Basic complete: packet parse, zlib decompress

.gitignore

@@ -44,3 +44,4 @@ bin/
 ### Mac OS ###
 .DS_Store
 /.idea/
+/bl-client/src/commonTest/resources/cookie.txt

bl-client/build.gradle.kts

@@ -19,12 +19,24 @@ kotlin {
         commonMain.dependencies {
             api(project(":bl-core"))
             implementation("io.ktor:ktor-client-core:$ktorVersion")
-            implementation("io.ktor:ktor-client-cio:$ktorVersion")
             implementation("io.ktor:ktor-client-websockets:$ktorVersion")
         }
 
+        appleMain.dependencies {
+            implementation("io.ktor:ktor-client-darwin:${ktorVersion}")
+        }
+
+        linuxMain.dependencies {
+            implementation("io.ktor:ktor-client-curl:${ktorVersion}")
+        }
+
+        mingwMain.dependencies {
+            implementation("io.ktor:ktor-client-winhttp:${ktorVersion}")
+        }
+
         commonTest.dependencies {
-            implementation(project(":bl-core"))
+            implementation(kotlin("test"))
+            implementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.11.0")
         }
     }
 }

bl-client/src/commonMain/kotlin/cn/rtast/bldm/client/bldm.kt

@@ -0,0 +1,91 @@
+/*
+ * Copyright © 2026 RTAkland
+ * Author: RTAkland
+ * Date: 2026/8/30
+ */
+
+
+@file:OptIn(InternalBldmApi::class)
+
+package cn.rtast.bldm.client
+
+import cn.rtast.bldm.core.BLDMConstants
+import cn.rtast.bldm.core.annotations.InternalBldmApi
+import cn.rtast.bldm.core.data.DMServerConf
+import cn.rtast.bldm.core.data.RealRoomId
+import cn.rtast.bldm.core.data.UserNavData
+import cn.rtast.bldm.core.protocol.Packet
+import cn.rtast.bldm.core.protocol.PacketDecoder
+import cn.rtast.bldm.core.protocol.PacketEncoder
+import cn.rtast.bldm.core.protocol.event.PacketEvents
+import cn.rtast.bldm.core.util._fromJson
+import cn.rtast.bldm.core.util.parseBuvidAndUid
+import io.ktor.client.plugins.websocket.*
+import io.ktor.client.request.*
+import io.ktor.client.statement.*
+import io.ktor.http.*
+import io.ktor.websocket.*
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
+import kotlin.time.Duration.Companion.seconds
+
+private val HEARTBEAT_INTERVAL = 30.seconds
+
+public suspend fun connectToBlDM(
+    roomId: Long,
+    cookie: String?,
+    events: PacketEvents.() -> Unit,
+) {
+    val parsedCookie = parseBuvidAndUid(cookie ?: "")
+    val packetEncoder = PacketEncoder()
+    val packetDecoder = PacketDecoder(events)
+    val realRoomId = httpClient.get(BLDMConstants.REAL_ROOM_ID_URL + roomId)
+        .bodyAsText()._fromJson<RealRoomId>()
+    val wbi = httpClient.get(BLDMConstants.USER_NAV_URL)
+        .bodyAsText()._fromJson<UserNavData>().signWbi(realRoomId.data.roomId)
+    val serverConf = httpClient.get(BLDMConstants.DM_SERVER_CONF_URL + "?$wbi") {
+        cookie?.let { header(HttpHeaders.Cookie, it) }
+    }.bodyAsText()._fromJson<DMServerConf>().data
+    val wsUrl = "ws://${serverConf.hostList.first().host}:${serverConf.hostList.first().wsPort}/sub"
+
+    httpClient.webSocket(wsUrl, {
+//        header(HttpHeaders.Host, "${serverConf.hostList.first().host}:${serverConf.hostList.first().wssPort}")
+//        header(HttpHeaders.Origin, "https://www.bilibili.com")
+    }) {
+        val authPacket = packetEncoder.authPacket(
+            parsedCookie.second ?: 0,
+            realRoomId.data.roomId,
+            parsedCookie.first ?: "",
+            serverConf.token
+        )
+        sendPacket(authPacket)
+        val heartbeatJob = launch {
+            val heartbeatPacket = packetEncoder.heartbeatPacket()
+            while (isActive) {
+                delay(HEARTBEAT_INTERVAL)
+                runCatching {
+                    sendPacket(heartbeatPacket)
+                }.onFailure {
+                    println("heartbeat failed ${it.message}")
+                }
+            }
+        }
+        try {
+            for (frame in incoming) {
+                if (frame !is Frame.Binary) continue
+                val data = frame.readBytes()
+                packetDecoder.decode(data)
+            }
+        } catch (e: Exception) {
+            e.printStackTrace()
+        } finally {
+            heartbeatJob.cancel()
+            println("Closed")
+        }
+    }
+    httpClient.close()
+}
+
+internal suspend fun DefaultWebSocketSession.sendPacket(packet: Packet) =
+    send(Frame.Binary(true, packet.toByteArray()))

