Develop Reference

How to resold syntax error in insert sql query (Node js)

I am trying to Insert data into the MSSQL database, but there is a syntax error
Code
app.get('/PostItem', (req, res) => {
let post = ['test', 'tesa', 1];
let sql = 'INSERT INTO [dbo].[Item](ItemCode,ItemName,CreatedBy) VALUES (?,?,?)';
let query = con.query(sql, post, err => {
if (err) {
throw err
}
res.send('Item added');
})
});
error
this the error
(node:8584) UnhandledPromiseRejectionWarning: RequestError: Incorrect syntax near '?'.
NOTE: "database connection is work"

SQL Server doesn't use ? then I change code like this and it works.
app.get('/PostItem', (req, res) => {
var post = ["'test'", "'test'", 1];
var sql = `INSERT INTO [dbo].[Item](ItemCode,ItemName,CreatedBy) VALUES (${post})`;
var query = con.query(sql, err => {
if (err) {
throw err
}
res.send('Item added');
});
});

Getting result from MySQL

My backend is consist of Api and DB. When I want to get response from DB I have had delayed output by 1 query.
API (I think api is ok. Start read DB first)
app.post('/api/query', (req, res) => {
console.log(`\n Query input : ${JSON.stringify(req.body)}`);
let queryInput = (Object.values(req.body).join(' '));
if(!dbApi.checkArray(queryInput)){ //If array is not made from clear strings
res.json(dbApi.queryFromUser(queryInput));
}
else{
res.json(dbApi.queryOutput);
}
});
app.listen(dbConfig.server.port, () =>
console.log(`Server running on port ${dbConfig.server.port}`));
DB
queryOutput = [];
const receivingQuery =(queryInput) => {
db.query(queryInput, (err, result) =>{
if(err) throw err+' : '+queryInput;
queryOutput = result;
console.log("\nQuery output "+ JSON.stringify(queryOutput)); //Output (result) is ok
});
return queryOutput //Here is Output from previous query (sends to API)
}
module.exports = {
queryOutput: queryOutput,
queryFromUser: receivingQuery,
}
I tryied callback method and I rewrite it couple of times. But I dont have enough skill to solve it.

If You want to return result of query so simply do following things:
add query method to db module:
function query(sql, args = []) {
return new Promise(function(resolve, reject) {
db.query(sql, args, (err, result) => {
if (err) return reject(err);
resolve(result);
});
});
}
// extra feature, getting user by id
async function getUserById(id) {
const result = await query('SELECT * FROM users WHER id = ? LIMIT 1', [id]);
if (Array.isArray(result) && result[0]) return result[0];
return null;
}
module.exports = {
query,
getUserById, // export user by id
queryOutput,
queryFromUser: receivingQuery,
}
use it (with async and await):
app.post('/api/query', async (req, res) => {
try {
console.log('Query input:', req.body);
const queryInput = Object.values(req.body).join(' ');
const result = await dbApi.query(queryInput);
res.json(result);
}
catch (error) {
console.error(error);
res.status(500).json({message: 'Please try again soon'});
}
});
app.get('/api/users/:id', async (req, res) => {
try {
const user = await dbApi.getUserById(req.params.id);
if (!user) return res.status(404).json({message: 'User not found'});
res.status(200).json(user);
}
catch (error) {
console.error(error);
res.status(500).json({message: 'Please try again soon'});
}
});
app.listen(dbConfig.server.port, () =>
console.log('Server running on port', dbConfig.server.port));

Passing a variable from ReactJS frontend to NodeJS back end using a GET route

I am working on a react app and am trying to find a way to pass a variable I define in my front-end (Question.js) to my back-end (server.js) so that I can issue different queries. I have the code
//Question.js
state = {
data: null
};
componentDidMount() {
this.callBackendAPI()
.then(res => this.setState({ data: res.express }))
.catch(err => console.log(err));
}
callBackendAPI = async () => {
const response = await fetch('/express_backend');
const body = await response.json();
if (response.status !== 200) {
throw Error(body.message)
}
return body;
};
//server.js
con.connect(function (err) {
if (err) throw err;
con.query("SELECT question FROM s1questions WHERE ID = 1", function (err, result, fields) {
if (err) throw err;
app.get('/express_backend', (req, res) => {
var x = JSON.stringify(result[0].question);
res.send({ express: `${x}` });
});
});
});

Your sever should probably split your database connection from your route handler definitions. Also, you could use query parameters to access questions based on their id in the database.
// question.js
callBackendAPI = async () => {
const response = await fetch(`/express_backend?questionId=1`);
const body = await response.json();
if (response.status !== 200) {
throw Error(body.message)
}
return body;
};
// server.js
app.get('/express_backend', (req, res) => {
const { questionId } = req.query;
// query database for question by id
});

I want to take out the result from mysql's connection.query and save it in global scope chain in nodejs

I tried bringing out result by storing in variable current product. But I cant use it outside the function, so my array returns empty
var connection = mysql.createConnection({
host: config.config.mysql.opencart_local.host,
user: config.config.mysql.opencart_local.user,
password: config.config.mysql.opencart_local.password,
database: config.config.mysql.opencart_local.database
})
var query_current_products = 'select * from table;';
var current_products = [];
connection.connect(function(err) {
if (err) throw err;
console.log("Connected!");
connection.query(query_current_products, function (err, result) {
if (err) throw err;
//console.log(result);
current_products = result;
});
}
)
console.log(current_products);
enter image description here

Try to use async/await syntax to get your results
const mysql = require('mysql'); // or use import if you use TS
const util = require('util');
const conn = mysql.createConnection({
host: config.config.mysql.opencart_local.host,
user: config.config.mysql.opencart_local.user,
password: config.config.mysql.opencart_local.password,
database: config.config.mysql.opencart_local.database
});
var current_products = [];
//
var query_current_products = 'select * from table;';
(async function getProducts () => {
try {
const rows = await query( query_current_products);
console.log(rows);
current_products=rows;
} finally {
conn.end();
}
})()

use this code:
var query_current_products = 'select * from users';
var current_products = [];
function f() {
return new Promise(resolve => {
con.connect(function (err) {
if (err) throw err;
console.log("Connected!");
con.query(query_current_products, function (err, result) {
if (err) throw err
resolve(result);
});
});
})
}
async function asyncCall() {
current_products = await f();
console.log("outside callback : ", current_products);
}
asyncCall();

express.js and soap calls

I am using express.js, node.js and node-soap.js and I am getting an error I can not fix.
I have the following code which fails with an exception and I can not see anything in the exception.
var soap = require('soap');
var url = 'http://www.webservicex.net/stockquote.asmx?WSDL';
var args = {
symbol : 'AMZN'
};
soap.createClient(url, function(err, client) {
client.GetQuote(args, function(err, result) {
if (err) {
console.log(err);
return;
}
console.log(result);
});
});
and in the console all I see is:
{ GetQuoteResult: [ 'exception' ] }
Thoughts?
Reza

this is the code that finally got working...
var args1 = {"tns:symbol": "AMZN"};
var url1 = "http://www.webservicex.net/stockquote.asmx?WSDL";
soap.createClient(url1, function(err, client) {
console.log(client.describe().StockQuote.StockQuoteSoap.GetQuote);
client.StockQuote.StockQuoteSoap.GetQuote(args1, function(err, result) {
if (err) {
console.error(err);
return;
}
console.log(result);
});
});