diff --git a/pom.xml b/pom.xml
index 00952d0..3a93d51 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
   <groupId>me.qwq</groupId>
   <artifactId>doghouse</artifactId>
-  <version>1.3.0</version>
+  <version>1.3.1</version>
   <packaging>jar</packaging>
 
   <name>Doghouse</name>
diff --git a/src/main/java/me/qwq/doghouse/BlogApplication.java b/src/main/java/me/qwq/doghouse/BlogApplication.java
index d95a4a4..aead262 100644
--- a/src/main/java/me/qwq/doghouse/BlogApplication.java
+++ b/src/main/java/me/qwq/doghouse/BlogApplication.java
@@ -8,6 +8,7 @@ import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.cache.annotation.EnableCaching;
 import org.springframework.context.annotation.EnableAspectJAutoProxy;
 import org.springframework.scheduling.annotation.EnableAsync;
+import org.springframework.scheduling.annotation.EnableScheduling;
 
 import lombok.extern.slf4j.Slf4j;
 
@@ -15,6 +16,7 @@ import lombok.extern.slf4j.Slf4j;
 @MapperScan("me.qwq.doghouse.dao")
 @SpringBootApplication
 @EnableAsync(proxyTargetClass=true)
+@EnableScheduling
 @EnableCaching(proxyTargetClass=true)
 @EnableAspectJAutoProxy(exposeProxy = true)
 @Slf4j
diff --git a/src/main/java/me/qwq/doghouse/component/DataSourcePostProcessor.java b/src/main/java/me/qwq/doghouse/component/DataSourcePostProcessor.java
index 2c31f17..508402f 100644
--- a/src/main/java/me/qwq/doghouse/component/DataSourcePostProcessor.java
+++ b/src/main/java/me/qwq/doghouse/component/DataSourcePostProcessor.java
@@ -36,7 +36,6 @@ public class DataSourcePostProcessor implements BeanPostProcessor {
      * <p>
      * application 指定的 jdbc url 位置存在则使用对应位置，且后续一直以该路径为准（包括调试时修改的数据）。
      * 若不存在则从 classpath 中取初始数据库复制到 jdbc url 指定的位置
-     * @param dataSource
      */
     @Override
     public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
diff --git a/src/main/java/me/qwq/doghouse/component/Rk.java b/src/main/java/me/qwq/doghouse/component/Rk.java
index 379ab88..b023ca1 100644
--- a/src/main/java/me/qwq/doghouse/component/Rk.java
+++ b/src/main/java/me/qwq/doghouse/component/Rk.java
@@ -1,241 +1,114 @@
-package me.qwq.doghouse.component;
-
-import java.security.SecureRandom;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Locale;
-import java.util.Map;
-import jakarta.annotation.PostConstruct;
-import lombok.extern.slf4j.Slf4j;
-
-import org.redisson.Redisson;
-import org.redisson.api.RBucket;
-import org.redisson.api.RedissonClient;
-import org.redisson.client.codec.StringCodec;
-import org.redisson.client.protocol.RedisCommands;
-import org.redisson.command.CommandAsyncExecutor;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.stereotype.Component;
-import org.sqids.Sqids;
-
-import me.qwq.doghouse.entity.Comment;
-import me.qwq.doghouse.entity.config.SiteConfig;
-import me.qwq.doghouse.util.Cryptos;
-/**
- * Redis Key Tool
- * @author Doghole
- *
- */
-@Component
-@Slf4j
-public class Rk {
-
-    static SiteConfig siteConfig;
-    
-    static RedissonClient redisson;
-    
-    
-    public static String SYSTEM_PREFIX;
-    
-    static final String NOTIFY_KEYSPACE_EVENTS = "notify-keyspace-events",
-                        x = "x", E = "E";
-
-    
-    @Autowired
-    public void setService(SiteConfig siteConfig, RedissonClient redisson) {
-        Rk.siteConfig = siteConfig;
-        Rk.redisson = redisson;
-    }
-    
-    @PostConstruct
-    private void init() {
-        
-        SYSTEM_PREFIX = "doghouse:" + siteConfig.getAddress().hashCode() + ":";
-        
-        // 使用 Redisson 设置 redis 服务端的 x(expired) 和 E(evicted) 事件
-        Redisson redissonImpl = (Redisson) redisson;
-        CommandAsyncExecutor executor = redissonImpl.getCommandExecutor();
-
-        @SuppressWarnings("unchecked")
-        Map<String, String> config = (Map<String, String>) executor
-                .readAsync("default", StringCodec.INSTANCE, RedisCommands.CONFIG_GET_MAP, NOTIFY_KEYSPACE_EVENTS)
-                .toCompletableFuture().join();
-        
-        String keyEvents = config.getOrDefault(NOTIFY_KEYSPACE_EVENTS, "");
-        boolean changed = false;
-        if (!keyEvents.contains(x)) {
-            keyEvents += x;
-            changed = true;
-        }
-        if (!keyEvents.contains(E)) {
-            keyEvents += E;
-            changed = true;
-        }
-        if (changed) {
-            log.debug("Redis setConfig {} value {}", NOTIFY_KEYSPACE_EVENTS, keyEvents);
-            executor
-                .writeAsync("default", StringCodec.INSTANCE, RedisCommands.CONFIG_SET, NOTIFY_KEYSPACE_EVENTS, keyEvents)
-                .toCompletableFuture()
-                .join();
-        }
-    }
-    
-    public static class Mail {
-        
-        public static final String ID = "mail:";
-        
-        private static String getMailKey(String subfix) {
-            return SYSTEM_PREFIX + ID + subfix;
-        }
-        
-        /**
-         * 获取所有过期事件的 key
-         * @return
-         */
-        public static Iterable<String> getAllExpirationTaskKeys() {
-            return redisson.getKeys()
-                    .getKeysByPattern(getMailKey("task-"));
-        }
-        
-        /**
-         * 获取邮件推送任务的 Bucket（不包括管理员邮件）
-         * @param commentId
-         * @return
-         */
-        public static RBucket<Object> getTaskBucket(Long commentId) {
-            return redisson.getBucket(getMailKey("task-" + commentId));
-        }
-
-        /**
-         * 获取邮件推送任务的 Comment 缓存 Bucket（不包括管理员邮件）
-         * @param commentId
-         * @return
-         */
-        public static RBucket<Comment> getTaskCommentBucket(Long commentId) {
-            return redisson.getBucket(getMailKey("task-" + commentId + "-comment"));
-        }
-        
-        /**
-         * 获取用户邮件订阅管理 UUID 缓存 Bucket
-         * @param mail
-         * @return 包含 uuid 的 Bucket，用以建立 email → uuid 的映射关系
-         */
-        public static RBucket<String> getMgrBucket(String mail) {
-            return redisson.getBucket(getMailKey("mgr-addr-" + mail));
-        }
-        
-        /**
-         * 获取用户邮件订阅管理邮箱地址缓存 Bucket
-         * @param uuid
-         * @return 包含 email 的 Bucket，用以建立 uuid → email 的映射关系
-         */
-        public static RBucket<String> getMgrUuidBucket(String uuid) {
-            return redisson.getBucket(getMailKey("mgr-uuid-" + uuid));
-        }
-        
-        /**
-         * 获取一个随机 Key 的用于过期事件的 Bucket
-         */
-        public static RBucket<Object> getRandomExpirationBucket(){
-            List<Long> list = new ArrayList<>();
-            SecureRandom random = new SecureRandom();
-            list.add(Math.abs(random.nextLong()));
-            list.add(Math.abs(random.nextLong()));
-            return redisson.getBucket(getMailKey(Sqids.builder().build().encode(list)));
-        }
-    }
-    
-    public static class Gravatar {
-
-        public static final String ID = "gravatar:";
-        
-        public static final String GRAVATAR_PREFIX = "image:";
-        
-        public static final String EMAIL_HASH_PREFIX = "email-hash:";
-        
-        public static final String PRIVATE_HASH_PREFIX = "private-hash:";
-        
-        public static final String SALT = "~D09H0U5E-9R4V474R^_^";
-        
-        private static String getGravatarKey(String subfix) {
-            return SYSTEM_PREFIX + ID + subfix;
-        }
-        
-        /**
-         * 获取对应 hash 和尺寸 size 的头像缓存 Bucket
-         * @param email
-         * @param size
-         * @return
-         */
-        public static RBucket<Object> getGravatarBucket(String dogHash, int size) {
-            return redisson.getBucket(getGravatarKey(GRAVATAR_PREFIX + dogHash + ":" + size));
-        }
-        
-        /**
-         * 清除 gravatar 图片缓存
-         */
-        public static void clearGravatarCache() {
-            for (String name : redisson.getKeys().getKeysByPattern(getGravatarKey(GRAVATAR_PREFIX + "*"))) {
-                redisson.getBucket(name).deleteAsync();
-            }
-        }
-        
-        /**
-         * 获取对应 email 的 hash，并且提前在 Redis 中存储对应关系
-         * @param email
-         * @return
-         */
-        public static String prepareDogHash(String email) {
-            if (email == null) email = "";
-            email = email.toLowerCase(Locale.ENGLISH);
-            
-            RBucket<String> gravatarHashBucket = redisson.getBucket(getGravatarKey(EMAIL_HASH_PREFIX + email));
-            if (gravatarHashBucket.isExists()) {
-                return gravatarHashBucket.get();
-            }
-            
-            byte[] hash = Cryptos.sha3((email + SALT).getBytes(), 256);
-            
-            List<Long> list = new ArrayList<>();
-            
-            for (int i = 0; i < 4; i++) {
-                Long x = 0L;
-                for (int j = 0; j < 8; j++) {
-                    x |= (((long) hash[i * 8 + j]) & 0xFFL) << ((7 - j) * 8);
-                }
-                i++;
-                for (int j = 0; j < 8; j++) {
-                    x ^= (((long) hash[i * 8 + j]) & 0xFFL) << ((7 - j) * 8);
-                }
-                if (x < 0) {
-                    list.add(0L);
-                    list.add(Math.abs(x));
-                }
-                else {
-                    list.add(x);
-                }
-            }
-            
-            String dogHash = Sqids.builder().build().encode(list);
-            gravatarHashBucket.set(dogHash);
-            String realHash = Cryptos.sha256(email);
-            
-            redisson.getBucket(getGravatarKey(PRIVATE_HASH_PREFIX + dogHash))
-                .set(realHash);
-            
-            log.info("Email: {}, real hash: {}, dog hash: {}", email, realHash, dogHash);
-            
-            return dogHash;
-        }
-        
-        /**
-         * 根据 hash 获取 gravatar md5
-         * @param dogHash
-         * @return
-         */
-        public static String getRealHash(String dogHash) {
-            RBucket<String> email = redisson.getBucket(getGravatarKey(PRIVATE_HASH_PREFIX + dogHash));
-            return email.get();
-        }
-    }
-}
+package me.qwq.doghouse.component;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+import org.redisson.api.RBucket;
+import org.redisson.api.RedissonClient;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+import org.sqids.Sqids;
+
+import lombok.extern.slf4j.Slf4j;
+import me.qwq.doghouse.entity.config.SiteConfig;
+import me.qwq.doghouse.util.Cryptos;
+
+/**
+ * Redis key tool.
+ * @author Doghole
+ */
+@Component
+@Slf4j
+public class Rk {
+
+    static SiteConfig siteConfig;
+
+    static RedissonClient redisson;
+
+    public static String SYSTEM_PREFIX;
+
+    @Autowired
+    public void setService(SiteConfig siteConfig, RedissonClient redisson) {
+        Rk.siteConfig = siteConfig;
+        Rk.redisson = redisson;
+        SYSTEM_PREFIX = "doghouse:" + siteConfig.getAddress().hashCode() + ":";
+    }
+
+    public static class Gravatar {
+
+        public static final String ID = "gravatar:";
+
+        public static final String GRAVATAR_PREFIX = "image:";
+
+        public static final String EMAIL_HASH_PREFIX = "email-hash:";
+
+        public static final String PRIVATE_HASH_PREFIX = "private-hash:";
+
+        public static final String SALT = "~D09H0U5E-9R4V474R^_^";
+
+        private static String getGravatarKey(String subfix) {
+            return SYSTEM_PREFIX + ID + subfix;
+        }
+
+        public static RBucket<Object> getGravatarBucket(String dogHash, int size) {
+            return redisson.getBucket(getGravatarKey(GRAVATAR_PREFIX + dogHash + ":" + size));
+        }
+
+        public static void clearGravatarCache() {
+            for (String name : redisson.getKeys().getKeysByPattern(getGravatarKey(GRAVATAR_PREFIX + "*"))) {
+                redisson.getBucket(name).deleteAsync();
+            }
+        }
+
+        public static String prepareDogHash(String email) {
+            if (email == null) {
+                email = "";
+            }
+            email = email.toLowerCase(Locale.ENGLISH);
+
+            RBucket<String> gravatarHashBucket = redisson.getBucket(getGravatarKey(EMAIL_HASH_PREFIX + email));
+            if (gravatarHashBucket.isExists()) {
+                return gravatarHashBucket.get();
+            }
+
+            byte[] hash = Cryptos.sha3((email + SALT).getBytes(), 256);
+
+            List<Long> list = new ArrayList<>();
+
+            for (int i = 0; i < 4; i++) {
+                Long x = 0L;
+                for (int j = 0; j < 8; j++) {
+                    x |= (((long) hash[i * 8 + j]) & 0xFFL) << ((7 - j) * 8);
+                }
+                i++;
+                for (int j = 0; j < 8; j++) {
+                    x ^= (((long) hash[i * 8 + j]) & 0xFFL) << ((7 - j) * 8);
+                }
+                if (x < 0) {
+                    list.add(0L);
+                    list.add(Math.abs(x));
+                }
+                else {
+                    list.add(x);
+                }
+            }
+
+            String dogHash = Sqids.builder().build().encode(list);
+            gravatarHashBucket.set(dogHash);
+            String realHash = Cryptos.sha256(email);
+
+            redisson.getBucket(getGravatarKey(PRIVATE_HASH_PREFIX + dogHash))
+                .set(realHash);
+
+            log.info("Email: {}, real hash: {}, dog hash: {}", email, realHash, dogHash);
+
+            return dogHash;
+        }
+
+        public static String getRealHash(String dogHash) {
+            RBucket<String> email = redisson.getBucket(getGravatarKey(PRIVATE_HASH_PREFIX + dogHash));
+            return email.get();
+        }
+    }
+}
diff --git a/src/main/java/me/qwq/doghouse/controller/admin/AssetController.java b/src/main/java/me/qwq/doghouse/controller/admin/AssetController.java
index 60dc615..2fa2bd6 100644
--- a/src/main/java/me/qwq/doghouse/controller/admin/AssetController.java
+++ b/src/main/java/me/qwq/doghouse/controller/admin/AssetController.java
@@ -4,13 +4,12 @@ import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
 import com.baomidou.mybatisplus.core.metadata.IPage;
 import com.github.yulichang.wrapper.MPJLambdaWrapper;
 