bl-client/src/commonMain/kotlin/cn/rtast/bldm/client/constant.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright © 2026 RTAkland
+ * Author: RTAkland
+ * Date: 2026/8/30
+ */
+
+
+package cn.rtast.bldm.client
+
+import io.ktor.client.*
+import io.ktor.client.plugins.defaultRequest
+import io.ktor.client.plugins.websocket.*
+import io.ktor.client.request.header
+import io.ktor.http.HttpHeaders
+
+internal val httpClient = HttpClient {
+    install(WebSockets)
+
+    defaultRequest {
+        header(HttpHeaders.UserAgent, USER_AGENT)
+    }
+}
+
+internal const val USER_AGENT =
+    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/151.0.0.0 Safari/537.36"

bl-client/src/commonTest/kotlin/test/TestClient.kt

@@ -0,0 +1,39 @@
+/*
+ * Copyright © 2026 RTAkland
+ * Author: RTAkland
+ * Date: 2026/8/30
+ */
+
+
+package test
+
+import cn.rtast.bldm.client.connectToBlDM
+import kotlinx.coroutines.test.runTest
+import kotlinx.io.buffered
+import kotlinx.io.files.Path
+import kotlinx.io.files.SystemFileSystem
+import kotlinx.io.readString
+import kotlin.test.Test
+
+class TestClient {
+
+    private val cookie = SystemFileSystem.source(Path("src/commonTest/resources/cookie.txt"))
+        .buffered().readString()
+
+    @Test
+    fun `test bldm client`() = runTest {
+        connectToBlDM(6, cookie) {
+            onHeartbeat {
+                println("Heartbeat")
+            }
+
+            onMessage {
+                println(it.content)
+            }
+
+            onAuthReply {
+                println("auth reply")
+            }
+        }
+    }
+}

bl-client/src/commonTest/resources/cookie.example.txt

@@ -0,0 +1 @@
+Rename this file to cookie.txt and paste cookie here

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/annotations/InternalBldmApi.kt

@@ -0,0 +1,13 @@
+/*
+ * Copyright © 2026 RTAkland
+ * Author: RTAkland
+ * Date: 2026/8/30
+ */
+
+
+package cn.rtast.bldm.core.annotations
+
+@RequiresOptIn(level = RequiresOptIn.Level.ERROR)
+@Retention(AnnotationRetention.BINARY)
+@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY)
+public annotation class InternalBldmApi

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/constant.kt

@@ -6,6 +6,9 @@
 
 package cn.rtast.bldm.core
 
+public object BLDMConstants {
     public const val REAL_ROOM_ID_URL: String = "https://api.live.bilibili.com/room/v1/Room/room_init?id="
-public const val DM_SERVER_CONF_URL: String = "https://api.live.bilibili.com/xlive/web-room/v1/index/getDanmuInfo?id="
     public const val USER_NAV_URL: String = "https://api.bilibili.com/x/web-interface/nav"
+    public const val DM_SERVER_CONF_URL: String =
+        "https://api.live.bilibili.com/xlive/web-room/v1/index/getDanmuInfo"
+}

