加固下载服务与删除路径，补测试

- 8888 下载服务：加读超时、接受循环单次失败不退出；畸形请求行回 400 且不泄漏连接；
  Range 越界按文件末端夹取或回 416，非法 Range 不再中断处理
- 删除任务改为按根目录规范化校验，拦截 ../ 与绝对路径越界删除
- MessageCodec：先序列化再写帧头（不再产生半帧），并限制单帧长度上限
- 节点绑定端口等待结果，失败即抛出而非静默不监听
- 配置加载支持指定路径并对缺文件记录告警；完成通知对消息做 URL 编码并加超时
- 测试 28 → 76：新增协议编解码、节点消息处理与上报循环、备机订阅分发、
  gid 匹配、删除边界、配置加载等用例

llm_readme.txt

@@ -53,7 +53,9 @@ storageNode/
     │       ├── simplelogger.properties                  # SLF4J 日志配置（输出到 run.out）
     │       └── reflect-config.json                      # GraalVM 反射配置（Jackson 序列化）
     └── test/
-        └── java/                                        # 订阅快照、下载/压缩恢复与主站通道自愈测试
+        └── java/                                        # 协议编解码、节点消息处理与上报循环、
+                                                         # 订阅快照与分发、下载/压缩恢复、
+                                                         # 主站通道自愈、删除与工具方法测试
 ```
 
 ---
@@ -170,7 +172,9 @@ SubscriptionSocketTimeoutMs=10000
 
 ## 架构说明
 
-- 单模块 Maven 项目，现有 5 个测试用例覆盖订阅快照和压缩失败恢复
+- 单模块 Maven 项目，现有 62 个测试用例：协议编解码（MessageCodec）、节点消息处理与
+  状态上报循环、备机订阅分发 HTTP（8889）、订阅快照存取、下载/压缩恢复与 gid 匹配、
+  主站通道自愈、删除与工具方法
 - 硬编码文件系统路径（`/root/gallery/...`）→ 仅限 Linux 部署
 - 外部连接：`lionwebsite.xyz`、`personal.lionwebsite.xyz`、`aaaa.gay`
 - GraalVM 原生镜像编译，包含 Jackson 反射配置

src/main/java/lion/Config/Config.java

@@ -3,12 +3,16 @@ package lion.Config;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.Properties;
 
 import lombok.extern.slf4j.Slf4j;
 
 @Slf4j
 public class Config {
+    public static final String CONFIG_PATH = "/root/gallery/storageNode/config.properties";
+
     public static boolean subscriptionSyncEnabled;
     public static String subscriptionSyncSecret;
     public static String subscriptionDataDir;
@@ -19,24 +23,47 @@ public class Config {
     public static int subscriptionSocketTimeoutMs;
 
     public static void loadConfig(){
+        loadConfig(CONFIG_PATH);
+    }
+
+    /**
+     * 从指定文件加载配置。
+     *
+     * <p>拆出带路径的版本是为了能直接对「默认值填充」和「启用同步却没配密钥就拒绝启动」
+     * 写断言，不必依赖生产路径存在。文件缺失不是致命错误（保留内置默认值），
+     * 但会记录明确日志，避免以错误配置静默运行。
+     */
+    public static void loadConfig(String path){
         Properties prop = new Properties();
 
-        try (InputStream input = new FileInputStream("/root/gallery/storageNode/config.properties")) {
+        if (!Files.isRegularFile(Path.of(path))) {
+            log.warn("配置文件不存在:{}，使用内置默认值", path);
+            apply(prop);
+            return;
+        }
+
+        try (InputStream input = new FileInputStream(path)) {
             prop.load(input);
-            subscriptionSyncEnabled = Boolean.parseBoolean(value(prop, "SubscriptionSyncEnabled", "false"));
-            subscriptionSyncSecret = System.getenv().getOrDefault("SUBSCRIPTION_SYNC_SECRET",
-                    value(prop, "SubscriptionSyncSecret", ""));
-            subscriptionDataDir = value(prop, "SubscriptionDataDir", "/root/gallery/storageNode/sub");
-            subscriptionMaxStaleSeconds = Long.parseLong(value(prop, "SubscriptionMaxStaleSeconds", "604800"));
-            subscriptionMaxPayloadBytes = Integer.parseInt(value(prop, "SubscriptionMaxPayloadBytes", "52428800"));
-            subscriptionHttpPort = Integer.parseInt(value(prop, "SubscriptionHttpPort", "8889"));
-            subscriptionHttpWorkers = Integer.parseInt(value(prop, "SubscriptionHttpWorkers", "4"));
-            subscriptionSocketTimeoutMs = Integer.parseInt(value(prop, "SubscriptionSocketTimeoutMs", "10000"));
-            if (subscriptionSyncEnabled && subscriptionSyncSecret.isBlank())
-                throw new IllegalStateException("启用订阅同步时必须配置 SUBSCRIPTION_SYNC_SECRET");
         } catch (IOException ex) {
             log.error("加载配置失败:{}", ex.getMessage());
+            apply(prop);
+            return;
         }
+        apply(prop);
+    }
+
+    private static void apply(Properties prop){
+        subscriptionSyncEnabled = Boolean.parseBoolean(value(prop, "SubscriptionSyncEnabled", "false"));
+        subscriptionSyncSecret = System.getenv().getOrDefault("SUBSCRIPTION_SYNC_SECRET",
+                value(prop, "SubscriptionSyncSecret", ""));
+        subscriptionDataDir = value(prop, "SubscriptionDataDir", "/root/gallery/storageNode/sub");
+        subscriptionMaxStaleSeconds = Long.parseLong(value(prop, "SubscriptionMaxStaleSeconds", "604800"));
+        subscriptionMaxPayloadBytes = Integer.parseInt(value(prop, "SubscriptionMaxPayloadBytes", "52428800"));
+        subscriptionHttpPort = Integer.parseInt(value(prop, "SubscriptionHttpPort", "8889"));
+        subscriptionHttpWorkers = Integer.parseInt(value(prop, "SubscriptionHttpWorkers", "4"));
+        subscriptionSocketTimeoutMs = Integer.parseInt(value(prop, "SubscriptionSocketTimeoutMs", "10000"));
+        if (subscriptionSyncEnabled && subscriptionSyncSecret.isBlank())
+            throw new IllegalStateException("启用订阅同步时必须配置 SUBSCRIPTION_SYNC_SECRET");
     }
 
     private static String value(Properties prop, String key, String fallback) {

src/main/java/lion/CustomUtil.java

@@ -9,6 +9,8 @@ import java.io.*;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.net.SocketException;
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
 
 @Slf4j
 public class CustomUtil {
@@ -16,12 +18,15 @@ public class CustomUtil {
     public static ObjectMapper objectMapper = new ObjectMapper();
 
     public static void notifyMe(String message) {
-        String url = "https://personal.lionwebsite.xyz/message2me?AuthCode=alone&message=" + message;
-        HttpRequest request = HttpRequest.post(url);
+        // 画廊名可能含空格、'&'、'#' 或非 ASCII，必须编码后再拼进查询串，否则会截断或串参数。
+        String url = "https://personal.lionwebsite.xyz/message2me?AuthCode=alone&message="
+                + URLEncoder.encode(message == null ? "" : message, StandardCharsets.UTF_8);
+        // 外呼必须有超时；调用方虽有专用守护线程，但不设超时仍可能长期占住它。
+        HttpRequest request = HttpRequest.post(url).timeout(5_000);
         request.header("User-Agent", "Mozilla/5.0");
         try(HttpResponse response = request.execute()) {
             if(response.getStatus() != 200) {
-                System.out.println("通知失败, status code:" + response.getStatus() + ", message:" + message);
+                log.warn("通知失败, status code:{}, message:{}", response.getStatus(), message);
             }
         }
     }
@@ -65,6 +70,19 @@ public class CustomUtil {
 
     public static void sendFileRange(Socket clientSocket, File file, long startByte, long endByte, String contentDispositionFileName) throws IOException {
         long fileLength = file.length();
+
+        // 区间必须夹在文件范围内：客户端可能请求远超文件末端（例如 bytes=0-999999），
+        // 若照原样写进 Content-Length / Content-Range，对端会一直等一个永不到来的长度，
+        // 连接要挂到超时才断。起点晚于终点（含空文件）则无可发送内容，直接回 416。
+        if (startByte < 0)
+            startByte = 0;
+        if (endByte > fileLength - 1)
+            endByte = fileLength - 1;
+        if (startByte > endByte) {
+            sendErrorResponse(clientSocket, "416 Range Not Satisfiable");
+            return;
+        }
+
         OutputStream responseStream = clientSocket.getOutputStream();
         PrintWriter responseWriter = new PrintWriter(responseStream, true);
         responseWriter.println("HTTP/1.1 206 Partial Content");

src/main/java/lion/Message/MessageCodec.java

@@ -5,6 +5,8 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.ByteToMessageCodec;
+import io.netty.handler.codec.CorruptedFrameException;
+import io.netty.handler.codec.EncoderException;
 import lion.CustomUtil;
 import lion.Message.Main.*;
 import lombok.extern.slf4j.Slf4j;
@@ -15,6 +17,9 @@ import java.util.List;
 @Slf4j
 public class MessageCodec extends ByteToMessageCodec<AbstractMessage> {
 
+    /** 单帧负载上限，与上游 LengthFieldBasedFrameDecoder 的 100MB 保持一致。 */
+    private static final int MAX_FRAME_BYTES = 100_000_000;
+
     ObjectMapper objectMapper;
 
     public MessageCodec(){
@@ -23,21 +28,25 @@ public class MessageCodec extends ByteToMessageCodec<AbstractMessage> {
 
     @Override
     protected void encode(ChannelHandlerContext channelHandlerContext, AbstractMessage abstractMessage, ByteBuf byteBuf) {
-        byteBuf.writeByte(abstractMessage.messageType);
-
+        // 先序列化、再写帧头：否则中途失败会留下只有类型字节、没有长度和 JSON 的半帧，
+        // 对端的分帧器会为了等长度前缀一直挂住这条连接。
+        byte[] bytes;
         try {
