/**
 * Set the database table prefix and the format specifiers for database
 * table columns.
 *
 * Columns not listed here default to `%s`.
 *
 * @since 3.0.0
 * @access private
 *
 * @global wpdb   $wpdb         The WordPress database class.
 * @global string $table_prefix The database table prefix.
 */
function wp_set_wpdb_vars()
{
    global $wpdb, $table_prefix;
    if (!empty($wpdb->error)) {
        dead_db();
    }
    $wpdb->field_types = array('post_author' => '%d', 'post_parent' => '%d', 'menu_order' => '%d', 'term_id' => '%d', 'term_group' => '%d', 'term_taxonomy_id' => '%d', 'parent' => '%d', 'count' => '%d', 'object_id' => '%d', 'term_order' => '%d', 'ID' => '%d', 'comment_ID' => '%d', 'comment_post_ID' => '%d', 'comment_parent' => '%d', 'user_id' => '%d', 'link_id' => '%d', 'link_owner' => '%d', 'link_rating' => '%d', 'option_id' => '%d', 'blog_id' => '%d', 'meta_id' => '%d', 'post_id' => '%d', 'user_status' => '%d', 'umeta_id' => '%d', 'comment_karma' => '%d', 'comment_count' => '%d', 'active' => '%d', 'cat_id' => '%d', 'deleted' => '%d', 'lang_id' => '%d', 'mature' => '%d', 'public' => '%d', 'site_id' => '%d', 'spam' => '%d');
    $prefix = $wpdb->set_prefix($table_prefix);
    if (is_wp_error($prefix)) {
        wp_load_translations_early();
        wp_die(sprintf(__('<strong>ERROR</strong>: %1$s in %2$s can only contain numbers, letters, and underscores.'), '<code>$table_prefix</code>', '<code>wp-config.php</code>'));
    }
}

 /**
  * Connect to and select database.
  *
  * If $allow_bail is false, the lack of database connection will need
  * to be handled manually.
  *
  * @since 3.0.0
  * @since 3.9.0 $allow_bail parameter added.
  *
  * @param bool $allow_bail Optional. Allows the function to bail. Default true.
  * @return bool True with a successful connection, false on failure.
  */
 public function db_connect($allow_bail = true)
 {
     $this->is_mysql = true;
     /*
      * Deprecated in 3.9+ when using MySQLi. No equivalent
      * $new_link parameter exists for mysqli_* functions.
      */
     $new_link = defined('MYSQL_NEW_LINK') ? MYSQL_NEW_LINK : true;
     $client_flags = defined('MYSQL_CLIENT_FLAGS') ? MYSQL_CLIENT_FLAGS : 0;
     if ($this->use_mysqli) {
         $this->dbh = mysqli_init();
         // mysqli_real_connect doesn't support the host param including a port or socket
         // like mysql_connect does. This duplicates how mysql_connect detects a port and/or socket file.
         $port = null;
         $socket = null;
         $host = $this->dbhost;
         $port_or_socket = strstr($host, ':');
         if (!empty($port_or_socket)) {
             $host = substr($host, 0, strpos($host, ':'));
             $port_or_socket = substr($port_or_socket, 1);
             if (0 !== strpos($port_or_socket, '/')) {
                 $port = intval($port_or_socket);
                 $maybe_socket = strstr($port_or_socket, ':');
                 if (!empty($maybe_socket)) {
                     $socket = substr($maybe_socket, 1);
                 }
             } else {
                 $socket = $port_or_socket;
             }
         }
         if (WP_DEBUG) {
             mysqli_real_connect($this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags);
         } else {
             @mysqli_real_connect($this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags);
         }
         if ($this->dbh->connect_errno) {
             $this->dbh = null;
             /* It's possible ext/mysqli is misconfigured. Fall back to ext/mysql if:
              *  - We haven't previously connected, and
              *  - WP_USE_EXT_MYSQL isn't set to false, and
              *  - ext/mysql is loaded.
              */
             $attempt_fallback = true;
             if ($this->has_connected) {
                 $attempt_fallback = false;
             } elseif (defined('WP_USE_EXT_MYSQL') && !WP_USE_EXT_MYSQL) {
                 $attempt_fallback = false;
             } elseif (!function_exists('mysql_connect')) {
                 $attempt_fallback = false;
             }
             if ($attempt_fallback) {
                 $this->use_mysqli = false;
                 $this->db_connect();
             }
         }
     } else {
         if (WP_DEBUG) {
             $this->dbh = mysql_connect($this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags);
         } else {
             $this->dbh = @mysql_connect($this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags);
         }
     }
     if (!$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;
         }
         $this->bail(sprintf(__("\n<h1>Error establishing a database connection</h1>\n<p>This either means that the username and password information in your <code>wp-config.php</code> file is incorrect or we can't contact the database server at <code>%s</code>. This could mean your host's database server is down.</p>\n<ul>\n\t<li>Are you sure you have the correct username and password?</li>\n\t<li>Are you sure that you have typed the correct hostname?</li>\n\t<li>Are you sure that the database server is running?</li>\n</ul>\n<p>If you're unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href='https://wordpress.org/support/'>WordPress Support Forums</a>.</p>\n"), htmlspecialchars($this->dbhost, ENT_QUOTES)), '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;
 }