-import jodd.io.FileUtil;
 import lombok.extern.slf4j.Slf4j;
 import me.qwq.doghouse.config.DoghouseProperties;
 import me.qwq.doghouse.controller.common.BaseController;
 import me.qwq.doghouse.entity.Asset;
-import me.qwq.doghouse.entity.config.SiteConfig;
 import me.qwq.doghouse.entity.Post;
+import me.qwq.doghouse.entity.config.SiteConfig;
 import me.qwq.doghouse.enums.FileTypeEnum;
 import me.qwq.doghouse.exception.RException;
 import me.qwq.doghouse.pojo.dto.LayPageReq;
@@ -22,17 +21,21 @@ import me.qwq.doghouse.util.DateUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Controller;
-import org.springframework.web.bind.annotation.*;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.multipart.MultipartFile;
 import org.sqids.Sqids;
 
 import java.awt.image.BufferedImage;
-import java.io.BufferedReader;
 import java.io.File;
 import java.io.IOException;
-import java.io.InputStreamReader;
+import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
 import java.security.SecureRandom;
 import java.time.LocalDateTime;
 import java.util.ArrayList;
@@ -43,174 +46,136 @@ import java.util.concurrent.TimeUnit;
 
 import javax.imageio.ImageIO;
 
-
 /**
- * 资产控制器
+ * Asset controller.
  * @author Doghole
  */
 @Controller
 @RequestMapping("/admin/v2/asset")
 @Slf4j
 public class AssetController extends BaseController {
-    
-    final private static SecureRandom SECURE_RANDOM = new SecureRandom();
-    
-    final private static Sqids SQIDS = Sqids.builder().build();
-    
+
+    private static final int IMAGE_ENCODE_TIMEOUT_SECONDS = 15;
+
+    private static final SecureRandom SECURE_RANDOM = new SecureRandom();
+
+    private static final Sqids SQIDS = Sqids.builder().build();
+
     @Autowired
     DoghouseProperties doghouseProperties;
-    
+
     @Autowired
     AssetService assetService;
-    
+
     @Autowired
     SiteConfig siteConfig;
 
     /**
-     * 主页
+     * Main page.
      * @return
      */
     @GetMapping({"", "/", "/index"})
     String index() {
         return "admin/asset/index";
     }
-    
+
     @ResponseBody
     @GetMapping("/list")
     public LayPageResp<?> getAssetList(LayPageReq<Asset> pageReq) {
-        
+
         MPJLambdaWrapper<Asset> ew = new MPJLambdaWrapper<Asset>()
                 .selectAll(Asset.class)
                 .leftJoin(Post.class, Post::getPostId, Asset::getFromPostId)
                 .orderByDesc(Asset::getCreateTime);
-        
+
         IPage<Asset> page = assetService.page(pageReq, ew);
-        
+
         LayPageResp<Asset> result = new LayPageResp<>(page);
         return result;
     }
-    
-    
+
     /**
-     * 上传文件
+     * Upload file.
      */
     @ResponseBody
     @PostMapping("/uploadFile")
     R<?> uploadFile(
             @RequestParam(name = "file") MultipartFile file,
             @RequestParam(name = "postId", required = false) Long postId) {
-        
-        String msg = "文件上传失败";
-        String suffix = getSuffix(file);
-        
-        if (suffix == null) {
-            return R.badRequest(msg);
+
+        if (file == null || file.isEmpty()) {
+            return R.badRequest("上传文件不能为空");
         }
-        
+
+        String suffix = getSuffix(file);
+        if (StringUtils.isBlank(suffix)) {
+            return R.badRequest("无法识别文件扩展名");
+        }
+        if (FileTypeEnum.isUploadDenied(suffix)) {
+            return R.badRequest("不允许上传该类型文件");
+        }
+
         String prefix = generateFilePrefix();
         String filename = prefix + '.' + suffix;
-        String originalFilename = file.getOriginalFilename();
-        String originalPrefix = originalFilename.substring(0, originalFilename.length() -
-                suffix.length() - 1);
-        
+        String originalFilename = StringUtils.defaultIfBlank(file.getOriginalFilename(), filename);
+        String originalPrefix = getOriginalPrefix(originalFilename, suffix);
 
         Calendar calendar = Calendar.getInstance();
         String yearAndMonth = String.format("%d/%02d", calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH) + 1);
-        Path filePlacedDirPath = Paths.get(doghouseProperties.getFileUploadPath(), yearAndMonth);
-        
-        File dir = filePlacedDirPath.toFile();
-        File destFile = filePlacedDirPath.resolve(filename).toFile();
-        Asset asset = new Asset();
+        Path uploadRoot = Paths.get(doghouseProperties.getFileUploadPath()).toAbsolutePath().normalize();
+        Path filePlacedDirPath = uploadRoot.resolve(yearAndMonth).normalize();
+        Path storedPath = null;
+        Path destPath = filePlacedDirPath.resolve(filename).normalize();
+
         try {
-            if (!dir.exists() && !dir.mkdirs()) {
-                msg = "创建文件夹 " + dir + " 失败";
-                log.error(msg);
-                return R.internalServerError(msg);
+            if (!filePlacedDirPath.startsWith(uploadRoot) || !destPath.startsWith(filePlacedDirPath)) {
+                throw RException.badRequest("非法上传路径");
             }
 
-            // file.transferTo(destFile); // 解决 jetty 上传文件问题
-            FileUtil.writeBytes(destFile, file.getBytes());
-            String fileUrl = 
-                    Paths.get(doghouseProperties.getFileSqlPath(), yearAndMonth, filename)
-                    .toString().replace('\\', '/');
-            
+            Files.createDirectories(filePlacedDirPath);
+            try (var input = file.getInputStream()) {
+                Files.copy(input, destPath, StandardCopyOption.REPLACE_EXISTING);
+            }
+            storedPath = destPath;
+
+            String fileUrl = getSqlPath(yearAndMonth, filename);
             FileTypeEnum fileType = FileTypeEnum.getFileType(suffix);
-            
-            asset
-                .setFromPostId(postId)
-                .setTitle(file.getOriginalFilename())
-                .setCreateTime(LocalDateTime.now())
-                .setFileType(fileType)
-                .setFileSize(destFile.length())
-                .setUpdateTime(LocalDateTime.now())
-                .setPath(fileUrl);
-            
-            if (fileType == FileTypeEnum.IMAGE) {
-                BufferedImage image = ImageIO.read(destFile);
-                if (image != null) {
-                    asset.setImageHeight(image.getHeight())
-                         .setImageWidth(image.getWidth());
-                    
-                    if (siteConfig.getImageCompress()) {
-                        
-                        File avifFile = getAvif(suffix, destFile.toString(), prefix, filePlacedDirPath);
-                        File webpFile = getWebp(suffix, destFile.toString(), prefix, filePlacedDirPath);
+            LocalDateTime now = LocalDateTime.now();
 
-                        File finalFile = null;
-                        String finalSuffix = null;
-                        
-                        if (webpFile != null && avifFile != null) {
-                            if (webpFile.length() >= avifFile.length()) {
-                                finalFile = webpFile;
-                                finalSuffix = ".webp";
-                                avifFile.delete();
-                            }
-                            else {
-                                finalFile = avifFile;
-                                finalSuffix = ".avif";
-                                webpFile.delete();
-                            }
-                        }
-                        else if (webpFile == null && avifFile != null) {
-                            finalFile = avifFile;
-                            finalSuffix = ".avif";
-                        }
-                        else if (webpFile != null && avifFile == null) {
-                            finalFile = webpFile;
-                            finalSuffix = ".webp";
-                        }
-                        
-                        if (finalFile != null) {
-                            
-                            fileUrl = Paths.get(doghouseProperties.getFileSqlPath(), yearAndMonth, finalFile.getName())
-                                    .toString().replace('\\', '/');
-                            
-                            asset
-                            .setPath(fileUrl)
-                            .setFileSize(finalFile.length())
-                            .setTitle(originalPrefix + finalSuffix);
-                            
-                            destFile.delete();
-                        }
-                    }
-                }
-                else {
-                    log.warn("Unsupported image format {}", suffix);
-                }
+            Asset asset = new Asset()
+                    .setFromPostId(postId)
+                    .setTitle(originalFilename)
+                    .setCreateTime(now)
+                    .setFileType(fileType)
+                    .setFileSize(Files.size(storedPath))
+                    .setUpdateTime(now)
+                    .setPath(fileUrl);
+
+            if (fileType == FileTypeEnum.IMAGE) {
+                storedPath = prepareImageAsset(asset, suffix, storedPath, prefix, originalPrefix, yearAndMonth);
             }
+
             if (assetService.save(asset)) {
                 return R.ok(asset);
             }
+            deleteQuietly(storedPath);
             throw RException.badRequest("文件上传成功但保存失败");
-            
-        } catch (IOException e) {
-            log.error(msg, e);
         }
-        return R.internalServerError(msg);
+        catch (IOException e) {
+            deleteQuietly(storedPath);
+            deleteQuietly(destPath);
+            log.error("文件上传失败", e);
+            return R.internalServerError("文件上传失败");
+        }
+        catch (RuntimeException e) {
+            deleteQuietly(storedPath);
+            deleteQuietly(destPath);
+            throw e;
+        }
     }
 
     /**
-     * 更新文件基本信息
+     * Update asset base info.
      * @param asset
      * @return
      */
@@ -218,17 +183,17 @@ public class AssetController extends BaseController {
     @PostMapping("/update")
     R<?> update(Asset asset) {
         if (Objects.isNull(asset) || Objects.isNull(asset.getAssetId())) {
-            throw RException.badRequest("提供的资产不能为空！");
+            throw RException.badRequest("提供的资源不能为空！");
         }
         LambdaUpdateWrapper<Asset> uw = new LambdaUpdateWrapper<>();
         uw.eq(Asset::getAssetId, asset.getAssetId())
           .set(Asset::getTitle, asset.getTitle())
           .set(Asset::getDescription, asset.getDescription());
-        return R.judge(assetService.update(uw), "更新资产信息失败！");
+        return R.judge(assetService.update(uw), "更新资源信息失败！");
     }
-    
+
     /**
-     * 删除资产
+     * Delete asset.
      * @param assetId
      * @return
      */
@@ -236,24 +201,29 @@ public class AssetController extends BaseController {
     @PostMapping("/delete")
     R<?> delete(Long assetId) {
         if (Objects.isNull(assetId)) {
-            throw RException.badRequest("提供的资产不能为空！");
+            throw RException.badRequest("提供的资源不能为空！");
         }
         Asset asset = assetService.getById(assetId);
         if (Objects.isNull(asset)) {
-            log.info("试图删除已不存在于数据库内的资产");
+            log.info("试图删除已不存在于数据库内的资源");
             return R.ok();
         }
-        String uploadPath = doghouseProperties.getFileUploadPath(asset);
-        File file = new File(uploadPath);
-        if (file.exists()) {
-            return R.judge(file.delete() && assetService.removeById(assetId), "删除文件失败");
+
+        Path file = resolveAssetUploadPath(asset);
+        if (Files.exists(file)) {
+            try {
+                Files.delete(file);
+            }
+            catch (IOException e) {
+                log.warn("删除文件失败 {}", file, e);
+                throw RException.badRequest("删除文件失败");
+            }
         }
         return R.judge(assetService.removeById(assetId), "删除文件失败");
     }
-    
 
     /**
-     * 解绑资产
+     * Unlink asset.
      * @param assetId
      * @return
      */
@@ -261,15 +231,15 @@ public class AssetController extends BaseController {
     @PostMapping("/unlink")
     R<?> unlink(Long assetId) {
         if (Objects.isNull(assetId)) {
-            throw RException.badRequest("提供的资产不能为空！");
+            throw RException.badRequest("提供的资源不能为空！");
         }
         Asset asset = assetService.getById(assetId);
         if (Objects.isNull(asset)) {
-            log.info("试图操作已不存在于数据库内的资产");
+            log.info("试图操作已不存在于数据库内的资源");
             return R.ok();
         }
         if (Objects.isNull(asset.getFromPostId())) {
-            return R.ok("该资产并未绑定 Post");
+            return R.ok("该资源并未绑定 Post");
         }
 
         return R.judge(
@@ -277,112 +247,190 @@ public class AssetController extends BaseController {
                     .eq(Asset::getAssetId, asset.getAssetId())
                     .set(Asset::getFromPostId, null)), "解绑失败");
     }
-    
+
     /**
-     * 获取文件后缀，不包含".", 返回小写
+     * Get lowercase filename suffix, without ".".
      */
-    public static String getSuffix(MultipartFile file){
+    public static String getSuffix(MultipartFile file) {
         if (file == null) {
             return null;
         }
         String fileName = file.getOriginalFilename();
-        if (StringUtils.isEmpty(fileName)) {
+        if (StringUtils.isBlank(fileName)) {
             return null;
         }
         int lastIndexOfDot = fileName.lastIndexOf('.');
         if (lastIndexOfDot == -1 || lastIndexOfDot == fileName.length() - 1) {
             return "";
         }
-        return fileName.substring(lastIndexOfDot + 1).toLowerCase();
+        return FileTypeEnum.normalizeExtension(fileName.substring(lastIndexOfDot + 1));
     }
-    
+
     /**
-     * 使用随机 Long + Sqids 作为文件名
-     * @param file
+     * Use timestamp + random Sqids as filename prefix.
      * @return
      */
     public static String generateFilePrefix() {
         String dateStr = DateUtils.format(LocalDateTime.now(), "yyyyMMdd_HHmmssSSS_");
-        
+
         StringBuilder sb = new StringBuilder();
         sb.append(dateStr);
-        
+
         List<Long> list = new ArrayList<>();
         list.add(Math.abs(SECURE_RANDOM.nextLong()));
-        
+
         String id = SQIDS.encode(list);
         sb.append(id);
         return sb.toString();
     }
-    
-    private static File getAvif(String suffix,
-            String originalFilePath, String finalPrefix, Path filePlacedDirPath) {
-        
+
+    private Path prepareImageAsset(
+            Asset asset,
+            String suffix,
+            Path originalFile,
+            String finalPrefix,
+            String originalPrefix,
+            String yearAndMonth) throws IOException {
+
+        BufferedImage image = readRasterImage(suffix, originalFile);
+        if (image != null) {
+            asset.setImageHeight(image.getHeight())
+                 .setImageWidth(image.getWidth());
+        }
+
+        if (!Boolean.TRUE.equals(siteConfig.getImageCompress()) || !FileTypeEnum.isImageCompressible(suffix)) {
+            return originalFile;
+        }
+
+        File avifFile = getAvif(suffix, originalFile.toString(), finalPrefix, originalFile.getParent());
+        File webpFile = getWebp(suffix, originalFile.toString(), finalPrefix, originalFile.getParent());
+        File finalFile = chooseCompressedFile(originalFile.toFile(), avifFile, webpFile);
+
+        if (finalFile == null) {
+            return originalFile;
+        }
+
+        String finalSuffix = getFileSuffix(finalFile.getName());
+        asset
+                .setPath(getSqlPath(yearAndMonth, finalFile.getName()))
+                .setFileSize(finalFile.length())
+                .setTitle(originalPrefix + '.' + finalSuffix);
+
+        deleteQuietly(originalFile);
+        return finalFile.toPath();
+    }
+
+    private static BufferedImage readRasterImage(String suffix, Path file) throws IOException {
+        if (!mustBeReadableRaster(suffix)) {
+            return null;
+        }
+        BufferedImage image = ImageIO.read(file.toFile());
+        if (image == null) {
+            throw RException.badRequest("不支持或损坏的图片文件");
+        }
+        return image;
+    }
+
+    private static boolean mustBeReadableRaster(String suffix) {
+        suffix = FileTypeEnum.normalizeExtension(suffix);
+        return "jpg".equals(suffix)
+                || "jpeg".equals(suffix)
+                || "png".equals(suffix)
+                || "gif".equals(suffix)
+                || "bmp".equals(suffix)
+                || "webp".equals(suffix);
+    }
+
+    private static File chooseCompressedFile(File originalFile, File avifFile, File webpFile) {
+        File finalFile = null;
+        if (isSmallerFile(avifFile, originalFile)) {
+            finalFile = avifFile;
+        }
+        if (isSmallerFile(webpFile, finalFile == null ? originalFile : finalFile)) {
+            deleteQuietly(finalFile);
+            finalFile = webpFile;
+        }
+        else {
+            deleteQuietly(webpFile);
+        }
+
+        if (finalFile != avifFile) {
+            deleteQuietly(avifFile);
+        }
+        return finalFile;
+    }
+
+    private static boolean isSmallerFile(File candidate, File base) {
+        return candidate != null
+                && candidate.exists()
+                && candidate.isFile()
+                && base != null
+                && candidate.length() > 0
+                && candidate.length() < base.length();
+    }
+
+    private static File getAvif(String suffix, String originalFilePath, String finalPrefix, Path filePlacedDirPath) {
+        suffix = FileTypeEnum.normalizeExtension(suffix);
         if (!"jpg".equals(suffix) && !"jpeg".equals(suffix) && !"png".equals(suffix)) {
             return null;
         }
-        
+
         String avifFilename = finalPrefix + ".avif";
         String avifPath = filePlacedDirPath.resolve(avifFilename).toString();
         List<String> avifCommand = List.of(
-                "avifenc", 
-                "-q", "60", 
-                "--qalpha", "80", 
+                "avifenc",
+                "-q", "60",
+                "--qalpha", "80",
                 "-s", "6",
-                "-j", "all", 
-                originalFilePath, 
+                "-j", "all",
+                originalFilePath,
                 avifPath);
-        
+
         return executeFile(avifCommand, avifPath);
     }
-    
 
-    private static File getWebp(String suffix,
-            String originalFilePath, String finalPrefix, Path filePlacedDirPath) {
-
-
-        if (!"jpg".equals(suffix) && !"jpeg".equals(suffix) && !"png".equals(suffix) && !"gif".equals(suffix)) {
+    private static File getWebp(String suffix, String originalFilePath, String finalPrefix, Path filePlacedDirPath) {
+        suffix = FileTypeEnum.normalizeExtension(suffix);
+        if (!FileTypeEnum.isImageCompressible(suffix)) {
             return null;
         }
-        
+
         String webpFilename = finalPrefix + ".webp";
         String webpPath = filePlacedDirPath.resolve(webpFilename).toString();
-        List<String> webpCommand = 
-            !"gif".equals(suffix) ? 
-                    List.of("cwebp", 
-                            "-z", "9", 
-                            "-q", "100", 
-                            "-near_lossless", "60", 
-                            "-m", "6", 
+        List<String> webpCommand =
+            !"gif".equals(suffix) ?
+                    List.of("cwebp",
+                            "-z", "9",
+                            "-q", "100",
+                            "-near_lossless", "60",
+                            "-m", "6",
                             "-mt", originalFilePath,
                             "-o", webpPath):
-                    List.of("gif2webp", 
-                            "-q", "90", 
-                            "-lossy", "-min_size", 
-                            "-m", "0", 
+                    List.of("gif2webp",
+                            "-q", "90",
+                            "-lossy", "-min_size",
+                            "-m", "0",
                             "-mt", originalFilePath,
                             "-o", webpPath);
         return executeFile(webpCommand, webpPath);
     }
-    
+
     private static File executeFile(List<String> command, String filePath) {
         ProcessBuilder pb = new ProcessBuilder(command);
-        pb.redirectErrorStream(true);
+        pb.redirectOutput(ProcessBuilder.Redirect.DISCARD);
+        pb.redirectError(ProcessBuilder.Redirect.DISCARD);
         try {
             Process process = pb.start();
-            
-            try (var reader = new BufferedReader(
-                    new InputStreamReader(process.getInputStream()))) {
-                String line;
-                while ((line = reader.readLine()) != null) {
-                    log.debug("[img-encode] {}", line);
-                }
+            boolean finished = process.waitFor(IMAGE_ENCODE_TIMEOUT_SECONDS, TimeUnit.SECONDS);
+            if (!finished) {
+                process.destroyForcibly();
+                log.warn("Execution timed out, command {}", command);
+                return null;
             }
 
-            int exitCode = process.waitFor(15, TimeUnit.SECONDS) ? process.exitValue() : -1;
-            
+            int exitCode = process.exitValue();
             if (exitCode == 0) {
-                File out = FileUtil.file(filePath);
+                File out = new File(filePath);
                 if (!out.exists()) {
                     log.warn("Command finished with code 0, but output file not found: {}", filePath);
                     return null;
@@ -392,9 +440,64 @@ public class AssetController extends BaseController {
             log.warn("Execution failed with exit code: {}, command {}", exitCode, command);
             return null;
         }
-        catch (IOException | InterruptedException e) {
-            log.warn("Cannot execute command {}, {}", command, e);
+        catch (IOException e) {
+            log.warn("Cannot execute command {}, {}", command, e.getMessage());
+            return null;
+        }
+        catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            log.warn("Execution interrupted, command {}", command);
             return null;
         }
     }
+
+    private String getSqlPath(String yearAndMonth, String filename) {
+        return Paths.get(doghouseProperties.getFileSqlPath(), yearAndMonth, filename)
+                .toString()
+                .replace('\\', '/');
+    }
+
+    private Path resolveAssetUploadPath(Asset asset) {
+        Path uploadRoot = Paths.get(doghouseProperties.getFileUploadPath()).toAbsolutePath().normalize();
+        Path file = Paths.get(doghouseProperties.getFileUploadPath(asset)).toAbsolutePath().normalize();
+        if (!file.startsWith(uploadRoot)) {
+            throw RException.badRequest("非法资源路径");
+        }
+        return file;
+    }
+
+    private static String getOriginalPrefix(String originalFilename, String suffix) {
+        int suffixLength = StringUtils.length(suffix);
+        int dotIndex = originalFilename.length() - suffixLength - 1;
+        if (dotIndex <= 0 || dotIndex >= originalFilename.length()) {
+            return originalFilename;
+        }
+        return originalFilename.substring(0, dotIndex);
+    }
+
+    private static String getFileSuffix(String filename) {
+        int lastIndexOfDot = filename.lastIndexOf('.');
+        if (lastIndexOfDot == -1 || lastIndexOfDot == filename.length() - 1) {
+            return "";
+        }
+        return filename.substring(lastIndexOfDot + 1);
+    }
+
+    private static void deleteQuietly(Path file) {
+        if (file == null) {
+            return;
+        }
+        try {
+            Files.deleteIfExists(file);
+        }
+        catch (IOException e) {
+            log.warn("Cannot delete file {}", file, e);
+        }
+    }
+
+    private static void deleteQuietly(File file) {
+        if (file != null) {
+            deleteQuietly(file.toPath());
+        }
+    }
 }
diff --git a/src/main/java/me/qwq/doghouse/controller/blog/VisitorController.java b/src/main/java/me/qwq/doghouse/controller/blog/VisitorController.java
index 1ba86dd..8057f3b 100644
--- a/src/main/java/me/qwq/doghouse/controller/blog/VisitorController.java
+++ b/src/main/java/me/qwq/doghouse/controller/blog/VisitorController.java
@@ -1,20 +1,13 @@
 package me.qwq.doghouse.controller.blog;
 
-
-import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
-
-import me.qwq.doghouse.component.Rk;
 import me.qwq.doghouse.controller.common.BaseController;
-import me.qwq.doghouse.entity.*;
 import me.qwq.doghouse.entity.config.MailConfig;
 import me.qwq.doghouse.service.*;
 
 import org.apache.commons.lang3.StringUtils;
-import org.redisson.api.RBucket;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
-import java.util.Locale;
 
 
 /**
@@ -25,7 +18,7 @@ import java.util.Locale;
 @RequestMapping("/system")
 public class VisitorController extends BaseController {
     
-    static final String TOKEN_ERROR = "token 不存在或已过期";
+    static final String TOKEN_ERROR = "token 不存在或已被使用";
     
     static final String MAIL_DISABLED = "站点未开启邮件功能";
     
@@ -53,8 +46,7 @@ public class VisitorController extends BaseController {
             return render(TOKEN_ERROR, null);
         }
         
-        RBucket<String> uuidBucket = Rk.Mail.getMgrUuidBucket(token);
-        String mail = uuidBucket.get();
+        String mail = commentService.getUnsubscribeEmail(token);
         if (StringUtils.isEmpty(mail)) {
             return render(TOKEN_ERROR, null);
         }
@@ -64,11 +56,9 @@ public class VisitorController extends BaseController {
         }
         
         if ("POST".equals(method)) {
-            uuidBucket.delete();
-            commentService.update(new LambdaUpdateWrapper<Comment>()
-                    .eq(Comment::getEmail, mail.toLowerCase(Locale.ROOT))
-                    .set(Comment::isSubscribeReply, false));
-            
+            if (commentService.unsubscribeByToken(token) == null) {
+                return render(TOKEN_ERROR, null);
+            }
             return render("操作成功", null);
         }
 
diff --git a/src/main/java/me/qwq/doghouse/dao/MailTaskMapper.java b/src/main/java/me/qwq/doghouse/dao/MailTaskMapper.java
new file mode 100644
index 0000000..642b7db
--- /dev/null
+++ b/src/main/java/me/qwq/doghouse/dao/MailTaskMapper.java
@@ -0,0 +1,8 @@
+package me.qwq.doghouse.dao;
+
+import com.github.yulichang.base.MPJBaseMapper;
+
+import me.qwq.doghouse.entity.MailTask;
+
+public interface MailTaskMapper extends MPJBaseMapper<MailTask> {
+}
diff --git a/src/main/java/me/qwq/doghouse/entity/Comment.java b/src/main/java/me/qwq/doghouse/entity/Comment.java
index 5a2beaf..9247f61 100644
--- a/src/main/java/me/qwq/doghouse/entity/Comment.java
+++ b/src/main/java/me/qwq/doghouse/entity/Comment.java
@@ -168,6 +168,12 @@ private static final long serialVersionUID=1L;
     
     @TableField("subscribe_reply")
     private boolean subscribeReply = false;
+
+    /**
+     * 邮件退订令牌
+     */
+    @TableField("unsubscribe_token")
+    private String unsubscribeToken;
     
     @TableField("mail_sent")
     private boolean mailSent = false;
diff --git a/src/main/java/me/qwq/doghouse/entity/MailTask.java b/src/main/java/me/qwq/doghouse/entity/MailTask.java
new file mode 100644
index 0000000..b4b2543
--- /dev/null
+++ b/src/main/java/me/qwq/doghouse/entity/MailTask.java
@@ -0,0 +1,85 @@
+package me.qwq.doghouse.entity;
+
+import java.io.Serializable;
+import java.time.LocalDateTime;
+
+import com.baomidou.mybatisplus.annotation.IdType;
+import com.baomidou.mybatisplus.annotation.TableField;
+import com.baomidou.mybatisplus.annotation.TableId;
+import com.baomidou.mybatisplus.annotation.TableName;
+import com.baomidou.mybatisplus.extension.activerecord.Model;
+
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+import lombok.experimental.Accessors;
+import me.qwq.doghouse.enums.MailTaskStatusEnum;
+import me.qwq.doghouse.enums.MailTaskTypeEnum;
+
+@Data
+@EqualsAndHashCode(callSuper = false)
+@Accessors(chain = true)
+@TableName("mail_task")
+public class MailTask extends Model<MailTask> implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+
+    /**
+     * 邮件任务 ID
+     */
+    @TableId(value = "id", type = IdType.AUTO)
+    private Long id;
+
+    /**
+     * 邮件任务类型
+     */
+    @TableField("task_type")
+    private MailTaskTypeEnum taskType;
+
+    /**
+     * 关联评论 ID
+     */
+    @TableField("comment_id")
+    private Long commentId;
+
+    /**
+     * 收件人邮箱地址
+     */
+    @TableField("recipient")
+    private String recipient;
+
+    /**
+     * 邮件任务状态
+     */
+    @TableField("status")
+    private MailTaskStatusEnum status = MailTaskStatusEnum.PENDING;
+
+    /**
+     * 计划发送时间
+     */
+    @TableField("send_after")
+    private LocalDateTime sendAfter;
+
+    /**
+     * 已尝试发送次数
+     */
+    @TableField("attempts")
+    private Integer attempts = 0;
+
+    /**
+     * 最近一次发送失败原因
+     */
+    @TableField("last_error")
+    private String lastError;
+
+    /**
+     * 任务创建时间
+     */
+    @TableField("create_time")
+    private LocalDateTime createTime;
+
+    /**
+     * 任务更新时间
+     */
+    @TableField("update_time")
+    private LocalDateTime updateTime;
+}
diff --git a/src/main/java/me/qwq/doghouse/enums/FileTypeEnum.java b/src/main/java/me/qwq/doghouse/enums/FileTypeEnum.java
index 59b2b03..df022de 100644
--- a/src/main/java/me/qwq/doghouse/enums/FileTypeEnum.java
+++ b/src/main/java/me/qwq/doghouse/enums/FileTypeEnum.java
@@ -1,6 +1,7 @@
 package me.qwq.doghouse.enums;
 
 import java.util.Objects;
+import java.util.Set;
 
 import org.apache.commons.lang3.StringUtils;
 
@@ -10,7 +11,7 @@ import me.qwq.doghouse.annotation.StaticAttribute;
 import me.qwq.doghouse.entity.Asset;
 
 /**
- * 文件类型枚举
+ * File category enum.
  **/
 @StaticAttribute
 public enum FileTypeEnum implements IQueryableEnum {
@@ -26,6 +27,29 @@ public enum FileTypeEnum implements IQueryableEnum {
     private final int status;
     private final String note;
 
+    private static final Set<String> IMAGE_EXTENSIONS = Set.of(
+            "jpg", "jpeg", "gif", "png", "apng", "bmp", "svg", "ico", "webp", "psd", "tif", "tiff", "raw", "avif");
+
+    private static final Set<String> ARCHIVE_EXTENSIONS = Set.of(
+            "zip", "rar", "7z", "001", "iso", "xz", "txz", "lzma", "tar", "cpio", "bz2", "bzip2", "tbz2", "tbz",
+            "gz", "gzip", "tgz", "tpz", "z", "taz", "lzh", "lha", "rpm", "deb", "arj", "vhd", "wim", "swm", "fat",
+            "ntfs", "dmg", "hfs", "xar", "squashfs");
+
+    private static final Set<String> DOCUMENT_EXTENSIONS = Set.of(
+            "doc", "docx", "dot", "dotx", "ppt", "pptx", "xls", "xlsx", "pdf", "txt", "rtf", "md");
+
+    private static final Set<String> MEDIA_EXTENSIONS = Set.of(
+            "mp3", "aac", "ac3", "amr", "ogg", "ogm", "ogv", "dts", "m1a", "m2a", "m4a", "mp2", "mpa", "mpc",
+            "flac", "mid", "wav", "wma", "wmv", "mp4", "webm", "swf", "rm", "rmvb", "mov", "mpeg", "mkv", "m4b",
+            "m4v", "m4p", "f4v", "flv", "3gp");
+
+    private static final Set<String> APPLICATION_EXTENSIONS = Set.of(
+            "exe", "msi", "bat", "cmd", "apk");
+
+    private static final Set<String> UPLOAD_DENY_EXTENSIONS = Set.of(
+            "bat", "cmd", "com", "cpl", "dll", "exe", "htm", "html", "hta", "jar", "js", "jsp", "msi", "php",
+            "ps1", "sh", "svg", "vbs", "war", "xhtml", "xml");
+
     FileTypeEnum(int status, String note) {
         this.status = status;
         this.note = note;
@@ -38,124 +62,56 @@ public enum FileTypeEnum implements IQueryableEnum {
     public int getStatus() {
         return status;
     }
-    
+
     public static FileTypeEnum getFileType(Asset asset) {
         if (Objects.isNull(asset)) {
             return OTHER;
         }
         return getFileType(asset.getExt());
     }
-    
+
     public static FileTypeEnum getFileType(String ext) {
+        ext = normalizeExtension(ext);
         if (StringUtils.isEmpty(ext)) {
             return OTHER;
         }
-        ext = ext.toLowerCase();
-        switch (ext) {
-        case "jpg":
-        case "jpeg":
-        case "gif":
-        case "png":
-        case "apng":
-        case "bmp":
-        case "svg":
-        case "ico":
-        case "webp":
-        case "psd":
-        case "tif":
-        case "raw":
-        case "avif":
+        if (IMAGE_EXTENSIONS.contains(ext)) {
             return IMAGE;
-        case "zip":
-        case "rar":
-        case "7z":
-        case "001":
-        case "iso":
-        case "xz":
-        case "txz":
-        case "lzma":
-        case "tar":
-        case "cpio":
-        case "bz2":
-        case "bzip2":
-        case "tbz2":
-        case "tbz":
-        case "gz":
-        case "gzip":
-        case "tgz":
-        case "tpz":
-        case "z":
-        case "taz":
-        case "lzh":
-        case "lha":
-        case "rpm":
-        case "deb":
-        case "arj":
-        case "vhd":
-        case "wim":
-        case "swm":
-        case "fat":
-        case "ntfs":
-        case "dmg":
-        case "hfs":
-        case "xar":
-        case "squashfs":
-            return ARCHIVE;
-        case "doc":
-        case "docx":
-        case "dot":
-        case "dotx":
-        case "ppt":
-        case "pptx":
-        case "xls":
-        case "xlsx":
-        case "pdf":
-        case "txt":
-        case "rtf":
-        case "md":
-            return DOCUMENT;
-        case "mp3":
-        case "aac":
-        case "ac3":
-        case "amr":
-        case "ogg":
-        case "ogm":
-        case "ogv":
-        case "dts":
-        case "m1a":
-        case "m2a":
-        case "m4a":
-        case "mp2":
-        case "mpa":
-        case "mpc":
-        case "flac":
-        case "mid":
-        case "wav":
-        case "wma":
-        case "wmv":
-        case "mp4":
-        case "webm":
-        case "swf":
-        case "rm":
-        case "rmvb":
-        case "mov":
-        case "mpeg":
-        case "mkv":
-        case "m4b":
-        case "m4v":
-        case "m4p":
-        case "f4v":
-        case "flv":
-        case "3gp":
-            return MEDIA;
-        case "exe":
-        case "msi":
-        case "bat":
-        case "cmd":
-        case "apk":
-            return APPLICATION;
-        default:
-            return OTHER;
         }
+        if (ARCHIVE_EXTENSIONS.contains(ext)) {
+            return ARCHIVE;
+        }
+        if (DOCUMENT_EXTENSIONS.contains(ext)) {
+            return DOCUMENT;
+        }
+        if (MEDIA_EXTENSIONS.contains(ext)) {
+            return MEDIA;
+        }
+        if (APPLICATION_EXTENSIONS.contains(ext)) {
+            return APPLICATION;
+        }
+        return OTHER;
+    }
+
+    public static boolean isUploadDenied(String ext) {
+        ext = normalizeExtension(ext);
+        return StringUtils.isNotEmpty(ext) && UPLOAD_DENY_EXTENSIONS.contains(ext);
+    }
+
+    public static boolean isImage(String ext) {
+        return getFileType(ext) == IMAGE;
+    }
+
+    public static boolean isImageCompressible(String ext) {
+        ext = normalizeExtension(ext);
+        return "jpg".equals(ext) || "jpeg".equals(ext) || "png".equals(ext) || "gif".equals(ext);
+    }
+
+    public static String normalizeExtension(String ext) {
+        if (StringUtils.isBlank(ext)) {
+            return "";
+        }
+        ext = ext.trim().toLowerCase();
+        return ext.startsWith(".") ? ext.substring(1) : ext;
     }
 }
diff --git a/src/main/java/me/qwq/doghouse/enums/MailTaskStatusEnum.java b/src/main/java/me/qwq/doghouse/enums/MailTaskStatusEnum.java
new file mode 100644
index 0000000..c7a8de7
--- /dev/null
+++ b/src/main/java/me/qwq/doghouse/enums/MailTaskStatusEnum.java
@@ -0,0 +1,31 @@
+package me.qwq.doghouse.enums;
+
+import com.baomidou.mybatisplus.annotation.EnumValue;
+
+public enum MailTaskStatusEnum implements IQueryableEnum {
+
+    PENDING(0, "等待发送"),
+    SENDING(1, "发送中"),
+    SENT(2, "已发送"),
+    FAILED(3, "发送失败"),
+    CANCELLED(4, "已取消");
+
+    @EnumValue
+    private final int status;
+    private final String note;
+
+    MailTaskStatusEnum(int status, String note) {
+        this.status = status;
+        this.note = note;
+    }
+
+    @Override
+    public int getStatus() {
+        return status;
+    }
+
+    @Override
+    public String getNote() {
+        return note;
+    }
+}
diff --git a/src/main/java/me/qwq/doghouse/enums/MailTaskTypeEnum.java b/src/main/java/me/qwq/doghouse/enums/MailTaskTypeEnum.java
new file mode 100644
index 0000000..5c0a349
--- /dev/null
+++ b/src/main/java/me/qwq/doghouse/enums/MailTaskTypeEnum.java
@@ -0,0 +1,28 @@
+package me.qwq.doghouse.enums;
+
+import com.baomidou.mybatisplus.annotation.EnumValue;
+
+public enum MailTaskTypeEnum implements IQueryableEnum {
+
+    REPLY_SUBSCRIPTION(0, "回复订阅通知"),
+    ADMIN_NOTIFICATION(1, "管理员通知");
+
+    @EnumValue
+    private final int status;
+    private final String note;
+
+    MailTaskTypeEnum(int status, String note) {
+        this.status = status;
+        this.note = note;
+    }
+
+    @Override
+    public int getStatus() {
+        return status;
+    }
+
+    @Override
+    public String getNote() {
+        return note;
+    }
+}
diff --git a/src/main/java/me/qwq/doghouse/service/CommentService.java b/src/main/java/me/qwq/doghouse/service/CommentService.java
index 216b4c3..c99d561 100644
--- a/src/main/java/me/qwq/doghouse/service/CommentService.java
+++ b/src/main/java/me/qwq/doghouse/service/CommentService.java
@@ -3,6 +3,7 @@ package me.qwq.doghouse.service;
 import com.baomidou.mybatisplus.core.conditions.Wrapper;
 import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
 import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
+import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
 import com.baomidou.mybatisplus.core.metadata.IPage;
 import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
 import com.github.yulichang.toolkit.LambdaUtils;
@@ -32,14 +33,18 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Objects;
 import java.util.Set;
+import java.util.UUID;
 import java.util.stream.Collectors;
 
 import org.apache.commons.lang3.ArrayUtils;
+import org.apache.commons.lang3.StringUtils;
 import org.springframework.aop.framework.AopContext;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.cache.CacheManager;
 import org.springframework.cache.annotation.Cacheable;
+import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 import org.springframework.util.CollectionUtils;
 
 /**
@@ -59,6 +64,9 @@ public class CommentService extends BaseServiceImpl<CommentMapper, Comment> {
     
     @Autowired
     CacheManager cacheManager;
+
+    @Autowired
+    JdbcTemplate jdbcTemplate;
     
