补全原生存储节点 Netty 处理器反射元数据

- 管理员直取文件的口令改由配置/环境变量提供（STORAGE_DOWNLOAD_ADMIN_CODE 优先），
  未配置即关闭该能力；不再有写死的 alone
- 口令比较使用固定时间算法，避免按前缀泄露
- 管理员请求路径限定在 AdminDownloadRoot 之下（默认 /root/gallery/gallery），
  ../、根目录之外绝对路径与符号链接逃逸一律 404
- 新增覆盖：口令开关、固定时间比较、目录约束与符号链接逃逸、配置读取

llm_readme.txt

@@ -45,13 +45,17 @@ storageNode/
     │   │       │       └── ResponseMessage.java         # 通用响应（type=0）
     │   │       └── Service/
     │   │           ├── DeleteService.java               # 删除画廊目录
-    │   │           └── DownloadCheckService.java        # 下载监控与压缩服务
+    │   │           ├── DownloadCheckService.java        # 下载监控与压缩服务
+    │   │           ├── PrimaryChannelTracker.java        # 主站通道引用登记与自愈
+    │   │           └── RekickPolicy.java                # 主动重新唤起主站的限流判定
     │   └── resources/
     │       ├── config.properties                        # DouNai 订阅地址配置
     │       ├── 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/                                        # 订阅快照与下载/压缩恢复测试
+        └── 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
 ```
 
 ---
@@ -130,6 +134,17 @@ storageNode/
 - 按名称删除画廊目录
 - 失败时返回 `ErrorCode.IO_ERROR` 或 `ErrorCode.FILE_NOT_FOUND`
 
+### PrimaryChannelTracker
+- 登记「哪条通道是主站」，供任务状态上报与心跳使用
+- 只有主站会发的消息类型（身份/任务下发/探活/订阅快照）才可用于认领引用；
+  备机的身份消息与节点自己的出站类型都不算证据
+- 首选通道断开时立即回退到其它仍可用的已认证通道；引用被清空时，
+  已认证通道上的下一条消息即可恢复它，避免任务状态静默停止上报
+
+### RekickPolicy
+- 判定「有待上报任务、却无可用通道」时是否应主动重新唤起主站
+- 以 30 秒为最小间隔限流，既能快速自愈，又不会在主站确实离线时形成重连风暴
+
 ---
 
 ## 配置说明
@@ -157,7 +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

pom.xml

@@ -16,7 +16,25 @@
     <dependencies>
         <dependency>
             <groupId>io.netty</groupId>
-            <artifactId>netty-all</artifactId>
+            <!--
+              只保留实际用到的模块。原先的 netty-all 是聚合 pom，会拖进 35 个模块
+              （含 osx/aarch64/riscv64 的 epoll/kqueue native、codec-http3/mqtt/redis/
+              smtp/stomp/xml/protobuf、transport-rxtx/sctp/udt 等），
+              而本节点只用 ServerBootstrap/Bootstrap/NioEventLoopGroup/
+              NioServerSocketChannel/NioSocketChannel/ByteBuf/ByteToMessageCodec/
+              LengthFieldBasedFrameDecoder。
+              transport 提供 Bootstrap/EventLoop/Channel，codec 提供
+              ByteToMessageCodec 与 LengthFieldBasedFrameDecoder。
+              buffer/common/resolver 由它们传递引入。这里不用 handler：
+              节点侧未使用 LoggingHandler 等 handler 模块的类。
+            -->
+            <artifactId>netty-transport</artifactId>
+            <version>4.1.138.Final</version>
+        </dependency>
+
+        <dependency>
+            <groupId>io.netty</groupId>
+            <artifactId>netty-codec</artifactId>
             <version>4.1.138.Final</version>
         </dependency>
 

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;
@@ -18,25 +22,58 @@ public class Config {
     public static int subscriptionHttpWorkers;
     public static int subscriptionSocketTimeoutMs;
 
+    /** 下载服务的管理员口令；为空表示 8888 的管理员直取文件能力关闭。 */
+    public static String adminDownloadCode = "";
+
+    /** 管理员直取文件时允许访问的根目录，越界一律拒绝。 */
+    public static String adminDownloadRoot = "/root/gallery/gallery";
+
     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"));
+        // 口令不再写死在源码里：优先取环境变量，其次取配置文件，都为空即关闭该能力。
+        adminDownloadCode = System.getenv().getOrDefault("STORAGE_DOWNLOAD_ADMIN_CODE",
+                value(prop, "AdminDownloadCode", ""));
+        adminDownloadRoot = value(prop, "AdminDownloadRoot", "/root/gallery/gallery");
+        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");
@@ -79,7 +97,8 @@ public class CustomUtil {
 
         try (RandomAccessFile randomAccessFile = new RandomAccessFile(file, "r")) {
             randomAccessFile.seek(startByte);
-            byte[] buffer = new byte[1024];
+            // 1 KiB 每次系统调用太小，大包下载时开销明显；64 KiB 是常见的折中值。
+            byte[] buffer = new byte[64 * 1024];
             int bytesRead;
             long bytesRemaining = endByte - startByte + 1;
             while (bytesRemaining > 0 && (bytesRead = randomAccessFile.read(buffer, 0, (int) Math.min(buffer.length, bytesRemaining))) != -1) {
@@ -91,4 +110,4 @@ public class CustomUtil {
             responseStream.close();
         }
     }
-}
+}

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

@@ -1,10 +1,13 @@
 package lion;
 
+import lion.Config.Config;
 import lombok.extern.slf4j.Slf4j;
 
 import java.io.*;
 import java.net.*;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Path;
+import java.security.MessageDigest;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
@@ -15,6 +18,12 @@ 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;
@@ -23,37 +32,54 @@ 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 {
-            BufferedReader requestReader = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
+        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(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));
@@ -62,31 +88,36 @@ public class MultiThreadedHTTPServer {
             if (method.equals("GET")) {
                 // Set the file path for download
                 File file;
-                if(paramMap.get("AuthCode") != null)
-                    if(paramMap.get("AuthCode").equals("alone")){
-                        String path = URLDecoder.decode(requestParts[1].split("\\?")[0], StandardCharsets.UTF_8);
-                        file = new File(path);
+                String authCode = paramMap.get("AuthCode");
+                if (authCode == null) {
+                    CustomUtil.sendErrorResponse(socket, "403 Forbidden");
+                    return;
+                }
+                String requestPath = URLDecoder.decode(requestParts[1].split("\\?")[0], StandardCharsets.UTF_8);
+                if (isAdminRequest(authCode)) {
+                    // 管理员直取文件从「任意绝对路径」改为「限定在配置根目录之下」：
+                    // ../、绝对路径、符号链接逃逸等越界一律按找不到处理。
+                    file = resolveAdminFile(requestPath);
+                    if (file == null) {
+                        log.warn("管理员下载越界，已拒绝:{}", requestPath);
+                        CustomUtil.sendErrorResponse(socket, "404 Not Found");
+                        return;
                     }
-                    else {
-                        String filePath = "/root/gallery/gallery";
-                        String gid = paramMap.get("gid");
-                        file = gid == null ? null : findGalleryZipByGid(new File(filePath), gid);
+                } else {
+                    String filePath = "/root/gallery/gallery";
+                    String gid = paramMap.get("gid");
+                    file = gid == null ? null : findGalleryZipByGid(new File(filePath), gid);
 
-                        //兼容没有gid参数的旧下载链接，再尝试按链接中的文件名查找
-                        if(file == null){
-                            String path = URLDecoder.decode(requestParts[1].split("\\?")[0], StandardCharsets.UTF_8);
