修复: SFTP连接首拉不显示与传输挂起

- watcher握手期伪触发致幻影本地列表，根因修复
- 连接探测2.5s超时竞速，握手10s预算
- 30s保活自动掐死半开连接，取连接时剔除已断开
- 副本命名与进度计数抽公共，下载缓存清理去重

app_sftp.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"fmt"
+	"path"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
@@ -124,6 +126,22 @@ func (a *App) SftpDownloadToTempCached(connID string, remotePath string, fileSiz
 	return a.ensureSftpService().DownloadToTempCached(connID, remotePath, fileSize, modTime)
 }
 
+// SftpDownloadToFile 下载远程文件/目录到用户指定目录（流式无上限，重名自动副本），返回本地落地路径
+func (a *App) SftpDownloadToFile(connID string, remotePath string, localDstDir string) (string, error) {
+	emitter := newTransferEmitter(a, "download", path.Base(remotePath))
+	localPath, err := a.ensureSftpService().DownloadToFile(connID, remotePath, localDstDir, emitter.progress)
+	emitter.finish(err)
+	return localPath, err
+}
+
+// SftpUploadFromFile 上传本地文件/目录到远程目录（流式，目录递归，重名自动副本）
+func (a *App) SftpUploadFromFile(connID string, localPath string, remoteDir string) error {
+	emitter := newTransferEmitter(a, "upload", filepath.Base(localPath))
+	err := a.ensureSftpService().UploadFromFile(connID, localPath, remoteDir, emitter.progress)
+	emitter.finish(err)
+	return err
+}
+
 // SftpGetCommonPaths 获取 SFTP 远程主机常用路径
 func (a *App) SftpGetCommonPaths(connID string) (map[string]string, error) {
 	return a.ensureSftpService().GetCommonPaths(connID)

internal/common/utils.go

@@ -1,8 +1,20 @@
 package common
 
 import (
+	"bytes"
+	"crypto/sha256"
 	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"regexp"
 	"runtime"
+	"strings"
+	"sync"
+	"unicode/utf8"
+
+	"golang.org/x/text/encoding/simplifiedchinese"
+	"golang.org/x/text/transform"
 )
 
 // InterfaceSliceToStringSlice 将 []interface{} 安全转换为 []string
@@ -16,8 +28,7 @@ func InterfaceSliceToStringSlice(slice []interface{}) []string {
 	return result
 }
 
-// FormatBytes 格式化字节大小为人类可读格式
-// 例如: 1024 → "1.00 KB", 1048576 → "1.00 MB"
+// FormatBytes 格式化字节大小为人类可读格式（uint64 版本）
 func FormatBytes(bytes uint64) string {
 	const unit = 1024
 	if bytes < unit {
@@ -31,6 +42,104 @@ func FormatBytes(bytes uint64) string {
 	return fmt.Sprintf("%.2f %cB", float64(bytes)/float64(div), "KMGTPE"[exp])
 }
 
+// FormatBytesInt 格式化字节大小（int64 版本，用于文件大小）
+func FormatBytesInt(bytes int64) string {
+	return FormatBytes(uint64(bytes))
+}
+
+// CopyFile 复制文件内容
+func CopyFile(src, dst string) error {
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+
+	out, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	_, err = out.ReadFrom(in)
+	return err
+}
+
+// BytesToString 智能编码转换：UTF-8 直接返回，否则尝试 GBK → UTF-8
+func BytesToString(data []byte) string {
+	if utf8.Valid(data) {
+		return string(data)
+	}
+	reader := transform.NewReader(bytes.NewReader(data), simplifiedchinese.GBK.NewDecoder())
+	decoded, err := io.ReadAll(reader)
+	if err != nil || !utf8.Valid(decoded) {
+		return string(data)
+	}
+	return string(decoded)
+}
+
+var (
+	htmlResRegex    = regexp.MustCompile(`(?:src|href|data-src|data-url|poster)=["']([^"']+)["']`)
+	htmlSrcsetRegex = regexp.MustCompile(`srcset\s*=\s*["']([^"']+)["']`)
+	htmlCssUrlRe    = regexp.MustCompile(`url\(\s*["']?([^"')]+)["']?\s*\)`)
+)
+
+// parseSrcsetUrls 从 srcset 属性值中提取各 URL
+// srcset 格式: "small.jpg 480w, large.jpg 1024w" → ["small.jpg", "large.jpg"]
+func parseSrcsetUrls(srcset string) []string {
+	var urls []string
+	for _, candidate := range strings.Split(srcset, ",") {
+		parts := strings.Fields(strings.TrimSpace(candidate))
+		if len(parts) > 0 {
+			urls = append(urls, parts[0])
+		}
+	}
+	return urls
+}
+
+// ExtractHtmlResources 从 HTML 内容提取资源路径
+func ExtractHtmlResources(html string) []string {
+	seen := make(map[string]bool)
+	var resources []string
+	add := func(v string) {
+		v = strings.TrimSpace(v)
+		if v != "" && !seen[v] {
+			seen[v] = true
+			resources = append(resources, v)
+		}
+	}
+	for _, m := range htmlResRegex.FindAllStringSubmatch(html, -1) {
+		if len(m) > 1 {
+			add(m[1])
+		}
+	}
+	for _, m := range htmlSrcsetRegex.FindAllStringSubmatch(html, -1) {
+		if len(m) > 1 {
+			for _, u := range parseSrcsetUrls(m[1]) {
+				add(u)
+			}
+		}
+	}
+	for _, m := range htmlCssUrlRe.FindAllStringSubmatch(html, -1) {
+		if len(m) > 1 {
+			add(m[1])
+		}
+	}
+	return resources
+}
+
+// ShouldSkipResource 判断资源路径是否应跳过
+func ShouldSkipResource(p string) bool {
+	return strings.HasPrefix(p, "data:") ||
+		strings.HasPrefix(p, "http://") ||
+		strings.HasPrefix(p, "https://") ||
+		strings.HasPrefix(p, "//") ||
+		strings.HasPrefix(p, "#") ||
+		strings.HasPrefix(p, "javascript:") ||
+		strings.HasPrefix(p, "mailto:") ||
+		strings.HasPrefix(p, "blob:")
+}
+
 // Contains 检查切片是否包含元素
 func Contains[T comparable](slice []T, item T) bool {
 	for _, s := range slice {
@@ -61,3 +170,81 @@ func IsWindows() bool {
 	return runtime.GOOS == "windows"
 }
 
