CI的适配器使用经验
本帖最后由 ^淡如清风 于 2013-9-24 15:40 编辑CI的适配器类有点像抽象类
使用 CodeIgniter 适配器：http://codeigniter.org.cn/user_guide/general/drivers.html
创建适配器：http://codeigniter.org.cn/user_g ... eating_drivers.html
首先看完以上两个教程，5-10分钟
然后转看使用适配器的缓存适配器 ：http://codeigniter.org.cn/user_guide/drivers/caching.html
适配器父类：
/application/libraries/Driver_name/Driver_name.php
适配器子类：
/application/libraries/Driver_name/drivers/Driver_name_subclass_1.php
/application/libraries/Driver_name/drivers/Driver_name_subclass_2.php
注意红色子的名称，这个是适配器的名称，全部必须相同
子类名称：命名方法是 适配器的名称（Driver_name）+下划线（_）+子类的名称（subclass_1、_subclass_2）
（另外子类的名称的前缀是可以修改的，继承的类中 给 ib_name 属性赋值，即可改变子类名称前缀的命名，如果没有的话，直接用类名作为子类的前缀名称）
关键点1：什么时候才会载入适配器的子类呢？
由于适配器父类继承自/system/libraries/Driver.php的class CI_Driver_Library
查看源代码可知：
当使用一个属性，且这个属性没有被定义时，这个属性其实就相当于实例化了这个子类，并赋值给这个属性
class CI_Driver_Library {
protected $valid_drivers = array();
protected $lib_name;
// The first time a child is used it won't exist, so we instantiate it
// subsequents calls will go straight to the proper child.
function __get($child)
{
if ( ! isset($this->lib_name))
{
$this->lib_name = get_class($this);
}
// The class will be prefixed with the parent lib
$child_class = $this->lib_name.'_'.$child;
// Remove the CI_ prefix and lowercase
$lib_name = ucfirst(strtolower(str_replace('CI_', '', $this->lib_name)));
$driver_name = strtolower(str_replace('CI_', '', $child_class));
if (in_array($driver_name, array_map('strtolower', $this->valid_drivers)))
{
// check and see if the driver is in a separate file
if ( ! class_exists($child_class))
{
// check application path first
foreach (get_instance()->load->get_package_paths(TRUE) as $path)
{
// loves me some nesting!
foreach (array(ucfirst($driver_name), $driver_name) as $class)
{
$filepath = $path.'libraries/'.$lib_name.'/drivers/'.$class.'.php';
if (file_exists($filepath))
{
include_once $filepath;
break;
}
}
}
// it's a valid driver, but the file simply can't be found
if ( ! class_exists($child_class))
{
log_message('error', "Unable to load the requested driver: ".$child_class);
show_error("Unable to load the requested driver: ".$child_class);
}
}
$obj = new $child_class;
$obj->decorate($this);
$this->$child = $obj;
return $this->$child;
}
// The requested driver isn't valid!
log_message('error', "Invalid driver requested: ".$child_class);
show_error("Invalid driver requested: ".$child_class);
}
// --------------------------------------------------------------------
}
// END CI_Driver_Library CLASS
说的神马... :@:@:@:@:@:@:@
页:
[1]