我有一个前端和一个服务器后端，我向后端发送一个请求来获取一些图书信息。然后后端调用一个API来获取这些信息，并将其返回给前端。在第一次请求时，一切正常。如果我从前端再发出一个请求，就会产生下面的错误。
我怎样才能做到这一点，使它有可能不断提出一个新的要求，从前端？

node:internal/errors:478
    ErrorCaptureStackTrace(err);
    ^

Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
    at new NodeError (node:internal/errors:387:5)
    at ServerResponse.setHeader (node:_http_outgoing:644:11)
    at ServerResponse.header (/Users/jeff/Documents/myProject/backend/node_modules/express/lib/response.js:794:10)
    at ServerResponse.send (/Users/jeff/Documents/myProject/backend/node_modules/express/lib/response.js:174:12)
    at ServerResponse.json (/Users/jeff/Documents/myProject/backend/node_modules/express/lib/response.js:278:15)
    at file:///Users/jeff/Documents/myProject/backend/controllers/model.js:22:14
    at file:///Users/jeff/Documents/myProject/backend/controllers/model.js:63:10
    at processTicksAndRejections (node:internal/process/task_queues:96:5) {
  code: 'ERR_HTTP_HEADERS_SENT'
}
[nodemon] app crashed - waiting for file changes before starting...

showBooks是来自前端的剩余呼叫的入口点。

export const showBooks = async (req, res) => {

   const books = req.body.books;

   await getBooksInfo(books, (err, results) => {
      if (err) {
         res.send(err);
      } else {
         res.json(results);
      }
   });
}

然后调用getBooksInfo，循环遍历所提供的书籍

const getBooksInfo = async (books, result) => {

   let all_books = [];

   books.forEach(async (book) => {

      if (book.type == "adventure") {

         const on_sale = book.meta.sale;

         if (on_sale == true) {

            let book_authors = book.meta.authors;

            try {
               for (const i in book_authors) { 

                  await book_api(book_authors[i].name, (err, results) => {
                     if (err) {
                        console.log(err);
                     } else {
                        all_books.push(results);
                     }
                  });
               }
            } catch (err) {
               console.log(err);
            }
         }
         result(null, { input: all_books });
      }
   });
}

book_api负责获取有关外部静止点的信息

export const book_api = async (author_name, result) => {

     try {
        const response = await axios.get(`https://book-service.com?author=${author_name}`);
  
        const author_info = response.data.author;
     
         let author = {
            "name" : author_info.name,
            "website" : author_info.website,
         };
        result(null, author);
     } catch (err) {
        result(err, null);
     }
  };