+// siteCacheDir 返回站点预览的确定性缓存目录路径
+func SiteCacheDir(transport, connID, remotePath string, fileSize int64, modTime string) string {
+	h := sha256.New()
+	h.Write([]byte(fmt.Sprintf("site:%s:%s:%s:%d:%s", transport, connID, remotePath, fileSize, modTime)))
+	hash := fmt.Sprintf("%x", h.Sum(nil))[:16]
+	return filepath.Join(os.TempDir(), "u-desk-cache", "site-"+hash)
+}
+
+// 站点预览补充下载限制（sftp 与 ossdrv 共用）
+const (
+	MaxSupplementFiles     = 50              // 每目录补充下载文件数上限
+	MaxSupplementFileSize  = 5 << 20         // 单文件补充下载大小上限（5MB）
+	SiteDownloadConcurrency = 8              // 相对路径资源并行下载并发数
+)
+
+// RunConcurrent 以最多 limit 个并发执行 tasks，全部完成后返回
+// fn 在独立 goroutine 中运行，需自行处理错误与共享状态的加锁
+func RunConcurrent[T any](tasks []T, limit int, fn func(t T)) {
+	if len(tasks) == 0 || limit <= 0 {
+		return
+	}
+	if limit > len(tasks) {
+		limit = len(tasks)
+	}
+	sem := make(chan struct{}, limit)
+	var wg sync.WaitGroup
+	for _, task := range tasks {
+		sem <- struct{}{}
+		wg.Add(1)
+		go func(t T) {
+			defer func() { <-sem; wg.Done() }()
+			fn(t)
+		}(task)
+	}
+	wg.Wait()
+}
+
+// UniqueName 返回不与现有条目冲突的文件名：重名时追加「 - 副本」「 - 副本 (2)」后缀（扩展名前插入）。
+// exists 报告候选文件名是否已被占用（本地文件系统与 SFTP 各自提供实现）。
+func UniqueName(name string, exists func(candidate string) (bool, error)) (string, error) {
+	taken, err := exists(name)
+	if err != nil {
+		return "", err
+	}
+	if !taken {
+		return name, nil
+	}
+	ext := filepath.Ext(name)
+	base := strings.TrimSuffix(name, ext)
+	for i := 1; ; i++ {
+		suffix := " - 副本"
+		if i > 1 {
+			suffix = fmt.Sprintf(" - 副本 (%d)", i)
+		}
+		candidate := base + suffix + ext
+		taken, err := exists(candidate)
+		if err != nil {
+			return "", err
+		}
+		if !taken {
+			return candidate, nil
+		}
+	}
+}
+
+// CountingReader 包装读取器，按实际读取字节数回调 OnN（n > 0 时）
+type CountingReader struct {
+	R   io.Reader
+	OnN func(n int64)
+}
+
+func (cr *CountingReader) Read(buf []byte) (int, error) {
+	n, err := cr.R.Read(buf)
+	if n > 0 {
+		cr.OnN(int64(n))
+	}
+	return n, err
+}

internal/oss/aliyun/client.go

@@ -11,6 +11,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"sort"
 	"strings"
 	"time"
 
@@ -122,14 +123,7 @@ func (c *Client) canonicalizeOSSHeaders(headers map[string]string) string {
 	}
 
 	// 按字典序排序
-	// 这里简单处理，实际应该用排序算法
-	for i := 0; i < len(ossHeaders); i++ {
-		for j := i + 1; j < len(ossHeaders); j++ {
-			if ossHeaders[i] > ossHeaders[j] {
-				ossHeaders[i], ossHeaders[j] = ossHeaders[j], ossHeaders[i]
-			}
-		}
-	}
+	sort.Strings(ossHeaders)
 
 	// 拼接结果
 	if len(ossHeaders) == 0 {
@@ -315,13 +309,14 @@ func (c *Client) GetFileInfo(ctx context.Context, key string) (*oss.FileInfo, er
 	size := resp.ContentLength
 	etag := resp.Header.Get("ETag")
 	contentType := resp.Header.Get("Content-Type")
-	_ = resp.Header.Get("Last-Modified") // 预留，可能需要解析时间
+	lastModified, _ := http.ParseTime(resp.Header.Get("Last-Modified"))
 
 	return &oss.FileInfo{
 		Key:          key,
 		Size:         size,
 		ETag:         strings.Trim(etag, "\""),
 		ContentType:  contentType,
+		LastModified: lastModified,
 	}, nil
 }
 
@@ -487,26 +482,23 @@ func (c *Client) DeleteMultiple(ctx context.Context, keys []string) (*oss.Delete
 
 // GetSignedURL 获取预签名URL
 func (c *Client) GetSignedURL(ctx context.Context, key string, expiresIn time.Duration) (string, error) {
-	// 阿里云 OSS 使用签名 URL
-	// 格式: ?OSSAccessKeyId=xxx&Expires=xxx&Signature=xxx
 	expiration := time.Now().Add(expiresIn).Unix()
 
-	// 构建签名
+	// 签名计算用原始 key（不编码）
 	path := "/" + c.config.Bucket + "/" + key
 	stringToSign := "GET\n\n\n" + fmt.Sprintf("%d", expiration) + "\n" + path
 	h := hmac.New(sha1.New, []byte(c.config.AccessKeySecret))
 	h.Write([]byte(stringToSign))
-	signature := base64.StdEncoding.EncodeToString(h.Sum(nil))
-	signature = strings.TrimRight(signature, "=") // URL Safe
+	signature := base64.URLEncoding.EncodeToString(h.Sum(nil))
 
 	scheme := "https://"
 	if !c.config.UseHTTPS {
 		scheme = "http://"
 	}
-	baseURL := scheme + c.config.Bucket + "." + c.config.Endpoint + "/" + key
+	baseURL := scheme + c.config.Bucket + "." + c.config.Endpoint + "/" + url.PathEscape(key)
 
 	signedURL := fmt.Sprintf("%s?OSSAccessKeyId=%s&Expires=%d&Signature=%s",
-		baseURL, c.config.AccessKeyID, expiration, signature)
+		baseURL, url.QueryEscape(c.config.AccessKeyID), expiration, url.QueryEscape(signature))
 
 	return signedURL, nil
 }

internal/ossdrv/service.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/base64"
 	"fmt"
+	"log"
 	"os"
 	"path"
 	"path/filepath"
@@ -12,6 +13,7 @@ import (
 	"sync"
 	"time"
 
