Connect to MySQL from PHP PDO using an SSL encrypted connection

If you want to connect securely to your MySQL database over SSL using PHP Data Objects (PDO), here is how…

<?php
$servername = "db_hostname";
$username = "db_username";
$password = "db_password";
$options = array(
	PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8',
	PDO::MYSQL_ATTR_SSL_CA => '/path/to/cacert.pem',
	PDO::MYSQL_ATTR_SSL_VERIFY_SERVER_CERT => false,
);

try {
    $conn = new PDO("mysql:host=$servername;port=3306;dbname=db_name", $username, $password, $options);
    // set the PDO error mode to exception
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "Connected successfully"; 
        var_dump($conn->query("SHOW STATUS LIKE 'Ssl_cipher';")->fetchAll());
        $conn = null;
}
catch(PDOException $e)
    {
    echo "Connection failed: " . $e->getMessage();
}
?>

Please note that the above code should only work correctly on Windows Server, due to path to cacert.pem. See below. The PDO option MYSQL_ATTR_SSL_VERIFY_SERVER_CERT is important to disable checking of the server certificate. If omitted, you’ll receive an error: `SQLSTATE[HY000] [2002]`.

Cross-platform MYSQL_ATTR_SSL_CA

As you may know, in your Windows Server IIS PHP config, you need to set an openssl.cafile directive, providing the path to a Certificate Authority (CA) file. This is not necessary on Linux, where the system default is used. MYSQL_ATTR_SSL_CA needs this path on Windows, and may be omitted on Linux.

To add this logic into your PDO test script, add an extra variable with your OS information and change the MYSQL_ATTR_SSL_CA line:

$OS = ( strtoupper( substr( PHP_OS, 0, 3 ) ) === 'WIN' );
PDO::MYSQL_ATTR_SSL_CA => $OS ? 'c:/path/to/cacert.pem' : '',

Your $options array becomes:

$OS = ( strtoupper( substr( PHP_OS, 0, 3 ) ) === 'WIN' );

$options = array(
    PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8',
	PDO::MYSQL_ATTR_SSL_CA => $OS ? 'c:/path/to/cacert.pem' : '',
	PDO::MYSQL_ATTR_SSL_VERIFY_SERVER_CERT => false,
);

If $OS === true (e.g $OS === 'WIN') use c:/path/to/cacert.pem as PDO::MYSQL_ATTR_SSL_CA file path, else we’re on Linux and omit the path. This way you are sure you can use this PHP code cross-platform on both Windows Server and Linux!

This may interest you:   How to flush MySQL query cache from time to time

Secure MySQL connection with WordPress

In WordPress you can use the Secure DB Connection plugin to set up and configure an SSL connection to your MySQL database. Don’t forget to set REQUIRE SSL in your database privileges.

Psstt: Curious how to boost PHP performance with WinCache and OPcache? Learn how to add SSL in WordPress.


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