     /**
      * 重写以启用缓存，类内调用需要 proxy()
@@ -237,11 +245,11 @@ public class CommentService extends BaseServiceImpl<CommentMapper, Comment> {
      * 按照从子到父的顺序，递归获取从指定 commentId 到父级的所有 Comment
      * <p>类内调用需要 proxy()</p>
      * @param commentId 指定的 commentId
-     * @param containsSelf 返回列表是否包含本级
+     * @param includeSelf 返回列表是否包含本级
      * @return
      */
     @Cacheable(value=CacheConstants.Comments.LIST_FROM_CHILD_TO_PARENT)
-    public List<Comment> listFromChildToParent(Long commentId, Boolean containsSelf) {
+    public List<Comment> listFromChildToParent(Long commentId, Boolean includeSelf) {
         List<Comment> list = new ArrayList<>();
         Comment post = getOne(
                 new LambdaQueryWrapper<Comment>()
@@ -251,7 +259,7 @@ public class CommentService extends BaseServiceImpl<CommentMapper, Comment> {
         if (post == null) {
             return list;
         }
-        if (containsSelf) {
+        if (includeSelf) {
             list.add(post);
         }
         Long parentId = post.getReplyTo();
@@ -329,6 +337,59 @@ public class CommentService extends BaseServiceImpl<CommentMapper, Comment> {
         distinctEmails.forEach(email -> Rk.Gravatar.prepareDogHash(email));
         return (long) distinctEmails.size();
     }
+
+    /**
+     * 为指定评论生成新的邮件退订令牌。
+     * @param commentId 评论 ID
+     * @return 新生成的退订令牌
+     */
+    public String refreshUnsubscribeToken(Long commentId) {
+        if (commentId == null) {
+            return null;
+        }
+        String token = UUID.randomUUID().toString();
+        boolean updated = update(new LambdaUpdateWrapper<Comment>()
+                .eq(Comment::getId, commentId)
+                .set(Comment::getUnsubscribeToken, token));
+        return updated ? token : null;
+    }
+
+    /**
+     * 消费指定退订令牌，并关闭该邮箱所有评论的回复订阅。
+     * <p>只删除本次使用的令牌，其他评论上未使用的令牌会保留。</p>
+     * @param token 退订令牌
+     * @return 令牌对应的邮箱，令牌不存在时返回 null
+     */
+    @Transactional
+    public String unsubscribeByToken(String token) {
+        if (StringUtils.isBlank(token)) {
+            return null;
+        }
+
+        Comment tokenComment = getUnsubscribeTokenComment(token);
+        if (tokenComment == null || StringUtils.isBlank(tokenComment.getEmail())) {
+            return null;
+        }
+
+        String email = tokenComment.getEmail().toLowerCase(Locale.ENGLISH).trim();
+        update(new LambdaUpdateWrapper<Comment>()
+                .eq(Comment::getId, tokenComment.getId())
+                .set(Comment::getUnsubscribeToken, null));
+        update(new LambdaUpdateWrapper<Comment>()
+                .eq(Comment::getEmail, email)
+                .set(Comment::isSubscribeReply, false));
+        return email;
+    }
+
+    /**
+     * 查询指定退订令牌对应的邮箱，不消费令牌。
+     * @param token 退订令牌
+     * @return 令牌对应的邮箱，令牌不存在时返回 null
+     */
+    public String getUnsubscribeEmail(String token) {
+        Comment tokenComment = getUnsubscribeTokenComment(token);
+        return tokenComment == null ? null : tokenComment.getEmail();
+    }
     