+	"u-desk/internal/common"
 	"u-desk/internal/filesystem"
 	"u-desk/internal/oss"
 	"u-desk/internal/oss/aliyun"
@@ -112,17 +114,12 @@ func (m *Manager) getOrCreateBucketClient(provider, bucket, region string) (oss.
 			UseHTTPS:  true,
 		})
 	case "aliyun":
-		// 有桶级 region 时不传账户 Endpoint，让 NewClient 从 region 派生正确的 endpoint
-		ep := c.Endpoint
-		if region != "" {
-			ep = ""
-		}
 		client, err = aliyun.NewClient(&aliyun.Config{
 			AccessKeyID:     c.AccessKey,
 			AccessKeySecret: c.SecretKey,
 			Bucket:          bucket,
 			Region:          region,
-			Endpoint:        ep,
+			Endpoint:        c.Endpoint,
 			UseHTTPS:        true,
 		})
 	default:
@@ -367,14 +364,14 @@ func (s *Service) ReadFile(connID string, rawPath string) (string, error) {
 		return "", fmt.Errorf("获取文件信息失败: %w", err)
 	}
 	if info.Size > maxSize {
-		return "", fmt.Errorf("文件过大 (%s)，超过 %d 限制", filesystem.FormatBytes(info.Size), maxSize)
+		return "", fmt.Errorf("文件过大 (%s)，超过 %d 限制", common.FormatBytesInt(info.Size), maxSize)
 	}
 
 	var buf bytes.Buffer
 	if err := c.Download(ctx, key, &buf); err != nil {
 		return "", fmt.Errorf("读取文件失败: %w", err)
 	}
-	return filesystem.BytesToString(buf.Bytes()), nil
+	return common.BytesToString(buf.Bytes()), nil
 }
 
 // WriteFile 写入文件内容
@@ -442,7 +439,7 @@ func (s *Service) GetFileInfo(connID string, rawPath string) (map[string]interfa
 		"name":     path.Base(info.Key),
 		"path":     bucketPrefix + info.Key,
 		"size":     info.Size,
-		"size_str": filesystem.FormatBytes(info.Size),
+		"size_str": common.FormatBytesInt(info.Size),
 		"is_dir":   strings.HasSuffix(info.Key, "/"),
 		"mod_time": info.LastModified.Format("2006-01-02 15:04:05"),
 	}, nil
@@ -474,7 +471,7 @@ func (s *Service) CreateDir(connID string, rawPath string) (*filesystem.FileOper
 		Path:    "/" + bucket + "/" + key,
 		Name:    name,
 		IsDir:   true,
-		SizeStr: filesystem.FormatBytes(0),
+		SizeStr: common.FormatBytesInt(0),
 	}, nil
 }
 
@@ -499,7 +496,7 @@ func (s *Service) CreateFile(connID string, rawPath string) (*filesystem.FileOpe
 		Path:    "/" + bucket + "/" + key,
 		Name:    path.Base(key),
 		IsDir:   false,
-		SizeStr: filesystem.FormatBytes(0),
+		SizeStr: common.FormatBytesInt(0),
 	}, nil
 }
 
@@ -661,23 +658,37 @@ func (s *Service) DownloadSiteForPreview(connID string, rawPath string) (string,
 
 	ctx := context.Background()
 
-	// 1. 创建临时目录，保留 OSS 目录结构
-	tmpDir, err := os.MkdirTemp("", "udesk-site-*")
-	if err != nil {
-		return "", fmt.Errorf("创建临时目录失败: %w", err)
+	// 1. 缓存检查：用确定性路径，命中直接返回
+	htmlInfo, _ := c.GetFileInfo(ctx, key)
+	var htmlSize int64
+	var htmlModTime string
+	if htmlInfo != nil {
+		htmlSize = htmlInfo.Size
+		htmlModTime = htmlInfo.LastModified.Format("2006-01-02 15:04:05")
 	}
+	cacheDir := common.SiteCacheDir("oss", connID, rawPath, htmlSize, htmlModTime)
 
 	keyDir := path.Dir(key)
-	var htmlLocalPath string
+	var htmlCachePath string
 	if keyDir != "" && keyDir != "." {
-		htmlLocalPath = filepath.Join(tmpDir, filepath.FromSlash(keyDir), path.Base(key))
+		htmlCachePath = filepath.Join(cacheDir, filepath.FromSlash(keyDir), path.Base(key))
+	} else {
+		htmlCachePath = filepath.Join(cacheDir, path.Base(key))
+	}
+	if _, err := os.Stat(htmlCachePath); err == nil {
+		return htmlCachePath, nil // 缓存命中
+	}
+	os.RemoveAll(cacheDir)
+	if err := os.MkdirAll(cacheDir, 0755); err != nil {
+		return "", fmt.Errorf("创建缓存目录失败: %w", err)
+	}
+	tmpDir := cacheDir
+
+	htmlLocalPath := htmlCachePath
 	if err := os.MkdirAll(filepath.Dir(htmlLocalPath), 0755); err != nil {
 		os.RemoveAll(tmpDir)
 		return "", fmt.Errorf("创建目录失败: %w", err)
 	}
-	} else {
-		htmlLocalPath = filepath.Join(tmpDir, path.Base(key))
-	}
 
 	// 2. 下载 HTML
 	f, err := os.Create(htmlLocalPath)
@@ -697,7 +708,7 @@ func (s *Service) DownloadSiteForPreview(connID string, rawPath string) (string,
 	if err != nil {
 		return htmlLocalPath, nil // HTML 已下载，资源解析失败不影响
 	}
-	resources := filesystem.ExtractHtmlResources(string(htmlContent))
+	resources := common.ExtractHtmlResources(string(htmlContent))
 
 	// 4. 下载资源
 	htmlOssDir := keyDir
@@ -717,8 +728,11 @@ func (s *Service) DownloadSiteForPreview(connID string, rawPath string) (string,
 		}
 	}
 
+	// 绝对路径资源：串行嗅探 siteRoot，相对路径：并行下载
+	type relativeTask struct{ ossKey, localPath string }
+	var relativeTasks []relativeTask
 	for _, resPath := range resources {
-		if filesystem.ShouldSkipResource(resPath) {
+		if common.ShouldSkipResource(resPath) {
 			continue
 		}
 
@@ -743,11 +757,19 @@ func (s *Service) DownloadSiteForPreview(connID string, rawPath string) (string,
 			} else {
 				ossKey = cleanPath
 			}
-			if downloadResource(c, ctx, ossKey, localPath) {
-				recordDir(ossKey)
+			relativeTasks = append(relativeTasks, relativeTask{ossKey, localPath})
 		}
 	}
+
+	// 相对路径资源并行下载（recordDir 需加锁，多 goroutine 并发回调）
+	var mu sync.Mutex
+	common.RunConcurrent(relativeTasks, common.SiteDownloadConcurrency, func(t relativeTask) {
+		if downloadResource(c, ctx, t.ossKey, t.localPath) {
+			mu.Lock()
+			recordDir(t.ossKey)
+			mu.Unlock()
 		}
+	})
 	// 5. 补充下载已发现目录中的剩余文件（覆盖 webpack 动态 chunk 等）
 	for _, dir := range discoveredDirs {
 		supplementDir(c, ctx, dir, tmpDir, siteRoot)
@@ -756,7 +778,6 @@ func (s *Service) DownloadSiteForPreview(connID string, rawPath string) (string,
 	return htmlLocalPath, nil
 }
 
