MySQL abstraction library

class.mysql.php

<?php
define('POSITIVE', 1);
define('NEGATIVE', -1);
define('DB_CONFIG_FILE', '/path/to/mysql.json');

/* MySQLi module does not have this function by default */
function mysqli_field_name($result, $field_offset) {
    $properties = mysqli_fetch_field_direct($result, $field_offset);
    return is_object($properties) ? $properties->name : null;
}

function mysqli_field_table($result, $field_offset) {
    $properties = mysqli_fetch_field_direct($result, $field_offset);
    return is_object($properties) ? $properties->table : null;
}

class mysqli_db {

    var $Hostname = '';
    var $Username = '';
    var $Password = '';
    var $Database = '';
    var $error;
    var $conn = null;
    var $sql;
    var $num_rows;
    public $lastID;
    var $_query_count;
    var $_log_query;
    var $Unbuffered = false;

    var $total_time = 0;

    var $resources = array();
    var $query_log = array();

    function __construct($hn = false, $un = false, $pw = false, $db = false) {
        try {
            // first variable might be a file path to json config.
            if (file_exists(DB_CONFIG_FILE)) {
                $config = @json_decode(file_get_contents(DB_CONFIG_FILE));
            } else {
                $config = false;
            }
        } catch (Exception $e) {
            $config = false;
        }
        if ($config) {
            if ($config->hostname) $this->Hostname = $config->hostname;
            if ($config->username) $this->Username = $config->username;
            if ($config->password) $this->Password = $config->password;
            if ($config->database) $this->Database = $config->database;
        } elseif (getenv('DB_HOSTNAME') && getenv('DB_USERNAME') && getenv('DB_PASSWORD') && getenv('DB_DATABASE')) {
            $this->Hostname = getenv('DB_HOSTNAME');
            $this->Username = getenv('DB_USERNAME');
            $this->Password = getenv('DB_PASSWORD');
            $this->Database = getenv('DB_DATABASE');
        } elseif ($hn && $un && $pw && $db) {
            $this->Hostname = $hn;
            $this->Username = $un;
            $this->Password = $pw;
            $this->Database = $db;
        }
    }

    function init_conn() {
        if ($this->conn != null) {
            return;
        }

        $this->conn = @mysqli_connect($this->Hostname, $this->Username, $this->Password);
        if (!$this->conn) {
            if (mysqli_connect_errno() == 1040) {
                die('The server is currently overloaded. Please try again in 10 minutes.');
            }
            die('The server is currently not available. Please try again in 10 minutes. e'.mysqli_connect_errno());
            return;

        }
        if (!mysqli_select_db($this->conn, $this->Database)) {
            die('The server is currently not available.');
        }
	   mysqli_set_charset($this->conn, "utf8mb4");
    }

    function disconnect(){
        return mysqli_close($this->conn);
    }

    function escape($string) {
        return mysqli_real_escape_string($this->conn, $string);
    }

    function & Query($sql = '', ...$args){
        $this->init_conn();
        global $_log_query;

        $this->sql = $sql;

        $_is_prepared = (func_num_args() > 1) == True;
        if ($_is_prepared) {
            // TODO: Refactor everything here to $args_types = get_args_types($args);
            $arg_list = $args;
            $args_types = '';
            $type_map = Array(
                "boolean" => "b",
                "integer" => "i",
                "double" => "d",
                "string" => "s",
                "array" => "s",
                "object" => "s",
                "resource" => "s",
                "NULL" => "s",
                "unknown type" => "s",
            );
            foreach ($arg_list as $arg) {
                $type = gettype($arg);
                $ctype = $type_map[$type];
                $args_types .= $ctype;
            }
        }
        # Measure query time
        $query_start = microtime(true);
        if (!$_is_prepared) {
            $sql = mysqli_query($this->conn, $sql);
            $this->num_rows = @mysqli_affected_rows($this->conn);
        } else {
            $p = $this->conn->prepare($sql);
            $p->bind_param($args_types, ...$arg_list);
            #call_user_func_array(array($p, 'bind_param'), $arg_list);
            $p->execute();
            $sql = $p->get_result();
            $p->store_result();
            $this->num_rows = $p->affected_rows;
            $p->close();
        }
        $query_end = microtime(true);
        $query_time = ($query_end - $query_start);
        $this->total_time += $query_time;

        $this->Unbuffered = false;

        $this->_query_count++;
        $this->resources[$this->_query_count] = &$sql;

