feat: 重构配置管理，集中管理环境变量并优化存储后端实现

config.py

@@ -0,0 +1,83 @@
+"""
+配置管理模块
+集中管理所有环境变量和应用配置
+"""
+
+import os
+from typing import Optional
+
+import dotenv
+
+# 加载环境变量
+dotenv.load_dotenv()
+
+
+class Config:
+    """应用配置类"""
+
+    # 存储配置
+    STORAGE_TYPE: str = os.getenv("STORAGE_TYPE", "").lower()
+
+    # R2 配置
+    R2_ACCOUNT_ID: Optional[str] = os.getenv("R2_ACCOUNT_ID")
+    R2_ACCESS_KEY_ID: Optional[str] = os.getenv("R2_ACCESS_KEY_ID")
+    R2_SECRET_ACCESS_KEY: Optional[str] = os.getenv("R2_SECRET_ACCESS_KEY")
+    R2_BUCKET_NAME: Optional[str] = os.getenv("R2_BUCKET_NAME")
+    R2_PUBLIC_DOMAIN: Optional[str] = os.getenv("R2_PUBLIC_DOMAIN")
+
+    # GitHub 配置
+    GITHUB_TOKEN: Optional[str] = os.getenv("GITHUB_TOKEN")
+    GITHUB_REPO: Optional[str] = os.getenv("GITHUB_REPO")  # 格式: owner/repo
+    GITHUB_BRANCH: str = os.getenv("GITHUB_BRANCH", "main")
+
+    # 应用配置
+    HOST: str = os.getenv("HOST", "0.0.0.0")
+    PORT: int = int(os.getenv("PORT", "5000"))
+    DEBUG: bool = os.getenv("DEBUG", "false").lower() == "true"
+
+    # 缩略图配置
+    THUMB_TTL_SECONDS: int = int(os.getenv("THUMB_TTL_SECONDS", "3600"))
+    THUMB_SIZE: tuple[int, int] = (300, 300)  # 缩略图尺寸
+
+    # URL过期时间配置
+    PRESIGNED_URL_EXPIRES: int = int(os.getenv("PRESIGNED_URL_EXPIRES", "3600"))
+
+    @classmethod
+    def validate(cls) -> None:
+        """验证必需的配置项是否已设置"""
+        if not cls.STORAGE_TYPE:
+            raise ValueError("STORAGE_TYPE environment variable is not set. Supported types: r2, github")
+
+        if cls.STORAGE_TYPE == "r2":
+            required = ["R2_ACCOUNT_ID", "R2_ACCESS_KEY_ID", "R2_SECRET_ACCESS_KEY", "R2_BUCKET_NAME"]
+            missing = [key for key in required if not getattr(cls, key)]
+            if missing:
+                raise ValueError(f"Missing required R2 configuration: {', '.join(missing)}")
+
+        elif cls.STORAGE_TYPE == "github":
+            required = ["GITHUB_TOKEN", "GITHUB_REPO"]
+            missing = [key for key in required if not getattr(cls, key)]
+            if missing:
+                raise ValueError(f"Missing required GitHub configuration: {', '.join(missing)}")
+
+        elif cls.STORAGE_TYPE not in ["r2", "github"]:
+            raise ValueError(f"Unsupported storage type: {cls.STORAGE_TYPE}. Supported types: r2, github")
+
+    @classmethod
+    def get_storage_config(cls) -> dict:
+        """获取当前存储类型的配置字典"""
+        if cls.STORAGE_TYPE == "r2":
+            return {
+                "account_id": cls.R2_ACCOUNT_ID,
+                "access_key_id": cls.R2_ACCESS_KEY_ID,
+                "secret_access_key": cls.R2_SECRET_ACCESS_KEY,
+                "bucket_name": cls.R2_BUCKET_NAME,
+                "public_domain": cls.R2_PUBLIC_DOMAIN,
+            }
+        elif cls.STORAGE_TYPE == "github":
+            return {
+                "token": cls.GITHUB_TOKEN,
+                "repo": cls.GITHUB_REPO,
+                "branch": cls.GITHUB_BRANCH,
+            }
+        return {}