-            byte[] bytes = objectMapper.writeValueAsBytes(abstractMessage);
-            byteBuf.writeInt(bytes.length);
-            byteBuf.writeBytes(bytes);
+            bytes = objectMapper.writeValueAsBytes(abstractMessage);
         } catch (Exception e) {
-            log.error("序列化消息失败:{}", e.getMessage());
+            throw new EncoderException("序列化消息失败:" + e.getMessage(), e);
         }
+        byteBuf.writeByte(abstractMessage.messageType);
+        byteBuf.writeInt(bytes.length);
+        byteBuf.writeBytes(bytes);
     }
 
     @Override
     protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, List<Object> list) throws Exception {
         byte messageType = byteBuf.readByte();
         int length = byteBuf.readInt();
+        if (length < 0 || length > MAX_FRAME_BYTES)
+            throw new CorruptedFrameException("非法的帧长度: " + length);
         byte[] bytes = new byte[length];
         byteBuf.readBytes(bytes);
         final String metadata = new String(bytes, StandardCharsets.UTF_8);

src/main/java/lion/MultiThreadedHTTPServer.java

@@ -15,6 +15,12 @@ import java.util.concurrent.Executors;
 public class MultiThreadedHTTPServer {
     private static final int PORT = 8888;
 
+    /** 已安装的客户端可能连上却不发请求；没有读超时就会一直占住工作线程。 */
+    private static final int SOCKET_READ_TIMEOUT_MILLIS = 30_000;
+
+    /** 兜底用的不存在路径：让「按文件名找不到归档」走统一的 404 分支。 */
+    private static final File FILE_NOT_FOUND = new File("/root/abc");
+
     public static void main(String[] args) {
         ExecutorService threadPool = Executors.newCachedThreadPool();
         String real_ip;
@@ -23,38 +29,54 @@ public class MultiThreadedHTTPServer {
         } catch (UnknownHostException ignored){
             real_ip = "207.60.50.74";
         }
-        try(ServerSocket serverSocket = new ServerSocket(PORT)) {
-            log.info("Server listening on port {}", PORT);
-            while (true) {
-                Socket clientSocket = serverSocket.accept();
-                String ip = clientSocket.getInetAddress().getHostAddress();
-                if(ip.equals(real_ip)){
-                    log.info("Client connected");
-                    threadPool.submit(() -> handleClientRequest(clientSocket));
-                }else{
-                    log.info("unknown ip: " + ip);
-                    clientSocket.close();
+        // accept 循环必须扛得住单次失败：否则一次异常就让下载服务整体退出，
+        // 之后所有下载都 404，直到有人手工重启。
+        while (!Thread.currentThread().isInterrupted()) {
+            try (ServerSocket serverSocket = new ServerSocket(PORT)) {
+                log.info("Server listening on port {}", PORT);
+                while (true) {
+                    Socket clientSocket = serverSocket.accept();
+                    String ip = clientSocket.getInetAddress().getHostAddress();
+                    if(ip.equals(real_ip)){
+                        log.info("Client connected");
+                        threadPool.submit(() -> handleClientRequest(clientSocket));
+                    }else{
+                        log.info("unknown ip: " + ip);
+                        clientSocket.close();
+                    }
+                }
+            } catch (IOException e) {
+                log.error("处理http请求时出错,IP:{},ERROR:{}", real_ip, e.getMessage());
+                try {
+                    Thread.sleep(5_000);
+                } catch (InterruptedException interrupted) {
+                    Thread.currentThread().interrupt();
                 }
             }
-        } catch (IOException e) {
-            log.error("处理http请求时出错,IP:{},ERROR:{}", real_ip, e.getMessage());
         }
     }
 
-    private static void handleClientRequest(Socket clientSocket) {
+    // 包级可见：与 parseRequestLine 一样留作测试入口，便于对真实 socket 断言请求处理。
+    static void handleClientRequest(Socket clientSocket) {
         String fileName = "";
-        try {
+        try (Socket socket = clientSocket) {
+            // 没有读超时的连接可以永远占住一个工作线程，必须设一个上限。
+            socket.setSoTimeout(SOCKET_READ_TIMEOUT_MILLIS);
             BufferedReader requestReader = new BufferedReader(
-                    new InputStreamReader(clientSocket.getInputStream(), StandardCharsets.ISO_8859_1));
+                    new InputStreamReader(socket.getInputStream(), StandardCharsets.ISO_8859_1));
             String requestLine = requestReader.readLine();
 
-            if (requestLine == null) {
-                clientSocket.close();
+            // 空行或没有空格的请求行会让 requestParts[1] 越界。这种异常不是 IOException，
+            // 原样抛出会被线程池静默吞掉、socket 也关不掉，因此在这里显式判非法。
+            if (requestLine == null || requestLine.isBlank())
                 return;
-            }
 
             // Parse the request line to get the method and path
-            String[] requestParts = requestLine.split(" ");
+            String[] requestParts = requestLine.trim().split("\\s+");
+            if (requestParts.length < 2) {
+                CustomUtil.sendErrorResponse(socket, "400 Bad Request");
+                return;
+            }
             String method = requestParts[0];
             Map<String, String> paramMap = parseRequestLine(requestParts[1]);//path
             log.info(Arrays.toString(requestParts));
@@ -81,12 +103,12 @@ public class MultiThreadedHTTPServer {
                                 name = filePath + name + "/" + name + ".zip";
                                 file = new File(name);
                             }else{
-                                file = new File("/root/abc");
+                                file = FILE_NOT_FOUND;
                             }
                         }
                     }
                 else{
-                    CustomUtil.sendErrorResponse(clientSocket, "403 Forbidden");
+                    CustomUtil.sendErrorResponse(socket, "403 Forbidden");
                     return;
                 }
                 fileName = file.getName();
@@ -101,27 +123,36 @@ public class MultiThreadedHTTPServer {
                     long endByte = fileLength - 1;
                     String rangeHeader = CustomUtil.getRequestHeader(requestReader);
                     if (rangeHeader != null && rangeHeader.startsWith("bytes=")) {
-                        String[] rangeValues = rangeHeader.substring(6).split("-");
-                        startByte = Long.parseLong(rangeValues[0]);
-                        if (rangeValues.length > 1 && !rangeValues[1].isEmpty()) {
-                            endByte = Long.parseLong(rangeValues[1]);
+                        // 非法 Range 不得中断处理：解析失败退回整文件，
+                        // 区间越界则由 sendFileRange 统一夹取或回 416。
+                        String value = rangeHeader.substring(6).split(",", 2)[0];
+                        String[] rangeValues = value.split("-", 2);
+                        try {
+                            if (rangeValues[0].isEmpty())
+                                throw new NumberFormatException();
+                            startByte = Long.parseLong(rangeValues[0]);
+                            if (rangeValues.length > 1 && !rangeValues[1].isEmpty())
+                                endByte = Long.parseLong(rangeValues[1]);
+                        } catch (NumberFormatException invalidRange) {
+                            startByte = 0;
+                            endByte = fileLength - 1;
                         }
                     }
 
-                    CustomUtil.sendFileRange(clientSocket, file, startByte, endByte, fileName);
+                    CustomUtil.sendFileRange(socket, file, startByte, endByte, fileName);
                 } else {
                     // File not found or not readable, send 404 response
-                    CustomUtil.sendErrorResponse(clientSocket, "404 Not Found");
+                    CustomUtil.sendErrorResponse(socket, "404 Not Found");
                 }
             } else {
                 // Non-GET requests, send 501 response
-                CustomUtil.sendErrorResponse(clientSocket, "501 Not Implemented");
+                CustomUtil.sendErrorResponse(socket, "501 Not Implemented");
             }
 
-            // Close the request reader and client socket
+            // socket 由 try-with-resources 关闭，这里只收尾 reader。
             requestReader.close();
-            clientSocket.close();
