I am new to node.js (and mysql in combination with that) and trying to update my database based on request parameter and a request body. My beginning of the file looks like this:
var express = require('express');
var bodyParser = require('body-parser');
var mysql = require('mysql');
var connection = mysql.createConnection({
host: 'localhost',
user: 'root',
password: 'root',
database: 'm3ttulat0r',
debug: true
});
var app = express();
app.use(bodyParser.json());
My request looks like this:
http://localhost:8080/mettmeister/1
The request body looks like this:
{
"mettmeister": "Jonas"
}
The connection to the database is successful. Then I have the following code:
app.post('/mettmeister/:mettwochId', function(req, res) {
var mettmeister = req.body.mettmeister;
var mettwochId = req.params.mettwochId;
var query = 'UPDATE mettwoch SET mettmeister = "'+ mettmeister +'" WHERE mettwoch_id = "'+ mettwochId +'"';
console.log(mettmeister, mettwochId);
connection.query(query, function(err, result) {
if (!err) {
res.status(201);
} else {
res.status(500);
}
});
});
console.log(mettmeister, mettwochId); returns Jonas 1 which is fine.
The problem is that it sends the request and the server gets the message according to the log but nothing happens. The server "stops" at executing the query apparently.
I have debugging turned on and the query looks fine.
--> ComQueryPacket
{ command: 3,
sql: 'UPDATE mettwoch SET mettmeister = "Jonas" WHERE mettwoch_id = "1"' }
If I execute the query manually in my database, it works.. I am really happy for any help. Thank you! :)
Use update query like this
connection.query('UPDATE mettwoch SET ? WHERE ?', [{ mettmeister: mettmeister }, { mettwoch_id: mettwochId }])
Well, I am stupid. Sorry guys :(
I did the following
res.status(201);
Actually you have to finish the request like this:
res.status(201).end();
Related
I am currently developing a node.js backend for a mobile app with potentially many users. However it's my first time in developing node.js. I was following a tutorial on how to connect to a mysql database via mysql pools.
I am able to create a single mysql connection and do queries via my routes.
The problem arises once I establish the file structure mentioned in the tutorial:
dbConnect
-[models]
--users.js
-db.js
-server-ks
I am not getting an error message regarding the connection of the mysql database - even if I enter a wrong password.
// server.js
///////////////////////////// basic setup ///////////////////////////////////
var restify = require('restify');
var bodyParser = require('body-parser');
var mysql = require('mysql');
var db = require('./db');
var users = require('./models/users');
///////////////////////////// initilisation of the server ///////////////////////////////////
var server = restify.createServer({
name: 'testUsers',
});
server.use(restify.bodyParser({ mapParams: true }));
///////////////////////////// Säuberung der URL //////////////////////////////////////////
server.pre(restify.pre.sanitizePath());
///////////////////////////// MySQL Instanz starten //////////////////////////////////////////
db.connect(db.MODE_PRODUCTION, function (err) {
if (err) {
console.log('Unable to connect to MySQL.')
process.exit(1)
} else {
server.listen(8080, function () {
console.log('Listening on port 8080 ...')
})
}
})
///////////////////////////// implementation of the routes ///////////////////////////////////
function send(req, res, next) {
var test = users.getAll();
res.json({ test: 'Hello ' + req.params.name });
return next();
};
My DB.js file looks the following:
var mysql = require('mysql'),
sync = require('async')
var PRODUCTION_DB = 'userDB',
TEST_DB = 'userDB'
exports.MODE_TEST = 'mode_test'
exports.MODE_PRODUCTION = 'mode_production'
var state = {
pool: null,
mode: null,
}
exports.connect = function (mode, done) {
state.pool = mysql.createPool({
connectionLimit: 50,
host: 'localhost',
user: 'user',
password: 'password',
database: 'userDB' // test
//mode === exports.MODE_PRODUCTION ? PRODUCTION_DB : TEST_DB
})
state.mode = mode
done()
}
exports.get = function () {
return state.pool
}
Could it be, that the tutorial spared out an essential part in utilizing mysql pools and node.js?
Thanks in advance for at least trying to answer that question.
Are there better methods sequelize(?) available to create performant connections to a MySQL database?
It looks like creating the pool object does not actually connect to the database. A big clue is that the createPool function is not asynchronous, which is what you would expect if it was actually connecting at that moment.
You have to make use of the returned pool object to perform a query, which IS asynchronous.
From the documentation:
var mysql = require('mysql');
var pool = mysql.createPool({
connectionLimit : 10,
host : 'example.org',
user : 'bob',
password : 'secret',
database : 'my_db'
});
pool.query('SELECT 1 + 1 AS solution', function(err, rows, fields) {
if (err) throw err;
console.log('The solution is: ', rows[0].solution);
});
I think I'm having some async issues with implementing a function that gets all rows from a table in a mysql database using node js. I'm using the node-mysql module.
I have already googled this, and have tried doing the accepted answer on this question says but still no luck. It tells me undefined is not a function on the throw err. Anyone know what the issue here is?
var express = require('express');
var mysql = require('mysql');
var router = express.Router();
router.get('/people', function(req, res, next) {
getAllPeople(function(err, people) {
res.json(people);
});
});
function getAllPeople(cb) {
var connection = mysql.createConnection({
host : 'localhost',
user : 'root',
password : 'root',
database : 'people'
});
connection.connect();
connection.query('SELECT * from people', function(err, rows, fields) {
connection.close();
cb(err, rows);
});
}
module.exports = router;
There is no close() method defined in connection object. Use connection.end()
I'm using Node.JS + Express.JS + Multer to handle file uploads. The problem is that I need to query the database to see if a file with this name has been uploaded in the past. If it hasn't been uploaded, then it should be accepted. Otherwise, the file should not be accepted. I'm trying to get this to work using the onFileUploadStart function; however, the database query is asynchronous and I see no way to return false given that the result of the query appears in a callback. If there is a way to execute the query synchronously, my goal will be easy to accomplish. Here is the code:
var express = require('express');
var router = express.Router();
var mysql = require('mysql');
var connection = mysql.createConnection({
//connection details
});
router.post('/upload', multer({
onFileUploadStart: function(file, req, res) {
var queryString = "SELECT count(fileName) as count FROM table WHERE fileName = ?;",
queryInserts = [file.originalname];
queryString = mysql.format(queryString, queryInserts);
connection.query(queryString, function(err, rows) {
if (err) {
// handle error
} else {
if (rows[0].count > 0) {
// file should not be accepted
} else {
// file should be accepted
}
}
});
},
dest: "./uploads/"
}), function(req, res) {
// do other stuff
});
Any ideas of how I can accomplish this will be greatly appreciated. Thanks.
My quick reaction would be to use promises. You could have your onFileUploadStart handler create a deferred, assign its promise to the active request object and handle the resolution or rejection of the promise. Then in the main handler for the upload route, you could use then.
I believe this would basically be the new code as applied to your current code. I Note that I am using the Q promises library, but there are other options (promises are also built into ES6 if you are using it).
var express = require('express');
var router = express.Router();
var mysql = require('mysql');
var Q = requires('q');
var connection = mysql.createConnection({
//connection details
});
router.post('/upload', multer({
onFileUploadStart: function(file, req, res) {
var deferred = Q.defer();
req.fileUploadPromise = deferred.promise;
var queryString = "SELECT count(fileName) as count FROM table WHERE fileName = ?;",
queryInserts = [file.originalname];
queryString = mysql.format(queryString, queryInserts);
connection.query(queryString, function(err, rows) {
if (err) {
// handle error
deferred.reject('You had an error...');
} else {
if (rows[0].count > 0) {
// file should not be accepted
deferred.reject('You had a duplicate file');
} else {
deferred.resolve(file); // ?? or something useful
// file should be accepted
}
}
});
},
dest: "./uploads/"
}), function(req, res) {
req.fileUploadPromise
.then(function(successResult){
// do other stuff
res.status(200).send('success');
})
.catch(function(errorResult){
// read the error result to provide correct code & error message for user
})
.done();
});
I'm studying Node.js + Express, coding a basic login example. My /login route is set inside the routes/login.js file:
var express = require('express');
var router = express.Router();
var mysql = require('mysql');
var connectionpool = mysql.createPool({
host : 'localhost',
user : 'user',
password : 'pass',
database : 'database'
});
router.post('/', function(req,res){
connectionpool.getConnection(function(err, connection) {
if (err) {
console.error('CONNECTION error: ',err);
res.statusCode = 503;
res.send({
result: 'error',
err: err.code
});
} else {
// Do something
}
});
});
module.exports = router;
I was wondering: how can I make the mysql or the connectionpool visible in the entire application? I don't want to redeclare them on each route file I'll create. I'm looking something like an include or require method.
Any idea?
Create a separate module to act as an interface to retrieving SQL connections like so:
var mysql = require('mysql');
var connectionpool = mysql.createPool({
host : 'localhost',
user : 'user',
password : 'pass',
database : 'database'
});
exports.getConnection = function (callback) {
connectionpool.getConnection(callback);
};
Then in another file:
var connections = require('./connections');
connections.getConnection(function (err, c) {
// Use c as a connection
c.query("select * from table limit 10 ",function(err,rows){
//this is important release part
c.release();
if(!err) {
console.log(rows);
}
});
});
I'm trying build rest-like API using mongodb(with mogoose) and node.js with restify.
I'm an absolute novice in the mongo world, and I'm not sure where problem is. Is this the db connection's problem, or something else?
So, I'm doing it this way:
rest-server.js
//start server
var restify = require('restify');
var server = restify.createServer();
server.use(restify.bodyParser());
//connect db
var config = require('./Config.js');
var mongoose = require('mongoose'),
db = mongoose.createConnection('localhost', 'travelers'),
Schema = mongoose.Schema,
ObjectId = mongoose.SchemaTypes.ObjectId;
db.on('error', console.error.bind(console, 'DB connection error:'));
db.once('open', function callback() {
console.log('db connection open');
});
var LoginModel = require('./models/LoginModel.js').make(Schema, mongoose);
var LoginResource = require('./resource/LoginResource.js')(server, LoginModel);
LoginModel.js
function make(Schema, mongoose) {
var LoginSchema = new Schema({
//id: (?)
username: String,
password: String,
traveler_id: Number,
contact_id: Number,
last_login: Date,
token: String
});
return mongoose.model('Login', LoginSchema);
}
module.exports.make = make;
LoginResource.js
exports = module.exports = function (server, LoginModel) {
var LoginRepository = require('../repository/LoginRepository.js');
server.get('/login/:username/:password', function (req, res, next) {
LoginRepository.getLogin(req, res, next, LoginModel);
});
}
LoginRepository.js
function getLogin(req, res, next, LoginModel) {
var query = LoginModel.find({ username: req.params.username, password: req.params.password});
query.exec(function (err, docs) {
console.log('got it!');
res.send(docs);
});
}
test query
curl localhost:8080/login/qqq/www
So I never got to res.send(docs);
Actually, I didn't add anything to the db. I just want to know that the query didn't find anything.
UPDATE:
I don't understand why, but this problem can be solved if I change the db connection code like this:
//connect db
var config = require('./Config.js');
var mongoose = require('mongoose/');
db = mongoose.connect(config.creds.mongoose_auth),
Schema = mongoose.Schema;
(use mongoose.connect and define db and Schema vars as global)
but in this case db.on() and db.once() throw an exception "no such methods".
In other words - problem mmm... solved but I still don't know why.
This looks like a helpful link: server.js example on github
Models that you've created by calling mongoose.model() use Mongoose's default connection pool when executing queries. The default connection pool is created by calling mongoose.connect(), and any queries you make using your created models will be queued up until you call that and it completes.
You can also create separate connection pools (that can have their own models!) by calling db = mongoose.createConnection() like you were originally doing, but you would have to create the models for that using db.model() which is why things weren't working for you originally.