Combining connect data into one file - php

Question

I have a PHP file that I use to include when I connect to my db. It looks something like this:
<?php
$mysqlhst = "localhost";
$database = "mydb1";
$username = "my_usr";
$password = "mypas2db1";
try {
$db = new PDO("mysql:host=$mysqlhst;dbname=$database;charset=UTF8", $username, $password);
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
catch(PDOException $e) {
echo "Connection failed: " . $e->getMessage();
}
?>
I also have a second database that I frequently access at the same time as the first one. Can I combine both connections like this or is there a better way of doing it?
<?php
$mysqlhst = "localhost";
$database = "mydb1";
$username = "my_usr1";
$password = "mypas2db1";
try {
$db = new PDO("mysql:host=$mysqlhst;dbname=$database;charset=UTF8", $username, $password);
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
catch(PDOException $e) {
echo "Connection failed: " . $e->getMessage();
}
$database = "mydb2";
$username = "my_usr2";
$password = "mypas2db2";
try {
$db2 = new PDO("mysql:host=$mysqlhst;dbname=$database;charset=UTF8", $username, $password);
$db2->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
catch(PDOException $e) {
echo "Connection failed: " . $e->getMessage();
}
?>

Answer 1

Assuming you're not using Classes, you could DRY (Do-not Repeat Yourself) up your code a little like the following. This allows for extending into even further databases/users/servers in the future if required:
<?php
$connections = [
'db1' => [
'host' = 'localhost';
'database' = 'mydb1';
'username' = 'my_usr1';
'password' = 'mypas2db1';
],
'db2' => [
'host' = 'localhost';
'database' = 'mydb2';
'username' = 'my_usr2';
'password' = 'mypas2db2';
],
];
function getDatabaseConnection($connectionName = 'db1'): ?PDO
{
global $connections;
if (empty($connections[$connectionName]) {
// Throw an exception because this connection doesn't exist.
throw new \Exception(
"Connection: {$connectionName} not specified."
);
}
$data = $connections[$connectionName];
$dbHost = $data['host'] ?: 'localhost';
$dbUsername = $data['username'] ?: '';
$dbPassword = $data['password'] ?: '';
$dbName = $data['database'] ?: '';
if (!$dbUsername || !$dbName) {
// We don't have a username or database to connect to. Fail.
throw new \Exception(
'No valid database name or user provided.'
);
}
$db = new PDO(
"mysql:host={$dbHost};dbname={$dbName};charset=UTF8",
$dbUsername,
$dbPassword
);
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
return $db;
}
// We don't need to specify a connection because we want the default, db1.
$db1 = getDatabaseConnection();
// Specify we want a connection to db2.
$db2 = getDatabaseConnection('db2');