How can i simulate PROTOCOL_CONNECTION_LOST error in node.js? - mysql

Question

how can i simulate the "PROTOCOL_CONNECTION_LOST" error in mysql for node.js?
If i get the error, my application crashes, and i dont know how to reproduce this error.
thank you.

Answer 1

it really sounds like your application is crashing because is not handling the error. You may want to check in the files where you initialize the MySQL connection if that's the case.
As for the error, the "PROTOCOL_CONNECTION_LOST" is just a Generic Error Object. If you want to throw it inside your application (not actually stopping MySQL from working):
const err = new Error('Connection lost: The server closed the connection.');
err.fatal = true;
err.code = 'PROTOCOL_CONNECTION_LOST';
throw err;
Put that in the line of code where you want to throw the error.
If you want to emulate that MySql is throwing this error, one (unrecommended way) is to hack into the lib. The Connections object has access to the Protocol object, which has a hidden method _delegateError that's the one fired when there's a protocol error. Source: https://github.com/mysqljs/mysql/blob/master/lib/protocol/Protocol.js

Answer 2

Here is solution for connection protocol lost. This solution solved me
Here the data base connection
const mysql = require('mysql');
const connection=mysql.createConnection({
host:'localhost',
user:'root',
password:'******',
database:'db_name'
});
connection.connect(function(error){
if(!!error) console.log(error);
else console.log('SQL Database Connected!');
});
module.exports = connection;
`
just run the node server using pm2
Ex. pm2 start app.js
install the npm pm2 package