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/data/UserNavData.kt

@@ -16,9 +16,15 @@ import kotlin.time.Clock
 
 @Serializable
 public data class UserNavData(
+    val data: NavData,
+) {
+
+    @Serializable
+    public data class NavData(
         @SerialName("wbi_img")
         val wbiImg: WbiImg,
-) {
+    )
+
     @Serializable
     public data class WbiImg(
         @SerialName("img_url")
@@ -67,8 +73,8 @@ public data class UserNavData(
      * get resorted mixin key
      */
     private fun getMixinKey(): String =
-        (wbiImg.imgUrl.substringAfterLast('/').removeSuffix(".png") +
-                wbiImg.subUrl.substringAfterLast('/').removeSuffix(".png")).let { s ->
+        (data.wbiImg.imgUrl.substringAfterLast('/').removeSuffix(".png") +
+                data.wbiImg.subUrl.substringAfterLast('/').removeSuffix(".png")).let { s ->
             buildString { repeat(32) { append(s[MIXIN_KEY_ENC_TAB[it]]) } }
         }
 

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/data/_wbi_sign_payload.kt

@@ -1,27 +0,0 @@
-/*
- * Copyright © 2026 RTAkland
- * Author: RTAkland
- * Date: 2026/8/30
- */
-
-
-package cn.rtast.bldm.core.data
-
-import kotlinx.serialization.Serializable
-
-@Serializable
-@Suppress("ClassName")
-internal data class _wbi_sign_payload(
-    /**
-     * room id
-     */
-    val id: Long,
-    /**
-     * always be 0
-     */
-    val type: Int,
-    /**
-     * current unix timestamp (seconds)
-     */
-    val wts: Long
-)

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/data/protocol/AuthPayload.kt

@@ -7,7 +7,6 @@
 
 package cn.rtast.bldm.core.data.protocol
 
-import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 
 @Serializable
@@ -15,7 +14,7 @@ internal data class AuthPayload(
     /**
      * user id
      */
-    val uid: Int,
+    val uid: Long,
     /**
      * room id
      */

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/data/protocol/DanmuMessage.kt

@@ -0,0 +1,15 @@
+/*
+ * Copyright © 2026 RTAkland
+ * Author: RTAkland
+ * Date: 2026/8/30
+ */
+
+
+package cn.rtast.bldm.core.data.protocol
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+public data class DanmuMessage(
+    val content: String
+)

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/data/protocol/PacketMetadata.kt

@@ -0,0 +1,17 @@
+/*
+ * Copyright © 2026 RTAkland
+ * Author: RTAkland
+ * Date: 2026/8/30
+ */
+
+
+package cn.rtast.bldm.core.data.protocol
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+public data class PacketMetadata(
+    val packetLength: Int,
+    val protocolType: Int,
+    val opCode: Int
+)

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/protocol/Packet.kt

@@ -78,6 +78,6 @@ public data class Packet(
         writeShort(protocolVersion)
         writeInt(packetType)
         writeInt(sequence)
-        write(body, body.size)
+        write(body, 0, body.size)
     }.readByteArray()
 }

