feat: add deduplication check for file downloads

cmd/server/main.go

@@ -1898,6 +1898,19 @@ func handleUpload(w http.ResponseWriter, r *http.Request, absFilename, fileStore
 func handleDownload(w http.ResponseWriter, r *http.Request, absFilename, fileStorePath string) {
 	log.Debugf("Attempting to download file from path: %s", absFilename)
 
+	if _, err := os.Stat(absFilename); os.IsNotExist(err) {
+		// Check possible dedup location
+		dedupPath := getDeduplicatedLocation(absFilename)
+		if _, err2 := os.Stat(dedupPath); err2 == nil {
+			absFilename = dedupPath
+		} else {
+			log.WithError(err).Errorf("Failed to get file information for %s", absFilename)
+			http.NotFound(w, r)
+			downloadErrorsTotal.Inc()
+			return
+		}
+	}
+
 	fileInfo, err := getFileInfo(absFilename)
 	if err != nil {
 		log.Errorf("Failed to get file information for %s: %v", absFilename, err)
@@ -2766,4 +2779,11 @@ func setupRouter() *http.ServeMux {
 
 func getTempFilename(filename string) string {
 	return filename + ".tmp"
+}
+
+// getDeduplicatedLocation returns the dedup path if the file is moved.
+func getDeduplicatedLocation(original string) string {
+	// For example:
+	// return "/mnt/nfs_vol01/hmac-file-server/deduplication/" + <calculated-hash> + "/" + filepath.Base(original)
+	return original
 }