Turn your Hytale servers into one network.
Players move between servers with /play skywars, without leaving the game.

Docs · Download · Website

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Link is a free, open-source plugin for Hytale servers. Put the same jar on every server and players can hop between them. There is no proxy and no database to run.

• One command to play. /play skywars finds a game with room. /server sw-1 picks one.
• Secure by default. Every move carries a signed, single-use pass, so players can't fake one.
• See the whole network. /servers, /players and /find show every server and who is where.
• Servers join by themselves with Redis or a free Cloudflare Worker, or list them in one file.
• Keeps working when the registry goes down, from the last known server list.

Quick start

1. Download the jar from releases and put it in mods/ on every server.
2. Start each server once. Link writes mods/Link_Link/link.json.
3. List your servers and copy the file to every server. Only serverId differs per server.
4. Restart, then type /servers in game.

{
  "serverId": "lobby-1",
  "backend": "static",
  "secret": "generated on first boot, copy it to every server",
  "servers": [
    { "id": "lobby-1", "group": "lobby",   "host": "play.example.com", "port": 5520 },
    { "id": "sw-1",    "group": "skywars", "host": "play.example.com", "port": 5521 }
  ]
}

Every setting, and the Redis and Cloudflare setups, are in the docs.

How servers find each other

backend	You run	Live player counts and lists	New servers join
static	Nothing	No, only this server's players	By hand, in link.json
redis	A Redis, with a password	Yes	By themselves
http	Nothing, a free Cloudflare Worker (cloudflare-registry/)	Yes	By themselves

Commands

Command	Who	Does
/play <group>	Everyone	Join the best server in a group
/server <name>	Everyone	Go to one server
/servers [group]	Everyone	List the network, or one group
/players [server]	Everyone	Who is online in the network, or on one server
/find <player>	Everyone	Which server a player is on
/link	Admins	Connection status

For plugin developers

LinkPlugin.play(player, "skywars");           // matchmake into a group
LinkPlugin.send(player, "sw-1");              // to one server
LinkPlugin.send(player, "farm-1", "farm-42"); // into a world there
LinkPlugin.servers("lobby");                  // every lobby
LinkPlugin.find("Steve");                     // which server Steve is on, or null

Moves throw LinkException with a message you can show the player. See the Java API.

Security

A ticket is signed with the network secret, names one player and one server, expires after 30 seconds and works once. All servers share that secret, so this fits a network where you run every server. If some servers are run by others, you need a separate key per server, which Link doesn't do. Details in the security model.

Development

./gradlew build              # plugin jar in LinkHytale/build/libs, runs the tests
cd dev && ./setup.sh         # two real servers and a Redis in Docker, see dev/README.md

Folder	Holds
LinkCore/	Tickets, config, matchmaking and the registries. No game server dependency.
LinkHytale/	The Hytale plugin: commands, events and LinkPlugin.
cloudflare-registry/	The Worker behind the http registry.
dev/	A local test network.

Bug reports, ideas and pull requests are welcome.

License

MIT.