NodeJS-从Post获取MySQL子查询的JSON？

我正在使用下面的控制器使用NodeJS在MySQL中创建一个“audiopost”行

exports.create = (req, res) => {
  if (!req.body) {
    res.status(400).send({
      message: "Content can not be empty!"
    });
  }

  const audiopost = new Audiopost({
    title: req.body.title,
    userid: req.body.userid,
    opid: req.body.opid 
  });

   Audiopost.create(audiopost, (err, data) => {
    if (err)
      res.status(500).send({
        message:
          err.message || "Some error occurred while creating the Audiopost."
      });
    else console.log(data);         
  });
};

创建帖子后，我需要检查是否存在可选标记

  Audiopost.create = (newAudiopost, result) => {
    
  sql.query("INSERT INTO audioposts SET ?", newAudiopost, (err, res) => {
  if (err) {
    console.log("error: ", err);
    result(err, null);
    return;
  } 
    
    sql.query("SELECT tagname, tagid FROM tags WHERE tagname = ?", [tag1], (err, res, fields) => {
    if (err) {
      console.log("error: ", err);
      result(err, null);
      return;
    }
    console.log("found tag1: ", { tag1 });
    result(null, { tag1 });
  })    
  })
});  
};

但是如何从端点获取

tag1

？下面是flatter中HTTP post的代码

final http.Response response = await http.post(
    'http://example.com:3000/createaudiopost',
    headers: <String, String>{
      'Content-Type': 'application/json; charset=UTF-8',
    },
    body: jsonEncode(<String, dynamic>{
      'title': audiotitle,
      'userid': currentuserid.toString(),
      'opid': currentaudioid.toString(),
      'tag1': tag1
    }),
  );

final http.Response=wait http.post(
'http://example.com:3000/createaudiopost',
标题：{
“内容类型”：“应用程序/json；字符集=UTF-8”，
},
正文：JSONECODE({
“标题”：音频标题，
“userid”：currentuserid.toString（），
“opid”：currentaudioid.toString（），
“tag1”：tag1
}),
);