/**
 * Load custom DB error or display WordPress DB error.
 *
 * If a file exists in the wp-content directory named db-error.php, then it will
 * be loaded instead of displaying the WordPress DB error. If it is not found,
 * then the WordPress DB error will be displayed instead.
 *
 * The WordPress DB error sets the HTTP status header to 500 to try to prevent
 * search engines from caching the message. Custom DB messages should do the
 * same.
 *
 * This function was backported to WordPress 2.3.2, but originally was added
 * in WordPress 2.5.0.
 *
 * @since 2.3.2
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 */
function dead_db()
{
    global $wpdb;
    wp_load_translations_early();
    // Load custom DB error template, if present.
    if (file_exists(WP_CONTENT_DIR . '/db-error.php')) {
        require_once WP_CONTENT_DIR . '/db-error.php';
        die;
    }
    // If installing or in the admin, provide the verbose message.
    if (defined('WP_INSTALLING') || defined('WP_ADMIN')) {
        wp_die($wpdb->error);
    }
    // Otherwise, be terse.
    status_header(500);
    nocache_headers();
    header('Content-Type: text/html; charset=utf-8');
    ?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"<?php 
    if (is_rtl()) {
        echo ' dir="rtl"';
    }
    ?>
>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
	<title><?php 
    _e('Database Error');
    ?>
</title>

</head>
<body>
	<h1><?php 
    _e('Error establishing a database connection');
    ?>
</h1>
</body>
</html>
<?php 
    die;
}

 /**
  * Connect to and select database
  *
  * @since 3.0.0
  */
 function db_connect()
 {
     $this->is_mysql = true;
     $new_link = defined('MYSQL_NEW_LINK') ? MYSQL_NEW_LINK : true;
     $client_flags = defined('MYSQL_CLIENT_FLAGS') ? MYSQL_CLIENT_FLAGS : 0;
     if (WP_DEBUG) {
         $this->dbh = mysql_connect($this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags);
     } else {
         $this->dbh = @mysql_connect($this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags);
     }
     if (!$this->dbh) {
         wp_load_translations_early();
         $this->bail(sprintf(__("\n<h1>Error establishing a database connection</h1>\n<p>This either means that the username and password information in your <code>wp-config.php</code> file is incorrect or we can't contact the database server at <code>%s</code>. This could mean your host's database server is down.</p>\n<ul>\n\t<li>Are you sure you have the correct username and password?</li>\n\t<li>Are you sure that you have typed the correct hostname?</li>\n\t<li>Are you sure that the database server is running?</li>\n</ul>\n<p>If you're unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href='http://wordpress.org/support/'>WordPress Support Forums</a>.</p>\n"), htmlspecialchars($this->dbhost, ENT_QUOTES)), 'db_connect_fail');
         return;
     }
     $this->set_charset($this->dbh);
     $this->ready = true;
     $this->select($this->dbname, $this->dbh);
 }