-// resolveAbsoluteResourcePath 解析绝对路径资源，首次嗅探网站根，后续直接使用
 // resolveAndDownload 解析绝对路径并下载：首次嗅探网站根，后续直接使用
 func resolveAndDownload(c oss.OSSProvider, ctx context.Context, htmlOssDir string, cleanPath string, localPath string, siteRoot *string) string {
 	if *siteRoot != "" {
@@ -815,37 +836,48 @@ func downloadResource(c oss.OSSProvider, ctx context.Context, ossKey string, loc
 }
 
 // supplementDir 补充下载远程目录中尚未下载的文件（只处理已知资源所在目录）
+// 数量与单文件大小上限见 common.MaxSupplementFiles / common.MaxSupplementFileSize
 func supplementDir(c oss.OSSProvider, ctx context.Context, remoteDir string, tmpDir string, siteRoot string) {
 	prefix := remoteDir + "/"
-	result, err := c.ListFiles(ctx, &oss.ListOptions{Prefix: prefix, MaxKeys: 200})
+	var marker string
+	count := 0
+	for count < common.MaxSupplementFiles {
+		result, err := c.ListFiles(ctx, &oss.ListOptions{Prefix: prefix, MaxKeys: 200, Marker: marker})
 		if err != nil {
 			return
 		}
 		for _, f := range result.Files {
-		if strings.HasSuffix(f.Key, "/") || f.Size == 0 {
+			if strings.HasSuffix(f.Key, "/") || f.Size == 0 || f.Size > common.MaxSupplementFileSize {
 				continue
 			}
+			if count >= common.MaxSupplementFiles {
+				log.Printf("[站点下载] 补充扫描达到上限: count=%d", common.MaxSupplementFiles)
+				return
+			}
 			localPath := filepath.Join(tmpDir, filepath.FromSlash(f.Key))
 			if _, err := os.Stat(localPath); err == nil {
 				continue
 			}
-		downloadResource(c, ctx, f.Key, localPath)
+			if downloadResource(c, ctx, f.Key, localPath) {
+				count++
+			}
+		}
+		if !result.IsTruncated {
+			return
+		}
+		marker = result.NextMarker
 	}
 }
 
 // DownloadToTemp 下载文件到本地临时目录（带 SQLite 缓存）
 func (s *Service) DownloadToTemp(connID string, rawPath string) (string, error) {
-	// 先获取文件元信息用于缓存键，确保远程文件变更时能淘汰旧缓存
-	var fileSize int64
-	var modTime string
-	if info, err := s.GetFileInfo(connID, rawPath); err == nil {
-		if sz, ok := info["size"].(int64); ok {
-			fileSize = sz
-		}
-		if mt, ok := info["mod_time"].(string); ok {
-			modTime = mt
-		}
+	// 获取文件元信息用于缓存键
+	info, err := s.GetFileInfo(connID, rawPath)
+	if err != nil {
+		return "", fmt.Errorf("获取文件信息失败: %w", err)
 	}
+	fileSize, _ := info["size"].(int64)
+	modTime, _ := info["mod_time"].(string)
 	return storage.DownloadToTempCached("oss", connID, rawPath, fileSize, modTime, func() (string, error) {
 		return s.downloadToTempDirect(connID, rawPath)
 	})
@@ -920,7 +952,7 @@ func toOssOperationResult(m map[string]interface{}, isDir bool) *filesystem.File
 		Path:    p,
 		Name:    name,
 		Size:    size,
-		SizeStr: filesystem.FormatBytes(size),
+		SizeStr: common.FormatBytesInt(size),
 		IsDir:   isDir,
 		ModTime: modTime,
 	}

internal/service/update.go

@@ -240,7 +240,7 @@ func replaceExecutableFile(newFilePath, execPath string) error {
 	}
 
 	// Unix-like: 直接替换
-	if err := copyFile(newFilePath, execPath); err != nil {
+	if err := common.CopyFile(newFilePath, execPath); err != nil {
 		return fmt.Errorf("复制文件失败: %v", err)
 	}
 	return os.Chmod(execPath, 0755)
@@ -256,13 +256,13 @@ func replaceExecutableFileWindows(newFilePath, execPath string) error {
 	os.Remove(newExecPathTemp)
 
 	// 复制新文件到临时位置
-	if err := copyFile(newFilePath, newExecPathTemp); err != nil {
+	if err := common.CopyFile(newFilePath, newExecPathTemp); err != nil {
 		return fmt.Errorf("复制新文件失败: %v", err)
 	}
 
 	// 尝试重命名当前文件（如果失败，说明文件正在使用）
 	if err := os.Rename(execPath, oldExecPath); err != nil {
-		return nil
+		return fmt.Errorf("当前文件正在使用，无法替换: %w", err)
 	}
 
 	// 替换文件
@@ -350,7 +350,7 @@ func rollbackFromBackup(backupPath string) error {
 	if err != nil {
 		return err
 	}
-	return copyFile(backupPath, execPath)
+	return common.CopyFile(backupPath, execPath)
 }
 
 // BackupApplication 备份当前应用
@@ -369,27 +369,21 @@ func BackupApplication() (string, error) {
 	backupFileName := fmt.Sprintf("u-desk-backup-%s%s", timestamp, filepath.Ext(execPath))
 	backupPath := filepath.Join(backupDir, backupFileName)
 
-	if err := copyFile(execPath, backupPath); err != nil {
+	if err := common.CopyFile(execPath, backupPath); err != nil {
 		return "", fmt.Errorf("复制文件失败: %v", err)
 	}
 
 	return backupPath, nil
 }
 
-// copyFile 复制文件
-func copyFile(src, dst string) error {
-	sourceFile, err := os.Open(src)
+// ReplacePendingFile 启动时完成上次更新遗留的 exe 替换。
+// 此时进程刚启动，exe 文件无占用，可安全完成上次因文件占用未完成的替换，
+// 并清理残留的 .old 备份。
+func ReplacePendingFile() {
+	execPath, err := os.Executable()
 	if err != nil {
-		return err
+		return
 	}
-	defer sourceFile.Close()
-
-	destFile, err := os.Create(dst)
-	if err != nil {
-		return err
-	}
-	defer destFile.Close()
-
-	_, err = destFile.ReadFrom(sourceFile)
-	return err
+	_ = replacePendingFile(execPath) // 完成遗留的 .new -> exe 替换
+	os.Remove(execPath + ".old")     // 清理残留备份
 }

internal/sftp/client.go

@@ -11,11 +11,22 @@ import (
 	"golang.org/x/crypto/ssh"
 )
 
