是否可以在Codeigniter中实现抽象基础模型？我创建了一个具有基本CRUD功能的抽象类，但我收到了“无法实例化抽象类”错误。
抽象模型位于/application/core/my_model.php中，只是
abstract class MY_Model extends CI_Model
{
无法实例化抽象类“在/system/core/Common.php的第174行
看起来Codeigniter正在尝试在加载时实例化my_model.php，我猜这是因为/ core文件夹中的文件被用作扩展核心系统文件（如Controller和Model）的地方。有没有办法阻止这个？我试图使用Phil Sturgeon's native autoload自动加载模型，但它没有帮助。
/*
| -------------------------------------------------------------------
| Native Auto-load
| -------------------------------------------------------------------
|
| Nothing to do with cnfig/autoload.php, this allows PHP autoload to work
| for base controllers and some third-party libraries.
|
*/
function __autoload($class)
{
if(strpos($class, 'CI_') !== 0)
{
@include_once( APPPATH . 'core/'. $class . EXT );
}
}
我意识到一个简单的方法就是将文件包含在我想要使用它的每个模型的顶部，但显然这不会是最佳的。
答案 0 :(得分：3)
为什么要让MY_Model抽象化？您可以将所有CRUD函数放入MY_Model中，并从MY_Model而不是CI_Model扩展模型。无需使用自动加载，因为只要您放入核心文件夹，CodeIgniter就允许您使用MY_Model扩展CI_Model。
一个好的MY_Model例子来自Jamie Rumbelow。你可以在这里找到它：https://github.com/jamierumbelow/codeigniter-base-model/
祝你好运！干杯
巴特
答案 1 :(得分：2)
我试图将Loader类调整为接受摘要和接口。
首先，我将所有编辑内容放入/application/core/MY_Loader.php中：
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
* CodeIgniter
*
* An open source application development framework for PHP 5.1.6 or newer
*
* @package CodeIgniter
* @author ExpressionEngine Dev Team
* @copyright Copyright (c) 2008 - 2011, EllisLab, Inc.
* @license http://codeigniter.com/user_guide/license.html
* @link http://codeigniter.com
* @since Version 1.0
* @filesource
*/
// ------------------------------------------------------------------------
// Joseff Betancourt - 11/14/2012 modified code by adding a autoloader and interface loader copied from model loader.
/**
* Loader Class
*
* Loads views and files
*
* @package CodeIgniter
* @subpackage Libraries
* @author ExpressionEngine Dev Team
* @category Loader
* @link http://codeigniter.com/user_guide/libraries/loader.html
*/
class MY_Loader extends CI_Loader {
// All these are set automatically. Don't mess with them.
/**
* Nesting level of the output buffering mechanism
*
* @var int
* @access protected
*/
protected $_ci_abstracts_paths = array();
/**
* List of paths to load models from
*
* @var array
* @access protected
*/
protected $_ci_interfaces_paths = array();
/**
* List of paths to load helpers from
*
* @var array
* @access protected
*/
protected $_ci_abstracts = array();
/**
* List of loaded interfaces
*
* @var array
* @access protected
*/
protected $_ci_interfaces = array();
/**
* List of loaded helpers
*
* @var array
* @access protected
*/
/**
* Constructor
*
* Sets the path to the view files and gets the initial output buffering level
*/
function __construct()
{
parent::__construct();
$this->_ci_abstracts_paths = array(APPPATH);
$this->_ci_interfaces_paths = array(APPPATH);
log_message('debug', "Loader Class Initialized");
}
// --------------------------------------------------------------------
/**
* Initialize the Loader
*
* This method is called once in CI_Controller.
*
* @param array
* @return object
*/
public function initialize()
{
$this->_ci_abstracts = array();
$this->_ci_interfaces = array();
$this->_ci_autoloader();
return $this;
}
// --------------------------------------------------------------------
/**
* Abstracts Loader
*
* This function lets users load and instantiate models.
*
* 11/14/2012 - Joseff Betancourt - Cloned from Models
*
* @param string the name of the class
* @param string name for the abstract
* @param bool database connection
* @return void
*/
public function abstracts($abstracts, $name = '', $db_conn = FALSE)
{
if (is_array($abstracts))
{
foreach ($abstracts as $babe)
{
$this->abstracts($babe);
}
return;
}
if ($abstracts == '')
{
return;
}
$path = '';
// Is the abstracts in a sub-folder? If so, parse out the filename and path.
if (($last_slash = strrpos($abstracts, '/')) !== FALSE)
{
// The path is in front of the last slash
$path = substr($abstracts, 0, $last_slash + 1);
// And the model name behind it
$abstracts = substr($abstracts, $last_slash + 1);
}
if ($name == '')
{
$name = $abstracts;
}
if (in_array($name, $this->_ci_abstracts, TRUE))
{
return;
}
$CI =& get_instance();
if (isset($CI->$name))
{
show_error('The model name you are loading is the name of a resource that is already being used: '.$name);
}
$abstracts = strtolower($abstracts);
foreach ($this->_ci_abstracts_paths as $mod_path)
{
if ( ! file_exists($mod_path.'abstracts/'.$path.$abstracts.'.php'))
{
continue;
}
if ($db_conn !== FALSE AND ! class_exists('CI_DB'))
{
if ($db_conn === TRUE)
{
$db_conn = '';
}
$CI->load->database($db_conn, FALSE, TRUE);
}
if ( ! class_exists('CI_Abstracts'))
{
load_class('Abstracts', 'core');
}
require_once($mod_path.'abstracts/'.$path.$abstracts.'.php');
$abstracts = ucfirst($abstracts);
$CI->$name = new $abstracts();
$this->_ci_abstracts[] = $name;
return;
}
// couldn't find the abstracts
show_error('Unable to locate the abstracts you have specified: '.$abstracts);
}
// --------------------------------------------------------------------
/**
* Interface Loader
*
* This function lets users load and instantiate interfaces.
*
* 11/14/2012 - Joseff Betancourt - Cloned from Models
*
* @param string the name of the class
* @param string name for the interface
* @param bool database connection
* @return void
*/
public function interfaces($interfaces, $name = '', $db_conn = FALSE)
{
if (is_array($interfaces))
{
foreach ($interfaces as $babe)
{
$this->interfaces($babe);
}
return;
}
if ($interfaces == '')
{
return;
}
$path = '';
// Is the abstracts in a sub-folder? If so, parse out the filename and path.
if (($last_slash = strrpos($interfaces, '/')) !== FALSE)
{
// The path is in front of the last slash
$path = substr($interfaces, 0, $last_slash + 1);
// And the model name behind it
$interfaces = substr($interfaces, $last_slash + 1);
}
if ($name == '')
{
$name = $interfaces;
}
if (in_array($name, $this->_ci_interfaces, TRUE))
{
return;
}
$CI =& get_instance();
if (isset($CI->$name))
{
show_error('The interface name you are loading is the name of a resource that is already being used: '.$name);
}
$interfaces = strtolower($interfaces);
foreach ($this->_ci_interfaces_paths as $mod_path)
{
if ( ! file_exists($mod_path.'interfaces/'.$path.$interfaces.'.php'))
{
continue;
}
if ($db_conn !== FALSE AND ! class_exists('CI_DB'))
{
if ($db_conn === TRUE)
{
$db_conn = '';
}
$CI->load->database($db_conn, FALSE, TRUE);
}
if ( ! class_exists('CI_Interfaces'))
{
load_class('Interfaces', 'core');
}
require_once($mod_path.'interfaces/'.$path.$interfaces.'.php');
$interfaces = ucfirst($interfaces);
$CI->$name = new $interfaces();
$this->_ci_interfaces[] = $name;
return;
}
// couldn't find the interfaces
show_error('Unable to locate the interfaces you have specified: '.$interfaces);
}
// --------------------------------------------------------------------
/**
* Autoloader
*
* The config/autoload.php file contains an array that permits sub-systems,
* libraries, and helpers to be loaded automatically.