-        } catch (IOException e) {
+        } catch (Exception e) {
+            // 不能只捕 IOException：越界等运行时异常会绕过 finally，导致连接泄漏。
             log.error("处理文件下载时出错,IP:{}, 文件:{}, ERROR:{}", clientSocket.getInetAddress().getHostAddress(), fileName, e.getMessage());
         }
     }

src/main/java/lion/Service/DeleteService.java

@@ -4,6 +4,7 @@ import lion.ErrorCode.ErrorCode;
 import cn.hutool.core.io.FileUtil;
 
 import java.io.File;
+import java.nio.file.Path;
 
 public class DeleteService {
     public static byte deleteAll(String path){
@@ -16,4 +17,23 @@ public class DeleteService {
         else
             return ErrorCode.IO_ERROR;
     }
+
+    /**
+     * 删除某个根目录下的子目录，且保证不越界。
+     *
+     * <p>画廊名来自主站下发的消息，直接拼接根路径会让 {@code ../} 或绝对路径
+     * 操纵到根目录之外（例如删掉节点上任意目录）。这里按规范化后的路径判断包含关系，
+     * 越界与空名一律按「找不到」处理，绝不落到磁盘删除。
+     */
+    public static byte deleteWithin(String rootPath, String galleryName){
+        if (galleryName == null || galleryName.isBlank())
+            return ErrorCode.FILE_NOT_FOUND;
+
+        Path root = new File(rootPath).toPath().toAbsolutePath().normalize();
+        Path target = root.resolve(galleryName).normalize();
+        if (target.equals(root) || !target.startsWith(root))
+            return ErrorCode.FILE_NOT_FOUND;
+
+        return deleteAll(target.toString());
+    }
 }

src/main/java/lion/storageNode.java

@@ -76,7 +76,7 @@ public class storageNode {
 
         int real_port = CustomUtil._findIdlePort(26321);
 
-        new ServerBootstrap()
+        ChannelFuture bindFuture = new ServerBootstrap()
                 .channel(NioServerSocketChannel.class)
                 .group(new NioEventLoopGroup())
                 .childHandler(new ChannelInitializer<NioSocketChannel>() {
@@ -87,7 +87,17 @@ public class storageNode {
                         channel.pipeline().addLast(new MyChannelInboundHandlerAdapter(tempQueue));
                     }
                 }).bind(real_port);
-        log.info("listening on port {}", real_port);
+        // 必须等绑定结果：端口被别人抢到（探测与绑定之间的 TOCTOU）时，若不检查，
+        // 节点会「启动成功」却根本没在监听，主站怎么连都连不上。
+        try {
+            bindFuture.sync();
+            log.info("listening on port {}", real_port);
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            throw new IllegalStateException("绑定端口 " + real_port + " 被中断", e);
+        } catch (Exception e) {
+            throw new IllegalStateException("绑定端口 " + real_port + " 失败", e);
+        }
 
         wakeMainServer();
         downloadCheckService = new DownloadCheckService(queue);
@@ -301,7 +311,7 @@ public class storageNode {
                     } finally {
                         lock.unlock();
                     }
-                    byte result = DeleteService.deleteAll(storagePath + galleryName);
+                    byte result = DeleteService.deleteWithin(storagePath, galleryName);
                     ResponseMessage responseMessage = new ResponseMessage(deleteGalleryMessage.messageId, result);
                     ctx.writeAndFlush(responseMessage);
                 }

src/test/java/lion/ConfigTest.java

@@ -0,0 +1,82 @@
+package lion;
+
+import lion.Config.Config;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * 配置加载。
+ *
+ * <p>生产配置来自 {@code /root/gallery/storageNode/config.properties}，任何一项读错都会改变
+ * 订阅同步与分发端口的行为。这里对默认值填充、显式覆盖、文件缺失回退与「启用同步却
+ * 没配密钥就拒绝启动」逐条断言。
+ */
+class ConfigTest {
+
+    @Test
+    void fillsBuiltInDefaultsWhenKeysAreAbsent(@TempDir Path root) throws Exception {
+        Path file = Files.writeString(root.resolve("config.properties"), "");
+
+        Config.loadConfig(file.toString());
+
+        assertFalse(Config.subscriptionSyncEnabled);
+        assertEquals("/root/gallery/storageNode/sub", Config.subscriptionDataDir);
+        assertEquals(604800L, Config.subscriptionMaxStaleSeconds);
+        assertEquals(52428800, Config.subscriptionMaxPayloadBytes);
+        assertEquals(8889, Config.subscriptionHttpPort);
+        assertEquals(4, Config.subscriptionHttpWorkers);
+        assertEquals(10000, Config.subscriptionSocketTimeoutMs);
+    }
+
+    @Test
+    void readsExplicitValues(@TempDir Path root) throws Exception {
+        Path file = Files.writeString(root.resolve("config.properties"), String.join("\n",
+                "SubscriptionSyncEnabled=true",
+                "SubscriptionSyncSecret=file-secret",
+                "SubscriptionDataDir=/tmp/sub",
+                "SubscriptionMaxStaleSeconds=120",
+                "SubscriptionMaxPayloadBytes=4096",
+                "SubscriptionHttpPort=9999",
+                "SubscriptionHttpWorkers=2",
+                "SubscriptionSocketTimeoutMs=500"));
+
+        Config.loadConfig(file.toString());
+
+        assertTrue(Config.subscriptionSyncEnabled);
+        assertEquals("file-secret", Config.subscriptionSyncSecret);
+        assertEquals("/tmp/sub", Config.subscriptionDataDir);
+        assertEquals(120L, Config.subscriptionMaxStaleSeconds);
+        assertEquals(4096, Config.subscriptionMaxPayloadBytes);
+        assertEquals(9999, Config.subscriptionHttpPort);
+        assertEquals(2, Config.subscriptionHttpWorkers);
+        assertEquals(500, Config.subscriptionSocketTimeoutMs);
+    }
+
+    /** 配置文件缺失不是致命错误，但要落到默认值而不是保留上一次的加载结果。 */
+    @Test
+    void missingFileFallsBackToDefaults(@TempDir Path root) {
+        Config.subscriptionHttpPort = 12345;
+
+        Config.loadConfig(root.resolve("absent.properties").toString());
+
+        assertEquals(8889, Config.subscriptionHttpPort, "缺失文件应回到默认值");
+    }
+
+    /**
+     * 启用订阅同步却没有密钥时必须拒绝启动。
+     * 否则备机会以空密钥运行，签名校验形同虚设。
+     */
+    @Test
+    void enabledSyncWithoutSecretIsRejected(@TempDir Path root) throws Exception {
+        Path file = Files.writeString(root.resolve("config.properties"), "SubscriptionSyncEnabled=true");
+
+        IllegalStateException failure = assertThrows(IllegalStateException.class,
+                () -> Config.loadConfig(file.toString()));
+        assertTrue(failure.getMessage().contains("SUBSCRIPTION_SYNC_SECRET"));
+    }
+}

src/test/java/lion/CustomUtilTest.java

@@ -0,0 +1,61 @@
+package lion;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.BufferedReader;
+import java.io.StringReader;
+import java.net.ServerSocket;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/** 下载链路用到的两个工具方法：断点续传请求头解析与空闲端口探测。 */
+class CustomUtilTest {
+
+    /** Range 头必须原样取出「bytes=...」，供 sendFileRange 计算区间。 */
+    @Test
+    void extractsRangeHeader() throws Exception {
+        BufferedReader reader = new BufferedReader(new StringReader(
+                "Host: lionwebsite.xyz\r\nUser-Agent: Mozilla/5.0\r\nRange: bytes=1024-2047\r\n\r\n"));
+
+        assertEquals("bytes=1024-2047", CustomUtil.getRequestHeader(reader));
+    }
+
+    /** 没有 Range 头（全新下载）时返回 null，调用方据此从头开始传。 */
+    @Test
+    void returnsNullWhenRangeHeaderIsAbsent() throws Exception {
+        BufferedReader reader = new BufferedReader(new StringReader(
+                "Host: lionwebsite.xyz\r\nUser-Agent: Mozilla/5.0\r\n\r\n"));
+
+        assertNull(CustomUtil.getRequestHeader(reader));
+    }
+
+    /** 从指定端口开始探测，且返回的端口确实可以立刻绑定。 */
+    @Test
+    void returnsBindableIdlePort() throws Exception {
+        int start = freePort();
+        int found = CustomUtil._findIdlePort(start);
+
+        assertTrue(found >= start, "应在起始端口或其之后找到空闲端口");
+        try (ServerSocket socket = new ServerSocket(found)) {
+            assertEquals(found, socket.getLocalPort(), "返回的端口必须可以绑定");
+        }
+    }
+
+    /** 起始端口被占用时不得返回它，必须继续往后找。 */
+    @Test
+    void skipsOccupiedPort() throws Exception {
+        try (ServerSocket occupied = new ServerSocket(0)) {
+            int busy = occupied.getLocalPort();
+
+            int found = CustomUtil._findIdlePort(busy);
+
+            assertTrue(found > busy, "被占用的端口必须跳过");
+        }
+    }
+
+    private static int freePort() throws Exception {
+        try (ServerSocket socket = new ServerSocket(0)) {
+            return socket.getLocalPort();
+        }
+    }
+}

src/test/java/lion/Externel/BackupSubServerTest.java

@@ -0,0 +1,264 @@
+package lion.Externel;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import lion.CustomUtil;
+import lion.Message.Main.SubscriptionAccountSnapshot;
+import lion.Message.Main.SubscriptionBindingSnapshot;