+// 连接建立全流程（拨号+认证+SFTP 子系统）的总超时预算
+const connectTimeout = 10 * time.Second
+
+// 保活参数：周期发送 keepalive 并等待回复，超过 keepaliveReplyWait 未回复判定连接已死
+const (
+	keepaliveInterval  = 30 * time.Second
+	keepaliveReplyWait = 30 * time.Second
+)
+
 // Client SFTP 客户端封装（单连接）
 type Client struct {
 	config    *Config
 	client    *sftp.Client
 	sshClient *ssh.Client
+	stopKeep  chan struct{} // 当前 SSH 连接保活循环的停止信号
+	closed    bool          // 保活失败或显式关闭后置位，供取连接时剔除
 	mu        sync.Mutex
 }
 
@@ -73,6 +84,11 @@ func (m *Manager) Disconnect(host string, port int) {
 	}
 }
 
+// Evict 从连接池剔除连接（底层已断开，仅移除不重复关闭）
+func (m *Manager) Evict(connID string) {
+	m.clients.Delete(connID)
+}
+
 // Shutdown 关闭所有连接
 func (m *Manager) Shutdown() {
 	m.clients.Range(func(key, value any) bool {
@@ -84,7 +100,18 @@ func (m *Manager) Shutdown() {
 
 // --- 内部 ---
 
+// newClient 建立连接并启动保活循环
 func newClient(config *Config) (*Client, error) {
+	c, err := buildClient(config)
+	if err != nil {
+		return nil, err
+	}
+	c.startKeepalive()
+	return c, nil
+}
+
+// buildClient 拨号+认证+SFTP 子系统建立（全程受 connectTimeout 约束），不启动保活
+func buildClient(config *Config) (*Client, error) {
 	sshConfig := &ssh.ClientConfig{
 		Config: ssh.Config{
 			KeyExchanges: []string{
@@ -131,10 +158,13 @@ func newClient(config *Config) (*Client, error) {
 	}
 
 	addr := fmt.Sprintf("%s:%d", config.Host, config.Port)
-	sshConn, err := net.DialTimeout("tcp", addr, config.Timeout)
+	// 拨号与认证、SFTP 子系统握手共享同一总超时预算，认证阶段无界挂起由 deadline 掐断
+	deadline := time.Now().Add(connectTimeout)
+	sshConn, err := net.DialTimeout("tcp", addr, connectTimeout)
 	if err != nil {
 		return nil, &ConnectionError{Op: "dial", Err: err}
 	}
+	sshConn.SetDeadline(deadline)
 
 	sshConnConn, chans, reqs, err := ssh.NewClientConn(sshConn, addr, sshConfig)
 	if err != nil {
@@ -143,7 +173,9 @@ func newClient(config *Config) (*Client, error) {
 	}
 
 	sshClient := ssh.NewClient(sshConnConn, chans, reqs)
+
 	sftpClient, err := sftp.NewClient(sshClient)
+	sshConn.SetDeadline(time.Time{})
 	if err != nil {
 		sshClient.Close()
 		return nil, &ConnectionError{Op: "sftp_init", Err: err}
@@ -156,6 +188,62 @@ func newClient(config *Config) (*Client, error) {
 	}, nil
 }
 
+// startKeepalive 启动当前 SSH 连接的保活循环（须持有 c.mu 或独占 Client 时调用）
+// 防止空闲连接被 NAT/防火墙杀掉；探测失败时关闭连接并置位 closed，唤醒所有阻塞中的操作
+func (c *Client) startKeepalive() {
+	stop := make(chan struct{})
+	sshClient := c.sshClient
+	c.stopKeep = stop
+	go func() {
+		t := time.NewTicker(keepaliveInterval)
+		defer t.Stop()
+		for {
+			select {
+			case <-stop:
+				return
+			case <-t.C:
+			}
+			if !sshKeepalive(sshClient, keepaliveReplyWait) {
+				c.markDead(sshClient)
+				return
+			}
+		}
+	}()
+}
+
+// sshKeepalive 发送一次 keepalive 请求并限时等待回复，超时或出错视作连接已死
+func sshKeepalive(sshClient *ssh.Client, wait time.Duration) bool {
+	done := make(chan error, 1)
+	go func() {
+		_, _, err := sshClient.SendRequest("keepalive@openssh.com", true, nil)
+		done <- err
+	}()
+	select {
+	case err := <-done:
+		return err == nil
+	case <-time.After(wait):
+		return false
+	}
+}
+
+// markDead 标记连接死亡并关闭底层资源
+// 仅当容器仍持有该 SSH 连接时生效，避免误杀 reconnect 换上的新连接
+func (c *Client) markDead(sshClient *ssh.Client) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.sshClient != sshClient {
+		return
+	}
+	c.closeLocked()
+}
+
+// IsClosed 连接是否已断开（保活失败或显式关闭）
+func (c *Client) IsClosed() bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return c.closed
+}
+
 // IsHealthy 检查连接是否健康（先取引用再解锁，避免持锁做 I/O）
 func (c *Client) IsHealthy() bool {
 	c.mu.Lock()
@@ -204,7 +292,8 @@ func (c *Client) WithRetry(fn func(*sftp.Client) error) error {
 }
 
 func (c *Client) reconnect() error {
-	nc, err := newClient(c.config)
+	// 用 buildClient 而非 newClient，避免保活循环绑定到即将丢弃的临时容器
+	nc, err := buildClient(c.config)
 	if err != nil {
 		return err
 	}
@@ -213,6 +302,8 @@ func (c *Client) reconnect() error {
 	c.closeLocked()
 	c.client = nc.client
 	c.sshClient = nc.sshClient
+	c.closed = false
+	c.startKeepalive()
 	return nil
 }
 
@@ -223,6 +314,10 @@ func (c *Client) Close() {
 }
 
 func (c *Client) closeLocked() {
+	if c.stopKeep != nil {
+		close(c.stopKeep)
+		c.stopKeep = nil
+	}
 	if c.client != nil {
 		c.client.Close()
 		c.client = nil
@@ -231,6 +326,7 @@ func (c *Client) closeLocked() {
 		c.sshClient.Close()
 		c.sshClient = nil
 	}
+	c.closed = true
 }
 
 // RunCommand 通过 SSH Session 执行远程命令，返回 stdout

internal/sftp/service.go

@@ -1,8 +1,12 @@
 package sftp
 
 import (
+	"sync"
 	"encoding/base64"
+	"errors"
 	"fmt"
+	"log"
+	"log/slog"
 	"io"
 	"io/fs"
 	"os"
@@ -12,6 +16,7 @@ import (
 	"strings"
 	"time"
 
