implement: proxy kick by maintenance or network full

Author: Dominic-Kaemereit

proxy-shared/src/main/kotlin/app/simplecloud/plugin/proxy/shared/ProxyPlugin.kt

@@ -1,6 +1,7 @@
 package app.simplecloud.plugin.proxy.shared
 
 import app.simplecloud.plugin.proxy.shared.config.YamlConfig
+import app.simplecloud.plugin.proxy.shared.config.message.MessageConfig
 import app.simplecloud.plugin.proxy.shared.config.placeholder.PlaceHolderConfiguration
 import app.simplecloud.plugin.proxy.shared.config.tablis.TabListConfiguration
 import app.simplecloud.plugin.proxy.shared.handler.CloudControllerHandler
@@ -13,8 +14,14 @@ open class ProxyPlugin(
     val config = YamlConfig(dirPath)
     val tabListConfiguration = config.load<TabListConfiguration>("tablist")!!
     val placeHolderConfiguration = config.load<PlaceHolderConfiguration>("placeholder")!!
+    val messagesConfiguration = config.load<MessageConfig>("messages")!!
     val cloudControllerHandler = CloudControllerHandler()
     val motdLayoutHandler = MotdLayoutHandler(config, this)
 
     var maintenance = true
+
+    companion object {
+        val JOIN_MAINTENANCE_PERMISSION = "simplecloud.proxy.join.maintenance"
+        val JOIN_FULL_PERMISSION = "simplecloud.proxy.join.full"
+    }
 }

proxy-shared/src/main/kotlin/app/simplecloud/plugin/proxy/shared/config/message/KickMessageConfig.kt

@@ -0,0 +1,9 @@
+package app.simplecloud.plugin.proxy.shared.config.message
+
+import org.spongepowered.configurate.objectmapping.ConfigSerializable
+
+@ConfigSerializable
+data class KickMessageConfig(
+    val networkMaintenance: String = "<red>The network is currently in maintenance mode. Please try again later.",
+    val networkFull: String = "<red>The network is currently full. Please try again later.",
+)

proxy-shared/src/main/kotlin/app/simplecloud/plugin/proxy/shared/config/message/MessageConfig.kt

@@ -0,0 +1,8 @@
+package app.simplecloud.plugin.proxy.shared.config.message
+
+import org.spongepowered.configurate.objectmapping.ConfigSerializable
+
+@ConfigSerializable
+data class MessageConfig(
+    var kickMessage: KickMessageConfig = KickMessageConfig(),
+)

proxy-shared/src/main/kotlin/app/simplecloud/plugin/proxy/shared/handler/CloudControllerHandler.kt

@@ -75,6 +75,34 @@ class CloudControllerHandler {
         } ?: logger.warning("Group name is not initialized.")
     }
 
+    suspend fun getOnlinePlayersInGroup(): Int {
+        return groupName?.let {
+            try {
+                controllerApi.getServers().getServersByGroup(it).sumBy { it.playerCount.toInt() }
+            } catch (e: Exception) {
+                logger.severe("Error retrieving online players in group: ${e.message}")
+                0
+            }
+        } ?: run {
+            logger.warning("Group name is not initialized.")
+            0
+        }
+    }
+
+    suspend fun getMaxPlayersInGroup(): Int {
+        return groupName?.let {
+            try {
+                controllerApi.getGroups().getGroupByName(it).maxPlayers.toInt()
+            } catch (e: Exception) {
+                logger.severe("Error retrieving max players in group: ${e.message}")
+                0
+            }
+        } ?: run {
+            logger.warning("Group name is not initialized.")
+            0
+        }
+    }
+
     private suspend fun retrievePropertyOrEmpty(retrieve: suspend () -> String?): String {
         return try {
             retrieve() ?: ""

proxy-velocity/src/main/kotlin/app/simplecloud/plugin/proxy/velocity/ProxyVelocityPlugin.kt