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/protocol/PacketDecoder.kt

@@ -4,8 +4,63 @@
  * Date: 2026/8/30
  */
 
-
 package cn.rtast.bldm.core.protocol
 
-class PacketDecoder {
+import cn.rtast.bldm.core.data.protocol.DanmuMessage
+import cn.rtast.bldm.core.protocol.ProtocolVersion.Raw
+import cn.rtast.bldm.core.protocol.ProtocolVersion.Zlib
+import cn.rtast.bldm.core.protocol.event.PacketEvents
+import cn.rtast.bldm.core.util.zlibDecompress
+import kotlinx.io.Buffer
+import kotlinx.io.readByteArray
+
+public class PacketDecoder(eventsBuilder: PacketEvents.() -> Unit) {
+    private val events = PacketEvents().apply(eventsBuilder)
+    private val persistentBuffer = Buffer()
+
+    public fun decode(bytes: ByteArray) {
+        persistentBuffer.write(bytes)
+        this.decodeBuffer(persistentBuffer)
+    }
+
+    private fun decodeBuffer(buffer: Buffer) {
+        while (buffer.size >= 16) {
+            val pk = buffer.peek()
+            val packetLength = pk.readInt()
+            val headerLength = pk.readShort()
+            val protocolVersion = pk.readShort()
+            val opCode = pk.readInt()
+
+            if (buffer.size < packetLength) break
+
+            val currentPacket = buffer.readByteArray(packetLength)
+            val bodySize = packetLength - headerLength
+            if (bodySize <= 0) continue
+
+            val body = currentPacket.copyOfRange(headerLength.toInt(), packetLength)
+
+            when (ProtocolVersion.fromCode(protocolVersion)) {
+                Raw -> handlePayload(opCode, body)
+                Zlib -> {
+                    val decompressed = body.zlibDecompress()
+                    val decompressedBuffer = Buffer().apply { write(decompressed) }
+                    decodeBuffer(decompressedBuffer)
+                }
+                null -> {}
+            }
+        }
+    }
+
+    private fun handlePayload(opCode: Int, body: ByteArray) {
+        when (PacketType.fromCode(opCode)) {
+            PacketType.AUTH_REPLY -> events.authReplyHandler?.invoke()
+            PacketType.HEARTBEAT_REPLY -> events.heartbeatHandler?.invoke()
+            PacketType.Message -> events.messageHandler?.invoke(decodeDanmuMessage(body))
+            else -> {}
+        }
+    }
+
+    private fun decodeDanmuMessage(bytes: ByteArray): DanmuMessage {
+        return DanmuMessage(bytes.decodeToString())
+    }
 }

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/protocol/PacketEncoder.kt

@@ -5,11 +5,14 @@
  */
 
 
+@file:OptIn(InternalBldmApi::class)
+
 package cn.rtast.bldm.core.protocol
 
+import cn.rtast.bldm.core.annotations.InternalBldmApi
 import cn.rtast.bldm.core.data.protocol.AuthPayload
 import cn.rtast.bldm.core.util.AutoIncrementInt
-import cn.rtast.bldm.core.util.encodeJson
+import cn.rtast.bldm.core.util._encodeJson
 
 public class PacketEncoder {
     public companion object {
@@ -18,10 +21,10 @@ public class PacketEncoder {
 
     private val _sequence by AutoIncrementInt()
 
-    public fun authPacket(uid: Int, roomId: Long, buvid: String, token: String): Packet {
+    public fun authPacket(uid: Long, roomId: Long, buvid: String, token: String): Packet {
         val payload = AuthPayload(uid, roomId, 2, buvid, "web", 2, token)
-            .encodeJson().encodeToByteArray()
-        return Packet(packetType = PacketType.AUTH, sequence = _sequence, body = payload)
+            ._encodeJson().encodeToByteArray()
+        return Packet(packetType = PacketType.AUTH.pkCode, sequence = _sequence, body = payload)
     }
 
     public fun heartbeatPacket(): Packet = Packet(packetType = 2, sequence = _sequence, body = HEARTBEAT_BODY)