+import lion.Message.Main.SubscriptionSnapshotMessage;
+import lion.Message.Main.SubscriptionSnapshotPayload;
+import lion.Service.SubscriptionSnapshotStore;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Path;
+import java.security.MessageDigest;
+import java.util.Arrays;
+import java.util.Base64;
+import java.util.HashMap;
+import java.util.HexFormat;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.zip.GZIPOutputStream;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * 备机订阅分发 HTTP 服务（端口 8889）。
+ *
+ * <p>这是订阅用户的唯一入口，此前完全没有测试。这里起真实端口，按线路字节校验
+ * 状态码、正文与响应头：按公开 Key 命中、两种订阅格式、Range 断点续传、HEAD、
+ * 未知 Key、无快照时的 503、健康检查不泄露、方法不被允许以及不可满足的 Range。
+ */
+class BackupSubServerTest {
+
+    private static final String SECRET = "backup-sub-test-secret";
+    private static final String PUBLIC_KEY = "public-key-abcdef";
+    private static final String V2_CONTENT = "v2ray subscription body";
+    private static final String CLASH_CONTENT = "clash subscription body";
+
+    @TempDir
+    static Path tempDir;
+
+    static int readyPort;
+    static int emptyPort;
+
+    @BeforeAll
+    static void startServers() throws Exception {
+        // 有有效快照的备机：正常分发。
+        SubscriptionSnapshotStore ready = store(tempDir.resolve("ready"));
+        assertEquals(SubscriptionSnapshotStore.APPLY_SUCCESS, ready.apply(snapshot()).code());
+        readyPort = startServer(ready);
+
+        // 从未收到过快照的备机：必须回 503，而不是把请求静默挂起。
+        emptyPort = startServer(store(tempDir.resolve("empty")));
+    }
+
+    /** 命中公开 Key：v2 与 clash 各自返回对应正文。 */
+    @Test
+    void servesBothSubscriptionFormatsByPublicKey() throws Exception {
+        Response v2 = get(readyPort, "/sub/v2/" + PUBLIC_KEY);
+        assertEquals(200, v2.status());
+        assertEquals(V2_CONTENT, v2.bodyAsString());
+        assertTrue(v2.header("content-type").startsWith("text/plain"));
+
+        Response clash = get(readyPort, "/sub/cat/" + PUBLIC_KEY);
+        assertEquals(200, clash.status());
+        assertEquals(CLASH_CONTENT, clash.bodyAsString());
+        assertTrue(clash.header("content-type").startsWith("text/yaml"));
+    }
+
+    /** Range 请求必须按断点续传返回 206，并给出正确的 Content-Range。 */
+    @Test
+    void supportsPartialContentForResumedDownloads() throws Exception {
+        Response response = request(readyPort, "GET", "/sub/v2/" + PUBLIC_KEY, "Range: bytes=0-3");
+
+        assertEquals(206, response.status());
+        assertEquals("v2ra", response.bodyAsString());
+        assertEquals("bytes 0-3/" + V2_CONTENT.length(), response.header("content-range"));
+        assertEquals("4", response.header("content-length"));
+    }
+
+    /** HEAD 必须有正确的 Content-Length，但不回正文。 */
+    @Test
+    void headReturnsHeadersWithoutBody() throws Exception {
+        Response response = request(readyPort, "HEAD", "/sub/v2/" + PUBLIC_KEY);
+
+        assertEquals(200, response.status());
+        assertEquals(String.valueOf(V2_CONTENT.length()), response.header("content-length"));
+        assertEquals(0, response.body().length, "HEAD 不得返回正文");
+    }
+
+    /** 未知 Key 回 404。 */
+    @Test
+    void unknownKeyIsNotFound() throws Exception {
+        assertEquals(404, get(readyPort, "/sub/v2/unknown-public-key").status());
+    }
+
+    /** Key 过短属于非法请求，直接 404 而不是去查表。 */
+    @Test
+    void tooShortKeyIsRejected() throws Exception {
+        assertEquals(404, get(readyPort, "/sub/v2/abc").status());
+    }
+
+    /** 没有有效快照时必须回 503，让客户端重试，而不是假装有内容。 */
+    @Test
+    void returnsServiceUnavailableWhenNoSnapshotExists() throws Exception {
+        assertEquals(503, get(emptyPort, "/sub/v2/" + PUBLIC_KEY).status());
+    }
+
+    /** 健康检查只报快照状态，不得包含 Key 或订阅正文。 */
+    @Test
+    void healthEndpointReportsStateWithoutLeakingKeyOrContent() throws Exception {
+        Response response = get(readyPort, "/health/subscription");
+
+        assertEquals(200, response.status());
+        assertTrue(response.header("content-type").startsWith("application/json"));
+        String body = response.bodyAsString();
+        assertTrue(body.contains("ready"), "有快照且新鲜时应报告 ready");
+        assertFalse(body.contains(PUBLIC_KEY), "健康检查不得泄露公开 Key");
+        assertFalse(body.contains(V2_CONTENT), "健康检查不得泄露订阅正文");
+    }
+
+    /** 非 GET/HEAD 方法回 405。 */
+    @Test
+    void rejectsUnsupportedMethods() throws Exception {
+        assertEquals(405, request(readyPort, "POST", "/sub/v2/" + PUBLIC_KEY).status());
+    }
+
+    /** 起点越界的 Range 回 416，而不是返回空 200。 */
+    @Test
+    void unsatisfiableRangeIsRejected() throws Exception {
+        assertEquals(416, request(readyPort, "GET", "/sub/v2/" + PUBLIC_KEY, "Range: bytes=999-1000").status());
+    }
+
+    // ---- 测试脚手架 ----
+
+    private static SubscriptionSnapshotStore store(Path root) {
+        return new SubscriptionSnapshotStore(root, SECRET, 3600, 1024 * 1024);
+    }
+
+    private static int startServer(SubscriptionSnapshotStore store) throws IOException {
+        int port;
+        try (ServerSocket probe = new ServerSocket(0)) {
+            port = probe.getLocalPort();
+        }
+        Thread thread = new Thread(new BackupSubServer(store, port, 2), "backup-sub-test-" + port);
+        thread.setDaemon(true);
+        thread.start();
+        return port;
+    }
+
+    private static Response get(int port, String path) throws IOException {
+        return request(port, "GET", path);
+    }
+
+    private static Response request(int port, String method, String path, String... headers) throws IOException {
+        try (Socket socket = new Socket("127.0.0.1", port)) {
+            socket.setSoTimeout(5_000);
+            StringBuilder request = new StringBuilder()
+                    .append(method).append(' ').append(path).append(" HTTP/1.1\r\n")
+                    .append("Host: 127.0.0.1\r\n");
+            for (String header : headers)
+                request.append(header).append("\r\n");
+            request.append("Connection: close\r\n\r\n");
+            socket.getOutputStream().write(request.toString().getBytes(StandardCharsets.US_ASCII));
+            socket.getOutputStream().flush();
+
+            byte[] raw = socket.getInputStream().readAllBytes();
+            int split = indexOfHeaderEnd(raw);
+            assertTrue(split > 0, "响应必须含完整的头部结束标记");
+            String head = new String(raw, 0, split, StandardCharsets.ISO_8859_1);
+            byte[] body = Arrays.copyOfRange(raw, split + 4, raw.length);
+
+            String[] lines = head.split("\r\n");
+            int status = Integer.parseInt(lines[0].split(" ")[1]);
+            Map<String, String> parsed = new HashMap<>();
+            for (int i = 1; i < lines.length; i++) {
+                int colon = lines[i].indexOf(':');
+                if (colon > 0)
+                    parsed.put(lines[i].substring(0, colon).trim().toLowerCase(Locale.ROOT),
+                            lines[i].substring(colon + 1).trim());
+            }
+            return new Response(status, parsed, body);
+        }
+    }
+
+    private static int indexOfHeaderEnd(byte[] raw) {
+        for (int i = 0; i + 3 < raw.length; i++)
+            if (raw[i] == '\r' && raw[i + 1] == '\n' && raw[i + 2] == '\r' && raw[i + 3] == '\n')
+                return i;
+        return -1;
+    }
+
+    private record Response(int status, Map<String, String> headers, byte[] body) {
+        String header(String name) {
+            return headers.get(name);
+        }
+
+        String bodyAsString() {
+            return new String(body, StandardCharsets.UTF_8);
+        }
+    }
+
+    private static SubscriptionSnapshotMessage snapshot() throws Exception {
+        ObjectMapper mapper = CustomUtil.objectMapper;
+        byte[] v2 = V2_CONTENT.getBytes(StandardCharsets.UTF_8);
+        byte[] clash = CLASH_CONTENT.getBytes(StandardCharsets.UTF_8);
+
+        SubscriptionAccountSnapshot account = new SubscriptionAccountSnapshot();
+        account.setAccountId(1);
+        account.setEnabled(true);
+        account.setV2ContentBase64(Base64.getEncoder().encodeToString(v2));
+        account.setV2Sha256(sha256(v2));
+        account.setClashContentBase64(Base64.getEncoder().encodeToString(clash));
+        account.setClashSha256(sha256(clash));
+
