抛出新的 ERR_HTTP_HEADERS_SENT('set'); ^ 错误 [ERR_HTTP_HEADERS_SENT]：发送到客户端后无法设置标头

Question

我正在尝试将附件发送到 API 端点 UploadFxPLink，但我不断收到以下错误：

Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
    at new NodeError (node:internal/errors:399:5)
    at ServerResponse.setHeader (node:_http_outgoing:645:11)
    at ServerResponse.header (D:\NIDC\BL1\node_modules\express\lib\response.js:771:10)
    at ServerResponse.send (D:\NIDC\BL1\node_modules\express\lib\response.js:170:12)
    at ServerResponse.json (D:\NIDC\BL1\node_modules\express\lib\response.js:267:15)
    at ServerResponse.send (D:\NIDC\BL1\node_modules\express\lib\response.js:158:21)
    at Request._callback (D:\NIDC\BL1\ors.js:2848:11)
    at self.callback (D:\NIDC\BL1\node_modules\request\request.js:185:22)
    at Request.emit (node:events:513:28)
    at Request.onRequestError (D:\NIDC\BL1\node_modules\request\request.js:877:8) {
  code: 'ERR_HTTP_HEADERS_SENT'
}

我理解此错误通常意味着在发送响应后设置标头（如状态代码或内容类型），但我检查了我的代码并确保为每个路径返回响应。

相关代码如下：

app.post('/UploadFxP', function (req, res) {
  var trackngNo = req.session.TrackingNo;
  var attachmentId = req.body.attachmentId;
  var trackNo = req.body.trackNo;
  var userId = req.session.userID;
  var token = req.session.token;
  var atachment = req.body.atachment;
  var attachment = atachment.replace("data:application/pdf;base64,", "");

  console.log('trackingNo: ', trackngNo)
  if (req.session.userID) {
    request({
      url: UploadFxPLink,
      method: 'POST',
      json: {
        trackNo: trackNo,
        trackngNo: trackngNo,
        userId: userId,
        attachmentId: attachmentId,
        atachment: attachment,
        token: token
      },
      headers: {
        'Authorization': `Bearer ${token}`
      }
    }, function (error, response, body) {
      if (error) {
        console.log("Failed to UploadFxP " + error);
        return res.send({ "failed": "failed" });  // added return here
      }

      return res.send({ "success": "success" });  // added return here
    });
  } else {
    res.redirect('/');
  }
});

Answer 1

尝试更换

  if (error) {
    console.log("Failed to UploadFxP " + error);
    return res.send({ "failed": "failed" });  // added return here
  }

  return res.send({ "success": "success" });  // added return here

与

  if (error) {
    console.log("Failed to UploadFxP " + error);
    res.send({ "failed": "failed" });  // added return here
  }
  else {res.send({ "success": "success" });  // added return here}