node.js - Node/ Mongoose - 错误 : Can't set headers after they are sent

Question

在我的 Mongoose Nodejs 代码中，我有一个 create 函数，它过去工作得很好，但是在调用该函数时发生了一些事情，它会触发并发出请求，但我收到此错误:

这是我的终端中的错误:

PUT /api/request/create 200 98.981 ms - 1929
events.js:160
      throw er; // Unhandled 'error' event
      ^

错误:发送后无法设置 header 。

这是我的功能:

exports.create = (req, res, next) => {
  const body = req.body;

  const Request = new Requests({
    //customer_id: body.customer_id,
    customer: body.customer,
    tasks: body.tasks,
    submitted_by: body.submitted_by,
    assignees: body.assignees,
    // safety_equipment: body.safety_equipment,
    special_instructions: body.special_instructions,
    area_instructions: body.area_instructions,
    additional_equipment: body.additional_equipment,
    access: body.access,
    training: body.training,
    ppe: body.ppe,
    description: body.description,
    square_footage: body.square_footage,
    flooring_type: body.flooring_type,
    due_date: body.due_date,
    is_converted: body.is_converted,
    quote_amount: body.quote_amount,
    is_billable: body.is_billable,
    budgeted_time: body.budgeted_time,
    site_visit: body.site_visit,
    locations: body.locations,
    job_number: body.job_number
  });

  Request.save( (err, request) => {
    if (err) {
      res.status(401).json({
        message: err
      });
      console.log(err);
    }

      res.status(200).json({
        request
      });

      return next();
  });
}

我的应用程序中还有其他地方使用几乎相同的代码，它们没有任何问题。是否存在某种我在这里没有考虑的竞争条件？

Answer 1

如果 err 为 true，那么您的代码将以状态 401 响应，然后再次尝试以状态 200 响应。所以尝试

 if (err) {
              res.status(401).json({
                message: err
              });
              console.log(err);
            }
// Add else
  else{

              res.status(200).json({
                request
              });
        }