     /**
      * 重写以启用缓存驱逐
@@ -339,6 +400,7 @@ public class CommentService extends BaseServiceImpl<CommentMapper, Comment> {
         Tag.Comments
     })
     public boolean save(Comment entity) {
+        prepareUnsubscribeToken(entity);
         Long replyTo = entity.getReplyTo();
         if (replyTo != -1L) {
             Comment replyToComment = proxy().getById(replyTo);
@@ -356,6 +418,7 @@ public class CommentService extends BaseServiceImpl<CommentMapper, Comment> {
         Tag.Comments
     })
     public boolean saveOrUpdate(Comment entity) {
+        prepareUnsubscribeToken(entity);
         Long replyTo = entity.getReplyTo();
         if (replyTo == null) entity.setReplyTo(-1L);
         else if (replyTo != -1L) {
@@ -380,4 +443,19 @@ public class CommentService extends BaseServiceImpl<CommentMapper, Comment> {
     private CommentService proxy() {
         return (CommentService) AopContext.currentProxy();
     }
+
+    private void prepareUnsubscribeToken(Comment entity) {
+        if (entity != null && entity.isSubscribeReply() && StringUtils.isBlank(entity.getUnsubscribeToken())) {
+            entity.setUnsubscribeToken(UUID.randomUUID().toString());
+        }
+    }
+
+    private Comment getUnsubscribeTokenComment(String token) {
+        if (StringUtils.isBlank(token)) {
+            return null;
+        }
+        return getOne(new LambdaQueryWrapper<Comment>()
+                .eq(Comment::getUnsubscribeToken, token)
+                .last("LIMIT 1"));
+    }
 }
diff --git a/src/main/java/me/qwq/doghouse/service/MailService.java b/src/main/java/me/qwq/doghouse/service/MailService.java
index 3e9cbef..40618de 100644
--- a/src/main/java/me/qwq/doghouse/service/MailService.java
+++ b/src/main/java/me/qwq/doghouse/service/MailService.java
@@ -1,438 +1,430 @@
-package me.qwq.doghouse.service;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.net.Proxy;
-import java.security.SecureRandom;
-import java.time.Duration;
-import java.time.LocalDateTime;
-import java.time.temporal.Temporal;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Locale;
-import java.util.Properties;
-import java.util.Set;
-import java.util.UUID;
-import java.util.concurrent.TimeUnit;
-import java.util.stream.Collectors;
-
-import javax.mail.Authenticator;
-import javax.mail.PasswordAuthentication;
-import javax.mail.Session;
-import javax.mail.Transport;
-import javax.mail.Message.RecipientType;
-import javax.mail.MessagingException;
-import javax.mail.internet.InternetAddress;
-import javax.mail.internet.MimeMessage;
-
-import org.apache.commons.lang3.StringUtils;
-import org.redisson.api.ExpiredObjectListener;
-import org.redisson.api.RBucket;
-import org.redisson.api.RedissonClient;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.core.io.ClassPathResource;
-import org.springframework.stereotype.Service;
-import org.sqids.Sqids;
-
-import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
-
-import lombok.extern.slf4j.Slf4j;
-import me.qwq.doghouse.component.Rk;
-import me.qwq.doghouse.entity.Comment;
-import me.qwq.doghouse.entity.config.MailConfig;
-import me.qwq.doghouse.entity.config.NetworkConfig;
-import me.qwq.doghouse.entity.config.SiteConfig;
-import me.qwq.doghouse.entity.Post;
-import me.qwq.doghouse.enums.CommentStatusEnum;
-import me.qwq.doghouse.service.post.PostService;
-
-/**
- * 邮件服务
- * @author Doghole
- *
- */
-@Service
-@Slf4j
-public class MailService {
-
-    static final String CONTENT_FORMAT = "text/html;charset=UTF-8";
-    static final String REPLY_SUBSCRIPTION_TEMPLATE = "system/mail/reply-subscription.html";
-
-    @Autowired
-    MailConfig mailConfig;
-    
-    @Autowired
-    NetworkConfig networkConfig;
-    
-    @Autowired
-    SiteConfig siteConfig;
-    
-    @Autowired
-    CommentService commentService;
-    
-    @Autowired
-    PostService postService;
-    
-    @Autowired
-    RedissonClient redis;
-    
-    public Session getMailSession(boolean debug) {
-        
-        String username = mailConfig.getUsername();
-        String password = mailConfig.getPassword();
-
-        Properties props = new Properties();
-        
-        props.put("mail.smtp.starttls.enable", mailConfig.isTlsEnable());
-        props.put("mail.smtp.host", mailConfig.getSmtpHost());
-        props.put("mail.smtp.port", mailConfig.getSmtpPort());
-        props.put("mail.smtp.auth", true);
-        
-        if (networkConfig.getProxyType() == Proxy.Type.SOCKS) {
-            props.put("mail.smtp.socks.host", networkConfig.getProxyHost());
-            props.put("mail.smtp.socks.port", networkConfig.getProxyPort());
-        }
-        else if (networkConfig.getProxyType() == Proxy.Type.HTTP) {
-            props.put("mail.smtp.proxy.host", networkConfig.getProxyHost());
-            props.put("mail.smtp.proxy.port", networkConfig.getProxyPort());
-        }
-        
-        Session session = Session.getInstance(props, new Authenticator() {
-            @Override
-            protected PasswordAuthentication getPasswordAuthentication() {
-                return new PasswordAuthentication(username, password);
-            }
-        });
-        
-        session.setDebug(debug);
-        return session;
-    }
-    
-    /**
-     * 重设邮件任务延迟，一般在修改邮件设置后触发
-     */
-    public void resetTaskDelay() {
-        
-        for (String key : Rk.Mail.getAllExpirationTaskKeys()) {
-            if (!key.endsWith("-comment")) {
-                RBucket<Object> task = redis.getBucket(key);
-                if (mailConfig.getSendingDelay() == 0L) {
-                    task.set(null, Duration.ofSeconds(1L));
-                }
-                else {
-                    task.set(null, Duration.ofMinutes(mailConfig.getSendingDelay()));
-                }
-            }
-        }
-    }
-    
-    /**
-     * 清除评论对应的延迟
-     * @param comment
-     * @return
-     */
-    public boolean clearTaskDelay(Comment comment) {
-        RBucket<Object> taskBucket = Rk.Mail.getTaskBucket(comment.getId());
-        return taskBucket.clearExpire() || taskBucket.isExists();
-    }
-    
-    /**
-     * 添加或更新发送队列
-     * @param comment
-     */
-    public void addOrUpdateSendQueue(Comment comment) {
-        
-        if (comment.isMailSent()) {
-            log.info("评论 ID 为 {} 的通知已发送，不会再次发送", comment.getId());
-            return;
-        }
-        
-        RBucket<Object> taskBucket = Rk.Mail.getTaskBucket(comment.getId());
-        RBucket<Comment> commentCache = Rk.Mail.getTaskCommentBucket(comment.getId());
-        
-        if (comment.getIsDeleted()) {
-            // 已删除，需要删除其任务
-            log.info("评论 ID 为 {} 的评论已删除，清除可能存在的通知任务", comment.getId());
-            taskBucket.deleteAsync();
-            commentCache.deleteAsync();
-            return;
-        }
-        
-        if (taskBucket.isExists()
-                && comment.getCommentStatus() != CommentStatusEnum.RELEASED) {
-            // 已存在，但变更了评论状态，不为发布状态，需要删除其任务
-            log.info("评论 ID 为 {} 的评论状态修改为 {}，清除其通知任务",
-                    comment.getId(), comment.getCommentStatusNote());
-            taskBucket.deleteAsync();
-            commentCache.deleteAsync();
-            return;
-        }
-        
-        if (taskBucket.isExists()) {
-            // 已存在，只更新 commentCache 和时间
-            
-            if (taskBucket.clearExpire()) {
-                // 有 TTL，重设时间
-                log.info("评论 ID 为 {} 的评论内容已变更，重设推送时间",
-                        comment.getId());
-                commentCache.set(comment);
-                taskBucket.expire(mailConfig.getMailDuration());
-                return;
-            }
-            else {
-                // 没 TTL, 继续时间
-                LocalDateTime now = LocalDateTime.now();
-                LocalDateTime commentDate = comment.getCreateTime();
-                
-                Duration delay = Duration.ofMinutes(mailConfig.getSendingDelay());
-                Temporal sendTime = delay.addTo(commentDate);
-                
-                Duration newDelay = Duration.between(now, sendTime);
-                if (newDelay.isNegative() || newDelay.isZero()) {
-                    newDelay = Duration.ofSeconds(1L);
-                }
-                commentCache.set(comment);
-                taskBucket.expire(newDelay);
-                return;
-            }
-            
-        }
-        
-        commentCache.set(comment);
-
-        
-        taskBucket.addListener(new ExpiredObjectListener() {
-            @Override
-            public void onExpired(String name) {
-                // 寻找本级至顶级的所有回复
-                Comment comment = commentCache.getAndDelete();
-                
-                if (comment == null) {
-                    log.info("评论 ID 为 {} 的评论无法获取推送缓存，可能状态已变更，推送不会进行");
-                    return;
-                }
-                if (!mailConfig.isMailOn()) {
-                    log.debug("邮件功能未开启，评论 ID 为 {} 的推送任务将不会进行被发送", comment.getId());
-                    return;
-                }
-                
-                log.info("触发评论 ID 为 {} 的推送任务...", comment.getId());
-                Post post = postService.getById(comment.getPostId());
-                if (post == null) {
-                    log.info("评论 ID 为 {} 的评论所属 Post Id = {} 不存在，可能状态已变更，推送不会进行");
-                    return;
-                }
-                List<Comment> parentComments = commentService.listFromChildToParent(comment.getId(), false);
-                Set<String> mailSet = parentComments.stream()
-                        .filter(c -> c.isSubscribeReply() && !c.getEmail().equalsIgnoreCase(comment.getEmail()))
-                        .map(c -> c.getEmail().toLowerCase(Locale.ENGLISH))
-                        .collect(Collectors.toSet());
-                if (!mailSet.isEmpty()) {
-                    MimeMessage message = new MimeMessage(getMailSession(false));
-                    try {
-                        message.setSubject(
-                                String.format("您在 %s 的 %s 文章评论有新回复",
-                                        siteConfig.getName(),
-                                        post.getTitle()));
-                        
-                        if (StringUtils.isEmpty(mailConfig.getFromUser())) {
-                            message.setFrom(mailConfig.getFromAddress());
-                        }
-                        else {
-                            message.setFrom(
-                                String.format("%s<%s>",
-                                mailConfig.getFromUser(),
-                                mailConfig.getFromAddress()));
-                        }
-                        
-                        String contentTemplate = getResourceText(REPLY_SUBSCRIPTION_TEMPLATE);
-                        if (contentTemplate == null) {
-                            log.warn("回复订阅通知模板文件路径 {} 无法找到, 通知将不会被发送",
-                                    REPLY_SUBSCRIPTION_TEMPLATE);
-                            return;
-                        }
-                        
-                        mailSet.forEach(mail -> {
-                            try {
-                                log.info("评论 ID 为 {} 的通知欲发送至 {}", 
-                                        comment.getId(), mail);
-                                RBucket<String> mgrBucket = Rk.Mail.getMgrBucket(mail);
-                                String uuid = null;
-                                if (mgrBucket.isExists()) {
-                                    uuid = mgrBucket.get();
-                                    log.debug("邮箱 {} 存在管理 UUID {}", mail, uuid);
-                                }
-                                else {
-                                    uuid = UUID.randomUUID().toString();
-                                    log.debug("邮箱 {} 不存在管理 UUID，生成 {}", mail, uuid);
-                                }
-                                
-                                String content = renderReplySubscriptionContent(
-                                        contentTemplate, siteConfig, post, comment, uuid);
-                                message.setContent(content, CONTENT_FORMAT);
-                                
-                                message.setRecipient(RecipientType.TO,
-                                        new InternetAddress(mail));
-                                Transport.send(message);
-                                
-                                // 发送成功了再存 :P
-                                RBucket<String> uuidBucket = Rk.Mail.getMgrUuidBucket(uuid);
-                                uuidBucket.setAsync(mail, 86400, TimeUnit.SECONDS);
-                                mgrBucket.setAsync(uuid, 86400, TimeUnit.SECONDS);
-                                
-                                log.debug("已为邮箱 {} 设置 UUID {}", mail, uuid);
-                                
-                                log.info("评论 ID 为 {} 的通知已发送至 {}", comment.getId(), mail);
-                            }
-                            catch (MessagingException e) {
-                                log.error("发送评论 ID 为 " + comment.getId() + " 的通知至 " + mail + " 时发生错误", e);
-                            }
-                        });
-                        // 更新已发送状态
-                        commentService.update(new LambdaUpdateWrapper<Comment>()
-                                .eq(Comment::getId, comment.getId())
-                                .set(Comment::isMailSent, true));
-                    }
-                    catch (MessagingException e) {
-                        log.error("初始化评论 ID 为 {} 的通知失败", comment.getId());
-                    }
-                }
-                else {
-                    // 本级到顶级没有找到能接收通知的邮箱，或找到的邮箱是回复者本人的邮箱
-                    log.debug("评论 ID 为 {} 的任务未找到可执行通知的邮箱，"
-                            + "或找到的邮箱为回复者本人邮箱，邮件不会发送。"
-                            + "若非您预期的结果，请检查：被回复的评论及上级"
-                            + "评论是否开启了邮件订阅？", 
-                            comment.getId());
-                }
-            }
-        });
-        Long sendingDelay = mailConfig.getSendingDelay();
-        if (sendingDelay == 0L) {
-            taskBucket.set(0, Duration.ofSeconds(1L));
-            log.debug("评论 ID 为 {} 的任务将在 1 秒后立即执行", comment.getId());
-        }
-        else {
-            taskBucket.set(0, Duration.ofMinutes(sendingDelay));
-            log.debug("评论 ID 为 {} 的任务将在 {} 分钟后执行", comment.getId(), sendingDelay);
-        }
-        log.info("评论 ID 为 {} 的通知任务已提交，等待执行", comment.getId());
-    }
-
-    /**
-     * 发送新评论通知到管理员邮箱
-     * @param comment
-     */
-    public void sendAdminNotification(Comment comment) {
-        
-        if (!mailConfig.isMailOn()) {
-            log.debug("邮件功能未开启，评论 ID 为 {} 的管理邮件将不会被发送", comment.getId());
-            return;
-        }
-        
-        Post post = postService.getByIdOrName(comment.getPostId(), comment.getPostPageName());
-        
-        RBucket<Object> expiredKey = Rk.Mail.getRandomExpirationBucket();
-        expiredKey.addListener(new ExpiredObjectListener() {
-            @Override
-            public void onExpired(String name) {
-                log.info("评论 ID 为 {} 的管理邮件任务开始", comment.getId());
-                try {
-                    MimeMessage message = new MimeMessage(getMailSession(false));
-                    message.setSubject(
-                            String.format("您在 %s 的 %s 文章有新回复",
-                            siteConfig.getName(),
-                            post.getTitle()));
-                    String content = String.format(
-                            "<p><b>%s</b>：%s<br>"
-                            + "<b>评论状态</b>：%s<br>"
-                            + "<a href=\"%s%s\" rel=\"noopener noreferrer\" target=\"_blank\">查看详情</a></p>"
-                            + "<p><i style=\"color: red\">该邮件由系统自动发出，请勿直接回复该邮件</i></p>",
-                            comment.getAuthor(),
-                            comment.getContent(),
-                            comment.getCommentStatusNote(),
-                            siteConfig.getAddress(),
-                            comment.getCommentStatus() == CommentStatusEnum.RELEASED ?
-                                    commentService.getJumpToUrl(comment.getId()):
-                                    "/admin/v2");
-                    message.setContent(content, CONTENT_FORMAT);
-                    
-                    if (StringUtils.isEmpty(mailConfig.getFromUser())) {
-                        message.setFrom(mailConfig.getFromAddress());
-                    }
-                    else {
-                        message.setFrom(
-                            String.format("%s<%s>",
-                            mailConfig.getFromUser(),
-                            mailConfig.getFromAddress()));
-                    }
-                    message.setRecipient(RecipientType.TO,
-                            new InternetAddress(mailConfig.getAdminAddress()));
-                    Transport.send(message);
-                    log.info("评论 ID 为 {} 的管理邮件发送成功", comment.getId());
-                }
-                catch (Exception e) {
-                    log.error("评论 ID 为 " + comment.getId() + " 的管理邮件发送失败", e);
-                }
-            }
-        });
-        expiredKey.set(1, Duration.ofSeconds(1L));
-        log.debug("评论 ID 为 {} 的管理邮件任务将在 1 秒后立即执行", comment.getId());
-    }
-    
-    String renderReplySubscriptionContent(
-            String template, SiteConfig siteConfig, Post post, Comment comment, String uuid) {
-        String blogName = siteConfig.getName();
-        String postName = post.getPostTitle();
-        String author = comment.getAuthor();
-        String content = comment.getContent();
-        String detailUrl = siteConfig.getAddress() + "/comments/go/" + comment.getId();
-        String unsubscribeUrl = siteConfig.getAddress() + "/system/unsubscribe-mail?token=" + uuid;
-        
-        List<Long> list = new ArrayList<>();
-        SecureRandom random = new SecureRandom();
-        list.add(Math.abs(random.nextLong()));
-        list.add(Math.abs(random.nextLong()));
-        String mess = Sqids.builder().build().encode(list);
-
-        String blogNameReplacement = "{{blogName" + mess + "}}";
-        String postNameReplacement = "{{postName" + mess + "}}";
-        String authorReplacement = "{{author" + mess + "}}";
-        String contentReplacement = "{{content" + mess + "}}";
-        String detailUrlReplacement = "{{detailUrl" + mess + "}}";
-        String unsubscribeUrlReplacement = "{{unsubscribeUrl" + mess + "}}";
-        
-        
-        return template
-                .replace("{{blogName}}", blogNameReplacement)
-                .replace("{{postName}}", postNameReplacement)
-                .replace("{{author}}", authorReplacement)
-                .replace("{{content}}", contentReplacement)
-                .replace("{{detailUrl}}", detailUrlReplacement)
-                .replace("{{unsubscribeUrl}}", unsubscribeUrlReplacement)
-                .replace(blogNameReplacement, blogName)
-                .replace(postNameReplacement, postName)
-                .replace(authorReplacement, author)
-                .replace(contentReplacement, content)
-                .replace(detailUrlReplacement, detailUrl)
-                .replace(unsubscribeUrlReplacement, unsubscribeUrl);
-    }
-    
-    /**
-     * 读取资源文件
-     * @param fileName
-     * @return
-     */
-    String getResourceText(String fileName) {
-        ClassPathResource resource = new ClassPathResource(fileName);
-        String content = null;
-        try (InputStream inputStream = resource.getInputStream()) {
-            content = new String(inputStream.readAllBytes());
-        }
-        catch (IOException e) {
-            log.error("读取 resource 文件 " + fileName + " 时发生错误", e);
-        }
-        return content;
-    }
-
-}
+package me.qwq.doghouse.service;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.Proxy;
+import java.nio.charset.StandardCharsets;
+import java.time.Duration;
+import java.time.LocalDateTime;
+import java.util.Locale;
+import java.util.Properties;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import javax.mail.Authenticator;
+import javax.mail.Message.RecipientType;
+import javax.mail.MessagingException;
+import javax.mail.PasswordAuthentication;
+import javax.mail.Session;
+import javax.mail.Transport;
+import javax.mail.internet.InternetAddress;
+import javax.mail.internet.MimeMessage;
+
+import org.apache.commons.lang3.StringUtils;
+import org.apache.commons.text.StringEscapeUtils;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.stereotype.Service;
+import org.thymeleaf.TemplateEngine;
+import org.thymeleaf.context.Context;
+import org.thymeleaf.templatemode.TemplateMode;
+import org.thymeleaf.templateresolver.StringTemplateResolver;
+
+import lombok.extern.slf4j.Slf4j;
+import me.qwq.doghouse.entity.Comment;
+import me.qwq.doghouse.entity.MailTask;
+import me.qwq.doghouse.entity.Post;
+import me.qwq.doghouse.entity.config.MailConfig;
+import me.qwq.doghouse.entity.config.NetworkConfig;
+import me.qwq.doghouse.entity.config.SiteConfig;
+import me.qwq.doghouse.enums.CommentStatusEnum;
+import me.qwq.doghouse.enums.MailTaskTypeEnum;
+import me.qwq.doghouse.service.post.PostService;
+import me.qwq.doghouse.util.MarkDownUtils;
+
+@Service
+@Slf4j
+public class MailService {
+
+    static final String CONTENT_FORMAT = "text/html;charset=UTF-8";
+    static final String REPLY_SUBSCRIPTION_TEMPLATE = "system/mail/reply-subscription.html";
+    static final TemplateEngine MAIL_TEMPLATE_ENGINE = createMailTemplateEngine();
+
+    public enum MailTaskResult {
+        SENT,
+        CANCELLED
+    }
+
+    @Autowired
+    MailConfig mailConfig;
+
+    @Autowired
+    NetworkConfig networkConfig;
+
+    @Autowired
+    SiteConfig siteConfig;
+
+    @Autowired
+    CommentService commentService;
+
+    @Autowired
+    PostService postService;
+
+    @Autowired
+    MailTaskService mailTaskService;
+
+    /**
+     * 创建用于渲染邮件正文的 Thymeleaf 字符串模板引擎。
+     * @return 邮件模板引擎
+     */
+    private static TemplateEngine createMailTemplateEngine() {
+        StringTemplateResolver templateResolver = new StringTemplateResolver();
+        templateResolver.setTemplateMode(TemplateMode.HTML);
+        templateResolver.setCacheable(false);
+
+        TemplateEngine templateEngine = new TemplateEngine();
+        templateEngine.setTemplateResolver(templateResolver);
+        return templateEngine;
+    }
+
+    /**
+     * @param debug 是否开启调试, 开启后会在输出打印邮件状态
+     * @return 邮件会话
+     */
+    public Session getMailSession(boolean debug) {
+
+        String username = mailConfig.getUsername();
+        String password = mailConfig.getPassword();
+
+        Properties props = new Properties();
+
+        props.put("mail.smtp.starttls.enable", mailConfig.isTlsEnable());
+        props.put("mail.smtp.host", mailConfig.getSmtpHost());
+        props.put("mail.smtp.port", mailConfig.getSmtpPort());
+        props.put("mail.smtp.auth", true);
+
+        if (networkConfig.getProxyType() == Proxy.Type.SOCKS) {
+            props.put("mail.smtp.socks.host", networkConfig.getProxyHost());
+            props.put("mail.smtp.socks.port", networkConfig.getProxyPort());
+        }
+        else if (networkConfig.getProxyType() == Proxy.Type.HTTP) {