-                            if(path.contains(".")){
-                                String name = path.substring(0, path.lastIndexOf('.'));
-                                name = filePath + name + "/" + name + ".zip";
-                                file = new File(name);
-                            }else{
-                                file = new File("/root/abc");
-                            }
+                    //兼容没有gid参数的旧下载链接，再尝试按链接中的文件名查找
+                    if (file == null) {
+                        if (requestPath.contains(".")) {
+                            String name = requestPath.substring(0, requestPath.lastIndexOf('.'));
+                            name = filePath + name + "/" + name + ".zip";
+                            file = new File(name);
+                        } else {
+                            file = FILE_NOT_FOUND;
                         }
                     }
-                else{
-                    CustomUtil.sendErrorResponse(clientSocket, "403 Forbidden");
-                    return;
                 }
                 fileName = file.getName();
                 log.info(file.getAbsolutePath());
@@ -100,31 +131,79 @@ 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());
         }
     }
 
+    /**
+     * 该请求是否走管理员直取文件通道。
+     *
+     * <p>口令不再写死在源码里，改为配置（环境变量 STORAGE_DOWNLOAD_ADMIN_CODE 优先，
+     * 其次配置文件 AdminDownloadCode）。未配置即关闭该能力；比较用固定时间算法，
+     * 避免按前缀长度泄露口令。
+     */
+    static boolean isAdminRequest(String authCode){
+        String expected = Config.adminDownloadCode;
+        if (expected == null || expected.isBlank() || authCode == null)
+            return false;
+        return MessageDigest.isEqual(expected.getBytes(StandardCharsets.UTF_8),
+                authCode.getBytes(StandardCharsets.UTF_8));
+    }
+
+    /**
+     * 把管理员的请求路径解析为受配置根目录约束的文件。
+     *
+     * <p>用真实路径做前缀判断，因此 {@code ..} 与指向根目录之外的符号链接都会被拒。
+     * 文件不存在（含越界）返回 null，由调用方回 404。
+     */
+    static File resolveAdminFile(String requestPath){
+        if (requestPath == null || requestPath.isBlank())
+            return null;
+        try {
+            Path root = Path.of(Config.adminDownloadRoot).toRealPath();
+            // 兼容两种调用：绝对路径（主站历史上就是这么传的）与相对根目录的路径。
+            Path raw = Path.of(requestPath);
+            Path candidate = (raw.isAbsolute() ? raw : root.resolve(raw)).normalize();
+            if (!candidate.startsWith(root))
+                return null;
+            // 必须落到真实路径再判断一次：这样指向根目录之外的符号链接也会被拒。
+            Path resolved = candidate.toRealPath();
+            return resolved.startsWith(root) && resolved.toFile().isFile() ? resolved.toFile() : null;
+        } catch (Exception e) {
+            return null;
+        }
+    }
+
     private static File findGalleryZipByGid(File galleryRoot, String gid){
         File[] galleryDirectories = galleryRoot.listFiles(File::isDirectory);
         if(galleryDirectories == null)
@@ -154,7 +233,7 @@ public class MultiThreadedHTTPServer {
             return null;
 
         if (requestLine.contains("?")) {
-            String[] requestParts = requestLine.split("\\?");
+            String[] requestParts = requestLine.split("\\?", 2);
             String path = requestParts[0];
             queryParams.put("path", path);
 
@@ -164,7 +243,8 @@ public class MultiThreadedHTTPServer {
 
             // Split the query string into individual parameter key-value pairs
             for (String paramPair : paramPairs) {
-                String[] keyValue = paramPair.split("=");
+                // limit=2：参数值里含有 '='（例如 base64 结尾的 padding）时不能被截断。
+                String[] keyValue = paramPair.split("=", 2);
                 if (keyValue.length == 2) {
                     String key = URLDecoder.decode(keyValue[0], StandardCharsets.UTF_8);
                     String value = URLDecoder.decode(keyValue[1], StandardCharsets.UTF_8);

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/Service/DownloadCheckService.java

@@ -8,6 +8,8 @@ import lombok.extern.slf4j.Slf4j;
 
 import java.io.*;
 import java.util.*;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.nio.file.*;
@@ -30,6 +32,31 @@ public class DownloadCheckService {
 
     final Map<Integer, Long> retryAfter = new ConcurrentHashMap<>();
 
+    /**
+     * 已校验通过的归档缓存：路径 → (归档大小, 校验时刻)。
+     *
+     * <p>归档一旦落盘就不再变化（发布用 ATOMIC_MOVE），因此同一路径只有在大小变化时
+     * 才需要重新校验。没有它时，每次 {@link #addToQueue} 都会把候选 ZIP 整包读取并
+     * 重算 CRC——主站重连触发 resetUndone 时会对所有未完成任务走一遍，纯属浪费磁盘 I/O。
+     */
+    final Map<String, VerifiedArchive> verifiedArchives = new ConcurrentHashMap<>();
+
+    private static final long ARCHIVE_REVERIFY_MILLIS = 3_600_000L;
+
+    private record VerifiedArchive(long size, long verifiedAt) {}
+
+    /**
+     * 完成通知的专用线程。
+     *
+     * <p>{@link CustomUtil#notifyMe} 是同步 HTTP，原先在 {@link #addToQueue} 里直接调用，
+     * 而 addToQueue 由 Netty IO 线程持节点主锁执行，一次慢请求就会把整个节点的状态上报
+     * 与删除处理一起卡住。改为异步投递后，外呼延迟不再占用锁。
+     */
+    private final ExecutorService notificationExecutor;
+
+    /** 是否发送完成通知；仅生产构造（启动调度器）时启用，单元测试保持静默不外呼。 */
+    private final boolean notificationsEnabled;
+
     public DownloadCheckService(Map<Integer, GalleryTask> queue){
         this(queue, true);
     }
@@ -38,6 +65,12 @@ public class DownloadCheckService {
     DownloadCheckService(Map<Integer, GalleryTask> queue, boolean startScheduler){
         this.queue = queue;
         compress_queue = new ArrayList<>(0);
+        this.notificationsEnabled = startScheduler;
+        this.notificationExecutor = Executors.newSingleThreadExecutor(r -> {
+            Thread thread = new Thread(r, "storage-node-notify");
+            thread.setDaemon(true);
+            return thread;
+        });
         if (startScheduler) {
             convert_thread = new ScheduledThreadPoolExecutor(1);
             convert_thread.scheduleWithFixedDelay(this::compress, 0, 5, TimeUnit.SECONDS);
@@ -199,7 +232,7 @@ public class DownloadCheckService {
             queue.remove(galleryTask.getGid());
             galleryTask.setName(storedDirectory.getName());
             galleryTask.setStatus(GalleryTask.COMPRESS_COMPLETE);
-            CustomUtil.notifyMe(String.format("任务:%s在添加时已下载完成，更新任务状态", galleryTask.getName()));
+            notifyAlreadyStored(galleryTask.getName());
             return galleryTask;
         }
 
@@ -242,12 +275,39 @@ public class DownloadCheckService {
 
         for(File directory : directories){
             if(matchesGid(directory.getName(), gid)
-                    && isValidArchive(new File(directory, directory.getName() + ".zip")))
+                    && isVerifiedArchive(new File(directory, directory.getName() + ".zip")))
                 return directory;
         }
         return null;
     }
 
+    /**
+     * 压缩包校验带缓存：归档按大小不变，校验结果可复用。
+     * 大小变化（重新压缩）或距上次校验超过一小时才重算，避免重复整包读取。
+     */
+    private boolean isVerifiedArchive(File archive){
+        if(!archive.isFile())
+            return false;
+        long size = archive.length();
+        long now = System.currentTimeMillis();
+        VerifiedArchive cached = verifiedArchives.get(archive.getPath());
+        if(cached != null && cached.size() == size && now - cached.verifiedAt() < ARCHIVE_REVERIFY_MILLIS)
+            return true;
+        if(!isValidArchive(archive)){
+            verifiedArchives.remove(archive.getPath());
+            return false;
+        }
+        verifiedArchives.put(archive.getPath(), new VerifiedArchive(size, now));
+        return true;
+    }
+
+    private void notifyAlreadyStored(String taskName){
+        if(!notificationsEnabled)
+            return;
+        notificationExecutor.execute(() ->
+                CustomUtil.notifyMe(String.format("任务:%s在添加时已下载完成，更新任务状态", taskName)));
+    }
+
     private File findDirectoryByGid(File parentDirectory, int gid){
         File[] directories = parentDirectory.listFiles(File::isDirectory);
         if(directories == null)

src/main/java/lion/Service/PrimaryChannelTracker.java

@@ -0,0 +1,92 @@
+package lion.Service;
+
+import io.netty.channel.Channel;
+import io.netty.util.AttributeKey;
+import lombok.extern.slf4j.Slf4j;
+
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * 「哪条通道是主站」的唯一登记处。
+ *
+ * <p>历史缺陷：主站重连期间可能出现多条已认证通道，节点先引用 X，随后被后建立的 Y
+ * 覆盖；Y 断开时把引用清空，而仍可用的 X 继续发送心跳与任务消息，节点却因为引用为空
+ * 不再上报任何任务状态。主站侧的存活探测又能收到 X 上的响应，双方于是都判定
+ * 「连接正常」，未完成任务的状态就此永久卡住。
+ *
+ * <p>因此把引用管理收敛到这里，并保留全部已认证通道：首选通道一旦失效，立即回退到
+ * 其它仍可用的已认证通道；引用被误清时，任何一条已认证通道上的消息也能把它恢复。
+ * 这样「有已认证通道在，就一定能上报」成为不变式，不必等人工重连或下一个探测周期。
+ *
+ * <p>「已认证」的口径是「该通道发来过只有主站会发的消息类型」。事故中出问题的那条通道
+ * 正是靠可用性探测消息证明自己仍在工作的，若只认 {@code IdentityMessage}，这条通道
+ * 就永远无法重新取得引用。节点数据端口本就只应面向主站开放，凭证由网络边界提供。
+ */
+@Slf4j
+public class PrimaryChannelTracker {
+
+    static final AttributeKey<Boolean> AUTHENTICATED = AttributeKey.valueOf("primaryAuthenticated");
+
+    /** 全部已认证通道，用于在首选通道失效时立即回退。 */
+    private final Set<Channel> authenticated = ConcurrentHashMap.newKeySet();
+
+    private volatile Channel primary;
+
+    /** 收到只有主站会发的消息：认证该通道；若当前引用不是它，则改指向它。 */
+    public void onPrimaryMessage(Channel channel) {
+        markAuthenticated(channel);
+        if (primary == null) {
+            primary = channel;
+            log.info("主站通道引用已建立");
+        } else if (channel != primary) {
+            switchTo(channel);
+        }
+    }
+
+    private void markAuthenticated(Channel channel) {
+        if (Boolean.TRUE.equals(channel.attr(AUTHENTICATED).get()))
+            return;
+        channel.attr(AUTHENTICATED).set(Boolean.TRUE);
+        channel.closeFuture().addListener(ignored -> unregister(channel));
+        authenticated.add(channel);
+    }
+
+    /** 通道退出：移出已认证集合，必要时把引用移交给其它仍可用的通道。 */
+    public void unregister(Channel channel) {
+        authenticated.remove(channel);
+        if (channel != primary)
+            return;
+        primary = firstUsable();
+    }
+
+    private void switchTo(Channel channel) {
+        log.info("主站通道引用已切换到仍在工作的通道");
+        primary = channel;
+    }
+
+    public Channel current() {
+        Channel channel = primary;
+        if (channel != null && channel.isActive())
+            return channel;
+        // 首选通道已失效：立即回退，避免出现「有可用通道却无人上报」的静默状态。
+        Channel fallback = firstUsable();
+        if (fallback != null && fallback != channel) {
+            log.info("主站首选通道不可用，回退到其它已认证通道");
+            primary = fallback;
+        }
+        return fallback;
+    }
+
+    /** 引用是否存在且仍可写。 */
+    public boolean usable() {
+        return current() != null;
+    }
+
+    private Channel firstUsable() {
+        for (Channel channel : authenticated)
+            if (channel.isActive())
+                return channel;
+        return null;
+    }
+}

src/main/java/lion/Service/RekickPolicy.java

@@ -0,0 +1,34 @@
+package lion.Service;
+
+/**
+ * 「是否该主动重新唤起主站」的判定。
+ *
+ * <p>节点持有待上报的任务状态却没有可用通道时，只等主站下一个探测周期可能长达半小时；
+ * 期间用户在下载器里看到的是任务永远停在「已提交」。这里按固定间隔限流地允许重连，
+ * 既能在几十秒内自愈，又不会在主站确实离线时形成重连风暴。
+ *
+ * <p>把判定单独拆出来是为了能直接对时间轴写断言，不必启动 Netty。
+ */
+public class RekickPolicy {
+
+    /** 两次主动唤起之间的最小间隔。 */
+    static final long MIN_INTERVAL_MILLIS = 30_000L;
+
+    private long lastAttemptMillis;
+
+    /**
+     * 本轮是否应当唤起主站。
+     *
+     * @param pendingReports 是否有待上报的任务状态
+     * @param channelUsable  是否已存在可用通道
+     * @param nowMillis      当前时间
+     */
+    public boolean shouldRekick(boolean pendingReports, boolean channelUsable, long nowMillis) {
+        if (!pendingReports || channelUsable)
+            return false;
+        if (lastAttemptMillis != 0 && nowMillis - lastAttemptMillis < MIN_INTERVAL_MILLIS)
+            return false;
+        lastAttemptMillis = nowMillis;
+        return true;
+    }
+}

src/main/java/lion/Service/SubscriptionSnapshotStore.java

@@ -38,6 +38,21 @@ public final class SubscriptionSnapshotStore {
     private final int maxPayloadBytes;
     private final ObjectMapper objectMapper = CustomUtil.objectMapper;
     private final AtomicReference<Snapshot> current = new AtomicReference<>();
+    /**
+     * 最近一次收到主站存活信号的时刻（本地接收时间）。
+     *
+     * <p>「过期」的语义是「主站已失联」，因此新鲜度必须由「主站的任何存活信号」驱动，
+     * 而不能只看「收到快照」。快照是内容寻址的：内容长期不变时主站没有理由反复推送，
+     * 若以收到快照为准，备机会在内容不动的第 7 天误判过期；反过来，若主站为此定时重发
+     * 整份快照，又只为续期而传输约 346 KiB/次。
+     *
+     * <p>主站本就有常规存活探测（每 30 分钟的 AvailableCheckMessage），节点回它以
+     * ResponseMessage。把该信号纳入新鲜度后：过期 ⇔ 主站失联超过有效期，
+     * 语义精确，且不再需要任何为「续期」而生的专用推送。
+     *
+     * <p>时刻取自节点本地时钟、不参与签名，攻击者无法通过重放旧 revision 续期。
+     */
+    private volatile long lastPrimaryContactAt;
 
     public SubscriptionSnapshotStore(Path root, String syncSecret, long maxStaleSeconds, int maxPayloadBytes) {
         this.root = Objects.requireNonNull(root);
@@ -72,6 +87,9 @@ public final class SubscriptionSnapshotStore {
             try {
                 Snapshot snapshot = loadSnapshot(root.resolve("snapshots").resolve(revision));
                 current.set(snapshot);
+                // 重启后还没有收到过主站快照，先以落盘内容的生成时间作为新鲜度起点，
+                // 否则重启即视为「刚同步过」，会让超期快照被错误续期。
+                lastPrimaryContactAt = snapshot.generatedAt();
                 writePointer(revision);
                 log.info("加载订阅快照成功 revision={} accounts={} bindings={}", shortRevision(revision), snapshot.accountCount(), snapshot.bindingCount());
                 return;
@@ -106,8 +124,11 @@ public final class SubscriptionSnapshotStore {
             SnapshotData data = validatePayload(payload);
             Snapshot old = current.get();
             if (old != null) {
-                if (message.getRevision().equals(old.revision()))
+                if (message.getRevision().equals(old.revision())) {
+                    // 内容未变但主站仍在同步：刷新新鲜度，避免备机因「内容长期不变」而误判过期。
+                    lastPrimaryContactAt = System.currentTimeMillis();
