[英]How can I make my Node.js MySQL connection as a promise work?
I have just started to work with node.js and my js knowledge is a bit rusty.我刚刚开始使用 node.js,我的 js 知识有点生疏。
I started with callbacks and then I found out about promises.我从回调开始,然后我发现了 Promise。 This syntax was more like my brain works, so I rewrote my code with promises.
这种语法更像是我的大脑工作,所以我用 promise 重写了我的代码。 But now my MySql connection does not work.
但是现在我的 MySql 连接不起作用。 It can't even get reached (I think...) I have logged the word "test" in the file userDB, that worked.
它甚至无法到达(我认为......)我已经在文件 userDB 中记录了“test”这个词,它起作用了。 But then in the mySql file the console.log "test2" didn't work.
但是在 mySql 文件中,console.log“test2”不起作用。
Thanks to you all!谢谢大家! Chris
克里斯
Here is my server.js (the file that node starts):这是我的 server.js(节点启动的文件):
/* REQUIRE */
const oAuth2Server = require('node-oauth2-server');
const express = require('express');
const bodyParser = require('body-parser');
const oAuthModel = require('./endpoints/auth/authModel');
const util = require('util');
const dbCon = require('./subsystem/mySql')
/* CONST */
const port = 3000;
const debug = true;
const app = express();
/* INIT */
app.oauth = oAuth2Server({
model: oAuthModel,
grants: ['password'],
debug: debug
})
/* ROUTER */
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
app.use(app.oauth.errorHandler());
const authRoutes = require('./router/auth')(express.Router(), app, dbCon)
app.use('/auth', authRoutes);
app.all('*', (req, res) => {
res.status(404).send({message: "This service was not found"});
});
/* Start Server */
app.listen(port, () => {
console.log(`listening on port ${port}`)
})
Here is my router file auth.js:这是我的路由器文件 auth.js:
module.exports = (router, expressApp, dbCon) => {
const userDB = require('../endpoints/user/userDB')(dbCon)
const authMiddleware = require('../endpoints/auth/authMiddleware')
const userMiddleware = require('../endpoints/user/userMiddleware')(userDB)
router.post('/registerUser', userMiddleware.registerUser)
//router.post('/login', expressApp.oauth.grant(), authMiddleware.login)
router.post('/login', expressApp.oauth.grant())
return router
}
Here is my userDB file:这是我的 userDB 文件:
let mySqlConnection;
module.exports = injectedMySqlConnection => {
mySqlConnection = injectedMySqlConnection
return {
registerUserInDB: registerUserInDB,
getUserFromCrentials: getUserFromCrentials,
doesUserExist: doesUserExist,
getUserByUsername: getUserByUsername
}
}
const registerUserInDB = (username, password) => {
return new Promise((resolve,reject) => {
//execute the query to register the user
mySqlConnection.query(`INSERT INTO users (username, user_password) VALUES ('${username}', SHA('${password}'))`)
.then(data => {resolve(true)})
.catch(error => {reject(error)})
})
}
const getUserFromCrentials = (username, password) => {
return new Promise((resolve,reject) => {
//create query using the data in the req.body to register the user in the db
const getUserQuery = `SELECT * FROM users WHERE username = '${username}' AND user_password = SHA('${password}')`
console.log('getUserFromCrentials query is: ', getUserQuery);
//execute the query to get the user
mySqlConnection.query(getUserQuery)
.then(data => {resolve(data)})
.catch(error => {reject(error)})
})
}
const doesUserExist = username => {
return new Promise((resolve,reject) => {
console.log('test');
//execute the query to check if the user exists
mySqlConnection.query(`SELECT * FROM users WHERE username = '${username}'`)
.then(data => {resolve(data.results !== null ? data.results.length == 1 ? true : false : false)})
.catch(error => {reject(error)})
})
}
const getUserByUsername = username => {
return new Promise((resolve,reject) => {
//execute the query to check if the user exists
mySqlConnection.query(`SELECT id, username FROM users WHERE username = '${username}'`)
.then(data => {resolve(data)})
.catch(error => {reject(error)})
})
}
Here is my userMiddleware (is this middleware?):这是我的 userMiddleware(这是中间件吗?):
let userDb;
module.exports = injectedUserDb => {
userDb = injectedUserDb
return {
registerUser: registerUser
}
}
function registerUser(req, res){
console.log(`authRoutesMethods: registerUser: req.body is:`, req.body);
//query db to see if the user exists already
userDb.doesUserExist(req.body.username)
.then(data => {
if(data)
{
sendResponse(res, "User already exists", 200)
return
}
else
{
//register the user in the db
userDb.registerUserInDB(req.body.username, req.body.password)
.then(data => {
userDb.getUserByUsername(req.body.username)
.then(data => {sendResponse(res, data.results, "")})
.catch(error => {sendResponse(res, "Failed to register user", error)})
})
.catch(error => {sendResponse(res, "Failed to register user", error)})
}
})
.catch(err => {
sendResponse(res, "User already exists", 200)
return
})
}
function sendResponse(res, message, error) {
res
.status(error !== null ? error !== null ? 400 : 200 : 400)
.json({
'message': message,
'error': error,
})
}
And last but not least my mySql.js file:最后但并非最不重要的是我的 mySql.js 文件:
var mySql = require('mysql');
const query = sql => {
return new Promise( ( resolve, reject ) => {
let connection = mysql.createConnection({
host: 'localhost',
user: 'root',
password: '',
database: 'oauth2test'
});
console.log('test2');
connection.query( sql, ( err, rows ) => {
if ( err )
{
connection.end();
reject( err );
}
else
{
connection.end();
resolve( rows );
}
});
});
}
module.exports.query = query;
You have a simple typo in your mySql.js file:您的 mySql.js 文件中有一个简单的错字:
The line线
var mySql = require('mysql');
should be replaced with应该替换为
var mysql = require('mysql');
Other than that the query code works ok on my machine:除此之外,查询代码在我的机器上运行正常:
var mysql = require('mysql');
const query = sql => {
return new Promise( ( resolve, reject ) => {
let connection = mysql.createConnection({
host: 'localhost',
user: 'root',
password: '',
database: 'oauth2test'
});
console.log('test2');
connection.query( sql, ( err, rows ) => {
if ( err )
{
connection.end();
reject( err );
}
else
{
connection.end();
resolve( rows );
}
});
});
}
module.exports.query = query;
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