Hurry Curry! protocol

The protocol schema is defined in protocol.ts

1. Connect to the server via WebSocket and send/receive json in WebSocket "Text" messages. The binary protocol uses "Binary" messages and is optional for servers and clients.
2. Wait for version packet and check version compatibiliy (see below).
3. Send the join packet with your username.
4. The server will send the current game state: - data once for setting important look-up tables - update_map for every tile - set_tile_item for every item on a tile - add_player for every player in the game - set_player_item for every item held by a player
5. Run the game loop - Send your position every 20ms - 40ms. - Send interact when the player interacts with a tile. - Receive packets
6. The Game ends. The server will remove all players and tiles. Then continue at step 4.

Collisions are handled by the clients. Whenever to players collide the player with the greater PlayerID is responsible for updating their own momentum and sending a packet to update that of the other player.

Ports

• 443: All uses with TLS
• 27032: Game Server Websocket
• 27033: Registry API HTTP / Local dicovery service
• 27034: Lobby Server Websocket
• 27035: Map Editor Server Websocket

Binary Protocol

Servers might also support the binary protocol. It uses Bincode to encode packets. If a server advertises bincode support with the init packet, you are free to use the binary protocol. By default the server will send JSON. For every packet you send, you can choose between bincode and JSON. After a client sent the first Bincode packet, the server might start to reply using Bincode aswell. Bincoded packets are sent with WebSocket "Binary" messages.

Protocol Versioning

The init packet sends minor and major version numbers of the protocol is use by the server. These are to be interpreted according to SemVer for the JSON protocol. The binary protocol can not be used if either minor or major version differs.

Movement

Movement is handled server-side but should be predicted by client for better latency. For this reason it implemented three times:

• In GDscript (for the Godot client): controllable_player.gd
• In Rust (for server, pixelcurry and customers): movement.rs
• In TypeScript (for test-client): movement.ts

Limits

The server currently enforces the following network limits:

• Server inbound json packets are at most 8196 bytes in size
• Server inbound binary packets are at most 4096 bytes in size
• Player names are no longer than 32 characters
• Player names are no longer than 64 bytes