+        SubscriptionBindingSnapshot binding = new SubscriptionBindingSnapshot();
+        binding.setPublicKeySha256(sha256(PUBLIC_KEY.getBytes(StandardCharsets.UTF_8)));
+        binding.setAccountId(1);
+
+        SubscriptionSnapshotPayload payload = new SubscriptionSnapshotPayload();
+        payload.setSchemaVersion(1);
+        payload.setAccounts(List.of(account));
+        payload.setBindings(List.of(binding));
+        byte[] json = mapper.writeValueAsBytes(payload);
+        byte[] compressed = gzip(json);
+
+        SubscriptionSnapshotMessage message = new SubscriptionSnapshotMessage();
+        message.setSchemaVersion(1);
+        message.setRevision(sha256(json));
+        message.setGeneratedAt(System.currentTimeMillis());
+        message.setPayloadBase64(Base64.getEncoder().encodeToString(compressed));
+        message.setPayloadSha256(sha256(compressed));
+        String input = "1\n" + message.getRevision() + "\n" + message.getGeneratedAt() + "\n" + message.getPayloadSha256();
+        Mac mac = Mac.getInstance("HmacSHA256");
+        mac.init(new SecretKeySpec(SECRET.getBytes(StandardCharsets.UTF_8), "HmacSHA256"));
+        message.setSignature(hex(mac.doFinal(input.getBytes(StandardCharsets.UTF_8))));
+        return message;
+    }
+
+    private static byte[] gzip(byte[] bytes) throws Exception {
+        ByteArrayOutputStream output = new ByteArrayOutputStream();
+        try (GZIPOutputStream gzip = new GZIPOutputStream(output)) {
+            gzip.write(bytes);
+        }
+        return output.toByteArray();
+    }
+
+    private static String sha256(byte[] bytes) throws Exception {
+        return hex(MessageDigest.getInstance("SHA-256").digest(bytes));
+    }
+
+    private static String hex(byte[] bytes) {
+        return HexFormat.of().formatHex(bytes);
+    }
+}

src/test/java/lion/MessageCodecTest.java

@@ -0,0 +1,232 @@
+package lion;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.embedded.EmbeddedChannel;
+import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
+import lion.Domain.GalleryTask;
+import lion.Message.AbstractMessage;
+import lion.Message.MessageCodec;
+import lion.Message.Main.AvailableCheckMessage;
+import lion.Message.Main.DeleteGalleryMessage;
+import lion.Message.Main.DownloadPostMessage;
+import lion.Message.Main.DownloadStatusMessage;
+import lion.Message.Main.IdentityMessage;
+import lion.Message.Main.MaintainMessage;
+import lion.Message.Main.ResponseMessage;
+import lion.Message.Main.SubscriptionSnapshotMessage;
+import org.junit.jupiter.api.Test;
+
+import java.nio.charset.StandardCharsets;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * 自定义 TCP 协议 {@code [1 字节类型][4 字节长度][JSON]} 的编解码。
+ *
+ * <p>这是节点与主站之间唯一的线路格式：类型字节决定反序列化成哪个消息类，
+ * 长度前缀决定帧边界。两边任何一处不一致都是掉线或错消息，而此前完全无覆盖。
+ */
+class MessageCodecTest {
+
+    /** 每种消息类型都要能按自身类型字节往返，且解出的类型正确。 */
+    @Test
+    void roundTripsEveryMessageType() {
+        assertRoundTrip(new ResponseMessage(7, (byte) 3), AbstractMessage.RESPONSE_MESSAGE);
+        assertRoundTrip(downloadPost(), AbstractMessage.DOWNLOAD_POST_MESSAGE);
+        assertRoundTrip(downloadStatus(), AbstractMessage.DOWNLOAD_STATUS_MESSAGE);
+        assertRoundTrip(deleteGallery(), AbstractMessage.DELETE_GALLERY_MESSAGE);
+        assertRoundTrip(identity(), AbstractMessage.IDENTITY_MESSAGE);
+        assertRoundTrip(new MaintainMessage(), AbstractMessage.MAINTAIN_MESSAGE);
+        assertRoundTrip(new AvailableCheckMessage(), AbstractMessage.AVAILABLE_CHECK_MESSAGE);
+        assertRoundTrip(snapshot(), AbstractMessage.SUBSCRIPTION_SNAPSHOT_MESSAGE);
+    }
+
+    /** 帧头就是「类型字节 + 大端 4 字节长度」，长度必须等于 JSON 负载的字节数。 */
+    @Test
+    void writesTypeByteAndBigEndianLengthPrefix() {
+        ByteBuf frame = encode(new ResponseMessage(7, (byte) 3));
+        try {
+            assertEquals(AbstractMessage.RESPONSE_MESSAGE, frame.readByte(), "首字节必须是消息类型");
+            int length = frame.readInt();
+            int jsonLength = frame.readableBytes();
+            assertEquals(jsonLength, length, "长度前缀必须等于 JSON 负载字节数");
+            assertTrue(jsonLength > 0);
+        } finally {
+            frame.release();
+        }
+    }
+
+    /** 未知类型字节必须被安静丢弃（不产出消息），而不是抛出或产出错误类型的消息。 */
+    @Test
+    void unknownTypeByteIsDroppedWithoutThrowing() {
+        EmbeddedChannel channel = new EmbeddedChannel(new MessageCodec());
+        try {
+            byte[] payload = "{}".getBytes(StandardCharsets.UTF_8);
+            ByteBuf frame = Unpooled.buffer();
+            frame.writeByte(99);
+            frame.writeInt(payload.length);
+            frame.writeBytes(payload);
+
+            channel.writeInbound(frame);
+
+            assertNull(channel.readInbound(), "未知类型不应产出任何消息");
+        } finally {
+            channel.finishAndReleaseAll();
+        }
+    }
+
+    /**
+     * 生产管线是「先分帧、再解码」：{@link LengthFieldBasedFrameDecoder} 负责等齐整帧，
+     * 紧跟其后的 {@link MessageCodec} 才假设长度前缀完整。半个帧到达时必须按兵不动、
+     * 等剩余字节，而不能抛异常或产出半条消息。
+     */
+    @Test
+    void incompleteFrameIsHeldByFrameDecoderUntilComplete() {
+        EmbeddedChannel channel = new EmbeddedChannel(
+                new LengthFieldBasedFrameDecoder(100_000_000, 1, 4), new MessageCodec());
+        try {
+            AvailableCheckMessage probe = new AvailableCheckMessage();
+            probe.messageId = 11;
+
+            ByteBuf frame = encode(probe);
+            byte[] bytes = new byte[frame.readableBytes()];
+            frame.getBytes(0, bytes);
+            frame.release();
+
+            int half = bytes.length / 2;
+            ByteBuf firstHalf = Unpooled.copiedBuffer(bytes, 0, half);
+            ByteBuf secondHalf = Unpooled.copiedBuffer(bytes, half, bytes.length - half);
+
+            assertFalse(channel.writeInbound(firstHalf), "半个帧不应产出消息");
+            assertNull(channel.readInbound());
+
+            channel.writeInbound(secondHalf);
+            AbstractMessage decoded = channel.readInbound();
+            assertInstanceOf(AvailableCheckMessage.class, decoded);
+            assertEquals(11, decoded.messageId);
+        } finally {
+            channel.finishAndReleaseAll();
+        }
+    }
+
+    /** 长度前缀来自线路，必须设上限；否则一个报文就能让对端按声明的长度申请内存。 */
+    @Test
+    void rejectsAbsurdDeclaredLength() {
+        EmbeddedChannel channel = new EmbeddedChannel(new MessageCodec());
+        try {
+            ByteBuf frame = Unpooled.buffer();
+            frame.writeByte(AbstractMessage.RESPONSE_MESSAGE);
+            frame.writeInt(Integer.MAX_VALUE);
+
+            assertThrows(Exception.class, () -> channel.writeInbound(frame),
+                    "超出上限的帧长度必须被拒绝，而不是按声明分配字节数组");
+        } finally {
+            channel.finishAndReleaseAll();
+        }
+    }
+
+    /**
+     * 序列化失败时绝不能写出半帧。
+     *
+     * <p>原实现先写类型字节、再序列化，失败时只记日志，于是留下「有类型字节、没有长度和
+     * JSON」的残帧，对端的分帧器会永远等长度前缀。现在必须先序列化成功再写帧头。
+     */
+    @Test
+    void serializationFailureDoesNotEmitHalfFrame() {
+        EmbeddedChannel channel = new EmbeddedChannel(new MessageCodec());
+        try {
+            assertThrows(Exception.class, () -> channel.writeOutbound(new UnserializableMessage()),
+                    "序列化失败必须抛错，而不是安静地留下半帧");
+            assertNull(channel.readOutbound(), "失败时不得产出任何字节");
+        } finally {
+            channel.finishAndReleaseAll();
+        }
+    }
+
+    /** 故意让 Jackson 在序列化属性时抛异常。 */
+    static class UnserializableMessage extends AbstractMessage {
+        UnserializableMessage() {
+            messageType = AbstractMessage.RESPONSE_MESSAGE;
+        }
+
+        @SuppressWarnings("unused")
+        public String getExplode() {
+            throw new IllegalStateException("boom");
+        }
+    }
+
+    private static void assertRoundTrip(AbstractMessage message, byte expectedType) {
+        ByteBuf frame = encode(message);
+        assertEquals(expectedType, frame.getByte(0), "线路上的类型字节必须与消息类匹配");
+
+        EmbeddedChannel channel = new EmbeddedChannel(
+                new LengthFieldBasedFrameDecoder(100_000_000, 1, 4), new MessageCodec());
+        try {
+            channel.writeInbound(frame);
+            AbstractMessage decoded = channel.readInbound();
+            assertNotNull(decoded, "整帧必须被解码出来");
+            assertEquals(message.getClass(), decoded.getClass(), "解码类型必须与编码类型一致");
