fix: match CHFS preview and listing behavior

chfs-ng/internal/api/server.go

@@ -2,9 +2,14 @@ package api
 
 import (
 	"archive/zip"
+	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
+	"image"
+	_ "image/gif"
+	_ "image/jpeg"
+	"image/png"
 	"io"
 	"mime/multipart"
 	"net"
@@ -19,6 +24,7 @@ import (
 	"chfs-ng/internal/auth"
 	"chfs-ng/internal/opslog"
 	"chfs-ng/internal/storage"
+	"github.com/anthonynsimon/bild/transform"
 	"github.com/emersion/go-webdav"
 )
 
@@ -34,6 +40,7 @@ type Server struct {
 	Allow          string
 	MultiRoot      bool
 	RemoveMode     int
+	ImagePreview   bool
 	Log            *opslog.Logger
 }
 type fileInfo struct {
@@ -463,7 +470,7 @@ func (s *Server) search(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	needle := strings.ToLower(strings.TrimSpace(r.URL.Query().Get("str")))
-	var out []fileInfo
+	out := make([]fileInfo, 0)
 	var walk func(string) error
 	walk = func(dir string) error {
 		items, err := s.Store.List(dir)
@@ -502,16 +509,39 @@ func (s *Server) shared(w http.ResponseWriter, r *http.Request) {
 }
 
 func (s *Server) preview(w http.ResponseWriter, r *http.Request) {
-	if !account(r, s).MaskFor(strings.Trim(r.URL.Query().Get("file"), "/")).HasRead() {
-		http.Error(w, "forbidden", 403)
-		return
-	}
-	file := strings.Trim(r.URL.Query().Get("file"), "/")
+	file := strings.Trim(strings.ReplaceAll(r.URL.Query().Get("file"), "\\", "/"), "/")
 	if file == "" {
 		http.Error(w, "file required", 400)
 		return
 	}
-	s.serveFile(w, r, file, false)
+	if !account(r, s).MaskFor(file).HasRead() {
+		http.Error(w, "forbidden", 403)
+		return
+	}
+	if !s.ImagePreview {
+		writeJSONError(w, http.StatusInternalServerError, "Open image file fail!")
+		return
+	}
+	f, err := s.Store.Open(file)
+	if err != nil {
+		writeJSONError(w, http.StatusInternalServerError, "Open image file fail!")
+		return
+	}
+	defer f.Close()
+	src, _, err := image.Decode(f)
+	if err != nil {
+		writeJSONError(w, http.StatusInternalServerError, "Open image file fail!")
+		return
+	}
+	thumb := transform.Resize(src, 64, 64, transform.Linear)
+	var buf bytes.Buffer
+	if err := png.Encode(&buf, thumb); err != nil {
+		writeJSONError(w, http.StatusInternalServerError, "Open image file fail!")
+		return
+	}
+	w.Header().Set("Cache-Control", "max-age=2592000")
+	w.Header().Set("Content-Type", "image/png")
+	_, _ = w.Write(buf.Bytes())
 }
 
 func (s *Server) fileHandler(w http.ResponseWriter, r *http.Request) {