feat: add srv record lookup

src/main/kotlin/cn/rtast/fancybot/commands/lookup/NslookupCommand.kt

@@ -8,27 +8,73 @@
 package cn.rtast.fancybot.commands.lookup
 
 import cn.rtast.fancybot.annotations.CommandDescription
+import cn.rtast.fancybot.configManager
 import cn.rtast.rob.entity.GroupMessage
 import cn.rtast.rob.util.BaseCommand
 import cn.rtast.rob.util.ob.MessageChain
 import cn.rtast.rob.util.ob.OneBotListener
+import cn.rtast.rob.util.ob.asNode
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 import java.net.InetAddress
 import java.net.UnknownHostException
+import java.util.Hashtable
+import javax.naming.directory.InitialDirContext
 
 @CommandDescription("解析域名获取IP地址")
 class NslookupCommand : BaseCommand() {
     override val commandNames = listOf("/ns")
 
+    companion object {
+        private const val MC_SRV_PREFIX = "_minecraft._tcp"
+        private val env = Hashtable<String, String>().also {
+            it["java.naming.factory.initial"] = "com.sun.jndi.dns.DnsContextFactory"
+        }
+        private val dirContext = InitialDirContext(env)
+    }
+
     override suspend fun executeGroup(listener: OneBotListener, message: GroupMessage, args: List<String>) {
-        val host = args.joinToString(" ")
+        val host = args.first()
+        val nsType = args[1]
+        val srvType = args.last()
         try {
-            val msg = MessageChain.Builder()
-                .addText("域名: ${host}解析后的IP地址为: ")
-                .addText(withContext(Dispatchers.IO) { InetAddress.getByName(host) }.hostAddress)
-                .build()
-            message.reply(msg)
+            if (nsType == "srv") {
+                when (srvType) {
+                    "mc" -> {
+                        val srvDomain = "$MC_SRV_PREFIX.$host"
+                        val attrs = dirContext.getAttributes(srvDomain, arrayOf("SRV"))
+                        val srvRecords = mutableListOf<String>()
+                        val srvAttr = attrs.get("SRV")
+                        if (srvAttr != null) {
+                            for (i in 0 until srvAttr.size()) {
+                                val srvRecord = srvAttr.get(i) as String
+                                srvRecords.add(srvRecord)
+                            }
+                        }
+                        val messages = mutableListOf<MessageChain>()
+                        srvRecords.forEach {
+                            val srv = it.split(" ")
+                            val priority = srv.first().toInt()
+                            val weight = srv[1].toInt()
+                            val port = srv[2].toInt()
+                            val host = srv.last()
+                            val msg = MessageChain.Builder()
+                                .addText("解析后的地址: $host:$port")
+                                .addNewLine()
+                                .addText("权重: $weight | 优先级: $priority")
+                                .build()
+                            messages.add(msg)
+                        }
+                        message.reply(messages.asNode(configManager.selfId))
+                    }
+                }
+            } else {
+                val msg = MessageChain.Builder()
+                    .addText("${host}解析后的IP地址为: ")
+                    .addText(withContext(Dispatchers.IO) { InetAddress.getByName(host) }.hostAddress)
+                    .build()
+                message.reply(msg)
+            }
         } catch (_: UnknownHostException) {
             message.reply("未知的主机名: $host")
         } catch (e: Exception) {