@@ -11,6 +11,7 @@ import app.simplecloud.plugin.proxy.velocity.handler.TabListHandler
 import app.simplecloud.plugin.proxy.velocity.listener.CloudListener
 import app.simplecloud.plugin.proxy.velocity.listener.ConfigureTagResolversListener
 import app.simplecloud.plugin.proxy.velocity.listener.ProxyPingListener
+import app.simplecloud.plugin.proxy.velocity.listener.ServerPreConnectListener
 import com.google.inject.Inject
 import com.velocitypowered.api.command.RawCommand
 import com.velocitypowered.api.command.SimpleCommand
@@ -42,12 +43,14 @@ class ProxyVelocityPlugin @Inject constructor(
     fun onProxyInitialize(event: ProxyInitializeEvent) {
         config.save("tablist", this.tabListConfiguration)
         config.save("placeholder", this.placeHolderConfiguration)
+        config.save("messages", this.messagesConfiguration)
 
         this.motdLayoutHandler.loadMotdLayouts()
 
         this.proxyServer.eventManager.register(this, ProxyPingListener(this))
         this.proxyServer.eventManager.register(this, ConfigureTagResolversListener(this))
         this.proxyServer.eventManager.register(this, CloudListener(this))
+        this.proxyServer.eventManager.register(this, ServerPreConnectListener(this))
 
         if (this.tabListConfiguration.tabListUpdateTime > 0)
             this.tabListHandler.startTabListTask()

proxy-velocity/src/main/kotlin/app/simplecloud/plugin/proxy/velocity/listener/ServerPreConnectListener.kt

@@ -0,0 +1,53 @@
+package app.simplecloud.plugin.proxy.velocity.listener
+
+import app.simplecloud.plugin.proxy.shared.ProxyPlugin
+import app.simplecloud.plugin.proxy.velocity.ProxyVelocityPlugin
+import com.velocitypowered.api.event.PostOrder
+import com.velocitypowered.api.event.Subscribe
+import com.velocitypowered.api.event.player.ServerPreConnectEvent
+import com.velocitypowered.api.proxy.Player
+import kotlinx.coroutines.runBlocking
+import java.util.logging.Logger
+
+class ServerPreConnectListener(
+    private val proxyPlugin: ProxyVelocityPlugin,
+) {
+    private val logger = Logger.getLogger(ServerPreConnectListener::class.java.name)
+
+    @Subscribe(order = PostOrder.EARLY)
+    fun handle(event: ServerPreConnectEvent) {
+        val player = event.player
+
+        if (proxyPlugin.maintenance && !player.hasPermission(ProxyPlugin.JOIN_MAINTENANCE_PERMISSION)) {
+            denyAccess(
+                player,
+                this.proxyPlugin.messagesConfiguration.kickMessage.networkMaintenance,
+                event
+            )
+            return
+        }
+
+        runBlocking {
+            try {
+                if (!isServerFull(player)) {
+                    return@runBlocking
+                }
+                denyAccess(player, proxyPlugin.messagesConfiguration.kickMessage.networkFull, event)
+            } catch (e: Exception) {
+                logger.severe("Error checking player limits: ${e.message}")
+            }
+        }
+    }
+
+    private suspend fun isServerFull(player: Player): Boolean {
+        val maxPlayers = proxyPlugin.cloudControllerHandler.getMaxPlayersInGroup()
+        val onlinePlayers = proxyPlugin.cloudControllerHandler.getOnlinePlayersInGroup()
+
+        return onlinePlayers >= maxPlayers && !player.hasPermission(ProxyPlugin.JOIN_FULL_PERMISSION)
+    }
+
+    private fun denyAccess(player: Player, message: String, event: ServerPreConnectEvent) {
+        player.disconnect(proxyPlugin.deserializeToComponent(message, player))
+        event.result = ServerPreConnectEvent.ServerResult.denied()
+    }
+}