修复文件存储路径错误的BUG

README.md

@@ -46,7 +46,7 @@ DINGTALK_SUPER_ADMIN_UNION_IDS=
 
 `DINGTALK_CLIENT_ID/SECRET` 填应用的 AppKey/AppSecret；`DINGTALK_CORP_ID` 填企业 CorpId；`DINGTALK_AGENT_ID` 用于标识工作台应用。当前免登接口不使用浏览器 OAuth 回调，但保留回调配置兼容旧入口。未配置免登参数时，普通浏览器仍可使用账号密码登录。
 
-MySQL 建表脚本位于 `backend/schema.sql`。未配置 `DATABASE_URL` 时，开发环境会自动使用 `backend/data/app.db` 运行，便于本地快速验收；上传截图保存在 `backend/data/uploads/screenshots`。
+MySQL 建表脚本位于 `backend/schema.sql`。未配置 `DATABASE_URL` 时，开发环境会自动使用 `backend/data/app.db` 运行，便于本地快速验收。上传截图只保存在服务器文件夹中，不在数据库保留副本。服务器部署时必须通过 `SCREENSHOT_STORAGE_DIR` 指向代码发布目录之外的持久化绝对路径，例如 `/www/wwwroot/wendajia_shared/screenshots`，并对该目录单独备份。目录不存在或不可写时，上传接口会返回明确的存储错误。
 
 ## 问答助手大模型配置
 

backend/.env.example

@@ -1,5 +1,6 @@
-DATABASE_URL=mysql+pymysql://ai_agent_test:WGzc6mKawk@49.233.179.206:3306/wendajia
-SCREENSHOT_STORAGE_DIR=data/uploads/screenshots
+DATABASE_URL=mysql+pymysql://user:password@127.0.0.1:3306/wendajia
+# 服务器建议填写代码目录之外、不会被发布覆盖的绝对路径，并单独备份。
+SCREENSHOT_STORAGE_DIR=/www/wwwroot/wendajia_shared/screenshots
 SECRET_KEY=replace-with-a-long-random-secret
 COOKIE_SECURE=false
 SESSION_HOURS=12

backend/app/screenshot_storage.py

@@ -1,4 +1,5 @@
 import hashlib
+import logging
 import mimetypes
 import uuid
 from pathlib import Path
@@ -7,6 +8,9 @@ from fastapi import HTTPException, Response
 from .config import settings
 
 
+logger = logging.getLogger(__name__)
+
+
 def _safe_extension(filename: str, content_type: str) -> str:
     extension = Path(filename or "").suffix.lower()
     if extension in {".jpg", ".jpeg", ".png", ".webp"}:
@@ -40,10 +44,23 @@ def store_screenshot(data: bytes, filename: str, content_type: str, category: st
 
 
 def screenshot_fields(data: bytes, filename: str, content_type: str, category: str) -> dict:
+    try:
+        file_path = store_screenshot(data, filename, content_type, category)
+    except (OSError, ValueError) as exc:
+        logger.exception(
+            "Screenshot file write failed: category=%s filename=%s storage_dir=%s",
+            category,
+            filename,
+            settings.screenshot_storage_dir,
+        )
+        raise HTTPException(
+            status_code=503,
+            detail="图片存储目录不可用，请联系管理员检查目录配置和写入权限",
+        ) from exc
     return {
         "filename": filename,
         "content_type": content_type,
-        "file_path": store_screenshot(data, filename, content_type, category),
+        "file_path": file_path,
         "image_data": None,
     }
 

backend/scripts/migrate_screenshots_to_files.py

@@ -5,8 +5,8 @@ Run from the project root with::
     python backend/scripts/migrate_screenshots_to_files.py
 
 Each row is committed only after the written file matches the source byte
-length and SHA-256 digest. Re-running is safe: rows with a valid file_path and
-an empty image_data value are skipped.
+length and SHA-256 digest. After verification, the database BLOB is cleared so
+screenshots exist only in the configured server storage directory.
 """
 
 import hashlib
@@ -19,7 +19,7 @@ BACKEND_ROOT = PROJECT_ROOT / "backend"
 if str(BACKEND_ROOT) not in sys.path:
     sys.path.insert(0, str(BACKEND_ROOT))
 
-from sqlalchemy import inspect, select, text  # noqa: E402
+from sqlalchemy import inspect, or_, select, text  # noqa: E402
 
 from app.config import settings  # noqa: E402
 from app.database import SessionLocal, engine  # noqa: E402
@@ -32,8 +32,6 @@ TARGETS = (
     (AskAssignmentBatchScreenshot, "ask_assignment_batch_screenshots", "ask-batches"),
     (AskAssignmentScreenshot, "ask_assignment_screenshots", "ask-assignments"),
 )
-
-
 def ensure_columns() -> None:
     for _model, table, _category in TARGETS:
         columns = {column["name"]: column for column in inspect(engine).get_columns(table)}
@@ -57,7 +55,10 @@ def migrate() -> None:
             with SessionLocal() as db:
                 image = db.scalar(
                     select(model)
-                    .where(model.image_data.is_not(None))
+                    .where(
+                        model.image_data.is_not(None),
+                        or_(model.file_path.is_(None), model.file_path == ""),
+                    )
                     .order_by(model.id)
                     .limit(1)
                 )
@@ -81,6 +82,7 @@ def migrate() -> None:
         print(f"{table}: complete rows={table_rows} bytes={table_bytes}", flush=True)
     print(f"TOTAL rows={migrated_rows} bytes={migrated_bytes}", flush=True)
     print(f"FILES {settings.screenshot_storage_dir.resolve()}", flush=True)
+    print("DATABASE_COPIES CLEARED", flush=True)
 
 
 if __name__ == "__main__":

backend/tests/test_screenshot_storage.py

@@ -0,0 +1,44 @@
+from types import SimpleNamespace
+
+from app import screenshot_storage
+
+
+def test_new_screenshot_is_stored_only_as_server_file(tmp_path, monkeypatch):
+    monkeypatch.setattr(screenshot_storage.settings, "screenshot_storage_dir", tmp_path)
+
+    fields = screenshot_storage.screenshot_fields(
+        b"image-content", "proof.png", "image/png", "answers"
+    )
+
+    assert fields["image_data"] is None
+    assert (tmp_path / fields["file_path"]).read_bytes() == b"image-content"
+
+
+def test_missing_file_falls_back_to_database_copy(tmp_path, monkeypatch):
+    monkeypatch.setattr(screenshot_storage.settings, "screenshot_storage_dir", tmp_path)
+    image = SimpleNamespace(
+        file_path="answers/missing.png",
+        image_data=b"database-backup",
+        content_type="image/png",
+    )
+
+    assert screenshot_storage.screenshot_bytes(image) == b"database-backup"
+
+
+def test_file_write_failure_returns_clear_service_error(tmp_path, monkeypatch):
+    monkeypatch.setattr(screenshot_storage.settings, "screenshot_storage_dir", tmp_path)
+    monkeypatch.setattr(
+        screenshot_storage,
+        "store_screenshot",
+        lambda *args, **kwargs: (_ for _ in ()).throw(PermissionError("read-only")),
+    )
+
+    try:
+        screenshot_storage.screenshot_fields(
+            b"image-content", "proof.png", "image/png", "answers"
+        )
+    except screenshot_storage.HTTPException as exc:
+        assert exc.status_code == 503
+        assert "图片存储目录不可用" in exc.detail
+    else:
+        raise AssertionError("expected screenshot storage error")