                     return new ApplyResult(APPLY_OLD, "revision 已存在");
+                }
                 if (message.getGeneratedAt() < old.generatedAt())
                     return new ApplyResult(APPLY_OLD, "快照时间早于当前版本");
             }
@@ -139,6 +160,7 @@ public final class SubscriptionSnapshotStore {
             Snapshot snapshot = new Snapshot(message.getRevision(), message.getGeneratedAt(), data.byKeyHash,
                     data.accounts.size(), data.bindingCount);
             current.set(snapshot);
+            lastPrimaryContactAt = System.currentTimeMillis();
             cleanupOldSnapshots(message.getRevision());
             return new ApplyResult(APPLY_SUCCESS, "同步成功");
         } catch (Exception e) {
@@ -162,7 +184,7 @@ public final class SubscriptionSnapshotStore {
 
     public Lookup lookup(String client, String publicKey) {
         Snapshot snapshot = current.get();
-        if (snapshot == null || snapshot.expired(System.currentTimeMillis(), maxStaleMillis))
+        if (snapshot == null || isStale(System.currentTimeMillis()))
             return null;
         AccountFiles account = snapshot.byKeyHash().get(sha256(publicKey.getBytes(StandardCharsets.UTF_8)));
         if (account == null)
@@ -174,9 +196,29 @@ public final class SubscriptionSnapshotStore {
         Snapshot snapshot = current.get();
         if (snapshot == null)
             return new Status("unavailable", null, 0, 0, 0);
-        long age = Math.max(0, System.currentTimeMillis() - snapshot.generatedAt());
-        boolean expired = snapshot.expired(System.currentTimeMillis(), maxStaleMillis);
-        return new Status(expired ? "expired" : "ready", snapshot.revision(), snapshot.accountCount(), snapshot.bindingCount(), age);
+        long now = System.currentTimeMillis();
+        long age = Math.max(0, now - lastPrimaryContactAt);
+        return new Status(isStale(now) ? "expired" : "ready", snapshot.revision(), snapshot.accountCount(), snapshot.bindingCount(), age);
+    }
+
+    /**
+     * 主站是否已失联超过最大有效期。
+     *
+     * <p>由主站的任何存活信号刷新（见 {@link #markPrimaryContact()}），不限于快照。
+     */
+    private boolean isStale(long now) {
+        return maxStaleMillis > 0 && now - lastPrimaryContactAt > maxStaleMillis;
+    }
+
+    /**
+     * 记录一次「主站仍在」的证据。
+     *
+     * <p>用于快照之外的常规存活信号（例如主站每 30 分钟的可用性检查）。
+     * 只要主站在线，本节点的新鲜度就会持续被刷新，因此备机不会因为
+     * 「订阅内容长期不变、主站没理由重发快照」而被判过期。
+     */
+    public void markPrimaryContact() {
+        lastPrimaryContactAt = System.currentTimeMillis();
     }
 
     private Snapshot loadSnapshot(Path directory) throws IOException {
@@ -323,7 +365,5 @@ public final class SubscriptionSnapshotStore {
     public record Status(String state, String revision, int accountCount, int bindingCount, long ageMillis) {}
     private record AccountFiles(Integer accountId, byte[] v2, byte[] clash) {}
     private record SnapshotData(Map<Integer, AccountFiles> accounts, Map<String, AccountFiles> byKeyHash, int bindingCount) {}
-    private record Snapshot(String revision, long generatedAt, Map<String, AccountFiles> byKeyHash, int accountCount, int bindingCount) {
-        boolean expired(long now, long maxAge) { return maxAge > 0 && now - generatedAt > maxAge; }
-    }
+    private record Snapshot(String revision, long generatedAt, Map<String, AccountFiles> byKeyHash, int accountCount, int bindingCount) {}
 }

src/main/java/lion/storageNode.java

@@ -7,6 +7,8 @@ import lion.Message.Main.*;
 import lion.Service.DeleteService;
 import lion.Service.SubscriptionSnapshotStore;
 import lion.Service.DownloadCheckService;
+import lion.Service.PrimaryChannelTracker;
+import lion.Service.RekickPolicy;
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.*;
 import io.netty.channel.nio.NioEventLoopGroup;
@@ -25,9 +27,25 @@ import java.util.concurrent.locks.ReentrantLock;
 @Slf4j
 public class storageNode {
 
-    Channel server;
+    // 主站通道引用由 PrimaryChannelTracker 统一管理，避免重复认证把可用通道误清空。
+    final PrimaryChannelTracker primaryChannel = new PrimaryChannelTracker();
 
-    Channel node;
+    // 有待上报任务却无可用通道时，主动重新唤起主站，避免干等下一个探测周期。
+    final RekickPolicy rekickPolicy = new RekickPolicy();
+
+    // 重新唤起主站是阻塞式端口探测（最多 21×3 秒），不得占用 5 秒调度线程，
+    // 否则下载进度扫描与压缩都会被拖住；同一时刻只允许一次探测。
+    final java.util.concurrent.atomic.AtomicBoolean rekicking = new java.util.concurrent.atomic.AtomicBoolean();
+
+    // 专门用于阻塞式重连探测；不能复用单线程的 checkThreadPool，
+    // 在同一个线程池里提交阻塞任务会把调度线程自己堵住。
+    final ExecutorService rekickExecutor = Executors.newSingleThreadExecutor(r -> {
+        Thread thread = new Thread(r, "storage-node-rekick");
+        thread.setDaemon(true);
+        return thread;
+    });
+
+    volatile Channel node;
 
     DownloadCheckService downloadCheckService;
 
@@ -58,7 +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>() {
@@ -69,8 +87,57 @@ 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);
+        checkThreadPool = Executors.newScheduledThreadPool(1);
+        checkThreadPool.scheduleAtFixedRate(this::mainThread, 5, 5, TimeUnit.SECONDS);
+    }
+
+    /**
+     * 在独立线程里重新唤起主站。
+     *
+     * <p>{@link #wakeMainServer()} 是阻塞的端口探测，最坏可占 21×3 秒；直接在
+     * {@link #mainThread()} 里调用会让下载扫描与压缩停摆，因此投递到独立线程执行。
+     * 该执行器与 5 秒调度器分离，避免阻塞任务把调度线程自己堵住；
+     * 同一时刻只允许一次探测，防止主站长时间离线时堆积。
+     */
+    void rekickMainServerAsync(){
+        if (!rekicking.compareAndSet(false, true))
+            return;
+        try {
+            rekickExecutor.execute(() -> {
+                try {
+                    wakeMainServer();
+                } finally {
+                    rekicking.set(false);
+                }
+            });
+        } catch (Exception e) {
+            rekicking.set(false);
+            log.warn("安排主站重连失败:{}", e.getMessage());
+        }
+    }
+
+    /**
+     * 按既定顺序敲主站监听端口，请它回来建立数据通道。
+     *
+     * <p>启动时调用一次，另在「有待上报任务但无可用通道」时按 {@link RekickPolicy}
+     * 限流重试。主站侧的可用性探测只能覆盖它认为连接仍在的情况；一旦双方都判定
+     * 对方不在，只有本方法能重新建立通道，否则任务状态会一直卡在未完成。
+     */
+    void wakeMainServer(){
         int i;
         for(i=0; i<=20; i++) {
             try (Socket socket = new Socket()) {
@@ -87,9 +154,6 @@ public class storageNode {
         if (i==20) {
             log.info("server connect failed");
         }
-        downloadCheckService = new DownloadCheckService(queue);
-        checkThreadPool = Executors.newScheduledThreadPool(1);
-        checkThreadPool.scheduleAtFixedRate(this::mainThread, 5, 5, TimeUnit.SECONDS);
     }
 
     public void mainThread(){
@@ -103,6 +167,19 @@ public class storageNode {
             } finally {
                 lock.unlock();
             }
+
+            // 有暂存内容却无可用通道：告警，并按限流主动重新唤起主站。
+            // 这里只告警与重连，不提前返回——本地下载与压缩必须继续推进，
+            // 否则主站恢复前任务会在节点侧整体停摆。
+            // 该判断在 downloadCheck 之前：正在下载、进度无变化的任务稍后会走
+            // 「无需上报」的提前返回路径，若只在回报分支里判定，通道失联后
+            // 这类任务既不会被发现也不会触发重连，就复现了历史上的静默卡死。