 /**
  * 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 ($this->use_mysqli) {
         if (@mysqli_ping($this->dbh)) {
             return true;
         }
     } else {
         if (@mysql_ping($this->dbh)) {
             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";
     $message .= '<p>' . sprintf(__('This means that we lost contact with the database server at %s. This could mean your host&#8217;s database server is down.'), '<code>' . htmlspecialchars($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&#8217;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();
 }

/**
 * Displays a failure message.
 *
 * Used when a blog's tables do not exist. Checks for a missing $wpdb->site table as well.
 *
 * @access private
 * @since 3.0.0
 */
function ms_not_installed()
{
    global $wpdb, $domain, $path;
    wp_load_translations_early();
    $title = __('Error establishing a database connection');
    $msg = '<h1>' . $title . '</h1>';
    if (!is_admin()) {
        die($msg);
    }
    $msg .= '<p>' . __('If your site does not display, please contact the owner of this network.') . '';
    $msg .= ' ' . __('If you are the owner of this network please check that MySQL is running properly and all tables are error free.') . '</p>';
    if (false && !$wpdb->get_var("SHOW TABLES LIKE '{$wpdb->site}'")) {
        $msg .= '<p>' . sprintf(__('<strong>Database tables are missing.</strong> This means that MySQL is not running, WordPress was not installed properly, or someone deleted <code>%s</code>. You really should look at your database now.'), $wpdb->site) . '</p>';
    } else {
        $msg .= '<p>' . sprintf(__('<strong>Could not find site <code>%1$s</code>.</strong> Searched for table <code>%2$s</code> in database <code>%3$s</code>. Is that right?'), rtrim($domain . $path, '/'), $wpdb->blogs, DB_NAME) . '</p>';
    }
    $msg .= '<p><strong>' . __('What do I do now?') . '</strong> ';
    $msg .= __('Read the <a target="_blank" href="http://codex.wordpress.org/Debugging_a_WordPress_Network">bug report</a> page. Some of the guidelines there may help you figure out what went wrong.');
    $msg .= ' ' . __('If you&#8217;re still stuck with this message, then check that your database contains the following tables:') . '</p><ul>';
    foreach ($wpdb->tables('global') as $t => $table) {
        if ('sitecategories' == $t) {
            continue;
        }
        $msg .= '<li>' . $table . '</li>';
    }
    $msg .= '</ul>';
    wp_die($msg, $title);
}

} elseif (@file_exists(dirname(ABSPATH) . '/wp-config.php') && !@file_exists(dirname(ABSPATH) . '/wp-settings.php')) {
    /** The config file resides one level above ABSPATH but is not part of another install */
    require_once dirname(ABSPATH) . '/wp-config.php';
} else {
    // A config file doesn't exist
    define('WPINC', 'wp-includes');
    require_once ABSPATH . WPINC . '/load.php';
    // Standardize $_SERVER variables across setups.
    wp_fix_server_vars();
    require_once ABSPATH . WPINC . '/functions.php';
    $path = wp_guess_url() . '/wp-admin/setup-config.php';
    /*
     * We're going to redirect to setup-config.php. While this shouldn't result
     * in an infinite loop, that's a silly thing to assume, don't you think? If
     * we're traveling in circles, our last-ditch effort is "Need more help?"
     */
    if (false === strpos($_SERVER['REQUEST_URI'], 'setup-config')) {
        header('Location: ' . $path);
        exit;
    }
    define('WP_CONTENT_DIR', ABSPATH . 'wp-content');
    require_once ABSPATH . WPINC . '/version.php';
    wp_check_php_mysql_versions();
    wp_load_translations_early();
    // Die with an error message
    $die = sprintf(__("There doesn't seem to be a %s file. I need this before we can get started."), '<code>wp-config.php</code>') . '</p>';
    $die .= '<p>' . sprintf(__("Need more help? <a href='%s'>We got it</a>."), __('https://codex.wordpress.org/Editing_wp-config.php')) . '</p>';
    $die .= '<p>' . sprintf(__("You can create a %s file through a web interface, but this doesn't work for all server setups. The safest way is to manually create the file."), '<code>wp-config.php</code>') . '</p>';
    $die .= '<p><a href="' . $path . '" class="button button-large">' . __("Create a Configuration File") . '</a>';
    wp_die($die, __('WordPress &rsaquo; Error'));
}

 /**
  * Connect to and select database.
  *
  * If $allow_bail is false, the lack of database connection will need
  * to be handled manually.
  *
  * @since 3.0.0
  * @since 3.9.0 $allow_bail parameter added.
  *
  * @param bool $allow_bail Optional. Allows the function to bail. Default true.
  * @return bool True with a successful connection, false on failure.
  */
 public function db_connect($allow_bail = true)
 {
     $this->is_mysql = true;
     /*
      * Deprecated in 3.9+ when using MySQLi. No equivalent
      * $new_link parameter exists for mysqli_* functions.
      */
     $new_link = defined('MYSQL_NEW_LINK') ? MYSQL_NEW_LINK : true;
     $client_flags = defined('MYSQL_CLIENT_FLAGS') ? MYSQL_CLIENT_FLAGS : 0;
     $new_link = true;
     ini_set('display_errors', 1);
     if (WP_DEBUG) {
         $this->dbh = sqlsrv_connect($this->dbhost, array("Database" => $this->dbname, "UID" => $this->dbuser, "PWD" => $this->dbpassword, 'ReturnDatesAsStrings' => true, 'MultipleActiveResultSets' => false));
     } else {
         $this->dbh = sqlsrv_connect($this->dbhost, array("Database" => $this->dbname, "UID" => $this->dbuser, "PWD" => $this->dbpassword, 'ReturnDatesAsStrings' => true, 'MultipleActiveResultSets' => false));
     }
     if (!$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;
         }
         $this->bail(sprintf(__("\n<h1>Error establishing a database connection</h1>\n<p>This either means that the username and password information in your <code>wp-config.php</code> file is incorrect or we can't contact the database server at <code>%s</code>. This could mean your host's database server is down.</p>\n<ul>\n\t<li>Are you sure you have the correct username and password?</li>\n\t<li>Are you sure that you have typed the correct hostname?</li>\n\t<li>Are you sure that the database server is running?</li>\n</ul>\n<p>If you're unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href='https://wordpress.org/support/'>WordPress Support Forums</a>.</p>\n"), htmlspecialchars($this->dbhost, ENT_QUOTES)), '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;
 }

/**
 * Displays a failure message.
 *
 * Used when a blog's tables do not exist. Checks for a missing $wpdb->site table as well.
 *
 * @access private
 * @since 3.0.0
 * @since 4.4.0 The `$domain` and `$path` parameters were added.
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param string $domain The requested domain for the error to reference.
 * @param string $path   The requested path for the error to reference.
 */
function ms_not_installed($domain, $path)
{
    global $wpdb;
    if (!is_admin()) {
        dead_db();
    }
    wp_load_translations_early();
    $title = __('Error establishing a database connection');
    $msg = '<h1>' . $title . '</h1>';
    $msg .= '<p>' . __('If your site does not display, please contact the owner of this network.') . '';
    $msg .= ' ' . __('If you are the owner of this network please check that MySQL is running properly and all tables are error free.') . '</p>';
    $query = $wpdb->prepare("SHOW TABLES LIKE %s", $wpdb->esc_like($wpdb->site));
    if (!$wpdb->get_var($query)) {
        $msg .= '<p>' . sprintf(__('<strong>Database tables are missing.</strong> This means that MySQL is not running, WordPress was not installed properly, or someone deleted %s. You really should look at your database now.'), '<code>' . $wpdb->site . '</code>') . '</p>';
    } else {
        $msg .= '<p>' . sprintf(__('<strong>Could not find site %1$s.</strong> Searched for table %2$s in database %3$s. Is that right?'), '<code>' . rtrim($domain . $path, '/') . '</code>', '<code>' . $wpdb->blogs . '</code>', '<code>' . DB_NAME . '</code>') . '</p>';
    }
    $msg .= '<p><strong>' . __('What do I do now?') . '</strong> ';
    /* translators: %s: Codex URL */
    $msg .= sprintf(__('Read the <a href="%s" target="_blank">bug report</a> page. Some of the guidelines there may help you figure out what went wrong.'), __('https://codex.wordpress.org/Debugging_a_WordPress_Network'));
    $msg .= ' ' . __('If you&#8217;re still stuck with this message, then check that your database contains the following tables:') . '</p><ul>';
    foreach ($wpdb->tables('global') as $t => $table) {
        if ('sitecategories' == $t) {
            continue;
        }
        $msg .= '<li>' . $table . '</li>';
    }
    $msg .= '</ul>';
    wp_die($msg, $title, array('response' => 500));
}

 /**
  * Method to do the database connection.
  *
  * This overrides wpdb::db_connect() to avoid using MySQL function.
  *
  * @see wpdb::db_connect()
  */
 public function db_connect($allow_bail = true)
 {
     if (WP_DEBUG) {
         $this->dbh = new PDOEngine();
     } else {
         // WP_DEBUG or not, we don't use @ which causes the slow execution
         // PDOEngine class will take the Exception handling.
         $this->dbh = new PDOEngine();
     }
     if (!$this->dbh) {
         wp_load_translations_early();
         //probably there's no translations
         $this->bail(sprintf(__("<h1>Error establlishing a database connection</h1><p>We have been unable to connect to the specified database. <br />The error message received was %s"), $this->dbh->errorInfo()));
         return;
     }
     $this->has_connected = true;
     $this->ready = true;
 }

 /**
  * Constructor
  */
 public function __construct()
 {
     date_default_timezone_set(AB_Utils::getTimezoneString());
     wp_load_translations_early();
     $now = new DateTime();
     $this->mysql_now = $now->format('Y-m-d H:i:s');
     $this->sms = new AB_SMS();
     $this->sms_authorized = $this->sms->loadProfile();
     $query = AB_Notification::query()->where('active', 1)->whereIn('type', array('staff_agenda', 'client_follow_up', 'client_reminder'));
     foreach ($query->find() as $notification) {
         $this->processNotification($notification);
     }
 }

 /**
  * Connect to and select database
  *
  * @since 3.0.0
  */
 function db_connect()
 {
     $this->is_mysql = true;
     $conn_string = "host=" . $this->dbhost . " dbname=" . $this->dbname . " user=" . $this->dbuser . " password=" . $this->dbpassword . " port=2345";
     $this->dbh = pg_connect($conn_string);
     if (!$this->dbh) {
         wp_load_translations_early();
         $this->bail(sprintf(__($conn_string . "\r\n<h1>Error establishing a database connection</h1>\r\n<p>This either means that the username and password information in your <code>wp-config.php</code> file is incorrect or we can't contact the database server at <code>%s</code>. This could mean your host's database server is down.</p>\r\n<ul>\r\n\t<li>Are you sure you have the correct username and password?</li>\r\n\t<li>Are you sure that you have typed the correct hostname?</li>\r\n\t<li>Are you sure that the database server is running?</li>\r\n</ul>\r\n<p>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='http://.org/support/'> Support Forums</a>.</p>\r\n"), htmlspecialchars($this->dbhost, ENT_QUOTES)), 'db_connect_fail');
         return;
     }
     $this->set_charset($this->dbh);
     $this->ready = true;
     $this->select($this->dbname, $this->dbh);
 }

 private function get_weekdays()
 {
     $out = '<div class="tm-weekdays-picker-wrap">';
     // load wp translations
     if (function_exists('wp_load_translations_early')) {
         wp_load_translations_early();
         global $wp_locale;
         for ($day_index = 0; $day_index <= 6; $day_index++) {
             $out .= '<span class="tm-weekdays-picker"><label><input class="tm-weekday-picker" type="checkbox" value="' . esc_attr($day_index) . '"><span>' . $wp_locale->get_weekday($day_index) . '</span></label></span>';
         }
         // in case something goes wrong
     } else {
         $weekday[0] = __('Sunday');
         $weekday[1] = __('Monday');
         $weekday[2] = __('Tuesday');
         $weekday[3] = __('Wednesday');
         $weekday[4] = __('Thursday');
         $weekday[5] = __('Friday');
         $weekday[6] = __('Saturday');
         for ($day_index = 0; $day_index <= 6; $day_index++) {
             $out .= '<span class="tm-weekdays-picker"><label><input type="checkbox" value="' . esc_attr($day_index) . '"><span>' . $weekday[$day_index] . '</span></label></span>';
         }
     }
     $out .= '</div>';
     return $out;
 }

 /**
  * Connect to and select database.
  *
  * If $allow_bail is false, the lack of database connection will need
  * to be handled manually.
  *
  * @since 3.0.0
  * @since 3.9.0 $allow_bail parameter added.
  *
  * @param bool $allow_bail Optional. Allows the function to bail. Default true.
  * @return bool True with a successful connection, false on failure.
  */
 public function db_connect($allow_bail = true)
 {
     $this->is_mysql = true;
     /*
      * Deprecated in 3.9+ when using MySQLi. No equivalent
      * $new_link parameter exists for mysqli_* functions.
      */
     $new_link = defined('MYSQL_NEW_LINK') ? MYSQL_NEW_LINK : true;
     $client_flags = defined('MYSQL_CLIENT_FLAGS') ? MYSQL_CLIENT_FLAGS : 0;
     if ($this->use_mysqli) {
         $this->dbh = mysqli_init();
         // mysqli_real_connect doesn't support the host param including a port or socket
         // like mysql_connect does. This duplicates how mysql_connect detects a port and/or socket file.
         $port = null;
         $socket = null;
         $host = $this->dbhost;
         $port_or_socket = strstr($host, ':');
         if (!empty($port_or_socket)) {
             $host = substr($host, 0, strpos($host, ':'));
             $port_or_socket = substr($port_or_socket, 1);
             if (0 !== strpos($port_or_socket, '/')) {
                 $port = intval($port_or_socket);
                 $maybe_socket = strstr($port_or_socket, ':');
                 if (!empty($maybe_socket)) {
                     $socket = substr($maybe_socket, 1);
                 }
             } else {
                 $socket = $port_or_socket;
             }
         }
         // Set SSL certs if we want to use secure DB connections
         if ($client_flags & MYSQLI_CLIENT_SSL) {
             $ssl_key = defined('MYSQL_SSL_KEY') && is_file(MYSQL_SSL_KEY) ? MYSQL_SSL_KEY : null;
             $ssl_cert = defined('MYSQL_SSL_CERT') && is_file(MYSQL_SSL_CERT) ? MYSQL_SSL_CERT : null;
             $ssl_ca = defined('MYSQL_SSL_CA') && is_file(MYSQL_SSL_CA) ? MYSQL_SSL_CA : null;
             $ssl_capath = defined('MYSQL_SSL_CA_PATH') && is_dir(MYSQL_SSL_CA_PATH) ? MYSQL_SSL_CA_PATH : null;
             $ssl_cipher = defined('MYSQL_SSL_CIPHER') ? MYSQL_SSL_CIPHER : null;
             mysqli_ssl_set($this->dbh, $ssl_key, $ssl_cert, $ssl_ca, $ssl_capath, $ssl_cipher);
         }
         mysqli_real_connect($this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags);
         if ($this->dbh->connect_errno) {
             $this->dbh = null;
             /* It's possible ext/mysqli is misconfigured. Fall back to ext/mysql if:
              *  - We haven't previously connected, and
              *  - WP_USE_EXT_MYSQL isn't set to false, and
              *  - ext/mysql is loaded.
              */
             $attempt_fallback = true;
             if ($this->has_connected) {
                 $attempt_fallback = false;
             } elseif (defined('WP_USE_EXT_MYSQL') && !WP_USE_EXT_MYSQL) {
                 $attempt_fallback = false;
             } elseif (!function_exists('mysql_connect')) {
                 $attempt_fallback = false;
             }
             if ($attempt_fallback) {
                 $this->use_mysqli = false;
                 return $this->db_connect($allow_bail);
             }
         }
     } else {
         $this->dbh = mysql_connect($this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags);
     }
     if (!$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";
         $message .= '<p>' . sprintf(__('This either means that the username and password information in your %1$s file is incorrect or we can&#8217;t contact the database server at %2$s. This could mean your host&#8217;s database server is down.'), '<code>wp-config.php</code>', '<code>' . htmlspecialchars($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 that you have typed the correct hostname?') . "</li>\n";
         $message .= '<li>' . __('Are you sure that the database server is running?') . "</li>\n";
         $message .= "</ul>\n";
         $message .= '<p>' . sprintf(__('If you&#8217;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";
         $this->bail($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();
//.........这里部分代码省略.........

/**
 * Batch WordPress without database
 *
 * Load the required WordPress include files for the task in hand.
 * These files are a subset of the full set of WordPress includes.
 * We may also need the oik-bwtrace plugin if there are any bw_trace2() calls temporarily inserted into the WordPress files for debugging purposes.
 *
 * This is not needed in oik-wp.php
 */
function oik_batch_load_wordpress_files()
{
    // Load the L10n library.
    require_once ABSPATH . WPINC . '/l10n.php';
    // for get_translations_for_domain()
    require_once ABSPATH . WPINC . "/formatting.php";
    require_once ABSPATH . WPINC . "/plugin.php";
    //require_once( ABSPATH . WPINC . "/option.php" );
    require_once ABSPATH . WPINC . "/functions.php";
    require_once ABSPATH . WPINC . '/class-wp-error.php';
    require_once ABSPATH . WPINC . "/load.php";
    // Not sure if we need to load cache.php ourselves
    // require_once( ABSPATH . WPINC . "/cache.php" );
    require_once ABSPATH . WPINC . "/version.php";
    require_once ABSPATH . WPINC . "/post.php";
    // for add_post_type_support()
    wp_load_translations_early();
}

/**
 * Load custom DB error or display WordPress DB error.
 *
 * If a file exists in the wp-content directory named db-error.php, then it will
 * be loaded instead of displaying the WordPress DB error. If it is not found,
 * then the WordPress DB error will be displayed instead.
 *
 * The WordPress DB error sets the HTTP status header to 500 to try to prevent
 * search engines from caching the message. Custom DB messages should do the
 * same.
 *
 * This function was backported to WordPress 2.3.2, but originally was added
 * in WordPress 2.5.0.
 *
 * @since 2.3.2
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 */
function dead_db()
{
    global $wpdb;
    wp_load_translations_early();
    // Load custom DB error template, if present.
    if (file_exists(WP_CONTENT_DIR . '/db-error.php')) {
        require_once WP_CONTENT_DIR . '/db-error.php';
        die;
    }
    // If installing or in the admin, provide the verbose message.
    if (defined('WP_INSTALLING') || defined('WP_ADMIN')) {
        wp_die($wpdb->error);
    }
    // Otherwise, be terse.
    status_header(500);
    nocache_headers();
    header('Content-Type: text/html; charset=utf-8');
    ?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"<?php 
    if (is_rtl()) {
        echo ' dir="rtl"';
    }
    ?>
>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
	<title><?php 
    _e('Database Error');
    ?>
</title>

</head>
<body>
	<h3 style="text-align:center"><?php 
    _e('Hiện tại website đang gặp sự cố quá tải do lượng truy cập lớn');
    ?>
</h3>
	<h3 style="text-align:center"><?php 
    _e('Rất mong các bạn thông cảm và hãy quay trở lại sau.');
    ?>
</h3>
</body>
</html>
<?php 
    die;
}