+            assertEquals(expectedType, decoded.messageType);
+        } finally {
+            channel.finishAndReleaseAll();
+        }
+    }
+
+    private static ByteBuf encode(AbstractMessage message) {
+        EmbeddedChannel channel = new EmbeddedChannel(new MessageCodec());
+        try {
+            channel.writeOutbound(message);
+            ByteBuf out = channel.readOutbound();
+            assertNotNull(out, "编码后必须产出字节");
+            return out;
+        } finally {
+            channel.finishAndReleaseAll();
+        }
+    }
+
+    private static DownloadPostMessage downloadPost() {
+        GalleryTask task = new GalleryTask();
+        task.setGid(4242);
+        task.setName("sample [4242]");
+        task.setStatus(GalleryTask.DOWNLOADING);
+        DownloadPostMessage message = new DownloadPostMessage();
+        message.messageId = 1;
+        message.setGalleryTask(task);
+        return message;
+    }
+
+    private static DownloadStatusMessage downloadStatus() {
+        GalleryTask task = new GalleryTask();
+        task.setGid(4242);
+        task.setName("sample [4242]");
+        task.setStatus(GalleryTask.COMPRESS_COMPLETE);
+        DownloadStatusMessage message = new DownloadStatusMessage();
+        message.setGalleryTasks(new GalleryTask[]{task});
+        return message;
+    }
+
+    private static DeleteGalleryMessage deleteGallery() {
+        DeleteGalleryMessage message = new DeleteGalleryMessage();
+        message.messageId = 5;
+        message.setGalleryName("sample [4242]");
+        return message;
+    }
+
+    private static IdentityMessage identity() {
+        IdentityMessage message = new IdentityMessage();
+        message.setIdentity("lionwebsite");
+        return message;
+    }
+
+    private static SubscriptionSnapshotMessage snapshot() {
+        SubscriptionSnapshotMessage message = new SubscriptionSnapshotMessage();
+        message.setSchemaVersion(1);
+        message.setRevision("a".repeat(64));
+        message.setGeneratedAt(1_700_000_000_000L);
+        message.setPayloadBase64("ZmFrZQ==");
+        message.setPayloadSha256("b".repeat(64));
+        message.setSignature("c".repeat(64));
+        return message;
+    }
+}

src/test/java/lion/MultiThreadedHTTPServerTest.java

@@ -1,8 +1,16 @@
 package lion;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicReference;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -58,4 +66,123 @@ class MultiThreadedHTTPServerTest {
     void returnsNullForNullRequestLine() {
         assertNull(MultiThreadedHTTPServer.parseRequestLine(null));
     }
+
+    // ---- 请求处理（真实 socket） ----
+
+    /**
+     * 畸形请求行（没有空格）不得打死处理线程，更不得泄漏连接。
+     *
+     * <p>原实现直接取 {@code requestParts[1]}，空行会抛 ArrayIndexOutOfBoundsException；
+     * 它不是 IOException，会被线程池静默吞掉，socket 也关不掉。现在应回 400 并关闭连接。
+     */
+    @Test
+    void malformedRequestLineIsRejectedWithoutCrashing() throws Exception {
+        try (ServerSocket server = new ServerSocket(0); Socket client = new Socket("127.0.0.1", server.getLocalPort())) {
+            client.setSoTimeout(5_000);
+            Thread handler = startHandler(server);
+
+            client.getOutputStream().write("GARBAGE\r\n\r\n".getBytes(StandardCharsets.US_ASCII));
+            client.getOutputStream().flush();
+
+            String head = readHead(client);
+            assertTrue(head.startsWith("HTTP/1.1 400"), "畸形请求行应回 400，实际：" + head.lines().findFirst().orElse(""));
+            handler.join(5_000);
+            assertFalse(handler.isAlive(), "处理器必须结束并关闭连接，不得挂住线程");
+        }
+    }
+
+    /** 只有空行的连接应被安静关闭，不产生响应也不抛异常。 */
+    @Test
+    void blankRequestLineClosesConnectionQuietly() throws Exception {
+        try (ServerSocket server = new ServerSocket(0); Socket client = new Socket("127.0.0.1", server.getLocalPort())) {
+            client.setSoTimeout(5_000);
+            AtomicReference<Throwable> failure = new AtomicReference<>();
+            Thread handler = startHandler(server, failure);
+
+            client.getOutputStream().write("\r\n".getBytes(StandardCharsets.US_ASCII));
+            client.getOutputStream().flush();
+
+            assertEquals(-1, client.getInputStream().read(), "应直接关闭连接而不回正文");
+            handler.join(5_000);
+            assertFalse(handler.isAlive(), "处理器必须结束");
+            assertNull(failure.get(), "空行不得抛异常： " + failure.get());
+        }
+    }
+
+    /**
+     * 请求的 Range 超过文件末端时必须夹到文件末尾。
+     *
+     * <p>原实现按未夹取的区间写 Content-Length，客户端拿到一个远大于实际发送量的长度，
+     * 会一直等下去。现在 Content-Range / Content-Length / 正文都必须只覆盖到文件末尾。
+     */
+    @Test
+    void oversizedRangeIsClampedToFileEnd(@TempDir Path root) throws Exception {
+        byte[] payload = "0123456789".getBytes(StandardCharsets.UTF_8);
+        Path archive = root.resolve("archive.zip");
+        Files.write(archive, payload);
+
+        String head = fetchRange(root, archive, "bytes=4-999999");
+
+        assertTrue(head.contains("Content-Range: bytes 4-9/10"), "Content-Range 必须夹到文件末尾：" + head);
+        assertTrue(head.contains("Content-Length: 6"), "Content-Length 必须与实际发送量一致：" + head);
+    }
+
+    /** Range 起点超过文件长度时无可发送内容，应回 416，而不是假装有长度。 */
+    @Test
+    void rangeStartingBeyondFileIsNotSatisfiable(@TempDir Path root) throws Exception {
+        Path archive = root.resolve("archive.zip");
+        Files.write(archive, "0123456789".getBytes(StandardCharsets.UTF_8));
+
+        String head = fetchRange(root, archive, "bytes=999-1000");
+
+        assertTrue(head.startsWith("HTTP/1.1 416"), "越界起点应回 416：" + head.lines().findFirst().orElse(""));
+    }
+
+    // ---- 测试脚手架 ----
+
+    /** 在守护线程里接受一个连接并交给真实的请求处理器。 */
+    private static Thread startHandler(ServerSocket server) {
+        return startHandler(server, new AtomicReference<>());
+    }
+
+    private static Thread startHandler(ServerSocket server, AtomicReference<Throwable> failure) {
+        Thread handler = new Thread(() -> {
+            try {
+                MultiThreadedHTTPServer.handleClientRequest(server.accept());
+            } catch (Throwable t) {
+                failure.set(t);
+            }
+        });
+        handler.setDaemon(true);
+        handler.start();
+        return handler;
+    }
+
+    /** 走 AuthCode=alone 路径请求指定文件，返回响应头。 */
+    private static String fetchRange(Path root, Path archive, String range) throws IOException {
+        try (ServerSocket server = new ServerSocket(0); Socket client = new Socket("127.0.0.1", server.getLocalPort())) {
+            client.setSoTimeout(5_000);
+            Thread handler = startHandler(server);
+
+            String request = "GET " + archive + "?AuthCode=alone HTTP/1.1\r\n"
+                    + "Host: 127.0.0.1\r\nRange: " + range + "\r\n\r\n";
+            client.getOutputStream().write(request.getBytes(StandardCharsets.US_ASCII));
+            client.getOutputStream().flush();
+
+            return readHead(client);
+        }
+    }
+
+    private static String readHead(Socket socket) throws IOException {
+        java.io.ByteArrayOutputStream buffer = new java.io.ByteArrayOutputStream();
+        int b;
+        while ((b = socket.getInputStream().read()) != -1) {
+            buffer.write(b);
+            byte[] bytes = buffer.toByteArray();
+            if (bytes.length >= 4 && bytes[bytes.length - 4] == '\r' && bytes[bytes.length - 3] == '\n'
+                    && bytes[bytes.length - 2] == '\r' && bytes[bytes.length - 1] == '\n')
+                break;
+        }
+        return buffer.toString(StandardCharsets.ISO_8859_1);
+    }
 }

src/test/java/lion/Service/DeleteServiceTest.java

@@ -0,0 +1,82 @@
+package lion.Service;
+
+import lion.ErrorCode.ErrorCode;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/** 画廊目录删除：成功归零，失败按 ErrorCode 区分「路径不存在」与其它 IO 错误。 */
+class DeleteServiceTest {
+
+    @Test
+    void deletesExistingDirectoryAndReturnsSuccess(@TempDir Path root) throws Exception {
+        Path gallery = Files.createDirectories(root.resolve("sample [123]"));
+        Files.writeString(gallery.resolve("1.jpg"), "image bytes");
+
+        assertEquals(0, DeleteService.deleteAll(gallery.toString()));
+        assertFalse(Files.exists(gallery), "目录应被整棵删除");
+    }
+
+    /** 路径不存在时必须回 FILE_NOT_FOUND，让主站能区分「本来就没有」。 */
+    @Test