+            if (!queue.isEmpty() && !primaryChannel.usable()) {
+                log.warn("主站通道不可用，{} 个任务状态暂存待上报", queue.size());
+                if (rekickPolicy.shouldRekick(true, false, System.currentTimeMillis()))
+                    rekickMainServerAsync();
+            }
+
             //检查，当任务状态发生变化即方法返回true时，再更新，否则return
             if (!downloadCheckService.downloadCheck()) {
                 boolean isSkip = true;
@@ -115,20 +192,27 @@ public class storageNode {
                         }
                 if(isSkip) {
                     counter++;
-                    if (server != null && server.isActive() && counter > 10) {
-                        server.writeAndFlush(new MaintainMessage());
+                    if (primaryChannel.usable() && counter > 10) {
+                        primaryChannel.current().writeAndFlush(new MaintainMessage());
                         counter = 0;
                     }
                     return;
                 }
             }
+            //主站未连接时不上报，队列保留、等主站重连时重放（无法写通道时上面的分支已兜住）。
+            Channel target = primaryChannel.current();
+            if (target == null)
+                return;
+            //没有待上报任务时不必发送空数组（此时 downloadCheck 为 false 且无压缩完成任务）。
+            if (queue.isEmpty())
+                return;
             //发送
             //上锁后再发送，避免出现发送完之后再下载完成
             lock.lock();
             try {
                 DownloadStatusMessage downloadStatusMessage = new DownloadStatusMessage();
                 downloadStatusMessage.setGalleryTasks(queue.values().toArray(GalleryTask[]::new));
-                server.writeAndFlush(downloadStatusMessage);
+                target.writeAndFlush(downloadStatusMessage);
 
                 queue.entrySet().removeIf(entry -> entry.getValue().is_compress_complete());
                 log.info("任务状态发送完成");
@@ -142,6 +226,27 @@ public class storageNode {
 
     int counter;
 
+    /**
+     * 该消息是否只有主站会发。
+     *
+     * <p>白名单而非黑名单：只有这些类型能证明对端是主站并据此认领通道引用。
+     * 名单严格等于主站在 {@code RemoteService} 里实际会发出的类型；
+     * {@code ResponseMessage}、{@code DownloadStatusMessage}、{@code MaintainMessage}
+     * 都是本节点自己的出站类型，备机（{@code lionwebsiteside}）也会发身份消息，
+     * 都不能用来认领主站引用。
+     */
+    static boolean isPrimaryEvidence(AbstractMessage message) {
+        if (message.messageType == AbstractMessage.IDENTITY_MESSAGE) {
+            // 备机也用身份消息自我介绍，只有 identity 为 lionwebsite 的才是主站。
+            IdentityMessage identity = (IdentityMessage) message;
+            return "lionwebsite".equals(identity.getIdentity());
+        }
+        return message.messageType == AbstractMessage.DOWNLOAD_POST_MESSAGE
+                || message.messageType == AbstractMessage.DELETE_GALLERY_MESSAGE
+                || message.messageType == AbstractMessage.AVAILABLE_CHECK_MESSAGE
+                || message.messageType == AbstractMessage.SUBSCRIPTION_SNAPSHOT_MESSAGE;
+    }
+
     class MyChannelInboundHandlerAdapter extends ChannelInboundHandlerAdapter{
         Map<Integer, GalleryTask> queue;
 
@@ -157,11 +262,21 @@ public class storageNode {
                 log.info(String.valueOf(msg));
             AbstractMessage abstractMessage = (AbstractMessage) msg;
 
+            // 只有主站会发的消息类型（身份/任务下发/删除/探活/订阅快照）同时承担两件事：
+            // 证明「主站仍在」，以及恢复通道引用。并发认证时引用可能先指向 X 再被 Y 覆盖，
+            // Y 断开后引用被清空，而仍可用的 X 继续发送探活等消息；收到这些消息即证明
+            // X 就是主站，必须无条件认领——引用被清空时 current() 为 null，
+            // 任何以其为前提的判断都不成立，自愈也就无从触发。
+            if (isPrimaryEvidence(abstractMessage)) {
+                primaryChannel.onPrimaryMessage(ctx.channel());
+                subscriptionSnapshotStore.markPrimaryContact();
+            }
+
             switch (abstractMessage.messageType){
                 case AbstractMessage.IDENTITY_MESSAGE -> {
                     IdentityMessage identityMessage = (IdentityMessage) abstractMessage;
                     if(identityMessage.getIdentity().equals("lionwebsite")) {
-                        server = ctx.channel();
+                        // 引用已在上面按消息类型认领，这里只保留「上线」日志语义。
                         log.info("server 上线");
                     } else if(identityMessage.getIdentity().equals("lionwebsiteside")){
                         node = ctx.channel();
@@ -176,7 +291,9 @@ public class storageNode {
                         GalleryTask currentTask = downloadCheckService.addToQueue(dpm.getGalleryTask());
                         DownloadStatusMessage downloadStatusMessage = new DownloadStatusMessage();
                         downloadStatusMessage.setGalleryTasks(new GalleryTask[]{currentTask});
-                        server.writeAndFlush(downloadStatusMessage);
+                        Channel target = primaryChannel.current();
+                        if (target != null && target.isActive())
+                            target.writeAndFlush(downloadStatusMessage);
                         log.info(String.valueOf(queue));
                     } finally {
                         lock.unlock();
@@ -194,7 +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);
                 }
@@ -205,7 +322,7 @@ public class storageNode {
                 }
                 case AbstractMessage.SUBSCRIPTION_SNAPSHOT_MESSAGE -> {
                     SubscriptionSnapshotMessage snapshotMessage = (SubscriptionSnapshotMessage) abstractMessage;
-                    if (!Config.subscriptionSyncEnabled || !ctx.channel().equals(server)) {
+                    if (!Config.subscriptionSyncEnabled || !ctx.channel().equals(primaryChannel.current())) {
                         ctx.writeAndFlush(new ResponseMessage(snapshotMessage.messageId, SubscriptionSnapshotStore.APPLY_INVALID));
                         return;
                     }
@@ -224,13 +341,13 @@ public class storageNode {
 
         @Override
         public void channelUnregistered(ChannelHandlerContext ctx) {
-            if(ctx.channel().equals(server)) {
+            if(ctx.channel().equals(primaryChannel.current())) {
                 log.info("server 下线");
-                server = null;
             } else if(ctx.channel().equals(node)){
                 log.info("node 下线");
                 node = null;
             }
+            primaryChannel.unregister(ctx.channel());
         }
     }
 

src/main/resources/reflect-config.json

@@ -124,5 +124,15 @@
     "allPublicMethods" : true,
     "allDeclaredFields" : true,
     "allPublicFields" : true
+  },
+  {
+    "name": "lion.storageNode$MyChannelInboundHandlerAdapter",
+    "allDeclaredMethods" : true,
+    "allPublicMethods" : true
+  },
+  {
+    "name": "lion.Message.MessageCodec",
+    "allDeclaredMethods" : true,
+    "allPublicMethods" : true
   }
 ]

src/test/java/lion/ConfigTest.java

@@ -0,0 +1,109 @@
+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");
+    }
+
+    /**
+     * 管理员口令默认必须为空（即关闭 8888 的管理员直取能力），
+     * 且不再有写死在源码里的默认口令。
+     */
+    @Test
+    void adminDownloadCodeDefaultsToDisabled(@TempDir Path root) throws Exception {
+        Path file = Files.writeString(root.resolve("config.properties"), "");
+
+        Config.loadConfig(file.toString());
+
+        assertEquals("", Config.adminDownloadCode, "未配置口令时管理员能力必须关闭");
+        assertEquals("/root/gallery/gallery", Config.adminDownloadRoot, "默认根目录应与下载目录一致");
+    }
+
+    /** 口令与根目录都应能从配置文件读入。 */
+    @Test
+    void readsAdminDownloadSettings(@TempDir Path root) throws Exception {
+        Path file = Files.writeString(root.resolve("config.properties"), String.join("\n",
+                "AdminDownloadCode=alone",
+                "AdminDownloadRoot=/root/gallery"));
+
+        Config.loadConfig(file.toString());
+
+        assertEquals("alone", Config.adminDownloadCode);
+        assertEquals("/root/gallery", Config.adminDownloadRoot);
+    }
+
+    /**
+     * 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

@@ -0,0 +1,255 @@
+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.*;
+
+/**
+ * 下载 HTTP 服务的请求行解析。
+ * 这条链路只接受主站 IP 的请求，解析细节直接决定能否按 gid 找到正确的压缩包。
+ */
+class MultiThreadedHTTPServerTest {
+
+    /** 普通请求：path 与各查询参数都要被拆出来。 */
+    @Test
+    void parsesPathAndQueryParameters() {
+        Map<String, String> params = MultiThreadedHTTPServer.parseRequestLine(
+                "/download?AuthCode=abc&gid=12345");
+
+        assertEquals("/download", params.get("path"));
+        assertEquals("abc", params.get("AuthCode"));
+        assertEquals("12345", params.get("gid"));
+    }
+
+    /** 无查询串时只回 path，且不应抛异常。 */
+    @Test
+    void parsesPathWithoutQueryString() {
+        Map<String, String> params = MultiThreadedHTTPServer.parseRequestLine("/archive/file.zip");
+        assertEquals("/archive/file.zip", params.get("path"));
+        assertNull(params.get("gid"));
+    }
+
+    /**
+     * 参数值里含 '=' 时必须完整保留。
+     * 回归：split("=") 无 limit 会在第一个 '=' 处截断，
+     * base64 padding（结尾的 '='）等取值会被悄悄改短。
+     */
+    @Test
+    void keepsEqualsSignInsideParameterValue() {
+        Map<String, String> params = MultiThreadedHTTPServer.parseRequestLine(
+                "/download?AuthCode=alone&token=YWJjZA==");
+
+        assertEquals("YWJjZA==", params.get("token"), "值内的 '=' 不得被截断");
+        assertEquals("alone", params.get("AuthCode"));
+    }
+
+    /** URL 编码的值必须解码回原文。 */
+    @Test
+    void decodesPercentEncodedValues() {
+        Map<String, String> params = MultiThreadedHTTPServer.parseRequestLine(
+                "/download?AuthCode=alone&name=a%20b");
+        assertEquals("a b", params.get("name"));
+    }
+
+    /** null 请求行返回 null，交由调用方兜底。 */
+    @Test
+    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(""));
+    }
+
+    // ---- 管理员直取文件的口令与目录约束 ----
+
+    /** 未配置口令时，管理员能力必须关闭，任何 AuthCode 都不能直取文件。 */
+    @Test
+    void adminCapabilityIsOffUntilCodeConfigured() {
+        lion.Config.Config.adminDownloadCode = "";
+
+        assertFalse(MultiThreadedHTTPServer.isAdminRequest("alone"));
+        assertFalse(MultiThreadedHTTPServer.isAdminRequest(""));
+    }
+
+    /** 配置口令后只认该口令，旧写死值与其他值都不再放行。 */
+    @Test
+    void onlyConfiguredAdminCodeIsAccepted() {
+        lion.Config.Config.adminDownloadCode = "s3cret-code";
+        try {
+            assertTrue(MultiThreadedHTTPServer.isAdminRequest("s3cret-code"));
+            assertFalse(MultiThreadedHTTPServer.isAdminRequest("alone"), "写死的旧值不应再有效");
+            assertFalse(MultiThreadedHTTPServer.isAdminRequest("s3cret"));
+            assertFalse(MultiThreadedHTTPServer.isAdminRequest(null));
+        } finally {
+            lion.Config.Config.adminDownloadCode = "";
+        }
+    }
+
+    /** 管理员直取文件只允许根目录之下的真实文件。 */
+    @Test
+    void adminDownloadIsConfinedToConfiguredRoot(@TempDir Path root) throws Exception {
+        Path galleryRoot = Files.createDirectories(root.resolve("gallery"));
+        Path archive = Files.write(galleryRoot.resolve("sample.zip"), "zip".getBytes(StandardCharsets.UTF_8));
+        Path outside = Files.write(root.resolve("secret.txt"), "top secret".getBytes(StandardCharsets.UTF_8));
+        lion.Config.Config.adminDownloadRoot = galleryRoot.toString();
+        try {
+            assertEquals(archive.toRealPath().toFile(), MultiThreadedHTTPServer.resolveAdminFile(archive.toString()));
+            assertEquals(archive.toRealPath().toFile(), MultiThreadedHTTPServer.resolveAdminFile("sample.zip"));
+
+            assertNull(MultiThreadedHTTPServer.resolveAdminFile("../secret.txt"), "../ 越界必须被拒");
+            assertNull(MultiThreadedHTTPServer.resolveAdminFile(outside.toString()), "根目录之外的绝对路径必须被拒");
+            assertNull(MultiThreadedHTTPServer.resolveAdminFile("/etc/passwd"), "任意系统文件必须被拒");
+            assertNull(MultiThreadedHTTPServer.resolveAdminFile(galleryRoot.toString()), "目录本身不是可下载文件");
+        } finally {
+            lion.Config.Config.adminDownloadRoot = "/root/gallery/gallery";
+        }
+    }
+
+    /** 指向根目录之外的符号链接也不得把文件泄漏出去。 */
+    @Test
+    void adminDownloadRejectsSymlinkEscape(@TempDir Path root) throws Exception {
+        Path galleryRoot = Files.createDirectories(root.resolve("gallery"));
+        Path outside = Files.write(root.resolve("secret.txt"), "top secret".getBytes(StandardCharsets.UTF_8));
+        Path link = galleryRoot.resolve("link.zip");
+        try {
+            Files.createSymbolicLink(link, outside);
+        } catch (UnsupportedOperationException | IOException e) {
+            return; // 平台不支持符号链接时跳过
+        }
+        lion.Config.Config.adminDownloadRoot = galleryRoot.toString();
+        try {
+            assertNull(MultiThreadedHTTPServer.resolveAdminFile("link.zip"), "指向根目录外的符号链接必须被拒");
+        } finally {
+            lion.Config.Config.adminDownloadRoot = "/root/gallery/gallery";
+        }
+    }
+
+    // ---- 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 {
+        lion.Config.Config.adminDownloadCode = "alone";
+        // 管理员直取已限定在 adminDownloadRoot 之下，测试把根目录指到临时目录。
+        lion.Config.Config.adminDownloadRoot = root.toString();
+        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/PrimaryChannelRecoveryTest.java

@@ -0,0 +1,88 @@
+package lion;
+
+import io.netty.channel.embedded.EmbeddedChannel;
+import lion.Message.AbstractMessage;
+import lion.Message.Main.AvailableCheckMessage;
+import lion.Message.Main.IdentityMessage;
+import lion.Service.PrimaryChannelTracker;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * 复现并锁定线上事故的通道恢复语义。
+ *
+ * <p>事故经过：主站重连期间节点先后认证了多条通道，引用被最后一条覆盖；那条通道断开后
+ * 引用被清空，而更早建立、仍然可用的通道继续发送可用性探测。节点因引用为空不再上报
+ * 任何任务状态，主站又能在旧通道上收到探活响应，双方都判定连接正常，未完成任务
+ * 便永久停在「已提交」，直到人工触发重连。
+ */
+class PrimaryChannelRecoveryTest {
+
+    @Test
+    void availableCheckOnSurvivingChannelRestoresReporting() {
+        PrimaryChannelTracker tracker = new PrimaryChannelTracker();
+        EmbeddedChannel survivor = new EmbeddedChannel();
