SQL Connection Manager

SQLConnections.php

<?php

namespace Ry167\SQL;

use InvalidArgumentException;

/**
 * SQL Connection Manager
 *
 * Manages a multiple SQL Connections and their initiation.
 * @author Ryan Halliday <[email protected]>
 * @link http://ry167.com
 * @version  0.1
 */
class Connections{

	/**
	 * Stores available connection options
	 * @var array
	 */
	private $Connections = array(
		'default' => null,
	);

	/**
	 * Stores available read-only connections
	 * @var array
	 */
	private $Reads = array();

	/**
	 * Stores available write connections
	 * @var array
	 */
	private $Writes = array();

	/**
	 * Default options for a connection to have
	 * @var array
	 */
	private $Options = array();

	/**
	 * What class to initiate upon calling a get*() method.
	 * @var string
	 */
	private $Class = '\PDO';

	/**
	 * Constructs the connector class and potentially adds a default connection
	 * @param string $dsn
	 * @param string $username
	 * @param string $password
	 * @param array  $options
	 */
	public function __construct($dsn = null, $username = null, $password = null, $options = array()){
		if (!is_null($dsn)) $this->addConnection('default',$dsn,$username,$password,$options);
	}

	/**
	 * Set the class to initiate upon calling a get*() method.
	 * @param  string $class
	 */
	public function setClass($class){
		$this->Class = $class;
	}

	/**
	 * Set default options for connections. Their own settings will override these defaults
	 * @param mixed|array $key Can be an array of Key => Value pairs of options or the key for the $val parameter.
	 * @param mixed       $val Value to be set for the previous key.
	 */
	public function setOptions($key,$val = null){
		if (is_array($key)){
			$this->Options = $this->Options + $key;
		}
		else $this->Options[$key] = $val;
	}

	/**
	 * Adds a named array of Connection settings to the Connections array
	 * @param string $name     Type of connection to add. Should be 'write', 'read' or 'default' unless it is being uniquely named, which is allowed.
	 * @param string $dsn      Data Source Name for PDO
	 * @param string $username Username for PDO
	 * @param string $password Password for PDO
	 * @param array  $options  
	 */
	public function add($name, $dsn, $username = null, $password = null, $options = array()){
		if (strtolower($name) == 'write' || strtolower($name) == 'read'){
			$this->{ucfirst(strtolower($name))."s"}[] = array(
				'dsn'      => $dsn,
				'username' => $username,
				'password' => $password,
				'options'  => $options
			);
		}
		else{
			$this->Connections[$name] = array(
				'dsn'      => $dsn,
				'username' => $username,
				'password' => $password,
				'options'  => $options
			);
		}
	}

	/**
	 * Get a named connection
	 * @param  string $name Name of the connection
	 * @throws InvalidArgumentException If there is no connection of the name specified
	 */
	public function get($name){
		if (isset($this->Connections[$name]) && !is_null($this->Connections)){
			$Options = $this->Options + $this->Connections[$name]['options'];
			return new $this->Class($this->Connections[$name]['dsn'],$this->Connections[$name]['username'],
				$this->Connections[$name]['password'],$Options);
		}
		else throw new InvalidArgumentException("No default connection available and none specified");
	}

	/**
	 * Initiate the default connection
	 * @see Connections::get() This is just an alias.
	 */
	public function getDefault(){
		return $this->get('default');
	}

	/**
	 * Gets a random writable connection
	 * @return mixed Instance of $this->Class (Default: PDO)
	 * @throws InvalidArgumentException If there is no write connections specified
	 */
	public function getWrite(){
		if (count($this->Writes) > 0){
			$Num = mt_rand(0,count($this->Writes)-1);
			$Options = $this->Options + $this->Writes[$Num]['options'];
			return new $this->Class($this->Writes[$Num]['dsn'],$this->Writes[$Num]['username'],
				$this->Writes[$Num]['password'],$Options);
		}
		else throw new InvalidArgumentException("There must be at least one write connection defined to be able to get one");
	}

	/**
	 * Gets a random readable connection
	 * @return mixed Instance of $this->Class (Default: PDO)
	 * @throws InvalidArgumentException If there is no read connections specified
	 */
	public function getRead(){
		if (count($this->Reads) > 0){
			$Num = mt_rand(0,count($this->Reads)-1);
			$Options = $this->Options + $this->Reads[$Num]['options'];
			return new $this->Class($this->Reads[$Num]['dsn'],$this->Reads[$Num]['username'],
				$this->Reads[$Num]['password'],$Options);
		}
		else throw new InvalidArgumentException("There must be at least one read connection defined to be able to get one");
	}
}