PHP - PDO WRAPPER

<?php
/**
 * @author Tom Gabrysiak
 * @version 1.2
 * PDO Wrapper Class
 * 
 * Example Usage:
 *
 * CONNECT:
 * $db = new DB("mysql:host=localhost;dbname=db", "dbuser", "dbpass");
 *
 * 
 * ERROR HANDLING
 * $db->setErrorCallbackFunction("myErrorHandler");
 *
 * 
 * SELECT:
 * var_dump($db->select('tablename', 'gender = "male"'));
 *
 * 
 * PREPARED SELECT:
 * $search = "J";
 * $bind = array(
 *   ":search" => "%$search"
 * );
 * $results = $db->select("mytable", "FName LIKE :search", $bind);
 *
 * 
 * DELETE:
 * $db->delete("mytable", "Age < 30");
 *
 * 
 * PREPARED DELETE:
 * $lname = "Doe";
 * $bind = array(
 *   ":lname" => $lname
 * )
 * $db->delete("mytable", "LName = :lname", $bind);
 *
 * 
 * INSERT:
 * $insert = array(
 *   "FName" => "John",
 *   "LName" => "Doe",
 *   "Age" => 26,
 *   "Gender" => "male"
 * );
 * $db->insert("mytable", $insert);
 *
 * 
 * UPDATE:
 * $update = array(
 *   "FName" => "Jane",
 *   "Gender" => "female"
 * );
 * $db->update("mytable", $update, "FName = 'John'");
 *
 * 
 * PREPARED UPDATE:
 * $update = array(
 *   "Age" => 24
 * );
 * $fname = "Jane";
 * $lname = "Doe";
 * $bind = array(
 *   ":fname" => $fname,
 *   ":lname" => $lname
 * );
 * $db->update("mytable", $update, "FName = :fname AND LName = :lname", $bind);
 * 
 *
 * RAW SQL QUERY:
 * $sql = <<<STR
 * CREATE TABLE mytable (
 *   ID int(11) NOT NULL AUTO_INCREMENT,
 *   FName varchar(50) NOT NULL,
 *   LName varchar(50) NOT NULL,
 *   Age int(11) NOT NULL,
 *   Gender enum('male','female') NOT NULL,
 *   PRIMARY KEY (ID)
 * ) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=11 ;
 * STR;
 * $db->run($sql);
 */

class DB extends PDO {
    
    /**
     * Error messages generated
     * @var mixed
     */
    private $error;

    /**
     * The query string
     * @var mixed
     */
    private $sql;

    /**
     * Optional prepared bind paramater array
     * @var array
     */
    private $bind;

    /**
     * Error callback to display the message defaults to "print_r" if non specified
     * @var mixed
     */
    private $errorCallbackFunction;

    /**
     * Format type of the error message defaults to "html" if non specified
     * @var mixed
     */
    private $errorMsgFormat;


    /**
     * Instantiate class
     * @param string $dsn
     * @param string $user
     * @param string $passwd
     */
    public function __construct($dsn, $user="", $passwd="") {
        $options = array(
            PDO::ATTR_PERSISTENT => true, 
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
        );

        try {
            parent::__construct($dsn, $user, $passwd, $options);
        } catch (PDOException $e) {
            $this->error = $e->getMessage();
        }
    }

    /**
     * Format bind parameter array
     * @param  mixed $bind
     * @return array
     */
    private function cleanup($bind) {
        if(!is_array($bind)) {
            if(!empty($bind))
                $bind = array($bind);
            else
                $bind = array();
        }
        return $bind;
    }

    /**
     * Called when error thown and returns properly formatted error message
     * using errorCallbackFunction if it has been set other wise use defaults
     * @return mixed
     */
    private function debug() {
        if(!empty($this->errorCallbackFunction)) {
            $error = array("Error" => $this->error);
            if(!empty($this->sql))
                $error["SQL Statement"] = $this->sql;
            if(!empty($this->bind))
                $error["Bind Parameters"] = trim(print_r($this->bind, true));

            $backtrace = debug_backtrace();
            if(!empty($backtrace)) {
                foreach($backtrace as $info) {
                    if($info["file"] != __FILE__)
                        $error["Backtrace"] = $info["file"] . " at line " . $info["line"];  
                }       
            }

            $msg = "";
            if($this->errorMsgFormat == "html") {
                if(!empty($error["Bind Parameters"]))
                    $error["Bind Parameters"] = "<pre>" . $error["Bind Parameters"] . "</pre>";
                $css = trim(file_get_contents(dirname(__FILE__) . "/error.css"));
                $msg .= '<style type="text/css">' . "\n" . $css . "\n</style>";
                $msg .= "\n" . '<div class="db-error">' . "\n\t<h3>SQL Error</h3>";
                foreach($error as $key => $val)
                    $msg .= "\n\t<label>" . $key . ":</label>" . $val;
                $msg .= "\n\t</div>\n</div>";
            }
            elseif($this->errorMsgFormat == "text") {
                $msg .= "SQL Error\n" . str_repeat("-", 50);
                foreach($error as $key => $val)
                    $msg .= "\n\n$key:\n$val";
            }