+        EmbeddedChannel overwriter = new EmbeddedChannel();
+        try {
+            // 主站两次上线：引用最终落在后建立的 overwriter 上。
+            tracker.onPrimaryMessage(survivor);
+            tracker.onPrimaryMessage(overwriter);
+
+            // overwriter 断开，引用被清空——事故的起点。
+            tracker.unregister(overwriter);
+
+            // 仍然可用的 survivor 发来探活消息：引用应当立即恢复。
+            AvailableCheckMessage probe = new AvailableCheckMessage();
+            assertEquals(AbstractMessage.AVAILABLE_CHECK_MESSAGE, probe.messageType);
+            tracker.onPrimaryMessage(survivor);
+
+            assertSame(survivor, tracker.current(), "探活消息应恢复引用");
+            assertTrue(tracker.usable(), "恢复后必须能继续上报任务状态");
+        } finally {
+            survivor.finishAndReleaseAll();
+            overwriter.finishAndReleaseAll();
+        }
+    }
+
+    /** 首选通道断开但仍有其它已认证通道时，不得出现「无通道可用」的空窗。 */
+    @Test
+    void referenceNeverDropsWhileAnotherAuthenticatedChannelLives() {
+        PrimaryChannelTracker tracker = new PrimaryChannelTracker();
+        EmbeddedChannel first = new EmbeddedChannel();
+        EmbeddedChannel second = new EmbeddedChannel();
+        try {
+            tracker.onPrimaryMessage(first);
+            tracker.onPrimaryMessage(second);
+
+            tracker.unregister(second);
+
+            assertTrue(tracker.usable(), "仍有已认证通道时必须可用");
+            assertSame(first, tracker.current());
+        } finally {
+            first.finishAndReleaseAll();
+            second.finishAndReleaseAll();
+        }
+    }
+
+    /**
+     * 备机的身份消息不得夺走主站引用。
+     *
+     * <p>备机在启动时同样会自我介绍，若按消息类型无条件认领，备机通道会被误当成主站，
+     * 任务状态将上报到错误的连接上。
+     */
+    @Test
+    void sidecarIdentityDoesNotStealPrimaryReference() {
+        assertTrue(storageNode.isPrimaryEvidence(identity("lionwebsite")), "主站身份应被认作证据");
+        assertFalse(storageNode.isPrimaryEvidence(identity("lionwebsiteside")),
+                "备机身份不是主站证据，否则任务状态会上报到错误的连接");
+        assertFalse(storageNode.isPrimaryEvidence(new lion.Message.Main.ResponseMessage()),
+                "响应消息是节点自己的出站类型，不能用来认领主站引用");
+    }
+
+    private static IdentityMessage identity(String value) {
+        IdentityMessage message = new IdentityMessage();
+        message.setIdentity(value);
+        return message;
+    }
+}

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/Service/DownloadCheckServiceTest.java

@@ -48,4 +48,31 @@ class DownloadCheckServiceTest {
         task.setGid(123);
         assertFalse(service.addToQueue(task).is_compress_complete());
     }
+
+    /**
+     * 已有有效归档时必须判为完成，且重复添加（命中校验缓存）行为保持一致。
+     * 校验缓存按「路径 + 大小」复用，目的是避免每次 addToQueue 都把整包读一遍，
+     * 但它绝不能让有效归档被误判为未完成。
+     */
+    @Test
+    void validArchiveIsRecognizedAcrossRepeatedQueueAdds(@TempDir Path root) throws Exception {
+        Path stored = Files.createDirectories(root.resolve("stored/sample [123]"));
+        Path zip = stored.resolve("sample [123].zip");
+        try (var out = new java.util.zip.ZipOutputStream(Files.newOutputStream(zip))) {
+            out.putNextEntry(new java.util.zip.ZipEntry("1.jpg"));
+            out.write("image bytes".getBytes(java.nio.charset.StandardCharsets.UTF_8));
+            out.closeEntry();
+        }
+        var service = new DownloadCheckService(new ConcurrentHashMap<>(), false);
+        service.storagePath = root.resolve("stored").toString();
+        service.downloadPath = root.resolve("downloads").toString();
+
+        GalleryTask first = new GalleryTask();
+        first.setGid(123);
+        assertTrue(service.addToQueue(first).is_compress_complete(), "存在有效归档时应判为完成");
+
+        GalleryTask second = new GalleryTask();
+        second.setGid(123);
+        assertTrue(service.addToQueue(second).is_compress_complete(), "第二次应命中校验缓存且结论一致");
+    }
 }

src/test/java/lion/Service/PrimaryChannelTrackerTest.java

@@ -0,0 +1,117 @@
+package lion.Service;
+
+import io.netty.channel.Channel;
+import io.netty.channel.embedded.EmbeddedChannel;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class PrimaryChannelTrackerTest {
+
+    /**
+     * 未认证通道退出时不得清空引用。
+     *
+     * <p>这正是线上事故的成因：并发认证让引用先指向 X 再被 Y 覆盖，
+     * Y 退出时把引用清空，而仍在工作的 X 从此不再被用于上报任务状态。
+     */
+    @Test
+    void unregisterOfNonPrimaryChannelKeepsReference() {
+        PrimaryChannelTracker tracker = new PrimaryChannelTracker();
+        EmbeddedChannel primary = new EmbeddedChannel();
+        EmbeddedChannel other = new EmbeddedChannel();
+        try {
+            tracker.onPrimaryMessage(primary);
+            tracker.onPrimaryMessage(other);
+            tracker.onPrimaryMessage(primary); // 引用回到仍在工作的那条通道
+
+            tracker.unregister(other);
+
+            assertSame(primary, tracker.current());
+            assertTrue(tracker.usable());
+        } finally {
+            primary.finishAndReleaseAll();
+            other.finishAndReleaseAll();
+        }
+    }
+
+    /**
+     * 首选通道退出时立即回退到其它仍可用的已认证通道。
+     *
+     * <p>事故中节点引用的那条通道退出后引用被清空，而另一条已认证通道仍然活跃，
+     * 任务状态就此无人上报。回退保证「有已认证通道在，就一定能上报」。
+     */
+    @Test
+    void unregisterOfPrimaryFallsBackToSurvivingChannel() {
+        PrimaryChannelTracker tracker = new PrimaryChannelTracker();
+        EmbeddedChannel survivor = new EmbeddedChannel();
+        EmbeddedChannel transientChannel = new EmbeddedChannel();
+        try {
+            tracker.onPrimaryMessage(survivor);
+            tracker.onPrimaryMessage(transientChannel);
+            tracker.unregister(transientChannel);
+
+            assertSame(survivor, tracker.current(), "应回退到仍可用的已认证通道");
+            assertTrue(tracker.usable());
+        } finally {
+            survivor.finishAndReleaseAll();
+            transientChannel.finishAndReleaseAll();
+        }
+    }
+
+    /** 实际在收发消息的已认证通道应当接管引用，即使原引用仍处于 active 状态。 */
+    @Test
+    void authenticatedChannelTakesOverOnMessage() {
+        PrimaryChannelTracker tracker = new PrimaryChannelTracker();
+        EmbeddedChannel stalePrimary = new EmbeddedChannel();
+        EmbeddedChannel live = new EmbeddedChannel();
+        try {
+            tracker.onPrimaryMessage(stalePrimary);
+            tracker.onPrimaryMessage(live);
+            tracker.onPrimaryMessage(stalePrimary); // 引用先落在 stalePrimary 上
+
+            tracker.onPrimaryMessage(live);
+
+            assertSame(live, tracker.current(), "说话的通道应成为引用");
+        } finally {
+            stalePrimary.finishAndReleaseAll();
+            live.finishAndReleaseAll();
+        }
+    }
+
+    /** 未经认证的通道不得占用引用，避免陌生连接抢走状态上报通道。 */
+    @Test
+    void unauthenticatedChannelCannotClaimReference() {
+        PrimaryChannelTracker tracker = new PrimaryChannelTracker();
+        EmbeddedChannel authenticated = new EmbeddedChannel();
+        EmbeddedChannel stranger = new EmbeddedChannel();
+        try {
+            tracker.onPrimaryMessage(authenticated);
+
+            // 未认证通道不会进入已认证集合，因此不能用它认领。
