DB Class

db.php

<?php

class DB{

    private static $connection = false;
    public static $host;
    public static $user;
    public static $password;
    public static $dbname;

    public function __construct($host, $user, $password, $dbname){
        self::$host = $host;
        self::$user = $user;
        self::$password = $password;
        self::$dbname = $dbname;
        if (!self::$connection) {
            try {
                $dsn = 'mysql:dbname=' . $dbname . ';host=' . $host;
                self::$connection = new PDO($dsn, $user, $password);
            } catch (PDOException $e) {
                echo 'Connection failed: ' . $e->getMessage();
            }
        }
    }

    public static function connect(){
        if (!self::$connection){
            try {
                $dsn = 'mysql:dbname=' . self::$dbname . ';host=' . self::$host;
                self::$connection = new PDO($dsn, self::$user, self::$password);
                //$query = $dbh->query('SELECT * FROM monitoring')->fetchAll();
                //var_dump($query);
            } catch (PDOException $e) {
                echo 'Connection failed: ' . $e->getMessage();
            }
        }

    }

    public static function showError(){
        $entry = self::$connection->errorInfo();
        print_r($entry);
        self::log($entry);

    }

    public static function log($entry){
        $backtrace = debug_backtrace();
        $caller = array_pop($backtrace);
        $caller_script = basename($caller['file']);
        file_put_contents('/tmp/' . $caller_script . '.log', date('Y-m-d H:i:s') . "\t" . (is_array($entry) || is_object($entry) ? print_r($entry,true) : $entry) . PHP_EOL, FILE_APPEND);
    }

    public static function select($sql){
        self::connect();
        $result = self::$connection->query($sql);
        if (!$result){
            self::showError();
            return false;
        }

        return $result->fetchAll();
    }


    public static function single($sql){
        self::connect();
        $result = self::$connection->query($sql);
        if (!$result){
            self::showError();
            return false;
        }

        return $result->fetch();
    }

    public static function insert($sql){
        self::connect();
        $result = self::$connection->query($sql);

        if (!$result){
            self::showError();
            return false;
        }

        return self::$connection->lastInsertId();
    }

    public static function query($sql){
        self::connect();
        $result = self::$connection->query($sql);
        if (!$result){
            self::showError();
            return false;
        }

        return true;
    }

    public static function getKey(){
        self::connect();
        $proc = self::$connection->prepare("SET @update_id := 0;UPDATE aws_keys SET in_use = '1', used= (used + 1), id = (SELECT @update_id := id) WHERE active = 1 AND in_use = '0' ORDER BY used ASC LIMIT 1;");
        $proc->execute();
        $proc->closeCursor();

        $result = self::$connection->query("SELECT * FROM aws_keys WHERE id = @update_id");
        if (!$result){
            self::showError();
            return false;
        }

        $key = $result->fetch(PDO::FETCH_ASSOC);

        return $key;
    }

    public static function update($sql){
        self::connect();
        $stm = self::$connection->prepare($sql);
        $result = $stm->execute();
        if (!$result){
            self::showError();
            return false;
        }

        return $stm->rowCount();
    }

    public static function close(){
        self::$connection = null;
    }

}