+            props.put("mail.smtp.proxy.host", networkConfig.getProxyHost());
+            props.put("mail.smtp.proxy.port", networkConfig.getProxyPort());
+        }
+
+        Session session = Session.getInstance(props, new Authenticator() {
+            @Override
+            protected PasswordAuthentication getPasswordAuthentication() {
+                return new PasswordAuthentication(username, password);
+            }
+        });
+
+        session.setDebug(debug);
+        return session;
+    }
+
+    /**
+     * 在邮件间隔设置变更后，重设邮件任务延时
+     */
+    public void resetTaskDelay() {
+        mailTaskService.resetReplyTaskDelay(mailConfig.getMailDuration());
+    }
+
+    /**
+     * 取消可编辑评论的待处理邮件任务
+     * @param comment
+     * @return 是否存在待处理任务并已将其取消
+     */
+    public boolean clearTaskDelay(Comment comment) {
+        if (comment == null || comment.getId() == null) {
+            return false;
+        }
+        return mailTaskService.cancelOutstandingTasks(comment.getId(), MailTaskTypeEnum.REPLY_SUBSCRIPTION);
+    }
+
+    /**
+     * 添加或更新邮件推送任务
+     * @param comment 需要处理的评论
+     */
+    public void addOrUpdateSendQueue(Comment comment) {
+        if (comment == null || comment.getId() == null) {
+            return;
+        }
+
+        if (comment.isMailSent()) {
+            log.info("ID 为 {} 的评论通知已发送，不会再次发送", comment.getId());
+            return;
+        }
+
+        if (comment.getIsDeleted() || comment.getCommentStatus() != CommentStatusEnum.RELEASED) {
+            log.info("ID 为 {} 的评论已删除或未发布，取消其回复订阅通知任务", comment.getId());
+            mailTaskService.cancelOutstandingTasks(comment.getId(), MailTaskTypeEnum.REPLY_SUBSCRIPTION);
+            return;
+        }
+
+        Set<String> recipients = getReplySubscriptionRecipients(comment);
+        if (recipients.isEmpty()) {
+            mailTaskService.cancelOutstandingTasks(comment.getId(), MailTaskTypeEnum.REPLY_SUBSCRIPTION);
+            log.debug("ID 为 {} 的评论未找到回复订阅通知收件人", comment.getId());
+            return;
+        }
+
+        LocalDateTime sendAfter = getSendAfter(comment);
+        mailTaskService.replaceReplyTasks(comment.getId(), recipients, sendAfter);
+        log.info("ID 为 {} 的评论回复订阅通知任务已提交，收件人数 {}", comment.getId(), recipients.size());
+    }
+
+    /**
+     * 为新评论发送管理员通知
+     * @param comment
+     */
+    public void sendAdminNotification(Comment comment) {
+        if (comment == null || comment.getId() == null) {
+            return;
+        }
+        if (!mailConfig.isMailOn()) {
+            log.debug("邮件功能未开启，评论 ID 为 {} 的管理员邮件不会入队", comment.getId());
+            return;
+        }
+        mailTaskService.enqueueAdminTask(comment.getId(), mailConfig.getAdminAddress());
+        log.debug("ID 为 {} 的评论的管理员邮件任务已提交", comment.getId());
+    }
+
+    /**
+     * 执行指定邮件任务，并根据任务类型分派到对应发送逻辑。
+     * @param task 待执行的邮件任务
+     * @return 邮件任务执行结果
+     * @throws MessagingException 邮件构造或发送失败时抛出
+     */
+    public MailTaskResult executeMailTask(MailTask task) throws MessagingException {
+        if (task == null || task.getTaskType() == null) {
+            return MailTaskResult.CANCELLED;
+        }
+        if (!mailConfig.isMailOn()) {
+            log.debug("邮件功能未开启，邮件任务 {} 取消", task.getId());
+            return MailTaskResult.CANCELLED;
+        }
+
+        if (task.getTaskType() == MailTaskTypeEnum.ADMIN_NOTIFICATION) {
+            return sendAdminNotificationTask(task);
+        }
+        if (task.getTaskType() == MailTaskTypeEnum.REPLY_SUBSCRIPTION) {
+            return sendReplySubscriptionTask(task);
+        }
+        return MailTaskResult.CANCELLED;
+    }
+
+    /**
+     * 发送评论回复订阅通知邮件。
+     * @param task 回复订阅邮件任务
+     * @return 邮件任务执行结果
+     * @throws MessagingException 邮件构造或发送失败时抛出
+     */
+    private MailTaskResult sendReplySubscriptionTask(MailTask task) throws MessagingException {
+        Comment comment = commentService.getById(task.getCommentId());
+        if (comment == null || comment.getIsDeleted() || comment.getCommentStatus() != CommentStatusEnum.RELEASED) {
+            return MailTaskResult.CANCELLED;
+        }
+        if (comment.isMailSent()) {
+            return MailTaskResult.CANCELLED;
+        }
+
+        String recipient = StringUtils.lowerCase(task.getRecipient(), Locale.ENGLISH);
+        if (!isReplySubscriptionRecipientStillValid(comment, recipient)) {
+            log.info("评论 ID 为 {} 的收件人 {} 已不再订阅该回复，任务取消", comment.getId(), recipient);
+            return MailTaskResult.CANCELLED;
+        }
+
+        Post post = postService.getByIdOrName(comment.getPostId(), comment.getPostPageName(), false);
+        if (post == null) {
+            return MailTaskResult.CANCELLED;
+        }
+
+        Comment subscriptionComment = getReplySubscriptionComment(comment, recipient);
+        if (subscriptionComment == null) {
+            return MailTaskResult.CANCELLED;
+        }
+
+        String contentTemplate = getResourceText(REPLY_SUBSCRIPTION_TEMPLATE);
+        if (contentTemplate == null) {
+            throw new MessagingException("回复订阅通知模板无法读取: " + REPLY_SUBSCRIPTION_TEMPLATE);
+        }
+
+        String token = commentService.refreshUnsubscribeToken(subscriptionComment.getId());
+        if (StringUtils.isBlank(token)) {
+            throw new MessagingException("无法生成邮件退订令牌");
+        }
+
+        MimeMessage message = new MimeMessage(getMailSession(false));
+        message.setSubject(String.format("您在 %s 的 %s 文章评论有新回复",
+                siteConfig.getName(), post.getTitle()));
+        setMessageFrom(message);
+        message.setRecipient(RecipientType.TO, new InternetAddress(recipient));
+        message.setContent(renderReplySubscriptionContent(
+                contentTemplate, siteConfig, post, comment, token), CONTENT_FORMAT);
+
+        Transport.send(message);
+
+        log.info("评论 ID 为 {} 的回复订阅通知已发送至 {}", comment.getId(), recipient);
+        return MailTaskResult.SENT;
+    }
+
+    /**
+     * 发送新评论管理员通知邮件。
+     * @param task 管理员通知邮件任务
+     * @return 邮件任务执行结果
+     * @throws MessagingException 邮件构造或发送失败时抛出
+     */
+    private MailTaskResult sendAdminNotificationTask(MailTask task) throws MessagingException {
+        Comment comment = commentService.getById(task.getCommentId());
+        if (comment == null || comment.getIsDeleted()) {
+            return MailTaskResult.CANCELLED;
+        }
+
+        Post post = postService.getById(comment.getPostId());
+        if (post == null) {
+            return MailTaskResult.CANCELLED;
+        }
+
+        MimeMessage message = new MimeMessage(getMailSession(false));
+        message.setSubject(String.format("您在 %s 的 %s 文章有新回复",
+                siteConfig.getName(), post.getTitle()));
+        setMessageFrom(message);
+        message.setRecipient(RecipientType.TO, new InternetAddress(task.getRecipient()));
+        message.setContent(String.format(
+                "<p><b>%s</b>：%s<br>"
+                + "<b>评论状态</b>：%s<br>"
+                + "<a href=\"%s%s\" rel=\"noopener noreferrer\" target=\"_blank\">查看详情</a></p>"
+                + "<p><i style=\"color: red\">该邮件由系统自动发出，请勿直接回复该邮件</i></p>",
+                comment.getAuthor(),
+                comment.getContent(),
+                comment.getCommentStatusNote(),
+                siteConfig.getAddress(),
+                comment.getCommentStatus() == CommentStatusEnum.RELEASED ?
+                        commentService.getJumpToUrl(comment.getId()) :
+                        "/admin/v2"), CONTENT_FORMAT);
+
+        Transport.send(message);
+        log.info("评论 ID 为 {} 的管理员邮件已发送至 {}", comment.getId(), task.getRecipient());
+        return MailTaskResult.SENT;
+    }
+
+    /**
+     * 从指定评论中获取开启了订阅的收件人
+     * @param comment 关联评论
+     * @return 收件人邮件地址 Set
+     */
+    private Set<String> getReplySubscriptionRecipients(Comment comment) {
+        return commentService.listFromChildToParent(comment.getId(), false)
+                .stream()
+                .filter(c -> c.isSubscribeReply())
+                .map(Comment::getEmail)
+                .filter(StringUtils::isNotBlank)
+                .map(email -> email.toLowerCase(Locale.ENGLISH).trim())
+                .filter(email -> !email.equalsIgnoreCase(comment.getEmail()))
+                .collect(Collectors.toSet());
+    }
+
+    /**
+     * @param comment 指定评论
+     * @param recipient 指定收件人
+     * @return 指定收件人是否存在于某评论的订阅中
+     */
+    private boolean isReplySubscriptionRecipientStillValid(Comment comment, String recipient) {
+        return getReplySubscriptionComment(comment, recipient) != null;
+    }
+
+    private Comment getReplySubscriptionComment(Comment comment, String recipient) {
+        if (StringUtils.isBlank(recipient)) {
+            return null;
+        }
+        String normalizedRecipient = recipient.toLowerCase(Locale.ENGLISH).trim();
+        return commentService.listFromChildToParent(comment.getId(), false)
+                .stream()
+                .filter(Comment::isSubscribeReply)
+                .filter(c -> StringUtils.isNotBlank(c.getEmail()))
+                .filter(c -> normalizedRecipient.equals(c.getEmail().toLowerCase(Locale.ENGLISH).trim()))
+                .filter(c -> !normalizedRecipient.equalsIgnoreCase(comment.getEmail()))
+                .findFirst()
+                .orElse(null);
+    }
+
+    /**
+     * 计算评论回复订阅通知的最早发送时间。
+     * @param comment 关联评论
+     * @return 最早发送时间
+     */
+    private LocalDateTime getSendAfter(Comment comment) {
+        LocalDateTime baseTime = comment.getCreateTime() == null ? LocalDateTime.now() : comment.getCreateTime();
+        Duration delay = mailConfig.getMailDuration();
+        LocalDateTime sendAfter = baseTime.plus(delay);
+        LocalDateTime minSendAfter = LocalDateTime.now().plusSeconds(1);
+        return sendAfter.isBefore(minSendAfter) ? minSendAfter : sendAfter;
+    }
+
+    /**
+     * 根据邮件配置设置发件人信息。
+     * @param message 待设置的邮件消息
+     * @throws MessagingException 发件人设置失败时抛出
+     */
+    private void setMessageFrom(MimeMessage message) throws MessagingException {
+        if (StringUtils.isEmpty(mailConfig.getFromUser())) {
+            message.setFrom(mailConfig.getFromAddress());
+        }
+        else {
+            message.setFrom(String.format("%s<%s>",
+                    mailConfig.getFromUser(),
+                    mailConfig.getFromAddress()));
+        }
+    }
+    
+    /**
+     * 渲染回复订阅内容
+     * @param template 模板源文本
+     * @param siteConfig 站点配置, 用以获取博客名、博客地址
+     * @param post 对应文章, 用以获取文章标题
+     * @param comment 订阅者发布的本条评论, 用以获取订阅者称呼、当前评论内容和评论 id, 其中评论 id 用作链接跳转
+     * @param token 对应评论发布者邮箱退订用令牌，用以鉴别发布者身份
+     * @return 渲染完毕后的邮件内容(html)
+     */
+    private String renderReplySubscriptionContent(
+            String template, SiteConfig siteConfig, Post post, Comment comment, String token) {
+        Context context = new Context(Locale.getDefault());
+        context.setVariable("blogName", siteConfig.getName());
+        context.setVariable("postName", post.getPostTitle());
+        context.setVariable("author", comment.getAuthor());
+        context.setVariable("contentHtml", renderSafeCommentContent(comment));
+        context.setVariable("detailUrl", siteConfig.getAddress() + "/comments/go/" + comment.getId());
+        context.setVariable("unsubscribeUrl", siteConfig.getAddress() + "/system/unsubscribe-mail?token=" + token);
+
+        return MAIL_TEMPLATE_ENGINE.process(template, context);
+    }
+
+    /**
+     * 将评论内容转换为可安全放入邮件正文的 HTML。
+     * @param comment 关联评论
+     * @return 可直接作为 HTML 输出的评论内容
+     */
+    private String renderSafeCommentContent(Comment comment) {
+        if (comment.isMarkdown()) {
+            return MarkDownUtils.commentToHtml(comment.getContent());
+        }
+        return StringEscapeUtils.escapeHtml4(comment.getContent());
+    }
+
+    /**
+     * 读取 classpath 下的文本资源内容。
+     * @param fileName 资源文件路径
+     * @return 资源文本内容，读取失败时返回 null
+     */
+    String getResourceText(String fileName) {
+        ClassPathResource resource = new ClassPathResource(fileName);
+        try (InputStream inputStream = resource.getInputStream()) {
+            return new String(inputStream.readAllBytes(), StandardCharsets.UTF_8);
+        }
+        catch (IOException e) {
+            log.error("读取 resource 文件 " + fileName + " 时发生错误", e);
+            return null;
+        }
+    }
+}
diff --git a/src/main/java/me/qwq/doghouse/service/MailTaskService.java b/src/main/java/me/qwq/doghouse/service/MailTaskService.java
new file mode 100644
index 0000000..cf7c147
--- /dev/null
+++ b/src/main/java/me/qwq/doghouse/service/MailTaskService.java
@@ -0,0 +1,212 @@
+package me.qwq.doghouse.service;
+
+import java.time.Duration;
+import java.time.LocalDateTime;
+import java.util.Collection;
+import java.util.List;
+
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
+import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
+
+import me.qwq.doghouse.dao.MailTaskMapper;
+import me.qwq.doghouse.entity.MailTask;
+import me.qwq.doghouse.enums.MailTaskStatusEnum;
+import me.qwq.doghouse.enums.MailTaskTypeEnum;
+
+@Service
+public class MailTaskService extends BaseServiceImpl<MailTaskMapper, MailTask> {
+
+    public static final int MAX_ATTEMPTS = 5;
+    private static final int DEFAULT_BATCH_SIZE = 10;
+
+    @Transactional
+    public void replaceReplyTasks(Long commentId, Collection<String> recipients, LocalDateTime sendAfter) {
+        cancelOutstandingTasks(commentId, MailTaskTypeEnum.REPLY_SUBSCRIPTION);
+        if (recipients == null || recipients.isEmpty()) {
+            return;
+        }
+
+        LocalDateTime now = LocalDateTime.now();
+        List<MailTask> tasks = recipients.stream()
+                .map(recipient -> new MailTask()
+                        .setTaskType(MailTaskTypeEnum.REPLY_SUBSCRIPTION)
+                        .setCommentId(commentId)
+                        .setRecipient(recipient)
+                        .setStatus(MailTaskStatusEnum.PENDING)
+                        .setSendAfter(sendAfter)
+                        .setAttempts(0)
+                        .setCreateTime(now)
+                        .setUpdateTime(now))
+                .toList();
+        saveBatch(tasks);
+    }
+
+    /**
+     * 入队新评论的管理员邮件通知
+     * @param commentId 评论 ID
+     * @param recipient 收件人地址
+     */
+    public void enqueueAdminTask(Long commentId, String recipient) {
+        if (commentId == null || recipient == null || recipient.isBlank()) {
+            return;
+        }
+
+        LocalDateTime now = LocalDateTime.now();
+        save(new MailTask()
+                .setTaskType(MailTaskTypeEnum.ADMIN_NOTIFICATION)
+                .setCommentId(commentId)
+                .setRecipient(recipient.toLowerCase())
+                .setStatus(MailTaskStatusEnum.PENDING)
+                .setSendAfter(now.plusSeconds(1))
+                .setAttempts(0)
+                .setCreateTime(now)
+                .setUpdateTime(now));
+    }
+
+    /**
+     * 取消未完成的评论邮件任务
+     * @param commentId 指定评论 id
+     * @param taskType 邮件任务类型
+     * @return 是否成功取消指定条件的任务
+     */
+    public boolean cancelOutstandingTasks(Long commentId, MailTaskTypeEnum taskType) {
+        if (commentId == null || taskType == null) {
+            return false;
+        }
+
+        LambdaQueryWrapper<MailTask> query = outstandingQuery(commentId, taskType);
+        boolean exists = count(query) > 0;
+        if (!exists) {
+            return false;
+        }
+
+        return update(new LambdaUpdateWrapper<MailTask>()
+                .eq(MailTask::getCommentId, commentId)
+                .eq(MailTask::getTaskType, taskType)
+                .in(MailTask::getStatus,
+                        MailTaskStatusEnum.PENDING,
+                        MailTaskStatusEnum.FAILED,
+                        MailTaskStatusEnum.SENDING)
+                .set(MailTask::getStatus, MailTaskStatusEnum.CANCELLED)
+                .set(MailTask::getUpdateTime, LocalDateTime.now()));
+    }
+
+    /**
+     * 重设订阅邮件任务延迟, 会将邮件类型为订阅邮件、邮件状态为 PEDING 和 FAILED 的重置为 PEDING, 并重设延迟
+     * @param delay 延迟
+     */
+    public void resetReplyTaskDelay(Duration delay) {
+        LocalDateTime sendAfter = LocalDateTime.now().plus(delay);
+        update(new LambdaUpdateWrapper<MailTask>()
+                .eq(MailTask::getTaskType, MailTaskTypeEnum.REPLY_SUBSCRIPTION)
+                .in(MailTask::getStatus, MailTaskStatusEnum.PENDING, MailTaskStatusEnum.FAILED)
+                .set(MailTask::getStatus, MailTaskStatusEnum.PENDING)
+                .set(MailTask::getSendAfter, sendAfter)
+                .set(MailTask::getUpdateTime, LocalDateTime.now()));
+    }
+
+    /**
+     * 查询当前满足发送条件的邮件任务, 详见查询条件
+     * @return 当前满足发送条件的邮件任务的列表
+     */
+    public List<MailTask> pollDueTasks() {
+        return list(new LambdaQueryWrapper<MailTask>()
+                .in(MailTask::getStatus, MailTaskStatusEnum.PENDING, MailTaskStatusEnum.FAILED)
+                .le(MailTask::getSendAfter, LocalDateTime.now())
+                .lt(MailTask::getAttempts, MAX_ATTEMPTS)
+                .orderByAsc(MailTask::getSendAfter)
+                .last("LIMIT " + DEFAULT_BATCH_SIZE));
+    }
+    
+    /**
+     * 将指定邮件任务标记为发送中
+     * @param task
+     * @return
+     */
+    public boolean markSending(MailTask task) {
+        if (task == null || task.getId() == null) {
+            return false;
+        }
+        return update(new LambdaUpdateWrapper<MailTask>()
+                .eq(MailTask::getId, task.getId())
+                .in(MailTask::getStatus, MailTaskStatusEnum.PENDING, MailTaskStatusEnum.FAILED)
+                .set(MailTask::getStatus, MailTaskStatusEnum.SENDING)
+                .set(MailTask::getUpdateTime, LocalDateTime.now()));
+    }
+
+    /**
+     * 将指定邮件任务标记为已发送
+     * @param task
+     */
+    public void markSent(MailTask task) {
+        update(new LambdaUpdateWrapper<MailTask>()
+                .eq(MailTask::getId, task.getId())
+                .set(MailTask::getStatus, MailTaskStatusEnum.SENT)
+                .set(MailTask::getLastError, null)
+                .set(MailTask::getUpdateTime, LocalDateTime.now()));
+    }
+
+    /**
+     * 将指定邮件任务标记为取消
+     * @param task
+     * @param reason
+     */
+    public void markCancelled(MailTask task, String reason) {
+        update(new LambdaUpdateWrapper<MailTask>()
+                .eq(MailTask::getId, task.getId())
+                .set(MailTask::getStatus, MailTaskStatusEnum.CANCELLED)
+                .set(MailTask::getLastError, trimError(reason))
+                .set(MailTask::getUpdateTime, LocalDateTime.now()));
+    }
+    
+    /**
+     * 将指定邮件任务标记为失败
+     * @param task
+     * @param e
+     */
+    public void markFailed(MailTask task, Exception e) {
+        int attempts = task.getAttempts() == null ? 0 : task.getAttempts();
+        int nextAttempts = attempts + 1;
+        MailTaskStatusEnum status = nextAttempts >= MAX_ATTEMPTS ?
+                MailTaskStatusEnum.FAILED :
+                MailTaskStatusEnum.PENDING;
+        long delayMinutes = Math.min(60L, 1L << Math.min(nextAttempts, 6));
+
+        update(new LambdaUpdateWrapper<MailTask>()
+                .eq(MailTask::getId, task.getId())
+                .set(MailTask::getStatus, status)
+                .set(MailTask::getAttempts, nextAttempts)
+                .set(MailTask::getLastError, trimError(e.getMessage()))
+                .set(MailTask::getSendAfter, LocalDateTime.now().plusMinutes(delayMinutes))
+                .set(MailTask::getUpdateTime, LocalDateTime.now()));
+    }
+
+    /**
+     * 查询指定评论 id 下是否有待处理邮件任务
+     * @param commentId
+     * @return 是否有待处理邮件任务
+     */
+    public boolean hasOutstandingReplyTasks(Long commentId) {
+        return count(outstandingQuery(commentId, MailTaskTypeEnum.REPLY_SUBSCRIPTION)) > 0;
+    }
+
+    private LambdaQueryWrapper<MailTask> outstandingQuery(Long commentId, MailTaskTypeEnum taskType) {
+        return new LambdaQueryWrapper<MailTask>()
+                .eq(MailTask::getCommentId, commentId)
+                .eq(MailTask::getTaskType, taskType)
+                .in(MailTask::getStatus,
+                        MailTaskStatusEnum.PENDING,
+                        MailTaskStatusEnum.FAILED,
+                        MailTaskStatusEnum.SENDING);
+    }
+
+    private static String trimError(String error) {
+        if (error == null) {
+            return null;
+        }
+        return error.length() > 1000 ? error.substring(0, 1000) : error;
+    }
+}
diff --git a/src/main/java/me/qwq/doghouse/task/MailTaskWorker.java b/src/main/java/me/qwq/doghouse/task/MailTaskWorker.java
new file mode 100644
index 0000000..242b762
--- /dev/null
+++ b/src/main/java/me/qwq/doghouse/task/MailTaskWorker.java
@@ -0,0 +1,65 @@
+package me.qwq.doghouse.task;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Component;
+
+import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
+
+import lombok.extern.slf4j.Slf4j;
+import me.qwq.doghouse.entity.Comment;
+import me.qwq.doghouse.entity.MailTask;
+import me.qwq.doghouse.enums.MailTaskTypeEnum;
+import me.qwq.doghouse.service.CommentService;
+import me.qwq.doghouse.service.MailService;
+import me.qwq.doghouse.service.MailTaskService;
+
+@Component
+@Slf4j
+public class MailTaskWorker {
+
+    @Autowired
+    MailTaskService mailTaskService;
+
+    @Autowired
+    MailService mailService;
+
+    @Autowired
+    CommentService commentService;
+
+    @Scheduled(fixedDelay = 5000L)
+    public void run() {
+        for (MailTask task : mailTaskService.pollDueTasks()) {
+            if (!mailTaskService.markSending(task)) {
+                continue;
+            }
+
+            try {
+                MailService.MailTaskResult result = mailService.executeMailTask(task);
+                if (result == MailService.MailTaskResult.CANCELLED) {
+                    mailTaskService.markCancelled(task, "任务已不满足发送条件");
+                }
+                else {
+                    mailTaskService.markSent(task);
+                    markCommentMailSentIfFinished(task);
+                }
+            }
+            catch (Exception e) {
+                log.error("邮件任务 {} 发送失败", task.getId(), e);
+                mailTaskService.markFailed(task, e);
+            }
+        }
+    }
+
+    private void markCommentMailSentIfFinished(MailTask task) {
+        if (task.getTaskType() != MailTaskTypeEnum.REPLY_SUBSCRIPTION) {
+            return;
+        }
+        if (mailTaskService.hasOutstandingReplyTasks(task.getCommentId())) {
+            return;
+        }
+        commentService.update(new LambdaUpdateWrapper<Comment>()
+                .eq(Comment::getId, task.getCommentId())
+                .set(Comment::isMailSent, true));
+    }
+}
diff --git a/src/main/java/me/qwq/doghouse/util/SessionUtils.java b/src/main/java/me/qwq/doghouse/util/SessionUtils.java
index 90b872d..1da3287 100644
--- a/src/main/java/me/qwq/doghouse/util/SessionUtils.java
+++ b/src/main/java/me/qwq/doghouse/util/SessionUtils.java
@@ -134,9 +134,7 @@ public class SessionUtils {
      * @param id
      */
     public static void addPostId(HttpServletRequest request, Long id) {
-        Set<Long> postIdSet = getPostIdSet(request);
-        postIdSet.add(id);
-        request.getSession().setAttribute(POST_ID_SET, postIdSet);
+        addPostId(request.getSession(), id);
     }
 
