Question

我是node.js的新手，所以请耐心等待。

我想知道将模型传递给节点中的控制器的正确方法是什么。我有点工作但是当我从我的控制器中的模型中调用一个方法时，我从模型中返回的是“未定义的”＃39;而且我不确定为什么。我与DB的连接很好。看看我的文件并查看我的评论。

routes.js

module.exports = function(app, dbConnection) {
 var theIndexModel = require('../models/index.server.models')(dbConnection);
 var index = require('../controllers/index.server.controller')(theIndexModel);

 app.get('/', index.homePage);
};

models.js

function IndexModel(dbConnection) {

  modelMethods = {};

  modelMethods.getAllUsers = function(req, res) {
      var query = "SELECT * FROM `users`";
      dbConnection.query(query, function(err, rows, fields) {
        return rows; //NOT RETURNING ANYTHING WHEN I CALL FROM CONTOLLER!!
      });
  };

 return modelMethods;
}

module.exports = IndexModel;

controller.js

function IndexController(theIndexModel) {
  controllerMethods = {};
  controllerMethods.homePage = function(req, res) {
    console.log(theIndexModel.getAllUsers()); //UNDEFINED HERE, WHEN I SHOULD BE GETTING USERS FROM THE DB
    res.render('index', {
        title: 'hello'
    });
  };


// Return the object that holds the methods.
return controllerMethods;
}

module.exports = IndexController;

我做错了什么？提前致谢。

Answer 1

正如NG所指出的，你的问题是asyc代码。返回行返回行，只有你永远不会捕获它。

要解决此问题，您可以了解承诺，或潜入回调地狱。

如果选择回调地狱，它将如下所示：

controller.js

function IndexController(theIndexModel) {
  controllerMethods = {};
  controllerMethods.homePage = function(req, res) {
   theIndexModel.getAllUsers(function(err, rows, fields){
     res.render('index', {
        title: 'hello,
        users: rows
     });
   });

  };


// Return the object that holds the methods.
return controllerMethods;
}

module.exports = IndexController;

和models.js

function IndexModel(dbConnection) {

  modelMethods = {};

  modelMethods.getAllUsers = function(cb) {
      var query = "SELECT * FROM `users`";
      dbConnection.query(query, cb);
  };

 return modelMethods;
}

module.exports = IndexModel;

node.js / express js模型和控制器之间的交互

1 个答案: