Setting MySQL Credentials in Linux Environment and Retrieving in PHP/JavaScript

This guide will walk you through the process of securely storing MySQL database credentials in the Linux environment and accessing them in your PHP or JavaScript code. By following these steps, you can keep your sensitive information separate from your codebase.

Prerequisites

Ubuntu Linux distribution
MySQL database server installed
PHP installed and configured with MySQL support

Step 1: Set Environment Variables

Open a terminal window.
Open the .bashrc file in your home directory using a text editor:
```
nano ~/.bashrc
```
Add the following lines at the end of the file to set the environment variables for your MySQL credentials:
```
export MYSQL_USER="your_username"
export MYSQL_PASSWORD="your_password"
export MYSQL_DATABASE="your_database"
```
Replace your_username, your_password, and your_database with your actual MySQL credentials.
Save the changes and exit the text editor (Ctrl+X, then Y, then Enter in nano).
Reload the .bashrc file to apply the changes:
```
source ~/.bashrc
```

Step 2: Retrieve Credentials in PHP

Create a new PHP file named mysql_credentials.php and add the following code:

<?php
// Retrieve MySQL credentials from environment variables
$mysql_user = getenv('MYSQL_USER');
$mysql_password = getenv('MYSQL_PASSWORD');
$mysql_database = getenv('MYSQL_DATABASE');

// Connect to the MySQL database
$conn = new mysqli('localhost', $mysql_user, $mysql_password, $mysql_database);

// Check the connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

echo "Connected successfully to the MySQL database.";

// Close the database connection
$conn->close();
?>

In this example, we use the getenv() function to retrieve the MySQL credentials from the environment variables set in Step 1. We then use these credentials to establish a connection to the MySQL database using the mysqli class.

Step 3: Retrieve Credentials in JavaScript (Node.js)

Create a new JavaScript file named mysql_credentials.js and add the following code:

const mysql = require('mysql');

// Retrieve MySQL credentials from environment variables
const mysql_user = process.env.MYSQL_USER;
const mysql_password = process.env.MYSQL_PASSWORD;
const mysql_database = process.env.MYSQL_DATABASE;

// Create a MySQL connection
const connection = mysql.createConnection({
  host: 'localhost',
  user: mysql_user,
  password: mysql_password,
  database: mysql_database
});

// Connect to the MySQL database
connection.connect((err) => {
  if (err) {
    console.error('Error connecting to the database: ' + err.stack);
    return;
  }
  console.log('Connected successfully to the MySQL database.');
});

// Close the database connection
connection.end();

In this example, we use the process.env object to retrieve the MySQL credentials from the environment variables. We then create a MySQL connection using the mysql module and the retrieved credentials.

Make sure to install the mysql module using npm before running this script:

npm install mysql

Conclusion

By following these steps, you can securely store your MySQL database credentials in the Linux environment and access them in your PHP or JavaScript code. This approach helps keep your sensitive information separate from your codebase and reduces the risk of exposing your credentials.[1][2][4][7]

Remember to never commit your .bashrc file or any other file containing sensitive information to version control systems like Git.[3]

When deploying your application to a production server, make sure to set the environment variables accordingly on the server.[2][6]

Citations: [1] https://dba.stackexchange.com/questions/149817/are-there-mysql-client-environment-variables-for-user-and-db-on-linux [2] https://stackoverflow.com/questions/58238853/providing-db-credentials-via-environment-and-not-hard-coded [3] https://dev.mysql.com/blog-archive/mysql-shell-8-0-12-storing-mysql-passwords-securely/ [4] https://stackoverflow.com/questions/11281198/how-do-i-set-mysql-environment-variable-in-ubuntu [5] https://dev.mysql.com/doc/refman/8.3/en/environment-variables.html [6] https://www.tutorialspoint.com/setting-mysql-environment-variables-on-linux [7] https://www.oreilly.com/library/view/php-cookbook/1565926811/ch14s02.html [8] https://www.sqlmaestro.com/products/mysql/phpgenerator/help/events_using_variables/ [9] https://www.sitepoint.com/community/t/is-there-a-secured-way-of-writing-mysql-credentials-in-nodejs/413190 [10] https://community.fly.io/t/how-to-set-password-as-environment-variable-to-connect-to-mysql/17032 [11] https://dev.mysql.com/doc/refman/8.0/en/setting-environment-variables.html [12] https://forum.codeselfstudy.com/t/tutorial-how-to-use-mysql-or-mariadb-with-node-js-and-express/2260 [13] https://www.sitepoint.com/using-node-mysql-javascript-client/ [14] https://help.fortrabbit.com/env-vars [15] https://www.reddit.com/r/PHPhelp/comments/17f1sjh/what_is_the_proper_way_of_storing_mysql/ [16] https://dev.to/fadymr/php-create-your-own-php-dotenv-3k2i [17] https://stackoverflow.com/questions/21619201/environment-variables-in-database-php [18] https://serverfault.com/questions/833974/where-should-i-write-my-database-credentials-in-node-js-app [19] https://processwire.com/talk/topic/26376-database-password-in-configphp/ [20] https://nilsnh.no/2019/05/03/how-to-connect-to-a-mysql-database-server-over-ssl-with-node.js/

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