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/protocol/PacketType.kt

@@ -7,12 +7,15 @@
 
 package cn.rtast.bldm.core.protocol
 
-public object PacketType {
-    public const val AUTH: Int = 7
-    public const val AUTH_REPLY: Int = 8
-    public const val HEARTBEAT: Int = 2
-    public const val HANDSHAKE_REPLY: Int = 1
-    public const val HEARTBEAT_REPLY: Int = 3
-    public const val SEND_MSG_REPLY: Int = 5
-    // TODO
+public enum class PacketType(public val pkCode: Int) {
+    AUTH(7),
+    AUTH_REPLY(8),
+    HEARTBEAT(2),
+    HEARTBEAT_REPLY(3),
+    Message(5);
+
+    public companion object {
+        private val map = PacketType.entries.associateBy { it.pkCode }
+        public fun fromCode(code: Int): PacketType? = map[code]
+    }
 }

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/protocol/ProtocolVersion.kt

@@ -0,0 +1,17 @@
+/*
+ * Copyright © 2026 RTAkland
+ * Author: RTAkland
+ * Date: 2026/8/30
+ */
+
+
+package cn.rtast.bldm.core.protocol
+
+internal enum class ProtocolVersion(val proto: Short) {
+    Raw(0), Zlib(2);
+
+    companion object {
+        private val map = entries.associateBy { it.proto }
+        fun fromCode(code: Short): ProtocolVersion? = map[code]
+    }
+}

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/protocol/event/PacketEvents.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright © 2026 RTAkland
+ * Author: RTAkland
+ * Date: 2026/8/30
+ */
+
+
+package cn.rtast.bldm.core.protocol.event
+
+import cn.rtast.bldm.core.data.protocol.DanmuMessage
+
+public class PacketEvents {
+    internal var messageHandler: ((DanmuMessage) -> Unit)? = null
+    internal var heartbeatHandler: (() -> Unit)? = null
+    internal var authReplyHandler: (() -> Unit)? = null
+
+    public fun onMessage(block: (DanmuMessage) -> Unit) {
+        messageHandler = block
+    }
+
+    public fun onHeartbeat(block: () -> Unit) {
+        heartbeatHandler = block
+    }
+
+    public fun onAuthReply(block: () -> Unit) {
+        authReplyHandler = block
+    }
+}

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/util/_cookie_parser.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright © 2026 RTAkland
+ * Author: RTAkland
+ * Date: 2026/8/30
+ */
+
+
+package cn.rtast.bldm.core.util
+
+/**
+ * get buvid and uid from a cookie
+ * first -> buvid
+ * second -> uid
+ */
+public fun parseBuvidAndUid(cookie: String): Pair<String?, Long?> {
+    if (cookie.isBlank()) return Pair(null, null)
+    var buvid: String? = null
+    var uid: Long? = null
+    cookie.split(';').forEach { entry ->
+        val parts = entry.split('=', limit = 2)
+        if (parts.size == 2) {
+            when (parts[0].trim()) {
+                "buvid3" -> buvid = parts[1].trim()
+                "DedeUserID" -> uid = parts[1].trim().toLongOrNull()
+            }
+        }
+    }
+    return buvid to uid
+}

bl-core/src/commonMain/kotlin/cn/rtast/bldm/core/util/json.kt

@@ -4,11 +4,21 @@
  * Date: 2026/8/30
  */
 
+@file:Suppress("FunctionName")
 
 package cn.rtast.bldm.core.util
 
+import cn.rtast.bldm.core.annotations.InternalBldmApi
 import kotlinx.serialization.json.Json
 
-internal inline fun <reified T> String.fromJson(): T = Json.decodeFromString(this)
+@InternalBldmApi
+@Suppress("ObjectPropertyName")
+public val _json: Json = Json {
+    ignoreUnknownKeys = true
+}
 