+	"u-desk/internal/common"
 	"u-desk/internal/filesystem"
 	"u-desk/internal/storage"
 
@@ -84,7 +89,7 @@ func (s *Service) ReadFile(connID string, filePath string) (string, error) {
 		fi, e := sc.Stat(filePath)
 		if e != nil { return e }
 		if fi.Size() > maxSize {
-			return fmt.Errorf("文件过大 (%s)，超过 %d 限制", filesystem.FormatBytes(fi.Size()), maxSize)
+			return fmt.Errorf("文件过大 (%s)，超过 %d 限制", common.FormatBytesInt(fi.Size()), maxSize)
 		}
 		return nil
 	})
@@ -105,7 +110,7 @@ func (s *Service) ReadFile(connID string, filePath string) (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("读取文件失败: %w", err)
 	}
-	return filesystem.BytesToString(data), nil
+	return common.BytesToString(data), nil
 }
 
 func (s *Service) WriteFile(connID string, filePath string, content string) error {
@@ -168,7 +173,7 @@ func (s *Service) GetFileInfo(connID string, filePath string) (map[string]interf
 		"name":     info.Name(),
 		"path":     toUnixPath(filePath),
 		"size":     info.Size(),
-		"size_str": filesystem.FormatBytes(info.Size()),
+		"size_str": common.FormatBytesInt(info.Size()),
 		"is_dir":   info.IsDir(),
 		"mod_time": info.ModTime().Format("2006-01-02 15:04:05"),
 		"mode":     info.Mode().String(),
@@ -209,7 +214,10 @@ func (s *Service) CreateFile(connID string, filePath string) (*filesystem.FileOp
 		return nil, fmt.Errorf("创建文件失败: %w", err)
 	}
 
-	infoMap, _ := s.GetFileInfo(connID, filePath)
+	infoMap, err := s.GetFileInfo(connID, filePath)
+	if err != nil {
+		slog.Warn("创建后获取详情失败", "path", filePath, "error", err)
+	}
 	return toFileOperationResult(infoMap, false), nil
 }
 
@@ -291,7 +299,7 @@ func (s *Service) downloadToTempDirect(connID string, remotePath string) (string
 		fi, e := sc.Stat(remotePath)
 		if e != nil { return e }
 		if fi.Size() > maxPreviewSize {
-			return fmt.Errorf("预览文件过大: %s", filesystem.FormatBytes(fi.Size()))
+			return fmt.Errorf("预览文件过大: %s", common.FormatBytesInt(fi.Size()))
 		}
 		return nil
 	})
@@ -345,11 +353,20 @@ func (s *Service) DownloadSiteForPreview(connID string, remotePath string) (stri
 		return "", err
 	}
 
-	// 1. 创建临时目录
-	tmpDir, err := os.MkdirTemp("", "udesk-sftp-site-*")
-	if err != nil {
-		return "", fmt.Errorf("创建临时目录失败: %w", err)
+	// 1. 缓存检查：用确定性路径，命中直接返回
+	htmlInfo, _ := s.GetFileInfo(connID, remotePath)
+	htmlSize, _ := htmlInfo["size"].(int64)
+	htmlModTime, _ := htmlInfo["mod_time"].(string)
+	cacheDir := common.SiteCacheDir("sftp", connID, remotePath, htmlSize, htmlModTime)
+	htmlCachePath := filepath.Join(cacheDir, filepath.FromSlash(path.Dir(remotePath)), path.Base(remotePath))
+	if _, err := os.Stat(htmlCachePath); err == nil {
+		return htmlCachePath, nil // 缓存命中
 	}
+	os.RemoveAll(cacheDir) // 清理旧缓存
+	if err := os.MkdirAll(cacheDir, 0755); err != nil {
+		return "", fmt.Errorf("创建缓存目录失败: %w", err)
+	}
+	tmpDir := cacheDir
 
 	// 2. 确定远程网站根目录（从 HTML 路径推断）
 	keyDir := path.Dir(remotePath)
@@ -379,7 +396,7 @@ func (s *Service) DownloadSiteForPreview(connID string, remotePath string) (stri
 	if err != nil {
 		return htmlLocalPath, nil
 	}
-	resources := filesystem.ExtractHtmlResources(string(htmlContent))
+	resources := common.ExtractHtmlResources(string(htmlContent))
 
 	// 5. 下载静态引用资源（嗅探网站根）
 	htmlRemoteDir := keyDir
@@ -399,8 +416,11 @@ func (s *Service) DownloadSiteForPreview(connID string, remotePath string) (stri
 		}
 	}
 
+	// 绝对路径资源：串行嗅探 siteRoot，相对路径：并行下载
+	type relativeTask struct{ remoteKey, localPath string }
+	var relativeTasks []relativeTask
 	for _, resPath := range resources {
-		if filesystem.ShouldSkipResource(resPath) {
+		if common.ShouldSkipResource(resPath) {
 			continue
 		}
 		isAbsolute := strings.HasPrefix(resPath, "/")
@@ -418,11 +438,19 @@ func (s *Service) DownloadSiteForPreview(connID string, remotePath string) (stri
 			}
 		} else {
 			remoteKey := path.Join(htmlRemoteDir, cleanPath)
-			if s.sftpTryDownload(c, remoteKey, localPath) {
-				recordDir(remoteKey)
+			relativeTasks = append(relativeTasks, relativeTask{remoteKey, localPath})
 		}
 	}
+
+	// 相对路径资源并行下载（recordDir 需加锁，多 goroutine 并发回调）
+	var mu sync.Mutex
+	common.RunConcurrent(relativeTasks, common.SiteDownloadConcurrency, func(t relativeTask) {
+		if s.sftpTryDownload(c, t.remoteKey, t.localPath) {
+			mu.Lock()
+			recordDir(t.remoteKey)
+			mu.Unlock()
 		}
+	})
 
 	// 6. 补充下载已发现目录中的剩余文件（覆盖动态 chunk 等）
 	for _, dir := range discoveredDirs {
@@ -494,6 +522,7 @@ func sftpResolveAndDownload(s *Service, c *Client, htmlDir string, cleanPath str
 }
 
