dingdanquanliucheng/backend/app/services/file_service.py

from datetime import datetime, timedelta

from sqlalchemy.exc import SQLAlchemyError
from sqlalchemy.orm import Session

from backend.app.core.config import get_settings
from backend.app.core.error_codes import ErrorCode
from backend.app.core.exceptions import AppException
from backend.app.repositories.file_repository import FileRepository
from backend.app.services.audit_service import audit_service
from backend.app.services.storage_service import storage_service


class FileService:
    def __init__(self) -> None:
        self.settings = get_settings()
        self.repository = FileRepository()
        self.attachments: list[dict] = []
        self.next_attachment_id = 8001

    def create_upload_token(self, payload: dict, session: Session | None = None) -> dict:
        if not payload["file_name"].strip():
            raise AppException(code=ErrorCode.PARAM_ERROR, message="文件名不能为空", status_code=400)
        if not payload["biz_type"].strip():
            raise AppException(code=ErrorCode.PARAM_ERROR, message="业务类型不能为空", status_code=400)

        file_category = self._detect_file_category(payload["file_type"], payload["file_name"])
        self._validate_file_size(file_category, payload["file_size"])
        token_payload = storage_service.create_upload_token(
            payload["biz_type"],
            payload["biz_id"],
            payload["file_name"],
            payload["file_size"],
        )
        token_payload["file_category"] = file_category
        return token_payload

    def save_attachment(self, payload: dict, session: Session | None = None) -> dict:
        if not payload["biz_type"].strip():
            raise AppException(code=ErrorCode.PARAM_ERROR, message="业务类型不能为空", status_code=400)
        if not payload["file_name"].strip():
            raise AppException(code=ErrorCode.PARAM_ERROR, message="文件名不能为空", status_code=400)
        if not payload["file_url"].strip():
            raise AppException(code=ErrorCode.PARAM_ERROR, message="文件地址不能为空", status_code=400)

        file_category = self._detect_file_category(payload["file_type"], payload["file_name"])
        self._validate_file_size(file_category, payload["file_size"])
        object_key = storage_service.extract_object_key(payload["file_url"])
        file_ext = self._extract_file_ext(payload["file_name"])
        self._validate_attachment_file(payload["file_name"], payload["file_url"], object_key)

        if session is not None:
            try:
                attachment = self.repository.create_attachment(
                    session,
                    {
                        "biz_type": payload["biz_type"],
                        "biz_id": payload["biz_id"],
                        "file_name": payload["file_name"],
                        "file_url": payload["file_url"],
                        "file_type": payload["file_type"],
                        "file_size": payload["file_size"],
                        "created_by": None,
                        "storage_provider": "aliyun_oss",
                        "bucket_name": self.settings.aliyun_oss_bucket,
                        "object_key": object_key,
                        "content_type": payload["file_type"],
                        "file_ext": file_ext,
                        "file_category": file_category,
                    },
                )
                audit_service.write_log(
                    session,
                    {
                        "operate_type": "attachment_create",
                        "biz_type": payload["biz_type"],
                        "biz_id": payload["biz_id"],
                        "before_value": None,
                        "after_value": self._map_attachment(attachment),
                        "remark": f"保存附件 {payload['file_name']}",
                    },
                )
                session.commit()
                return self._map_attachment(attachment)
            except AppException:
                session.rollback()
                raise
            except SQLAlchemyError:
                session.rollback()

        attachment = {
            "attachment_id": self.next_attachment_id,
            "biz_type": payload["biz_type"],
            "biz_id": payload["biz_id"],
            "file_name": payload["file_name"],
            "file_url": payload["file_url"],
            "file_type": payload["file_type"],
            "file_size": payload["file_size"],
            "storage_provider": "aliyun_oss",
            "bucket_name": self.settings.aliyun_oss_bucket,
            "object_key": object_key,
            "content_type": payload["file_type"],
            "file_ext": file_ext,
            "file_category": file_category,
            "created_at": datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
        }
        self.next_attachment_id += 1
        self.attachments.append(attachment)
        return attachment

    def _validate_attachment_file(self, file_name: str, file_url: str, object_key: str) -> None:
        expected_name = file_name.strip()
        object_name = object_key.rsplit("/", 1)[-1]
        # 保存附件时再次核对对象 key 与文件名，避免前端绕过上传凭证直接塞入不匹配文件。
        if expected_name and expected_name not in object_name:
            raise AppException(code=ErrorCode.FILE_UPLOAD_FAILED, message="附件文件名与对象地址不匹配", status_code=400)
        if not file_url.startswith(("http://", "https://")):
            raise AppException(code=ErrorCode.FILE_UPLOAD_FAILED, message="附件地址格式不正确", status_code=400)

    def _detect_file_category(self, file_type: str, file_name: str) -> str:
        content_type = (file_type or "").lower()
        suffix = self._extract_file_ext(file_name).lower()
        if content_type.startswith("image/") or suffix in {"jpg", "jpeg", "png", "gif", "webp"}:
            return "image"
        if content_type.startswith("video/") or suffix in {"mp4", "mov", "avi"}:
            return "video"
        if suffix in {"xlsx", "xls", "csv"}:
            return "import"
        return "document"

    def _validate_file_size(self, file_category: str, file_size: int) -> None:
        max_mb = (
            self.settings.oss_upload_max_image_mb
            if file_category == "image"
            else self.settings.oss_upload_max_video_mb
            if file_category == "video"
            else max(self.settings.oss_upload_max_image_mb, self.settings.oss_upload_max_video_mb)
        )
        if file_size > max_mb * 1024 * 1024:
            raise AppException(code=ErrorCode.FILE_UPLOAD_FAILED, message="文件大小超出限制", status_code=400)

    def _extract_file_ext(self, file_name: str) -> str:
        parts = file_name.rsplit(".", 1)
        return parts[1] if len(parts) == 2 else ""

    def _map_attachment(self, attachment) -> dict:
        return {
            "attachment_id": attachment.id,
            "biz_type": attachment.biz_type,
            "biz_id": attachment.biz_id,
            "file_name": attachment.file_name,
            "file_url": attachment.file_url,
            "file_type": attachment.file_type,
            "file_size": attachment.file_size,
            "storage_provider": attachment.storage_provider,
            "bucket_name": attachment.bucket_name,
            "object_key": attachment.object_key,
            "content_type": attachment.content_type,
            "file_ext": attachment.file_ext,
            "file_category": attachment.file_category,
            "created_at": attachment.created_at.strftime("%Y-%m-%d %H:%M:%S") if attachment.created_at else "",
        }


file_service = FileService()