            $func = $this->errorCallbackFunction;
            $func($msg);
        }
    }

    /**
     * Create database delete query
     * @param  string $table
     * @param  string $where
     * @param  string $bind
     * @return object
     */
    public function delete($table, $where, $bind="") {
        $sql = "DELETE FROM " . $table . " WHERE " . $where . ";";
        $this->run($sql, $bind);
    }

    /**
     * Get database metadata
     * @param  string $table
     * @param  string $info
     * @return array
     */
    private function filter($table, $info) {
        $driver = $this->getAttribute(PDO::ATTR_DRIVER_NAME);
        if($driver == 'sqlite') {
            $sql = "PRAGMA table_info('" . $table . "');";
            $key = "name";
        }
        elseif($driver == 'mysql') {
            $sql = "DESCRIBE " . $table . ";";
            $key = "Field";
        }
        else {  
            $sql = "SELECT column_name FROM information_schema.columns WHERE table_name = '" . $table . "';";
            $key = "column_name";
        }   

        if(false !== ($list = $this->run($sql))) {
            $fields = array();
            foreach($list as $record)
                $fields[] = $record[$key];
            return array_values(array_intersect($fields, array_keys($info)));
        }
        return array();
    }

    /**
     * Create a database insert query clean it up and execute
     * @param  string $table
     * @param  array  $info
     * @return object
     */
    public function insert($table, $info) {
        $fields = $this->filter($table, $info);
        $sql = "INSERT INTO " . $table . " (" . implode($fields, ", ") . ") VALUES (:" . implode($fields, ", :") . ");";
        $bind = array();
        foreach($fields as $field)
            $bind[":$field"] = $info[$field];
        return $this->run($sql, $bind);
    }

    /**
     * Create a database select query clean it up and execute
     * @param  string $table
     * @param  string $where
     * @param  string $bind
     * @param  string $fields
     * @return object
     */
    public function select($table, $where="", $bind="", $fields="*") {
        $sql = "SELECT " . $fields . " FROM " . $table;
        if(!empty($where))
            $sql .= " WHERE " . $where;
        $sql .= ";";
        return $this->run($sql, $bind);
    }

    /**
     * Create database update query clean it up and execute
     * @param  string $table
     * @param  array  $info
     * @param  string $where
     * @param  string $bind
     * @return object
     */
    public function update($table, $info, $where, $bind="") {
        $fields = $this->filter($table, $info);
        $fieldSize = sizeof($fields);

        $sql = "UPDATE " . $table . " SET ";
        for($f = 0; $f < $fieldSize; ++$f) {
            if($f > 0)
                $sql .= ", ";
            $sql .= $fields[$f] . " = :update_" . $fields[$f]; 
        }
        $sql .= " WHERE " . $where . ";";

        $bind = $this->cleanup($bind);
        foreach($fields as $field)
            $bind[":update_$field"] = $info[$field];
        
        return $this->run($sql, $bind);
    }

    /**
     * Execute query using PDO 
     * @param  string $sql
     * @param  string $bind
     * @return object
     */
    public function run($sql, $bind="") {
        $this->sql = trim($sql);
        $this->bind = $this->cleanup($bind);
        $this->error = "";

        try {
            $pdostmt = $this->prepare($this->sql);
            if($pdostmt->execute($this->bind) !== false) {
                if(preg_match("/^(" . implode("|", array("select", "describe", "pragma")) . ") /i", $this->sql))
                    return $pdostmt->fetchAll(PDO::FETCH_ASSOC);
                elseif(preg_match("/^(" . implode("|", array("delete", "insert", "update")) . ") /i", $this->sql))
                    return $pdostmt->rowCount();
            }   
        } catch (PDOException $e) {
            $this->error = $e->getMessage();    
            $this->debug();
            return false;
        }
    }

    /**
     * Set the type of errorCallbackFunction to use
     * @param string $errorCallbackFunction
     * @param string $errorMsgFormat
     */
    public function setErrorCallbackFunction($errorCallbackFunction, $errorMsgFormat="html") {
        //Variable functions for won't work with language constructs such as echo and print, so these are replaced with print_r.
        if(in_array(strtolower($errorCallbackFunction), array("echo", "print")))
            $errorCallbackFunction = "print_r";

        if(function_exists($errorCallbackFunction)) {
            $this->errorCallbackFunction = $errorCallbackFunction;  
            if(!in_array(strtolower($errorMsgFormat), array("html", "text")))
                $errorMsgFormat = "html";
            $this->errorMsgFormat = $errorMsgFormat;    
        }   
    }
}   
?>