-internal inline fun <reified T> T.encodeJson(): String = Json.encodeToString(this)
+@InternalBldmApi
+public inline fun <reified T> String._fromJson(): T = _json.decodeFromString(this)
+
+@InternalBldmApi
+public inline fun <reified T> T._encodeJson(): String = _json.encodeToString(this)

bl-core/src/commonTest/kotlin/test/TestWbiSign.kt

@@ -16,7 +16,7 @@ class TestWbiSign {
     fun `test wbi sign`() {
         val imgUrl = "https://i0.hdslb.com/bfs/wbi/7cd084941338484aae1ad9425b84077c.png"
         val subUrl = "https://i0.hdslb.com/bfs/wbi/4932caff0ff746eab6f01bf08b70ac45.png"
-        val signWbi = UserNavData(UserNavData.WbiImg(imgUrl, subUrl)).signWbi(27245513)
+        val signWbi = UserNavData(UserNavData.NavData(UserNavData.WbiImg(imgUrl, subUrl))).signWbi(27245513)
         println(signWbi)
     }
 }

bl-core/src/jvmMain/kotlin/cn/rtast/bldm/core/util/zlib.jvm.kt

@@ -11,7 +11,7 @@ import java.io.ByteArrayOutputStream
 import java.util.zip.Inflater
 
 public actual fun ByteArray.zlibDecompress(): ByteArray {
-    val inflater = Inflater(true)
+    val inflater = Inflater(false)
     val outputStream = ByteArrayOutputStream(this.size)
     val buffer = ByteArray(1024)
     inflater.setInput(this)

bl-core/src/nativeMain/kotlin/cn/rtast/bldm/core/util/zlib.native.kt

@@ -4,7 +4,6 @@
  * Date: 2026/8/30
  */
 
-
 @file:OptIn(ExperimentalForeignApi::class)
 
 package cn.rtast.bldm.core.util
@@ -12,7 +11,7 @@ package cn.rtast.bldm.core.util
 import kotlinx.cinterop.*
 import platform.zlib.*
 
-private const val MAX_WBITS = 15
+private const val ENABLE_ZLIB_GZIP_HEADER = 15 + 32
 
 public actual fun ByteArray.zlibDecompress(): ByteArray {
     if (isEmpty()) return ByteArray(0)
@@ -21,7 +20,14 @@ public actual fun ByteArray.zlibDecompress(): ByteArray {
         stream.zalloc = null
         stream.zfree = null
         stream.opaque = null
-        check(inflateInit2_(stream.ptr, MAX_WBITS, ZLIB_VERSION, sizeOf<z_stream>().toInt()) == Z_OK) { "inflateInit2_ failed" }
+
+        val initResult = inflateInit2_(
+            stream.ptr,
+            ENABLE_ZLIB_GZIP_HEADER,
+            ZLIB_VERSION,
+            sizeOf<z_stream>().toInt()
+        )
+        check(initResult == Z_OK) { "inflateInit2_ failed with code: $initResult" }
 
         val inputPinned = this@zlibDecompress.pin()
         try {
@@ -31,14 +37,15 @@ public actual fun ByteArray.zlibDecompress(): ByteArray {
             val bufferSize = 4096
             val tempBuffer = ByteArray(bufferSize)
             val tempPinned = tempBuffer.pin()
-            val output = ArrayList<Byte>(this@zlibDecompress.size * 2)
+            val output = ArrayList<Byte>(this@zlibDecompress.size * 3)
 
             try {
+                var result: Int
                 do {
                     stream.next_out = tempPinned.addressOf(0).reinterpret()
                     stream.avail_out = bufferSize.toUInt()
 
-                    val result = inflate(stream.ptr, Z_NO_FLUSH)
+                    result = inflate(stream.ptr, Z_NO_FLUSH)
                     check(result == Z_OK || result == Z_STREAM_END) { "inflate error: $result" }
 
                     val bytesDecompressed = bufferSize - stream.avail_out.toInt()
@@ -47,7 +54,7 @@ public actual fun ByteArray.zlibDecompress(): ByteArray {
                     }
 
                     if (result == Z_STREAM_END) break
-                } while (stream.avail_out == 0u)
+                } while (stream.avail_in > 0u || stream.avail_out == 0u)
             } finally {
                 tempPinned.unpin()
             }