a2s-java

A Valve Steam Query Protocol (A2S) implementation for Java using Netty.

This library allows you to query game servers that implement the Source Engine Query protocol, such as Counter-Strike, Team Fortress 2, Rust, ARK, and many others.

Note

This code is based on and used from yeetus-desastroesus/A2S-Java.

Features

• A2S_INFO: Get server information (name, map, player count, etc.).
• A2S_PLAYER: Get detailed list of players currently on the server.
• A2S_RULES: Get server rules/CVars.
• Asynchronous: Built on Netty for high-performance, non-blocking I/O.
• Server Implementation: Includes a basic A2S server implementation for testing or mocking.

Installation

The library is published on GitHub Packages. To use it, you need to configure your build tool to include the GitHub Maven repository.

Maven

1. Add the following repository to your pom.xml:

<repositories>
    <repository>
        <id>github</id>
        <url>https://maven.pkg.github.com/g-portal/a2s-java</url>
    </repository>
</repositories>

2. Add the following dependency to your pom.xml:

<dependency>
    <groupId>com.gportal</groupId>
    <artifactId>a2s</artifactId>
    <version>1.0.1</version> <!-- Use the desired release tag version -->
</dependency>

Gradle

1. Add the following repository to your build.gradle:

repositories {
    maven {
        url = uri("https://maven.pkg.github.com/g-portal/a2s-java")
    }
}

2. Add the following to your build.gradle dependencies:

dependencies {
    implementation 'com.gportal:a2s:1.0.0' // Use the desired release tag version
}

Usage

Querying a Server (Client)

import com.gportal.a2s.QueryClient;
import com.gportal.a2s.ServerInfo;
import com.gportal.a2s.PlayerInfo;
import java.net.InetSocketAddress;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CompletableFuture;

public class Example {
    public static void main(String[] args) throws Exception {
        QueryClient client = new QueryClient();
        InetSocketAddress address = new InetSocketAddress("127.0.0.1", 27015);

        // Query Server Info
        CompletableFuture<ServerInfo> infoFuture = client.queryServer(address);
        infoFuture.thenAccept(info -> System.out.println("Server Name: " + info.name()));

        // Query Players
        CompletableFuture<List<PlayerInfo>> playersFuture = client.queryPlayers(address);
        playersFuture.thenAccept(players -> players.forEach(p -> System.out.println("Player: " + p.name())));

        // Query Rules
        CompletableFuture<Map<String, String>> rulesFuture = client.queryRules(address);
        rulesFuture.thenAccept(rules -> System.out.println("Rules count: " + rules.size()));

        // Don't forget to shutdown when done
        // client.shutdown();
    }
}

Starting an A2S Server

import com.gportal.a2s.QueryServer;
import com.gportal.a2s.ServerInfo;
import com.gportal.a2s.PlayerInfo;

public class ServerExample {
    public static void main(String[] args) {
        ServerInfo info = new ServerInfo(
            null, (byte)17, "My Java Game Server", "de_dust2", "csgo", "Counter-Strike: Global Offensive",
            (short)730, (byte)0, (byte)20, (byte)0, 'd', 'l', false, true, "1.0.0.0",
            null, null, null, null, null, null
        );

        QueryServer server = new QueryServer(27015, info);
        
        // Add some players or rules
        server.players.add(new PlayerInfo((byte)0, "Gordon Freeman", (short)100, 300.0f));
        server.rules.put("mp_timelimit", "30");

        System.out.println("A2S Server started on port 27015");
    }
}

License

This project is licensed under the MIT License - see the LICENSE.md file for details.