+    void missingPathReportsFileNotFound(@TempDir Path root) {
+        assertEquals(ErrorCode.FILE_NOT_FOUND, DeleteService.deleteAll(root.resolve("absent").toString()));
+    }
+
+    /** 目标是普通文件（而非目录）时同样按 FILE_NOT_FOUND 处理，不得误删文件。 */
+    @Test
+    void plainFileIsNotTreatedAsDirectory(@TempDir Path root) throws Exception {
+        Path file = root.resolve("not-a-directory.txt");
+        Files.writeString(file, "keep me");
+
+        assertEquals(ErrorCode.FILE_NOT_FOUND, DeleteService.deleteAll(file.toString()));
+        assertTrue(Files.exists(file), "普通文件不应被删除");
+    }
+
+    /** 正常的子目录名应在根目录内被删除。 */
+    @Test
+    void deleteWithinRemovesChildOfRoot(@TempDir Path root) throws Exception {
+        Path gallery = Files.createDirectories(root.resolve("sample [123]"));
+
+        assertEquals(0, DeleteService.deleteWithin(root.toString(), "sample [123]"));
+        assertFalse(Files.exists(gallery));
+    }
+
+    /**
+     * 画廊名来自主站下发的消息，带 {@code ../} 时必须被拒绝。
+     * 否则路径会被规范化到根目录之外，删掉节点上的任意目录。
+     */
+    @Test
+    void deleteWithinRejectsPathTraversal(@TempDir Path root) throws Exception {
+        Path outside = Files.createDirectories(root.resolve("important"));
+        Path galleryRoot = Files.createDirectories(root.resolve("gallery"));
+
+        byte result = DeleteService.deleteWithin(galleryRoot.toString(), "../important");
+
+        assertEquals(ErrorCode.FILE_NOT_FOUND, result, "越界路径必须按找不到处理");
+        assertTrue(Files.exists(outside), "根目录之外的内容绝不能被删除");
+    }
+
+    /** 绝对路径同样不得越过根目录。 */
+    @Test
+    void deleteWithinRejectsAbsolutePath(@TempDir Path root) throws Exception {
+        Path outside = Files.createDirectories(root.resolve("important"));
+        Path galleryRoot = Files.createDirectories(root.resolve("gallery"));
+
+        assertEquals(ErrorCode.FILE_NOT_FOUND, DeleteService.deleteWithin(galleryRoot.toString(), outside.toString()));
+        assertTrue(Files.exists(outside));
+    }
+
+    /** 空名会导致规范化结果等于根目录本身，必须拒绝。 */
+    @Test
+    void deleteWithinRejectsEmptyName(@TempDir Path root) throws Exception {
+        Path galleryRoot = Files.createDirectories(root.resolve("gallery"));
+
+        assertEquals(ErrorCode.FILE_NOT_FOUND, DeleteService.deleteWithin(galleryRoot.toString(), "  "));
+        assertTrue(Files.exists(galleryRoot), "根目录本身不得被删除");
+    }
+}

src/test/java/lion/Service/DownloadCheckServiceGidMatchingTest.java

@@ -0,0 +1,113 @@
+package lion.Service;
+
+import lion.Domain.GalleryTask;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * 入队时按 gid 定位磁盘内容。
+ *
+ * <p>gid 稳定、目录名不稳定（下载器会追加分辨率等后缀），因此匹配不能只看名字相等，
+ * 而要按 {@code [gid]} / {@code [gid-...]} 标记判断；同时绝不能把 {@code [1234]}
+ * 误判成 gid 123，否则会把下载链接指向错误的画廊。
+ */
+class DownloadCheckServiceGidMatchingTest {
+
+    /** 目录名带后缀时也要能按 gid 命中已有归档，并判为压缩完成。 */
+    @Test
+    void matchesStoredArchiveWhenDirectoryNameHasSuffix(@TempDir Path root) throws Exception {
+        DownloadCheckService service = service(root);
+        Path directory = Files.createDirectories(
+                Path.of(service.storagePath, "sample [123-456]"));
+        writeValidZip(directory.resolve("sample [123-456].zip"));
+
+        GalleryTask result = service.addToQueue(task(123));
+
+        assertTrue(result.is_compress_complete(), "gid 命中已有归档应判为已完成");
+        assertEquals("sample [123-456]", result.getName(), "名称应取实际目录名");
+    }
+
+    /** 尚未出现 galleryinfo.txt：判为下载中，并统计已下载页数。 */
+    @Test
+    void marksTaskDownloadingWhileGalleryInfoMissing(@TempDir Path root) throws Exception {
+        DownloadCheckService service = service(root);
+        Path directory = Files.createDirectories(Path.of(service.downloadPath, "sample [123-456]"));
+        Files.writeString(directory.resolve("1.jpg"), "x");
+        Files.writeString(directory.resolve("2.jpg"), "y");
+
+        GalleryTask result = service.addToQueue(task(123));
+
+        assertEquals(GalleryTask.DOWNLOADING, result.getStatus());
+        assertEquals(2, result.getProceeding(), "应统计除 galleryinfo.txt 外的页数");
+        assertEquals("sample [123-456]", result.getName());
+    }
+
+    /** 出现 galleryinfo.txt：判为下载完成，并记录源目录用于后续压缩。 */
+    @Test
+    void marksTaskCompleteWhenGalleryInfoPresent(@TempDir Path root) throws Exception {
+        DownloadCheckService service = service(root);
+        Path directory = Files.createDirectories(Path.of(service.downloadPath, "sample [123]"));
+        Files.writeString(directory.resolve("1.jpg"), "x");
+        Files.writeString(directory.resolve("galleryinfo.txt"), "meta");
+
+        GalleryTask result = service.addToQueue(task(123));
+
+        assertEquals(GalleryTask.DOWNLOAD_COMPLETE, result.getStatus());
+        assertEquals(directory.toString(), result.getPath());
+    }
+
+    /** gid 前缀相同但实际不同的目录不得被匹配。 */
+    @Test
+    void doesNotMatchLongerGidSharingTheSamePrefix(@TempDir Path root) throws Exception {
+        DownloadCheckService service = service(root);
+        Files.createDirectories(Path.of(service.downloadPath, "sample [1234]"));
+
+        GalleryTask result = service.addToQueue(task(123));
+
+        assertEquals(0, result.getStatus(), "[1234] 不得被当成 gid 123 的目录");
+        assertNull(result.getName(), "未命中时不应改写任务名称");
+    }
+
+    /** 归档校验：空文件与不存在的路径都不算有效归档。 */
+    @Test
+    void rejectsEmptyAndMissingArchives(@TempDir Path root) throws Exception {
+        Path empty = Files.createFile(root.resolve("empty.zip"));
+        assertFalse(DownloadCheckService.isValidArchive(empty.toFile()));
+        assertFalse(DownloadCheckService.isValidArchive(root.resolve("missing.zip").toFile()));
+
+        Path valid = root.resolve("valid.zip");
+        writeValidZip(valid);
+        assertTrue(DownloadCheckService.isValidArchive(valid.toFile()));
+    }
+
+    private static DownloadCheckService service(Path root) throws Exception {
+        DownloadCheckService service = new DownloadCheckService(new ConcurrentHashMap<>(), false);
+        service.downloadPath = Files.createDirectories(root.resolve("download")).toString();
+        service.storagePath = Files.createDirectories(root.resolve("gallery")).toString();
+        return service;
+    }
+
+    private static GalleryTask task(int gid) {
+        GalleryTask task = new GalleryTask();
+        task.setGid(gid);
+        return task;
+    }
+
+    private static void writeValidZip(Path zip) throws Exception {
+        Files.createDirectories(zip.getParent());
+        try (ZipOutputStream out = new ZipOutputStream(Files.newOutputStream(zip))) {
+            out.putNextEntry(new ZipEntry("1.jpg"));
+            out.write("image bytes".getBytes(StandardCharsets.UTF_8));
+            out.closeEntry();
+        }
+    }
+}

src/test/java/lion/StorageNodeMessageHandlingTest.java

@@ -0,0 +1,297 @@
+package lion;
+
+import io.netty.channel.embedded.EmbeddedChannel;
+import lion.Config.Config;
+import lion.Domain.GalleryTask;
+import lion.ErrorCode.ErrorCode;
+import lion.Message.Main.AvailableCheckMessage;
+import lion.Message.Main.DeleteGalleryMessage;
+import lion.Message.Main.DownloadPostMessage;
+import lion.Message.Main.DownloadStatusMessage;
+import lion.Message.Main.IdentityMessage;
+import lion.Message.Main.ResponseMessage;
+import lion.Message.Main.SubscriptionSnapshotMessage;
+import lion.Service.SubscriptionSnapshotStore;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * 节点消息处理与状态上报循环。
+ *
+ * <p>{@link storageNode.MyChannelInboundHandlerAdapter} 与 {@link storageNode#mainThread()}
+ * 约 250 行，承载任务下发、删除、探活、订阅快照分发与队列重放，此前只有静态方法
+ * {@code isPrimaryEvidence} 被间接覆盖。这里用 {@link EmbeddedChannel} 把入站消息直接
+ * 喂给真实处理器，断言回包与队列副作用，同时锁定「无可用通道时不得丢弃任务」的语义。
+ */
+class StorageNodeMessageHandlingTest {
+
+    @TempDir
+    static Path tempDir;
+
+    static storageNode node;
+
+    @BeforeAll
+    static void startNode() throws Exception {
+        Path storageRoot = Files.createDirectories(tempDir.resolve("gallery"));
+        Path subscriptionRoot = Files.createDirectories(tempDir.resolve("sub"));
+
+        storageNode.storagePath = storageRoot + "/";
+        SubscriptionSnapshotStore store =
+                new SubscriptionSnapshotStore(subscriptionRoot, "test-secret", 3600, 1024 * 1024);
+        node = new storageNode(store);
+        // 订阅同步默认关闭：快照消息必须被拒绝，也不触发异步落盘。
+        Config.subscriptionSyncEnabled = false;