*
* @param array
* @return void
*/
private function _ci_autoloader()
{
// Abstracts models
if (isset($autoload['abstracts']))
{
$this->model($autoload['abstracts']);
}
// Interfaces models
if (isset($autoload['interfaces']))
{
$this->model($autoload['interfaces']);
}
}
// --------------------------------------------------------------------
}
/* End of file Loader.php */
/* Location: ./system/core/Loader.php */
然后我将核心Model.php复制到Abstracts.php和Interfaces.php（将word替换为或者）并将它们放在application / core /文件夹中。
在Autoload中我添加了
/*
| -------------------------------------------------------------------
| Auto-load Interfaces
| -------------------------------------------------------------------
| Prototype:
|
| $autoload['interfaces'] = array('interface1', 'interface2');
|
*/
$autoload['interfaces'] = array();
/*
| -------------------------------------------------------------------
| Auto-load Abstracts
| -------------------------------------------------------------------
| Prototype:
|
| $autoload['abstracts'] = array('abstract1', 'abstract2');
|
*/
$autoload['abstracts'] = array();
最后我在app文件夹中添加了一个用于摘要和接口的目录。尚未完全证明，但我认为这是一种更全面的方法，允许一个人在需要引用时加载摘要。
此外，您还要在抽象文件夹中创建一个抽象，如下所示：
abstract class MY_Model extends CI_Model
{
blah
}
答案 2 :(得分：0)
将文件保存在/application/core/MY_model.php中：
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class MY_model extends CI_Model
{
public function __construct()
{
parent::__construct();
}
// Return all records in the table
public function get_all($table)
{
$q = $this->db->get($table);
if($q->num_rows() > 0)
{
return $q->result();
}
return array();
}
// Return only one row
public function get_row($table,$primaryfield,$id)
{
$this->db->where($primaryfield,$id);
$q = $this->db->get($table);
if($q->num_rows() > 0)
{
return $q->row();
}
return false;
}
// Return one only field value
public function get_data($table,$primaryfield,$fieldname,$id)
{
$this->db->select($fieldname);
$this->db->where($primaryfield,$id);
$q = $this->db->get($table);
if($q->num_rows() > 0)
{
return $q->result();
}
return array();
}
// Insert into table
public function add($table,$data)
{
return $this->db->insert($table, $data);
}
// Update data to table
public function update($table,$data,$primaryfield,$id)
{
$this->db->where($primaryfield, $id);
$q = $this->db->update($table, $data);
return $q;
}
// Delete record from table
public function delete($table,$primaryfield,$id)
{
$this->db->where($primaryfield,$id);
$this->db->delete($table);
}
// Check whether a value has duplicates in the database
public function has_duplicate($value, $tabletocheck, $fieldtocheck)
{
$this->db->select($fieldtocheck);
$this->db->where($fieldtocheck,$value);
$result = $this->db->get($tabletocheck);
if($result->num_rows() > 0) {
return true;
}
else {
return false;
}
}
// Check whether the field has any reference from other table
// Normally to check before delete a value that is a foreign key in another table
public function has_child($value, $tabletocheck, $fieldtocheck)
{
$this->db->select($fieldtocheck);
$this->db->where($fieldtocheck,$value);
$result = $this->db->get($tabletocheck);
if($result->num_rows() > 0) {
return true;
}
else {
return false;
}
}
// Return an array to use as reference or dropdown selection
public function get_ref($table,$key,$value,$dropdown=false)
{
$this->db->from($table);
$this->db->order_by($value);
$result = $this->db->get();
$array = array();
if ($dropdown)
$array = array("" => "Please Select");
if($result->num_rows() > 0) {
foreach($result->result_array() as $row) {
$array[$row[$key]] = $row[$value];
}
}
return $array;
}
}
然后像这样延伸
class any_model extends MY_Model
{
public function __construct()
{
parent::__construct();
}
}