wpdb::db_connect() │ public │ WP 3.0.0

Connects to and selects database.

If $allow_bail is false, the lack of database connection will need to be handled manually.

Method of the class: wpdb{}

No Hooks.

Return

true|false. True with a successful connection, false on failure.

Usage

global $wpdb;
$wpdb->db_connect( $allow_bail );

$allow_bail(true|false)

Allows the function to bail.
Default: true

Changelog

wpdb::db_connect() wpdb::db connect code ^{WP 6.6.2}

public function db_connect( $allow_bail = true ) {
	$this->is_mysql = true;

	$client_flags = defined( 'MYSQL_CLIENT_FLAGS' ) ? MYSQL_CLIENT_FLAGS : 0;

	/*
	 * Set the MySQLi error reporting off because WordPress handles its own.
	 * This is due to the default value change from `MYSQLI_REPORT_OFF`
	 * to `MYSQLI_REPORT_ERROR|MYSQLI_REPORT_STRICT` in PHP 8.1.
	 */
	mysqli_report( MYSQLI_REPORT_OFF );

	$this->dbh = mysqli_init();

	$host    = $this->dbhost;
	$port    = null;
	$socket  = null;
	$is_ipv6 = false;

	$host_data = $this->parse_db_host( $this->dbhost );
	if ( $host_data ) {
		list( $host, $port, $socket, $is_ipv6 ) = $host_data;
	}

	/*
	 * If using the `mysqlnd` library, the IPv6 address needs to be enclosed
	 * in square brackets, whereas it doesn't while using the `libmysqlclient` library.
	 * @see https://bugs.php.net/bug.php?id=67563
	 */
	if ( $is_ipv6 && extension_loaded( 'mysqlnd' ) ) {
		$host = "[$host]";
	}

	if ( WP_DEBUG ) {
		mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
	} else {
		// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
		@mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
	}

	if ( $this->dbh->connect_errno ) {
		$this->dbh = null;
	}

	if ( ! $this->dbh && $allow_bail ) {
		wp_load_translations_early();

		// Load custom DB error template, if present.
		if ( file_exists( WP_CONTENT_DIR . '/db-error.php' ) ) {
			require_once WP_CONTENT_DIR . '/db-error.php';
			die();
		}

		$message = '<h1>' . __( 'Error establishing a database connection' ) . "</h1>\n";

		$message .= '<p>' . sprintf(
			/* translators: 1: wp-config.php, 2: Database host. */
			__( 'This either means that the username and password information in your %1$s file is incorrect or that contact with the database server at %2$s could not be established. This could mean your host&#8217;s database server is down.' ),
			'<code>wp-config.php</code>',
			'<code>' . htmlspecialchars( $this->dbhost, ENT_QUOTES ) . '</code>'
		) . "</p>\n";

		$message .= "<ul>\n";
		$message .= '<li>' . __( 'Are you sure you have the correct username and password?' ) . "</li>\n";
		$message .= '<li>' . __( 'Are you sure you have typed the correct hostname?' ) . "</li>\n";
		$message .= '<li>' . __( 'Are you sure the database server is running?' ) . "</li>\n";
		$message .= "</ul>\n";

		$message .= '<p>' . sprintf(
			/* translators: %s: Support forums URL. */
			__( 'If you are unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href="%s">WordPress support forums</a>.' ),
			__( 'https://wordpress.org/support/forums/' )
		) . "</p>\n";

		$this->bail( $message, 'db_connect_fail' );

		return false;
	} elseif ( $this->dbh ) {
		if ( ! $this->has_connected ) {
			$this->init_charset();
		}

		$this->has_connected = true;

		$this->set_charset( $this->dbh );

		$this->ready = true;
		$this->set_sql_mode();
		$this->select( $this->dbname, $this->dbh );

		return true;
	}

	return false;
}