feat: 重构配置管理，集中管理环境变量并优化存储后端实现

utils.py

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+"""
+工具函数模块
+集中管理常用的辅助函数
+"""
+
+from datetime import datetime
+from typing import Optional
+
+
+def format_timestamp(timestamp) -> str:
+    """
+    格式化时间戳为人类可读的格式
+
+    Args:
+        timestamp: 时间戳对象（datetime 或其他）
+
+    Returns:
+        格式化后的时间字符串
+    """
+    if isinstance(timestamp, datetime):
+        return timestamp.strftime("%Y-%m-%d %H:%M:%S")
+    return str(timestamp)
+
+
+def format_file_size(size_bytes: Optional[int]) -> str:
+    """
+    格式化文件大小为人类可读的格式
+
+    Args:
+        size_bytes: 文件大小（字节）
+
+    Returns:
+        格式化后的大小字符串（如 "1.23MB"）
+    """
+    try:
+        if size_bytes is None:
+            return "-"
+        num = float(size_bytes)
+    except (ValueError, TypeError):
+        return "-"
+
+    for unit in ["B", "KB", "MB", "GB", "TB"]:
+        if num < 1024:
+            # 对于字节，显示整数
+            if unit == "B":
+                return f"{int(num)}{unit}"
+            # 其他单位保留两位小数
+            return f"{num:.2f}{unit}"
+        num = num / 1024.0
+    return f"{num:.2f}PB"
+
+
+def get_file_icon(filename: Optional[str]) -> str:
+    """
+    根据文件名返回对应的 Font Awesome 图标类名
+
+    Args:
+        filename: 文件名
+
+    Returns:
+        Font Awesome 图标类名
+    """
+    if not filename:
+        return "fas fa-file"
+
+    ext = filename.lower().split(".")[-1] if "." in filename else ""
+
+    # 定义文件类型映射
+    icon_map = {
+        "fas fa-image": ["jpg", "jpeg", "png", "gif", "bmp", "webp", "svg"],
+        "fas fa-music": ["mp3", "wav", "ogg", "flac", "m4a", "aac"],
+        "fas fa-video": ["mp4", "webm", "avi", "mov", "wmv", "flv", "mkv"],
+        "fas fa-file-alt": ["pdf", "doc", "docx", "txt", "md", "rtf"],
+        "fas fa-file-archive": ["zip", "rar", "7z", "tar", "gz"],
+        "fas fa-file-code": ["py", "js", "html", "css", "java", "cpp", "c", "php"],
+        "fas fa-file-excel": ["xls", "xlsx", "csv"],
+        "fas fa-file-powerpoint": ["ppt", "pptx"],
+    }
+
+    for icon, extensions in icon_map.items():
+        if ext in extensions:
+            return icon
+
+    return "fas fa-file"
+
+
+def normalize_path(path: str, is_folder: bool = False) -> str:
+    """
+    规范化路径格式
+
+    Args:
+        path: 原始路径
+        is_folder: 是否为文件夹
+
+    Returns:
+        规范化后的路径（文件夹以 / 结尾）
+    """
+    path = path.strip()
+    if is_folder and not path.endswith("/"):
+        return path + "/"
+    if not is_folder and path.endswith("/"):
+        return path.rstrip("/")
+    return path
+
+
+def get_file_extension(filename: str) -> str:
+    """
+    获取文件扩展名
+
+    Args:
+        filename: 文件名
+
+    Returns:
+        小写的文件扩展名（不含点）
+    """
+    if not filename or "." not in filename:
+        return ""
+    return filename.lower().split(".")[-1]
+
+
+def is_image_file(filename: str) -> bool:
+    """
+    判断文件是否为图片
+
+    Args:
+        filename: 文件名
+
+    Returns:
+        如果是图片文件返回 True
+    """
+    image_extensions = ["jpg", "jpeg", "png", "gif", "bmp", "webp", "svg", "ico"]
+    return get_file_extension(filename) in image_extensions
+
+
+def is_video_file(filename: str) -> bool:
+    """
+    判断文件是否为视频
+
+    Args:
+        filename: 文件名
+
+    Returns:
+        如果是视频文件返回 True
+    """
+    video_extensions = ["mp4", "webm", "ogg", "mov", "avi", "mkv", "m4v"]
+    return get_file_extension(filename) in video_extensions
+
+
+def is_audio_file(filename: str) -> bool:
+    """
+    判断文件是否为音频
+
+    Args:
+        filename: 文件名
+
+    Returns:
+        如果是音频文件返回 True
+    """
+    audio_extensions = ["mp3", "wav", "ogg", "m4a", "aac", "flac", "opus", "weba"]
+    return get_file_extension(filename) in audio_extensions