Question

我正在尝试获取目录中的电影列表，解析标题，获取TMDB上的电影信息，而不是检查电影信息是否存储在mysql数据库中，如果未存储，则将信息插入数据库。

我正在使用NodeJS/Express和mysql。

到目前为止，这是我的代码：

exports.checkForMovies = function (req, res, next) {
  const testFolder = './test/';
  var movieList = [];
  var movieResultsPromise = [];
  var movieResults = [];

  fs.readdirSync(testFolder).forEach(file => {
    movieList.push(tnp(file));
  });

  movieList.forEach(movie => {
    var waitPromise = searchTMDB(movie.title);
    movieResultsPromise.push(waitPromise);
  });

  Promise.all(movieResultsPromise).then(result => {
    movieResults = result;

    movieResults.forEach(movie => {
      checkMoviesInDB(movie.id, (err, data) => {
        if (err) {
          console.log(err)
        }

        if (data && data.update === true) {

          var movieObj = {
            m_tmdb_id: movie.id
          };

          insertMoviesToDB(movieObj, (resp, err) => {
            if (err) {
              console.log(err);
            } else {
              return res.json(resp);
            }
          });
        } else {
          return res.json(data);
        }
      });
    });
  });
}

function checkMoviesInDB(id, cb) {
  var sql = "SELECT * FROM ?? WHERE m_tmdb_id = ?"
  var table = ['movie', id];

  sql = mysql.format(sql, table);

  connection.query(sql, function (err, rows) {
    if (err) {
      return cb(err);
    }

    if (rows.length > 0) {
      return cb(null, {
        success: true,
        update: false,
        message: 'Movies up to date!'
      })
    } else {
      return cb(null, {
        update: true,
        message: 'Updating database!'
      })
    }
  });
}

function insertMoviesToDB(movie, cb) {
  var sql = "INSERT INTO ?? SET ?";
  var table = ['movie', movie];

  sql = mysql.format(sql, table);

  connection.query(sql, function (err, rows) {
    if (err) {
      return cb(err);
    } else {
      return cb(null, {
        success: true,
        message: 'Movie database updated!'
      })
    }
  });
}

function searchTMDB(title) {
  return new Promise((resolve, reject) => {
    https.get(config.tmdbURL + title, response => {
      var body = "";
      response.setEncoding("utf8");

      response.on("data", data => {
        body += data;
      });
      response.on("end", () => {
        body = JSON.parse(body);
        resolve(body.results[0]);
      });
      response.on("error", (err) => {
        reject(err);
      });
    });
  });
}

代码执行后，它会在数据库中插入电影信息，或者使用＆＃34;电影最新的＃34;但我收到此错误并且NodeJS崩溃：

错误：发送后无法设置标头。

感谢任何帮助，谢谢！

修改<！/强>

这是新代码，我仍然遇到同样的错误...

exports.checkForMovies = function (req, res) { const testFolder = './test/'; var movieList = []; var movieResults = []; fs.readdirSync(testFolder).forEach(file => { movieList.push(tnp(file)); }); var movieObj = movieList.map(movie => { var tmp = []; return searchTMDB(movie.title).then(data => { tmp.push(data); return tmp }); }); var checkDB = Promise.all(movieObj).then(moviesData => { moviesData.map(movieData => { checkMoviesInDB(movieData[0]).then(checkResponse => { if (!checkResponse.movieToInsert) { res.json(checkResponse); } else { var insertArray = checkResponse.movieToInsert; var inserting = insertArray.map(movie => { var movieObject = { m_tmdb_id: movie.id, m_name: movie.title, m_year: movie.release_date, m_desc: movie.overview, m_genre: undefined, m_poster: movie.poster_path, m_watched: 0 }; insertMoviesToDB(movieObject).then(insertResponse => { res.json(insertResponse); }); }); } }); }); }); } function checkMoviesInDB(movie) { var moviesToInsert = []; return new Promise((resolve, reject) => { var sql = "SELECT * FROM ?? WHERE m_tmdb_id = ?" var table = ['movie', movie.id]; sql = mysql.format(sql, table); connection.query(sql, function (err, rows) { if (err) { return reject(err); } if (rows.length === 0) { moviesToInsert.push(movie); resolve({ success: true, movieToInsert: moviesToInsert }); } else { resolve({ success: true, message: 'No movie to insert' }); } }); }); } function insertMoviesToDB(movie) { return new Promise((resolve, reject) => { var sql = "INSERT INTO ?? SET ?"; var table = ['movie', movie]; sql = mysql.format(sql, table); connection.query(sql, function (err, rows) { if (err) { return reject(err); } else { resolve({ success: true, message: 'Movie added!' }); } }); }); } function searchTMDB(title) { return new Promise((resolve, reject) => { https.get(config.tmdbURL + title, response => { var body = ""; response.setEncoding("utf8"); response.on("data", data => { body += data; }); response.on("end", () => { body = JSON.parse(body); resolve(body.results[0]); }); response.on("error", (err) => { reject(err); }); }); }); }

Auth.js

const config = require('./config'); const jwt = require('jsonwebtoken'); module.exports = function (req, res, next) { var token = req.body.token || req.params.token || req.headers['x-access-token']; if (token) { jwt.verify(token, config.secret, function (err, decoded) { if (err) { return res.json({ success: false, message: 'Failed to authenticate token.' }); } else { req.decoded = decoded; next(); } }); } else { return res.status(403).send({ success: false, message: 'Please login in to countinue!' }); } };

Answer 1

希望这会有所帮助：

// Bad Way
const checkForMovies = (req, res) => {
  const movieList = ['Braveheart', 'Highlander', 'Logan'];
  movieList.forEach(movie => {
    res.json(movie);   // Will get Error on second loop: Can't set headers after they are sent.
  })
}

// Good Way
const checkForMovies = (req, res) => {
  const movieList = ['Braveheart', 'Highlander', 'Logan'];
  const payload = { data: { movieList: [] } };
  movieList.forEach(movie => {
    payload.data.movieList.push(movie);
  });
  // send res once after the loop with aggregated data
  res.json(payload);
}

/* GET home page. */
router.get('/', checkForMovies);

mysql节点：发送后不能设置标头

1 个答案: