feat: netty server default port (#2822)

* use port 15000 by default for netty server

* fix detekt issue

* update theme readme

src-theme/README.md

@@ -9,8 +9,7 @@ This directory contains the source code of LiquidBounce's default theme made wit
 1. Install [Node.js](https://nodejs.org/en) on your computer (either latest or stable should be fine).
 2. Install required dependencies using `npm install`.
 3. Set `IN_DEV` in [host.ts](https://github.com/CCBlueX/LiquidBounce/blob/nextgen/src-theme/src/integration/host.ts) to `true`.
-4. Change `PORT` to `15000` in [NettyServer.kt](https://github.com/CCBlueX/LiquidBounce/blob/nextgen/src/main/kotlin/net/ccbluex/liquidbounce/web/socket/netty/NettyServer.kt).
-5. Launch the client.
-6. Run `npm run dev` to start a development server.
+4. Launch the client.
+5. Run `npm run dev` to start a development server.
 
 Make sure not to push the changes made to `host.ts` and `NettyServer.kt`!

src/main/kotlin/net/ccbluex/liquidbounce/web/socket/netty/NettyServer.kt

@@ -30,15 +30,28 @@ import io.netty.handler.logging.LogLevel
 import io.netty.handler.logging.LoggingHandler
 import net.ccbluex.liquidbounce.utils.client.ErrorHandler
 import net.ccbluex.liquidbounce.utils.client.logger
+import java.net.Socket
 
 
 internal class NettyServer {
 
     companion object {
 
-        val PORT = (15000..17000).random()
+        private const val DEFAULT_PORT = 15000
+
+        val PORT = findAvailablePort()
         val NETTY_ROOT = "http://127.0.0.1:$PORT"
 
+        @Suppress("SwallowedException")
+        private fun findAvailablePort() = try {
+            Socket("localhost", DEFAULT_PORT).use {
+                logger.info("Default port unavailable. Falling back to random port.")
+                (15001..17000).random()
+            }
+        } catch (e: Exception) {
+            logger.info("Default port $DEFAULT_PORT available.")
+            DEFAULT_PORT
+        }
     }
 
     fun startServer(port: Int = PORT) {