines whether it lobby connection or game connection (pipe) If structure has a string "Ayia!" then it's game connection. Otherwise lobby connection is assumed.

Since connection type is determined, than appropriate handshaking is expected.

• For Lobby coneection

  • protocol version - one byte
  • string encoding. Check one byte - if zero, then utf-8 is assumed. If non-zero, this byte stands for encoding name size. Then next bytes are read to get encoding name. Examples: 5utf-8, 6cp1251

• For Pipe connection

  • Fist struct is always Ayia!
  • Second struct is either client or server
  • Third struct is stands for uuid xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

Lobby protocol

Lobby protocol has different format for client and server messages. This file describes only server protocol. See vcmi documentation for client protocol

Overall format of server protocol: <COMMAND>ARGUMENT(s)

• <GREETINGS>username
  • expected to be first command. Autorizes client in lobby
• <VER>version
  • full vcmi version
• <MSG>message
  • ask server to broadcast message to other players. Can have target like @username or @all to send to everyone
• <NEW>name
  • ask server to create new room with name specified. Client will be joined to this room as host.
• <PSWD>password
  • if client is a host of room, new room password will be set. Otherwise, password will be checked before joining to the room
• <COUNT>players
  • sets total amount of players to be set for new room
• <JOIN>name
  • asks server to join player to the room with name specified
• <HOSTMODE>mode
  • asks server to set room into mode specified (must be integer) and broadcast it
• <MODS>mods
  • notifies server about mods client has. Mods has following format: mod1_name&mod1_version;mod2_name&mod2_version;...
• <LEAVE>name
  • ask server to leave room with name specified
  • If client is a host for that room, then room will be destroyed
• <KICK>username
  • ask sever to kick player with username specified from room which current client is joined
  • client must be room host
• <READY>name
  • notifies server about client reasiness for room name specified. Client must be joined to this room
• <FORCESTART>name
  • asks server to start session for room with name specified immediately.
  • This command used to ensure backward compatibility with older clients who cannot send READY command
• <ROOT>field
  • debug command to be typed manually. Used to obtain statistic from the server. See lobby.py for information about fields
• <ALIVE>any
  • obsolete command, unused. Server ignores it.