将var导出到路由文件expressjs [英] export var to routes files expressjs

问题描述

我对来自PHP的nodejs + expressjs完全陌生，并且在如何将var导出/包含到我的route/users.js文件中时遇到了麻烦.

I'm completely new to nodejs + expressjs comming from php and I'm getting trouble how to export/include a var to my routes/users.js file.

在app.js上，我有:

on app.js I have:

//database connection
var connection = mysql.createConnection({
  host     : 'localhost',
  user     : 'root',
  password : '',
  database : 'dbNodeExpress'
});

...一些代码

var user = require('./routes/user'); //这里我包含了我的路由/文件(我不知道在这里添加路由是否正确-出于学习目的现在可以使用

var user = require('./routes/user'); //here I include my routes/files (I dont know if it's right to include the routes here - for learning purposes it works for now)

...更多代码，直到启动服务器

... more code until starts the server

在我的/routes/user.js

On my /routes/user.js

app = require('../app');
 //var mysql = require('mysql');
 var baseUrl = app.get('baseUrl');

app.get('/users_mysql', function(req, res){
  connection.query('SELECT * FROM users', function(err, users){
    res.json(users);
  });
});

我得到明确的错误:500 ReferenceError:未定义连接

and I get the express error: 500 ReferenceError: connection is not defined

该连接之所以有效，是因为如果我将内容从users.js移到app.js，则可以查询数据库.

The connection works because if I move the content from users.js to app.js I can query the database.

我的问题是如何注入要在route/users.js上使用的var连接

My questions is how to inject the var connection to be used on routes/users.js

任何帮助/提示，​​以了解这一点非常感谢.预先感谢.

Any help / hint to understand this is very appreciated. Thanks in advance.

推荐答案

有几种方法可以做到这一点.几个解决方案可能是:

There are several ways you could do this. A couple solutions might be:

1. 创建一个用于创建和导出连接的resources.js文件.然后在您需要的每个源文件中使用require()resources.js.

1. Create a resources.js file that creates and exports the connection. Then require() resources.js in every source file where you need it.

将连接传递到您的用户路由文件.像这样的东西:

Pass the connection to your user route file. Something like this:

// app.js
var connection = mysql.createConnection({
  host     : 'localhost',
  user     : 'root',
  password : '',
  database : 'dbNodeExpress'
});
require('./routes/user')(connection);


// routes/user.js
module.exports = function(connection) {
  app.get('/users_mysql', function(req, res){
    connection.query('SELECT * FROM users', function(err, users){
      res.json(users);
    });
  });
};

这篇关于将var导出到路由文件expressjs的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！