 // sftpSupplementDir 补充下载远程目录中尚未下载的文件（只处理已知资源所在目录）
+// 数量与单文件大小上限见 common.MaxSupplementFiles / common.MaxSupplementFileSize
 func sftpSupplementDir(s *Service, c *Client, remoteDir string, tmpDir string, siteRoot string) {
 	var entries []fs.FileInfo
 	err := c.WithRetry(func(sc *sftpclient.Client) error {
@@ -504,19 +533,254 @@ func sftpSupplementDir(s *Service, c *Client, remoteDir string, tmpDir string, s
 	if err != nil {
 		return
 	}
+	count := 0
 	for _, entry := range entries {
-		if entry.IsDir() || entry.Size() == 0 {
+		if entry.IsDir() || entry.Size() == 0 || entry.Size() > common.MaxSupplementFileSize {
 			continue
 		}
+		if count >= common.MaxSupplementFiles {
+			log.Printf("[站点下载] 补充扫描达到上限: count=%d", common.MaxSupplementFiles)
+			break
+		}
 		fullPath := path.Join(remoteDir, entry.Name())
 		localPath := filepath.Join(tmpDir, filepath.FromSlash(fullPath))
 		if _, err := os.Stat(localPath); err == nil {
 			continue
 		}
 		s.sftpTryDownload(c, fullPath, localPath)
+		count++
 	}
 }
 
+// DownloadToFile 下载远程文件/目录到用户指定的本地目录（流式，无大小上限），返回实际落地路径
+// 目标重名自动追加「 - 副本」后缀；onProgress 按累计字节回调（name 为当前文件名）
+func (s *Service) DownloadToFile(connID, remotePath, localDstDir string, onProgress func(fileName string, copied, total int64)) (string, error) {
+	c, err := s.getClient(connID)
+	if err != nil {
+		return "", err
+	}
+
+	var info fs.FileInfo
+	err = c.WithRetry(func(sc *sftpclient.Client) error {
+		var e error
+		info, e = sc.Stat(remotePath)
+		return e
+	})
+	if err != nil {
+		return "", fmt.Errorf("获取远程文件信息失败: %w", err)
+	}
+
+	// 单文件：直接流式落地
+	if !info.IsDir() {
+		dstPath := filesystem.UniquePath(filepath.Join(localDstDir, path.Base(remotePath)))
+		var copied int64
+		if err := s.downloadFileTo(c, remotePath, dstPath, &copied, info.Size(), onProgress); err != nil {
+			return "", err
+		}
+		return dstPath, nil
+	}
+
+	// 目录：先收集远端文件清单并统计总大小
+	type remoteEntry struct {
+		remote, local string
+		size          int64
+	}
+	var entries []remoteEntry
+	var total int64
+	var walk func(dir, localDir string) error
+	walk = func(dir, localDir string) error {
+		var list []fs.FileInfo
+		err := c.WithRetry(func(sc *sftpclient.Client) error {
+			var e error
+			list, e = sc.ReadDir(dir)
+			return e
+		})
+		if err != nil {
+			return err
+		}
+		for _, fi := range list {
+			rp := path.Join(dir, fi.Name())
+			lp := filepath.Join(localDir, fi.Name())
+			if fi.IsDir() {
+				if err := walk(rp, lp); err != nil {
+					return err
+				}
+			} else if fi.Mode().IsRegular() {
+				entries = append(entries, remoteEntry{rp, lp, fi.Size()})
+				total += fi.Size()
+			}
+		}
+		return nil
+	}
+
+	dstDir := filesystem.UniquePath(filepath.Join(localDstDir, path.Base(remotePath)))
+	if err := walk(remotePath, dstDir); err != nil {
+		return "", fmt.Errorf("遍历远程目录失败: %w", err)
+	}
+
+	var copied int64
+	for _, e := range entries {
+		if err := s.downloadFileTo(c, e.remote, e.local, &copied, total, onProgress); err != nil {
+			return "", err
+		}
+	}
+	return dstDir, nil
+}
+
+// downloadFileTo 流式下载单个远程文件，进度按累计字节回调
+func (s *Service) downloadFileTo(c *Client, remotePath, localPath string, copied *int64, total int64, onProgress func(fileName string, copied, total int64)) error {
+	if err := os.MkdirAll(filepath.Dir(localPath), 0755); err != nil {
+		return fmt.Errorf("创建本地目录失败: %w", err)
+	}
+	return c.WithRetry(func(sc *sftpclient.Client) error {
+		src, err := sc.Open(remotePath)
+		if err != nil {
+			return err
+		}
+		defer src.Close()
+		dst, err := os.Create(localPath)
+		if err != nil {
+			return err
+		}
+		defer dst.Close()
+		var reader io.Reader = src
+		if onProgress != nil {
+			reader = &common.CountingReader{R: src, OnN: func(n int64) {
+				*copied += n
+				onProgress(path.Base(remotePath), *copied, total)
+			}}
+		}
+		_, err = io.Copy(dst, reader)
+		return err
+	})
+}
+
+// UploadFromFile 上传本地文件/目录到远程目录（流式），远端重名自动追加副本后缀
+func (s *Service) UploadFromFile(connID, localPath, remoteDir string, onProgress func(fileName string, copied, total int64)) error {
+	c, err := s.getClient(connID)
+	if err != nil {
+		return err
+	}
+
+	info, err := os.Stat(localPath)
+	if err != nil {
+		return fmt.Errorf("本地路径不存在: %w", err)
+	}
+
+	// 单文件：直接流式上传
+	if !info.IsDir() {
+		remotePath, err := s.uniqueRemotePath(c, path.Join(remoteDir, filepath.Base(localPath)))
+		if err != nil {
+			return err
+		}
+		var copied int64
+		return s.uploadFileTo(c, localPath, remotePath, &copied, info.Size(), onProgress)
+	}
+
+	// 目录：本地清单 + 总大小（相对根路径，远端落地根确定后再拼完整路径）
+	type localEntry struct {
+		local, rel string
+		size       int64
+	}
+	var files []localEntry
+	var total int64
+	err = filepath.WalkDir(localPath, func(p string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if !d.Type().IsRegular() {
+			return nil
+		}
+		fi, e := d.Info()
+		if e != nil {
+			return e
+		}
+		rel, e := filepath.Rel(localPath, p)
+		if e != nil {
+			return e
+		}
+		files = append(files, localEntry{p, filepath.ToSlash(rel), fi.Size()})
+		total += fi.Size()
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("遍历本地目录失败: %w", err)
+	}
+
+	remoteRoot, err := s.uniqueRemotePath(c, path.Join(remoteDir, filepath.Base(localPath)))
+	if err != nil {
+		return err
+	}
+	var copied int64
+	for _, f := range files {
+		if err := s.uploadFileTo(c, f.local, path.Join(remoteRoot, f.rel), &copied, total, onProgress); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// uploadFileTo 流式上传单个本地文件（自动创建远端父目录），进度按累计字节回调
+func (s *Service) uploadFileTo(c *Client, localPath, remotePath string, copied *int64, total int64, onProgress func(fileName string, copied, total int64)) error {
+	return c.WithRetry(func(sc *sftpclient.Client) error {
+		if err := sc.MkdirAll(path.Dir(remotePath)); err != nil {
+			return err
+		}
+		src, err := os.Open(localPath)
+		if err != nil {
+			return err
+		}
+		defer src.Close()
+		dst, err := sc.Create(remotePath)
+		if err != nil {
+			return err
+		}
+		defer dst.Close()
+		var reader io.Reader = src
+		if onProgress != nil {
+			reader = &common.CountingReader{R: src, OnN: func(n int64) {
+				*copied += n
+				onProgress(filepath.Base(localPath), *copied, total)
+			}}
+		}
+		_, err = io.Copy(dst, reader)
+		return err
+	})
+}
+
+// uniqueRemotePath 远端重名时追加「 - 副本」「 - 副本 (2)」后缀（扩展名前插入）
+// 命名循环复用 common.UniqueName（与本地 UniquePath 同源）
+func (s *Service) uniqueRemotePath(c *Client, remotePath string) (string, error) {
+	dir := path.Dir(remotePath)
+	unique, err := common.UniqueName(path.Base(remotePath), func(candidate string) (bool, error) {
+		return s.remoteExists(c, path.Join(dir, candidate))
+	})
+	if err != nil {
+		return "", err
+	}
+	return path.Join(dir, unique), nil
+}
+
+// remoteExists 判断远程路径是否存在（区分不存在与网络错误）
+func (s *Service) remoteExists(c *Client, p string) (bool, error) {
+	var notExist bool
+	err := c.WithRetry(func(sc *sftpclient.Client) error {
+		_, e := sc.Stat(p)
+		if e == nil {
+			return nil
+		}
+		if errors.Is(e, fs.ErrNotExist) {
+			notExist = true
+			return nil
+		}
+		return e
+	})
+	if err != nil {
+		return false, err
+	}
+	return !notExist, nil
+}
+
 // GetCommonPaths 返回 SFTP 远程主机常用路径
 func (s *Service) GetCommonPaths(connID string) (map[string]string, error) {
 	c := s.manager.GetClient(connID)
@@ -676,6 +940,11 @@ func (s *Service) getClient(connID string) (*Client, error) {
 	if c == nil {
 		return nil, fmt.Errorf("SFTP 连接不存在: %s", connID)
 	}
+	if c.IsClosed() {
+		// 保活失败或显式断开置位，剔除死连接避免后续操作继续挂在上面
+		s.manager.Evict(connID)
+		return nil, fmt.Errorf("SFTP 连接已断开，请重新连接: %s", connID)
+	}
 	return c, nil
 }
 
@@ -694,7 +963,7 @@ func toFileOperationResult(m map[string]interface{}, isDir bool) *filesystem.Fil
 		Path:    p,
 		Name:    name,
 		Size:    size,
-		SizeStr: filesystem.FormatBytes(size),
+		SizeStr: common.FormatBytesInt(size),
 		IsDir:   isDir,
 		ModTime: modTime,
 		Mode:    mode,

internal/storage/download_cache.go

@@ -4,8 +4,10 @@ import (
 	"crypto/sha256"
 	"fmt"
 	"log/slog"
+	"u-desk/internal/common"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"u-desk/internal/storage/models"
@@ -129,7 +131,7 @@ func DownloadToTempCached(transport, connID, remotePath string, fileSize int64,
 	// 移动文件到确定性路径
 	if err := os.Rename(tempPath, deterministicPath); err != nil {
 		// Rename 可能跨卷失败，尝试 Copy+Delete
-		if copyFile(tempPath, deterministicPath) != nil {
+		if common.CopyFile(tempPath, deterministicPath) != nil {
 			SaveCache(transport, connID, remotePath, fileSize, modTime, tempPath)
 			return tempPath, nil
 		}
@@ -166,23 +168,37 @@ func deterministicCachePath(transport, connID, remotePath string, fileSize int64
 	return filepath.Join(cacheTempDir, fileName), nil
 }
 
-// copyFile 复制文件内容
-func copyFile(src, dst string) error {
-	in, err := os.Open(src)
-	if err != nil {
-		return err
+// CleanupSiteCacheDirs 清理超过 24h 的站点预览缓存目录
+// os.TempDir() 下两个前缀是旧版 MkdirTemp 随机目录残留（sftp 与 oss 各一种）
+func CleanupSiteCacheDirs() {
+	cutoff := time.Now().Add(-downloadCacheTTL)
+	cleaned := cleanupExpiredDirs(cacheTempDir, "site-", cutoff)
+	cleaned += cleanupExpiredDirs(os.TempDir(), "udesk-site-", cutoff)
+	cleaned += cleanupExpiredDirs(os.TempDir(), "udesk-sftp-site-", cutoff)
+	if cleaned > 0 {
+		slog.Info("清理过期站点缓存目录", "count", cleaned)
 	}
-	defer in.Close()
+}
 
-	out, err := os.Create(dst)
+// cleanupExpiredDirs 删除 dir 下修改时间早于 cutoff 的 prefix 前缀子目录，返回清理数量
+func cleanupExpiredDirs(dir, prefix string, cutoff time.Time) int {
+	entries, err := os.ReadDir(dir)
 	if err != nil {
-		return err
+		return 0
 	}
-	defer out.Close()
-
-	if _, err := out.ReadFrom(in); err != nil {
-		os.Remove(dst)
-		return err
+	cleaned := 0
+	for _, e := range entries {
+		if !e.IsDir() || !strings.HasPrefix(e.Name(), prefix) {
+			continue
+		}
+		info, err := e.Info()
+		if err != nil {
+			continue
+		}
+		if info.ModTime().Before(cutoff) {
+			os.RemoveAll(filepath.Join(dir, e.Name()))
+			cleaned++
+		}
 	}
-	return nil
+	return cleaned
 }

internal/storage/sqlite.go

@@ -61,6 +61,8 @@ func InitFast() (*gorm.DB, error) {
 		db.Exec("UPDATE connection_profiles SET provider = type, type = 'oss' WHERE type IN ('qiniu', 'aliyun')")
 		// 为旧 BGM 播放列表补充 profile_id（找第一个 OSS profile）
 		db.Exec("UPDATE bgm_playlist SET profile_id = (SELECT CAST(id AS VARCHAR) FROM connection_profiles WHERE type = 'oss' LIMIT 1) WHERE (profile_id = '' OR profile_id IS NULL) AND path NOT LIKE '%:'")
+		// 清理历史版本 id 断链重复 INSERT 堆积的重复服务器配置，保留每组 id 最小的一行
+		db.Exec("DELETE FROM connection_profiles WHERE id NOT IN (SELECT MIN(id) FROM connection_profiles GROUP BY name, type, host, port, bucket)")
 		globalDB = db
 	})
 	if initErr != nil {