FastAPI 返回一个空的 SQLAlchemy 作为响应

Question

我有这个功能和其他类似功能（有同样的问题）：

async def update_row_by_id(db: Session, tableOrm, tableModel, object_id:int):
    obj_update = fetch_object_by_id(db, tableOrm, object_id)
    for field in tableModel.model_dump(exclude_unset=True):
        setattr(obj_update, field, getattr(tableModel, field))

    try:
        if(obj_update.updated_by is None):
            obj_update.updated_by = db.query(literal_column("current_user"))
        obj_update.updated_at = datetime.now()
    except AttributeError:
        pass
    try:
        db.commit()
    except (ProgrammingError,IntegrityError, PendingRollbackError) as e:
        db.rollback()
        print(e._message())
        raise HTTPException(status_code = status.HTTP_406_NOT_ACCEPTABLE, detail = e._message())
    return obj_update

它的名字是这样的：

    @router.put(urlIdRoute, status_code=200)
    async def crud_update_by_id(obj_id:int, obj_model:modelBase):
        db = SessionLocal()
        try:
            res = await update_row_by_id(db, orm, obj_model, obj_id)
            return res
        finally:
            db.close()

问题是，在 fastapi/docs 中，当我测试此端点时，它返回 {}，但数据已提交到数据库中。 另一个问题/解决方案是：如果我在 return 语句之前放置 print(obj_update) ，端点将正确返回数据。

为什么我的代码受到 print 语句的影响以及如何修复此问题而不需要放置 print(obj_update)？

我尝试在获取数据时创建async/await，但出现其他错误，这是object_fetch函数：

def fetch_object_by_id(db: Session, tableOrm, object_id:int):
    obj = db.scalar(select(tableOrm).filter_by(id = object_id))
    if obj is None:
        raise common_404_exception(tableOrm.__tablename__, object_id)
    return obj

Answer 1

您的

fetch_object_by_id

需要使用async/await来处理数据库调用

async def fetch_object_by_id(db: Session, tableOrm, object_id:int):
    obj = await db.scalar(select(tableOrm).filter_by(id = object_id))
    if obj is None:
        raise common_404_exception(tableOrm.__tablename__, object_id)
    return obj

然后在您的路线中使用

obj_update = await fetch_object_by_id(db, tableOrm, object_id)