<?php
/**
* @author Karen Ziv <karen@perlessence.com>
* @see http://github.com/foobarbazquux/daonut/wikis/daofactory
**/
if (!class_exists('DynamicDao')) {
require dirname(__FILE__) . DIRECTORY_SEPARATOR . 'dynamicdao.inc.php';
}
class DAOFactory {
const DIR_CONNECTORS = '/connectors/'; // TODO : can slashes be turned to DIRECTORY_SEPARATOR?
const DIR_RESOURCES = '/resources/'; // TODO : can slashes be turned to DIRECTORY_SEPARATOR?
const QUERY_BUILDER = 'querybuilder.inc.php';
protected static $connectors = array(); // Pool of existing connectors for reuse
protected static $resources = array(); // Pool of existing resources for reuse
public static $dsn2connector = array(); // DSN -> connector mappings
public static $db2dsn = array(); // database -> DSN mappings
public static $test_factory; // This is a unit-testing hook. Do NOT use it for anything else
/**
* Gets a connector object based on a daonut resource string
* This method is shorthand for getConnector(getConnectionString(getDSN('DB.Table')))
* @param {str} daonut resource string in format DB.Table
* @return {obj} New instance of connector class
**/
public static function connect($resource) {
$resource = trim($resource);
if (empty($resource)) {
error_log("Invalid resource string '$resource'");
return FALSE;
}
list($db, $table) = explode('.', $resource);
$dsn = self::getDSN($db);
if (!$dsn) {
error_log("No DSN alias found for DB '$db'");
return FALSE;
}
$connection_string = self::getConnectionString($dsn);
if (!$connection_string) {
error_log("No connection string found for DSN alias '$dsn'");
return FALSE;
}
$connector = self::getConnector($connection_string);
if (!$connector) {
error_log("Could not create connector for connection string '$connection_string'");
return FALSE;
}
if (!$connector->connect($connection_string)) {
$error = $connector->getError();
error_log("Can't connect: " . $error['message']);
return FALSE;
}
return $connector;
}
/**
* Gets a connector object based on a connection string
* @param {str} Connection string in parse_url format
* @return {obj} New instance of connector class
**/
public static function getConnector($connection_string) {
if (empty($connection_string)) {
return FALSE;
}
// If an existing version of this connector exists, no need to recreate
if (isset(self::$connectors[$connection_string])) {
return self::$connectors[$connection_string];
}
// Unit testing static method
if (self::$test_factory && method_exists(self::$test_factory, 'getConnector')) {
$f = self::$test_factory;
return $f->getConnector($connection_string);
}
// Create and store a new connector
$scheme = parse_url($connection_string, PHP_URL_SCHEME);
if (empty($scheme)) {
error_log("No scheme type in connection string '" . $connection_string . "'");
return FALSE;
}
$class_name = 'Connector_' . $scheme;
if (!class_exists($class_name)) {
$connector_path = dirname(__FILE__) . self::DIR_CONNECTORS . $scheme . '.connector.php';
@include $connector_path;
if (!class_exists($class_name)) {
error_log("Connector '" . $class_name . "' not found in '$connector_path'");
return FALSE;
}
}
self::$connectors[$connection_string] = new $class_name();
return self::$connectors[$connection_string];
}
/**
* Creates a connection to a data resource
* @param {str} daonut resource string in format DB.Table
* @param {str} Query type (default: 'select')
* @return {obj} Instance of a DynamicDao class
* @todo Reuse a DynamicDao if it already exists
**/
public static function create($resource, $type = 'select') {
if (!class_exists('DynamicDao')) {
error_log("Base class 'DynamicDao' has not been defined");
}
$resource = trim($resource);
if (empty($resource)) {
error_log("No table resource defined.");
return FALSE;
}
// Make sure query is of valid type
$allowed_query_types = array('select', 'update', 'insert', 'delete','info');
$type = strtolower($type);
if (!in_array($type, $allowed_query_types)) {
error_log("Invalid query type '" . $type . "' for resource '" . $resource . "'");
return FALSE;
}
$resource = strtolower($resource);
// If a data resource file exists, load its info
$class_name = 'DAO_' . str_replace('.', '_', $resource);
if (!class_exists($class_name)) {
@include dirname(__FILE__) . self::DIR_RESOURCES . str_replace('.', DIRECTORY_SEPARATOR, $resource) . '.dao.php';
}
// If the correct DAO exists in a file, use it
if (class_exists($class_name)) {
$dao = new $class_name();
if (!$dao instanceof DynamicDao) {
error_log("Resource '" . $resource . "' is not a valid DynamicDao");
return FALSE;
}
}
else { // No resource file found for this resource string
// Create a generic resource based on the resource string
$dao = new DynamicDao();
list($dao->db, $dao->table) = explode('.', $resource);
}
$connector = self::connect($resource);
// Create a QueryBuilder for the DynamicDao
if (class_exists('QueryBuilder')) {
$dao->setQueryBuilder(new QueryBuilder(array(get_class($connector), 'escape')));
$dao->querytype($type);
$dao->from($dao->table);
}
else {
// Try to include the QueryBuilder class file
@include dirname(__FILE__) . DIRECTORY_SEPARATOR . self::QUERY_BUILDER;
if (class_exists('QueryBuilder')) {
$dao->setQueryBuilder(new QueryBuilder(array(get_class($connector), 'escape')));
$dao->querytype($type);
$dao->from($dao->table);
}
}
$dao->connector = $connector;
$dao->usedb($dao->db);
return $dao;
}
/**
* Gets the connection string for a DSN alias
* Loads the DSN mapping information and returns the connection string for the given
* DSN alias.
* @param {str} DSN Alias
* @param {str} Mapping file name
* @return {str} Connection string in parse_url format
**/
public static function getConnectionString($alias, $file = 'dsn2connector.inc.php') {
// Unit testing static method
if (self::$test_factory && method_exists(self::$test_factory, __METHOD__)) {
$f = self::$test_factory;
return $f->__METHOD__($alias, $file);
}
if (empty(self::$dsn)) {
if (substr($file, 0, 1) == '/') {
@include $file;
}
else {
@include dirname(__FILE__) . DIRECTORY_SEPARATOR . $file ;
}
if (!isset($map)) {
return FALSE;
}
self::$dsn2connector = $map;
unset($map);
}
return isset(self::$dsn2connector[$alias])
? self::$dsn2connector[$alias]
: FALSE;
}
/**
* Gets the DSN alias for a database
* Loads the database mapping information and returns the DSN alias
* for the given database.
* @param {str} Database name
* @param {str}
**/
public static function getDSN($db, $file = 'db2dsn.inc.php') {
if (empty(self::$db2dsn)) {
if (substr($file, 0, 1) == '/') {
@include $file;
}
else {
@include dirname(__FILE__) . DIRECTORY_SEPARATOR . $file ;
}
if (!isset($map)) {
return FALSE;
}
self::$db2dsn = $map;
unset($map);
}
return isset(self::$db2dsn[$db])
? self::$db2dsn[$db]
: FALSE;
}
}
) is private.
