Question

新手到Python 3.5以及新的async和await功能

以下代码仅返回将来的对象。如何从数据库中获取实际的书籍项目并将其写入json？什么是使用异步等待和电机龙卷风的最佳做法？

async def get(self, book_id=None):
    if book_id:
        book = await self.get_book(book_id)
        self.write(json_util.dumps(book.result()))
    else:
        self.write("Need a book id")

async def get_book(self, book_id):
    book = self.db.books.find_one({"_id":ObjectId(book_id)})
    return book

Answer 1

不需要＆＃34;结果（）＆＃34;。因为你的＆＃34;得到＆＃34;方法是一个本地协程（它用＆＃34; async def＆＃34;定义），然后使用＆＃34; await＆＃34;意味着结果已经返回给您：

async def get(self, book_id=None):
    if book_id:
        # Correct: "await" resolves the Future.
        book = await self.get_book(book_id)
        # No resolve(): "book" is already resolved to a dict.
        self.write(json_util.dumps(book))
    else:
        self.write("Need a book id")

但是你也必须＆＃34;等待＆＃34;未来＆＃34; get_book＆＃34;为了在返回之前解决它：

async def get_book(self, book_id):
    book = await self.db.books.find_one({"_id":ObjectId(book_id)})
    return book

与龙卷风和电机同步使用

1 个答案: