Express and mysql. rows are undefined - mysql

Question

This is my code. I am writing API and I want to send information about products that client has input.
const express = require('express');
const mysql = require('mysql');
const morgan = require('morgan');
const app = express();
app.use(morgan('short'));
app.use(express.static('./public'));
// app.get('/', (req, res, next)=>{
// res.send('Hello World');
// });
function getConnection(){
return mysql.createConnection({
host: 'localhost',
user: 'root',
password:'samsung793',
database: 'demo2'
})
}
app.get('/models/:id', (req, res, next)=>{
console.log('Fetching id ' + req.params.id);
const connection = getConnection();
const queryStr = 'SELECT * FROM products WHERE id=?'
const modelId = req.params.id;
connection.query( queryStr, [modelId], (err, rows, fields)=>{
if (err){
res.send('<h1>500 bad request</h1> Error! Sorry for error, we are working on it!');
res.sendStatus(500);
return;
//throw err;
}
console.log('Ready');
res.json(rows);
})
// res.end();
})
app.get('/:name', (req, res, next)=>{
console.log('Fetching name ' + req.params.name);
const connection = getConnection();
const queryStr = `SELECT * FROM products WHERE MATCH(name) AGAINST(${req.params.name}, in natural language)`
const modelName = req.params.name;
connection.query( queryStr, [modelName], (err, rows, fields)=>{
if (err){
res.send('<h1>500 bad request</h1> <h3>Error!</h3> <h4>Sorry for error, we are working on it!</h4>');
res.sendStatus(500);
return;
//throw err;
}
console.log('Ready');
res.json(rows);
console.log(rows);
})
// res.end();
})
app.listen(3000, ()=>{
console.log('server is listening on port 3000');
} )
when I log to console the rows, it is undefined. How can I fix it? What is the problem?
Sorry for first post. I edit and add all code now. Please help me to solve this problem.

Answer 1

You need to check if any error occur while querying
app.get('/:name', (req, res, next) => {
console.log('Fetching name ' + req.params.name);
const connection = getConnection();
const queryStr = 'SELECT * FROM products WHERE MATCH(name) AGAINST(?, in natural language mode)';
const modelName = req.params.name;
connection.query( queryStr, [modelName], (err, rows, fields)=>{
console.log('Ready');
if(err) {
console.log(err);
return res.status(500).send(err);
}
console.log(rows);
res.json(rows);
})
})
If you are using prepared statement, you do not need to pass ${req.params.name}, just pass ?

Answer 2

Thank you for answers. I write code here in case someone needs it.
It works this way:
app.get('/:name', (req, res, next)=>{
console.log('Fetching name ' + req.params.name);
const connection = getConnection();
const queryStr = `SELECT * FROM products WHERE MATCH(name, url) AGAINST(? IN NATURAL LANGUAGE MODE) `
const modelName = req.params.name;
connection.query( queryStr, modelName, (err, rows, fields)=>{
console.log(rows);
if (err){
res.status(404).send(" Something went wrong");
// res.sendStatus(500);
throw err;
}
console.log('Ready');
res.json(rows);
})
// res.end();
})