+
+            assertSame(authenticated, tracker.current());
+        } finally {
+            authenticated.finishAndReleaseAll();
+            stranger.finishAndReleaseAll();
+        }
+    }
+
+    /** 已下线的通道即使曾被认证，也不能再占用引用。 */
+    @Test
+    void inactiveChannelIsNotUsable() {
+        PrimaryChannelTracker tracker = new PrimaryChannelTracker();
+        EmbeddedChannel channel = new EmbeddedChannel();
+        tracker.onPrimaryMessage(channel);
+        channel.finishAndReleaseAll();
+
+        assertFalse(tracker.usable());
+    }
+
+    @Test
+    void emptyTrackerHasNoUsableChannel() {
+        PrimaryChannelTracker tracker = new PrimaryChannelTracker();
+
+        assertNull(tracker.current());
+        assertFalse(tracker.usable());
+    }
+}

src/test/java/lion/Service/RekickPolicyTest.java

@@ -0,0 +1,47 @@
+package lion.Service;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class RekickPolicyTest {
+
+    @Test
+    void noPendingReportsNeverRekicks() {
+        RekickPolicy policy = new RekickPolicy();
+
+        assertFalse(policy.shouldRekick(false, false, 1_000L));
+    }
+
+    @Test
+    void usableChannelNeverRekicks() {
+        RekickPolicy policy = new RekickPolicy();
+
+        assertFalse(policy.shouldRekick(true, true, 1_000L));
+    }
+
+    @Test
+    void pendingWithoutChannelRekicksThenRateLimits() {
+        RekickPolicy policy = new RekickPolicy();
+        long now = 1_000_000L;
+
+        assertTrue(policy.shouldRekick(true, false, now), "首次应允许重连");
+        assertFalse(policy.shouldRekick(true, false, now + 1), "间隔内应被限流");
+        assertFalse(policy.shouldRekick(true, false, now + RekickPolicy.MIN_INTERVAL_MILLIS - 1));
+        assertTrue(policy.shouldRekick(true, false, now + RekickPolicy.MIN_INTERVAL_MILLIS),
+                "超过最小间隔后应再次允许");
+    }
+
+    /** 限流只抑制连击，不应把「已限流」永久锁死后续尝试。 */
+    @Test
+    void rateLimitDoesNotBlockForever() {
+        RekickPolicy policy = new RekickPolicy();
+        long now = 500_000L;
+
+        policy.shouldRekick(true, false, now);
+        for (int i = 0; i < 5; i++)
+            policy.shouldRekick(true, false, now + i * 1_000L);
+
+        assertTrue(policy.shouldRekick(true, false, now + 10 * RekickPolicy.MIN_INTERVAL_MILLIS));
+    }
+}

src/test/java/lion/Service/SubscriptionSnapshotStoreTest.java

@@ -58,6 +58,83 @@ class SubscriptionSnapshotStoreTest {
         assertArrayEquals("clash-content".getBytes(StandardCharsets.UTF_8), second.lookup("cat", "public-key-1").content());
     }
 
+    /**
+     * 回归：节点曾按「内容里的 generatedAt」判过期，而 revision 是内容寻址的——
+     * 内容长期不变时主站每分钟重发同一 revision 会被判为 APPLY_OLD 直接丢弃，
+     * 新鲜度永远停在首次接收那天，于是主站在线且持续同步，备机仍在第 7 天开始 503。
+     * 现在过期只取决于「最近一次成功接收主站快照的时刻」。
+     */
+    @Test
+    void repeatedSameRevisionRefreshesFreshnessAndNeverExpires(@TempDir Path directory) throws Exception {
+        // 有效期 1 秒，便于在用例内观察「不续期会过期、续期后恢复」。
+        SubscriptionSnapshotStore store = new SubscriptionSnapshotStore(directory, SECRET, 1, 1024 * 1024);
+        SubscriptionSnapshotMessage message = message("public-key-1", "v2-content", "clash-content", System.currentTimeMillis());
+
+        assertEquals(SubscriptionSnapshotStore.APPLY_SUCCESS, store.apply(message).code());
+        assertEquals("ready", store.status().state());
+
+        // 超过有效期且期间没有任何推送 → 过期（证明判定确实生效，不是恒 ready）
+        Thread.sleep(1_200);
+        assertEquals("expired", store.status().state(), "超过有效期且无推送应判过期");
+
+        // 同 revision 重发：仍是 APPLY_OLD（内容幂等），但必须刷新新鲜度
+        assertEquals(SubscriptionSnapshotStore.APPLY_OLD, store.apply(message).code());
+        assertEquals("ready", store.status().state(), "重新收到同 revision 后应恢复可用");
+        assertNotNull(store.lookup("v2", "public-key-1"), "持续同步期间必须能取到订阅");
+    }
+
+    /** 超过有效期后仍未收到任何快照，才判过期并停止分发。 */
+    @Test
+    void expiresOnlyAfterNoSnapshotArrivesWithinMaxAge(@TempDir Path directory) throws Exception {
+        SubscriptionSnapshotStore store = new SubscriptionSnapshotStore(directory, SECRET, 3600, 1024 * 1024);
+        // 内容生成于 2 小时前，且重启后再没收到主站推送 → 超期。
+        SubscriptionSnapshotMessage message = message("public-key-1", "v2-content", "clash-content",
+                System.currentTimeMillis() - 7_200_000L);
+        assertEquals(SubscriptionSnapshotStore.APPLY_SUCCESS, store.apply(message).code());
+
+        SubscriptionSnapshotStore reloaded = new SubscriptionSnapshotStore(directory, SECRET, 3600, 1024 * 1024);
+        reloaded.load();
+        assertEquals("expired", reloaded.status().state(), "重启后未再收到快照，超期应判过期");
+        assertNull(reloaded.lookup("v2", "public-key-1"), "过期快照不得继续分发");
+    }
+
+    /**
+     * 主站的常规存活信号（例如每 30 分钟的可用性检查）必须刷新新鲜度。
+     *
+     * <p>这是「过期 ⇔ 主站失联」的关键：快照是内容寻址的，内容长期不变时主站没有理由
+     * 重发整份快照；若新鲜度只由「收到快照」驱动，备机会在内容不动的第 7 天误判过期。
+     */
+    @Test
+    void primaryContactWithoutNewSnapshotKeepsSubscriptionFresh(@TempDir Path directory) throws Exception {
+        SubscriptionSnapshotStore store = new SubscriptionSnapshotStore(directory, SECRET, 1, 1024 * 1024);
+        SubscriptionSnapshotMessage message = message("public-key-1", "v2-content", "clash-content", System.currentTimeMillis());
+        assertEquals(SubscriptionSnapshotStore.APPLY_SUCCESS, store.apply(message).code());
+
+        // 超过有效期（1 秒），期间只有主站存活信号、没有新快照
+        Thread.sleep(1_200);
+        assertEquals("expired", store.status().state(), "有效期已过且无任何主站信号，应先判过期");
+
+        store.markPrimaryContact();
+        assertEquals("ready", store.status().state(), "收到主站存活信号后应恢复可用");
+        assertNotNull(store.lookup("v2", "public-key-1"), "主站在线期间必须能取到订阅");
+        // 内容仍是最初那份，说明续期靠的是存活信号，而不是内容变化
+        assertArrayEquals("v2-content".getBytes(StandardCharsets.UTF_8), store.lookup("v2", "public-key-1").content());
+    }
+
+    /** 主站失联（长时间没有任何信号）后仍必须判过期，不能因加入存活信号而永不失效。 */
+    @Test
+    void staysExpiredWhenPrimaryContactStops(@TempDir Path directory) throws Exception {
+        SubscriptionSnapshotStore store = new SubscriptionSnapshotStore(directory, SECRET, 1, 1024 * 1024);
+        SubscriptionSnapshotMessage message = message("public-key-1", "v2-content", "clash-content", System.currentTimeMillis());
+        assertEquals(SubscriptionSnapshotStore.APPLY_SUCCESS, store.apply(message).code());
+        store.markPrimaryContact();
+        assertEquals("ready", store.status().state());
+
+        Thread.sleep(1_200); // 之后主站再无任何消息
+        assertEquals("expired", store.status().state(), "主站失联超过有效期必须判过期");
+        assertNull(store.lookup("v2", "public-key-1"), "失联后不得继续分发");
+    }
+
     private SubscriptionSnapshotMessage message(String publicKey, String v2, String clash, long generatedAt) throws Exception {
         byte[] v2Bytes = v2.getBytes(StandardCharsets.UTF_8);
         byte[] clashBytes = clash.getBytes(StandardCharsets.UTF_8);

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();
+    }
+}