        // build backtrace
        $backtrace = debug_backtrace(0,3);
        $stacktrace = array();
        foreach ($backtrace as $key => $arr) {
            if ($arr['file'] == __FILE__) {
                continue;
            }
            $stacktrace[] = array(
                'file' => str_replace($_SERVER['DOCUMENT_ROOT'], '', $arr['file']), 
                'line' => $arr['line'], 
                'function' => $arr['function']);
        }
        $this->query_log[$this->_query_count] = array('query' => $this->sql, 'time'=>$query_time, 'stacktrace' => $stacktrace);

        //$this->num_rows = @mysqli_affected_rows($this->conn);
        $this->lastID = @mysqli_insert_id($this->conn);
        $this->error = '';

        # FIXME: Should not be recursive
        if (mysqli_errno($this->conn) == 1205) { // Lock Timeout Exceeded
            sleep(1);
            $sql = $this->Query($this->sql);
        } elseif (mysqli_errno($this->conn) == 1213) { // Deadlock found
            sleep(1);
            $sql = $this->Query($this->sql);
        } elseif (mysqli_error($this->conn) && !$this->skipNextError) {
            $this->error = mysqli_errno($this->conn) . ': ' . mysqli_error($this->conn);
            trigger_error(htmlentities($this->sql).'<br /><br />'.htmlentities($this->error), E_USER_ERROR);
        }
        $this->skipNextError = false;

        return $sql;
    }

    function & rQuery($sql, ...$args){
        $result = $this->Query($sql, ...$args);
        if ($this->num_rows > 1) trigger_error('Multiple row selection for rQuery call', E_USER_WARNING);
        if (!$result) return false;
        $return = mysqli_fetch_object($result);
        mysqli_free_result($result);
        return $return;
    }
    function & aQuery($sql, ...$args) {
        $result = $this->Query($sql, ...$args);
        if ($this->num_rows > 1) trigger_error('Multiple row selection for aQuery call', E_USER_WARNING);
        if (!$result) return false;

        $return = mysqli_fetch_assoc($result);
        mysqli_free_result($result);
        return $return;
    }

    function & oQuery($sql, ...$args){
        $result = $this->Query($sql, ...$args);
        if ($this->num_rows > 1) trigger_error('Multiple row selection for oQuery call', E_USER_WARNING);
        if ($result) {
            list($sql) = mysqli_fetch_row($result);
            mysqli_free_result($result);
        }
        else
            $sql = NULL;

        return $sql;
    }

    function & cQuery($sql, ...$args){
        $this->Unbuffered = 1;
        $result = $sql = $this->Query($sql, ...$args);
        $csql = array();
        if ($result) {
            while (list($_) = mysqli_fetch_row($sql)) $csql[] = $_;
            mysqli_free_result($result);
        }

        return $csql;
    }
    function & keyQuery($sql, ...$args){
        $this->Unbuffered = 1;
        $result = $sql = $this->Query($sql, ...$args);
        $csql = array();
        if ($result) {
            while (list($_) = mysqli_fetch_row($sql)) $csql[$_] = true;
            mysqli_free_result($result);
        }

        return $csql;
    }

    function & kvQuery($sql, ...$args) {
        $this->Unbuffered = 1;
        $result = $sql = $this->Query($sql, ...$args);
        $csql = array();
        while ($q = mysqli_fetch_row($sql))
            $csql[$q[0]] = $q[1];

        mysqli_free_result($result);

        return $csql;
    }

    function & rowsQuery($sql, ...$args) {
        // Same as krQuery but does allows prepared statements and does not accept custom key
        // The key will be the first column
        $result = $sql = $this->Query($sql, ...$args);
        if (!$result) return array();
        $key = mysqli_field_name($result, 0);
        $csql = array();
        while ($q = mysqli_fetch_object($sql)) {
            $csql[$q->$key] = $q;
        }

        mysqli_free_result($result);

        return $csql;
    }
    function & krQuery($key, $sql = false) {
        // Some code leverages the $key variable. Until that is removed this function can't be deprecated
        // once $key is not in use - replace rowsQuery with krQuery()
        if (!$sql) {
            $sql = $key;
            $key = false;
        }
        $result = $sql = $this->Query($sql);
        if (!$result) return array();
        if (!$key) {
            $key = mysqli_field_name($result, 0);
        }
        $csql = array();
        while ($q = mysqli_fetch_object($sql)) {
            $csql[$q->$key] = $q;
        }

        mysqli_free_result($result);

        return $csql;
    }
}

$db = new mysqli_db('/path/to/mysql.json');
?>