feat(screenshots): serve thumbnails while keeping original for preview and copy

routes/api_screenshots.py

@@ -11,12 +11,21 @@ from app_config import get_config
 from app_security import is_safe_path
 from flask import Blueprint, jsonify, send_from_directory
 from flask_login import current_user, login_required
+from PIL import Image, ImageOps
 from services.client_log import log_to_client
 from services.time_utils import BEIJING_TZ
 
 config = get_config()
 SCREENSHOTS_DIR = config.SCREENSHOTS_DIR
 _IMAGE_EXTENSIONS = (".png", ".jpg", ".jpeg")
+_THUMBNAIL_DIR = os.path.join(SCREENSHOTS_DIR, ".thumbs")
+_THUMBNAIL_MAX_SIZE = (480, 270)
+_THUMBNAIL_QUALITY = 80
+
+try:
+    _RESAMPLE_FILTER = Image.Resampling.LANCZOS
+except AttributeError:  # Pillow<9 fallback
+    _RESAMPLE_FILTER = Image.LANCZOS
 
 api_screenshots_bp = Blueprint("api_screenshots", __name__)
 
@@ -49,6 +58,48 @@ def _build_display_name(filename: str) -> str:
     return filename
 
 
+def _thumbnail_name(filename: str) -> str:
+    stem, _ = os.path.splitext(filename)
+    return f"{stem}.thumb.jpg"
+
+
+def _thumbnail_path(filename: str) -> str:
+    return os.path.join(_THUMBNAIL_DIR, _thumbnail_name(filename))
+
+
+def _ensure_thumbnail(source_path: str, thumb_path: str) -> bool:
+    if not os.path.exists(source_path):
+        return False
+
+    source_mtime = os.path.getmtime(source_path)
+    if os.path.exists(thumb_path) and os.path.getmtime(thumb_path) >= source_mtime:
+        return True
+
+    os.makedirs(_THUMBNAIL_DIR, exist_ok=True)
+
+    with Image.open(source_path) as image:
+        image = ImageOps.exif_transpose(image)
+        if image.mode != "RGB":
+            image = image.convert("RGB")
+        image.thumbnail(_THUMBNAIL_MAX_SIZE, _RESAMPLE_FILTER)
+        image.save(
+            thumb_path,
+            format="JPEG",
+            quality=_THUMBNAIL_QUALITY,
+            optimize=True,
+            progressive=True,
+        )
+
+    os.utime(thumb_path, (source_mtime, source_mtime))
+    return True
+
+
+def _remove_thumbnail(filename: str) -> None:
+    thumb_path = _thumbnail_path(filename)
+    if os.path.exists(thumb_path):
+        os.remove(thumb_path)
+
+
 @api_screenshots_bp.route("/api/screenshots", methods=["GET"])
 @login_required
 def get_screenshots():
@@ -85,7 +136,7 @@ def get_screenshots():
 @api_screenshots_bp.route("/screenshots/<filename>")
 @login_required
 def serve_screenshot(filename):
-    """提供截图文件访问"""
+    """提供原图文件访问"""
     user_id = current_user.id
     username_prefix = _get_user_prefix(user_id)
 
@@ -98,6 +149,34 @@ def serve_screenshot(filename):
     return send_from_directory(SCREENSHOTS_DIR, filename)
 
 
+@api_screenshots_bp.route("/screenshots/thumb/<filename>")
+@login_required
+def serve_screenshot_thumbnail(filename):
+    """提供缩略图访问（失败时自动回退原图）"""
+    user_id = current_user.id
+    username_prefix = _get_user_prefix(user_id)
+
+    if not _is_user_screenshot(filename, username_prefix):
+        return jsonify({"error": "无权访问"}), 403
+
+    if not is_safe_path(SCREENSHOTS_DIR, filename):
+        return jsonify({"error": "非法路径"}), 403
+
+    source_path = os.path.join(SCREENSHOTS_DIR, filename)
+    if not os.path.exists(source_path):
+        return jsonify({"error": "文件不存在"}), 404
+
+    thumb_path = _thumbnail_path(filename)
+
+    try:
+        if _ensure_thumbnail(source_path, thumb_path) and os.path.exists(thumb_path):
+            return send_from_directory(_THUMBNAIL_DIR, os.path.basename(thumb_path), max_age=86400, conditional=True)
+    except Exception:
+        pass
+
+    return send_from_directory(SCREENSHOTS_DIR, filename, max_age=3600, conditional=True)
+
+
 @api_screenshots_bp.route("/api/screenshots/<filename>", methods=["DELETE"])
 @login_required
 def delete_screenshot(filename):
@@ -115,6 +194,7 @@ def delete_screenshot(filename):
         filepath = os.path.join(SCREENSHOTS_DIR, filename)
         if os.path.exists(filepath):
             os.remove(filepath)
+            _remove_thumbnail(filename)
             log_to_client(f"删除截图: {filename}", user_id)
             return jsonify({"success": True})
         return jsonify({"error": "文件不存在"}), 404
@@ -133,6 +213,7 @@ def clear_all_screenshots():
         deleted_count = 0
         for entry in _iter_user_screenshot_entries(username_prefix):
             os.remove(entry.path)
+            _remove_thumbnail(entry.name)
             deleted_count += 1
 
         log_to_client(f"清理了 {deleted_count} 个截图文件", user_id)