/**
* Check that the connection to the database is still up. If not, try to reconnect.
*
* If this function is unable to reconnect, it will forcibly die, or if after the
* the template_redirect hook has been fired, return false instead.
*
* If $allow_bail is false, the lack of database connection will need
* to be handled manually.
*
* @since 3.9.0
*
* @param bool $allow_bail Optional. Allows the function to bail. Default true.
*
* @return bool|void True if the connection is up.
*/
public function check_connection($allow_bail = true)
{
if ($this->dbh->ping()) {
return true;
}
$error_reporting = false;
// Disable warnings, as we don't want to see a multitude of "unable to connect" messages
if (WP_DEBUG) {
$error_reporting = error_reporting();
error_reporting($error_reporting & ~E_WARNING);
}
for ($tries = 1; $tries <= $this->reconnect_retries; $tries++) {
// On the last try, re-enable warnings. We want to see a single instance of the
// "unable to connect" message on the bail() screen, if it appears.
if ($this->reconnect_retries === $tries && WP_DEBUG) {
error_reporting($error_reporting);
}
if ($this->db_connect(false)) {
if ($error_reporting) {
error_reporting($error_reporting);
}
return true;
}
sleep(1);
}
// If template_redirect has already happened, it's too late for wp_die()/dead_db().
// Let's just return and hope for the best.
if (did_action('template_redirect')) {
return false;
}
if (!$allow_bail) {
return false;
}
wp_load_translations_early();
$message = '<h1>' . __('Error reconnecting to the database') . "</h1>\n";
$message .= '<p>' . sprintf(__('This means that we lost contact with the database server at %s. This could mean your host’s database server is down.'), '<code>' . htmlspecialchars($this->dbhost, ENT_QUOTES) . '</code>') . "</p>\n";
$message .= "<ul>\n";
$message .= '<li>' . __('Are you sure that the database server is running?') . "</li>\n";
$message .= '<li>' . __('Are you sure that the database server is not under particularly heavy load?') . "</li>\n";
$message .= "</ul>\n";
$message .= '<p>' . sprintf(__('If you’re 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/')) . "</p>\n";
// We weren't able to reconnect, so we better bail.
$this->bail($message, 'db_connect_fail');
// Call dead_db() if bail didn't die, because this database is no more. It has ceased to be (at least temporarily).
dead_db();
}