     /**
@@ -145,6 +143,7 @@ public class SessionUtils {
      * @param id
      */ 
     public static void addPostId(HttpSession session, Long id) {
+        if (session == null) return;
         Set<Long> postIdSet = getPostIdSet(session);
         postIdSet.add(id);
         session.setAttribute(POST_ID_SET, postIdSet);
@@ -197,22 +196,21 @@ public class SessionUtils {
     }
     
     /**
-     * 对指定 Session 中添加指定评论 ID
-     * @param request
+     * 在指定 Session 中添加指定评论 ID, 使得同 session 用户可以管理自己的评论
+     * @param request 相关请求, 从中提取 session
      * @param id
      */
     public static void addCommentId(HttpServletRequest request, Long id) {
-        Set<Long> commentIdList = getCommentIdSet(request);
-        commentIdList.add(id);
-        request.getSession().setAttribute(COMMENT_ID_LIST, commentIdList);
+        addCommentId(request.getSession(), id);
     }
 
     /**
-     * 对指定 Session 中添加指定评论 ID
-     * @param session
+     * 在指定 Session 中添加指定评论 ID, 使得同 session 用户可以管理自己的评论
+     * @param session 相关 session
      * @param id
      */ 
     public static void addCommentId(HttpSession session, Long id) {
+        if (session == null) return;
         Set<Long> commentIdList = getCommentIdSet(session);
         commentIdList.add(id);
         session.setAttribute(COMMENT_ID_LIST, commentIdList);
diff --git a/src/main/resources/application.yml b/src/main/resources/application.yml
index 95451d6..d917628 100644
--- a/src/main/resources/application.yml
+++ b/src/main/resources/application.yml
@@ -1,4 +1,5 @@
 server:
+  address: 127.0.0.1 # 此处是不开 0.0.0.0, 避免内网访问
   port: 7778
   compression:
     enabled: true
diff --git a/src/main/resources/blog.db b/src/main/resources/blog.db
index 6cd1cdc..f9cb703 100644
Binary files a/src/main/resources/blog.db and b/src/main/resources/blog.db differ
diff --git a/src/main/resources/mapper/MailTaskMapper.xml b/src/main/resources/mapper/MailTaskMapper.xml
new file mode 100644
index 0000000..8ff0881
--- /dev/null
+++ b/src/main/resources/mapper/MailTaskMapper.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
+<mapper namespace="me.qwq.doghouse.dao.MailTaskMapper">
+
+</mapper>
diff --git a/src/main/resources/system/mail/reply-subscription.html b/src/main/resources/system/mail/reply-subscription.html
index 704dfcc..1548c0f 100644
--- a/src/main/resources/system/mail/reply-subscription.html
+++ b/src/main/resources/system/mail/reply-subscription.html
@@ -1,28 +1,27 @@
-<div style="max-width: 800px; text-align: justify">
-<p>
-您在 {{blogName}} 中文章 {{postName}} 下的评论有新回复。
-<br>
-There is a new reply to your comment under post {{postName}} in {{blogName}}.
-<br>
-<blockquote>
-<b>{{author}}</b>: {{content}}<br>
-<a href="{{detailUrl}}" rel="noopener noreferrer" target="_blank">查看详情</a>
-</blockquote>
-</p>
-<p>
+<div style="max-width: 800px; text-align: justify">
+<p>
+您在 <span th:text="${blogName}">博客名</span> 中文章 <span th:text="${postName}">文章标题</span> 下的评论有新回复。
+<br>
+There is a new reply to your comment under post <span th:text="${postName}">post title</span> in <span th:text="${blogName}">blog name</span>.
+<br>
+<blockquote>
+<b th:text="${author}">评论者</b>: <span th:utext="${contentHtml}">评论内容</span><br>
+<a th:href="${detailUrl}" rel="noopener noreferrer" target="_blank">查看详情</a>
+</blockquote>
+</p>
+<p>
 	<i style="color: gray; font-size: small;">
 		本邮件为系统自动发出，请勿回复该邮件。
-		邮件内容仅为转发评论者内容，不代表本博客站长立场。
-		若要退订，请在收到邮件的 24 小时内点击该<a
-		href="{{unsubscribeUrl}}" rel="noopener noreferrer" target="_blank">链接</a>退订。
-		This email is automatically sent by the system.
-		Please do not reply to this email.
-		The content of the email is only for forwarding the
-		commenter's content and does not represent
-		the position of the webmaster of this blog.
-		To unsubscribe, please click this
-		<a href="{{unsubscribeUrl}}" rel="noopener noreferrer" target="_blank">link</a>
-		within 24 hours of receiving the email.
-	</i>
-</p>
-</div>
\ No newline at end of file
+		邮件内容仅为转发评论者内容，不代表本博客站长立场。
+		若要退订，请点击该<a
+		th:href="${unsubscribeUrl}" rel="noopener noreferrer" target="_blank">链接</a>退订。
+		This email is automatically sent by the system.
+		Please do not reply to this email.
+		The content of the email is only for forwarding the
+		commenter's content and does not represent
+		the position of the webmaster of this blog.
+		To unsubscribe, please click this
+		<a th:href="${unsubscribeUrl}" rel="noopener noreferrer" target="_blank">link</a>.
+	</i>
+</p>
+</div>