+    }
+
+    @AfterAll
+    static void stopNode() {
+        node.subscriptionApplyExecutor.shutdownNow();
+        node.rekickExecutor.shutdownNow();
+    }
+
+    @BeforeEach
+    void resetState() {
+        node.queue.clear();
+        node.tempQueue.clear();
+    }
+
+    /**
+     * 任务下发：先按 gid 入队并立即回传当前状态，再回执响应。
+     *
+     * <p>回传顺序不能反——主站的单任务重试接口依赖「先收到状态、再收到响应」。
+     */
+    @Test
+    void downloadPostEnqueuesTaskAndReportsStatusBeforeResponse() {
+        EmbeddedChannel channel = nodeChannel();
+        try {
+            DownloadPostMessage post = new DownloadPostMessage();
+            post.setGalleryTask(task(90001));
+            post.messageId = 7;
+
+            channel.writeInbound(post);
+
+            DownloadStatusMessage status = channel.readOutbound();
+            assertNotNull(status, "应先把当前任务状态回传给主站");
+            assertEquals(1, status.getGalleryTasks().length);
+            assertEquals(90001, status.getGalleryTasks()[0].getGid());
+
+            ResponseMessage response = channel.readOutbound();
+            assertNotNull(response, "随后应回执响应");
+            assertEquals(7, response.messageId, "响应必须带上下发方的 messageId");
+            assertEquals(0, response.getResult());
+
+            assertTrue(node.queue.containsKey(90001), "任务应已进入待处理队列");
+            assertTrue(node.primaryChannel.usable(), "主站消息应认领通道引用");
+        } finally {
+            close(channel);
+        }
+    }
+
+    /** 删除任务：既清理待上报队列，也删掉磁盘目录，并回执成功。 */
+    @Test
+    void deleteGalleryRemovesQueuedTaskAndDirectory() throws Exception {
+        EmbeddedChannel channel = nodeChannel();
+        try {
+            Path directory = Files.createDirectories(Path.of(storageNode.storagePath, "sample [90002]"));
+            node.queue.put(90002, task(90002));
+
+            DeleteGalleryMessage delete = new DeleteGalleryMessage();
+            delete.setGalleryName("sample [90002]");
+            delete.messageId = 3;
+            channel.writeInbound(delete);
+
+            ResponseMessage response = channel.readOutbound();
+            assertNotNull(response);
+            assertEquals(3, response.messageId);
+            assertEquals(0, response.getResult(), "目录删除成功应回 0");
+
+            assertFalse(node.queue.containsKey(90002), "已删除的任务不得继续上报状态");
+            assertFalse(Files.exists(directory), "磁盘目录应被删除");
+        } finally {
+            close(channel);
+        }
+    }
+
+    /** 删除不存在的目录时仍要回包，并如实返回 FILE_NOT_FOUND。 */
+    @Test
+    void deleteGalleryMissingDirectoryReportsFileNotFound() {
+        EmbeddedChannel channel = nodeChannel();
+        try {
+            DeleteGalleryMessage delete = new DeleteGalleryMessage();
+            delete.setGalleryName("never-existed [90003]");
+            delete.messageId = 4;
+
+            channel.writeInbound(delete);
+
+            ResponseMessage response = channel.readOutbound();
+            assertNotNull(response, "无论删除成败都必须回执，否则主站会一直等待");
+            assertEquals(4, response.messageId);
+            assertEquals(ErrorCode.FILE_NOT_FOUND, response.getResult());
+        } finally {
+            close(channel);
+        }
+    }
+
+    /** 探活：必须原样带回 messageId，供主站配对。 */
+    @Test
+    void availableCheckEchoesMessageId() {
+        EmbeddedChannel channel = nodeChannel();
+        try {
+            AvailableCheckMessage probe = new AvailableCheckMessage();
+            probe.messageId = 42;
+
+            channel.writeInbound(probe);
+
+            ResponseMessage response = channel.readOutbound();
+            assertNotNull(response);
+            assertEquals(42, response.messageId);
+            assertEquals(0, response.getResult());
+        } finally {
+            close(channel);
+        }
+    }
+
+    /** 主站身份消息认领通道引用；备机身份消息不得认领，否则状态会上报到错误连接。 */
+    @Test
+    void onlyPrimaryIdentityClaimsChannelReference() {
+        EmbeddedChannel primary = nodeChannel();
+        EmbeddedChannel sidecar = nodeChannel();
+        try {
+            sidecar.writeInbound(identity("lionwebsiteside"));
+            assertFalse(node.primaryChannel.usable(), "备机身份不得占用主站引用");
+            assertSame(sidecar, node.node, "备机通道应登记为 node");
+
+            primary.writeInbound(identity("lionwebsite"));
+            assertTrue(node.primaryChannel.usable(), "主站身份应认领引用");
+            assertSame(primary, node.primaryChannel.current());
+        } finally {
+            close(primary);
+            close(sidecar);
+        }
+    }
+
+    /** 未开启订阅同步时，快照消息必须被拒绝。 */
+    @Test
+    void subscriptionSnapshotRejectedWhenSyncDisabled() {
+        EmbeddedChannel channel = nodeChannel();
+        try {
+            SubscriptionSnapshotMessage snapshot = new SubscriptionSnapshotMessage();
+            snapshot.messageId = 9;
+            snapshot.setSchemaVersion(1);
+            snapshot.setRevision("a".repeat(64));
+
+            channel.writeInbound(snapshot);
+
+            ResponseMessage response = channel.readOutbound();
+            assertNotNull(response);
+            assertEquals(9, response.messageId);
+            assertEquals(SubscriptionSnapshotStore.APPLY_INVALID, response.getResult());
+        } finally {
+            close(channel);
+        }
+    }
+
+    /** 有待上报任务且通道可用时，mainThread 应上报并清空已完成的压缩任务。 */
+    @Test
+    void mainThreadReportsCompletedTaskAndDrainsQueue() {
+        EmbeddedChannel channel = nodeChannel();
+        try {
+            channel.writeInbound(identity("lionwebsite"));
+            drainOutbound(channel);
+
+            GalleryTask done = task(90004);
+            done.setStatus(GalleryTask.COMPRESS_COMPLETE);
+            node.queue.put(90004, done);
+
+            node.mainThread();
+
+            DownloadStatusMessage status = readStatusMessage(channel);
+            assertNotNull(status, "通道可用时必须上报任务状态");
+            assertEquals(1, status.getGalleryTasks().length);
+            assertEquals(90004, status.getGalleryTasks()[0].getGid());
+            assertFalse(node.queue.containsKey(90004), "压缩完成的任务上报后应出队");
+        } finally {
+            close(channel);
+        }
+    }
+
+    /**
+     * 无可用通道时不得上报，也绝不能丢弃任务——队列要保留到主站重连后重放。
+     * 这是「状态永久卡在已提交」的另一半成因。
+     */
+    @Test
+    void mainThreadKeepsTasksWhenNoChannelIsUsable() {
+        assertFalse(node.primaryChannel.usable(), "前置条件：本用例开始时不应有已认证通道");
+
+        GalleryTask done = task(90005);
+        done.setStatus(GalleryTask.COMPRESS_COMPLETE);
+        node.queue.put(90005, done);
+
+        node.mainThread();
+
+        assertTrue(node.queue.containsKey(90005), "无通道时任务必须保留在队列中等待重放");
+        assertNull(node.primaryChannel.current());
+    }
+
+    /** 队列为空时不得发送任务状态消息（心跳不算）。 */
+    @Test
+    void mainThreadSendsNoStatusWhenQueueIsEmpty() {
+        EmbeddedChannel channel = nodeChannel();
+        try {
+            channel.writeInbound(identity("lionwebsite"));
+            drainOutbound(channel);
+
+            node.mainThread();
+
+            assertNull(readStatusMessage(channel), "没有任务可报时不应发送状态消息");
+        } finally {
+            close(channel);
+        }
+    }
+
+    private static EmbeddedChannel nodeChannel() {
+        return new EmbeddedChannel(node.new MyChannelInboundHandlerAdapter(node.tempQueue));
+    }
+
+    private static GalleryTask task(int gid) {
+        GalleryTask task = new GalleryTask();
+        task.setGid(gid);
+        task.setName("sample [" + gid + "]");
+        return task;
+    }
+
+    private static IdentityMessage identity(String value) {
+        IdentityMessage message = new IdentityMessage();
+        message.setIdentity(value);
+        return message;
+    }
+
+    /** 读出并丢弃全部出站消息，用于清场。 */
+    private static int drainOutbound(EmbeddedChannel channel) {
+        int count = 0;
+        while (channel.readOutbound() != null)
+            count++;
+        return count;
+    }
+
+    /** 找出第一条任务状态消息；容忍调度线程可能插入的心跳等消息。 */
+    private static DownloadStatusMessage readStatusMessage(EmbeddedChannel channel) {
+        Object outbound;
+        while ((outbound = channel.readOutbound()) != null)
+            if (outbound instanceof DownloadStatusMessage status)
+                return status;
+        return null;
+    }
+
+    private static void close(EmbeddedChannel channel) {
+        channel.finishAndReleaseAll();
+    }
+}