Codeigniter：核心类中的加载库 [英] Codeigniter: Load Library in a Core Class
问题描述
我想用几个函数扩展 /system/core/Log.php 库。如果发生错误，则一个函数应通过自定义函数 sendMail（）发送邮件，该函数是 Custom_library.php 。
I want to extend the /system/core/Log.php library with a couple of functions. One function should send a mail in case of an error via the custom function sendMail() which is part of the Custom_library.php.
因此，我创建了文件 /application/core/MY_Log.php
class MY_Log extends CI_Log {
public function __construct()
{
parent::__construct();
}
public function write_log($level, $msg)
{
$result = parent::write_log($level, $msg);
return $result;
}
}
问题：我无法加载 Custom_library.php 。这些方法都不起作用：
The problem: I'm not able to load the Custom_library.php. None of these approaches worked:
//approach 1
$this->load->library('Custom_library');
//approach 2
$CI =& get_instance();
$CI->load->library('Custom_library');
方法2的错误消息：
Fatal error: Uncaught Error: Class 'CI_Controller' not found in /home/gp/public_html/system/core/CodeIgniter.php:366 Stack trace: #0 /home/gp/public_html/application/core/MY_Log.php(13): get_instance() #1 /home/gp/public_html/system/core/Common.php(478): MY_Log->write_log('error', 'Severity: error...') #2 /home/gp/public_html/system/core/Exceptions.php(105): log_message('error', 'Severity: error...') #3 /home/gp/public_html/system/core/Common.php(662): CI_Exceptions->log_exception('error', 'Exception: Clas...', '/home/gp/public...', 366) #4 [internal function]: _exception_handler(Object(Error)) #5 {main} thrown in /home/gp/public_html/system/core/CodeIgniter.php on line 366
问题：是否可以在核心类中加载和利用库？
The question: Is it possible to load and utilize a Library in a Core Class?
我尝试了通过函数& load_class 。
function &load_class($class, $directory = 'libraries', $param = NULL)
{
static $_classes = array();
// Does the class exist? If so, we're done...
if (isset($_classes[$class]))
{
return $_classes[$class];
}
$name = FALSE;
// Look for the class first in the local application/libraries folder
// then in the native system/libraries folder
foreach (array(APPPATH, BASEPATH) as $path)
{
if (file_exists($path.$directory.'/'.$class.'.php'))
{
$name = 'CI_'.$class;
if (class_exists($name, FALSE) === FALSE)
{
require_once($path.$directory.'/'.$class.'.php');
}
break;
}
}
// Is the request a class extension? If so we load it too
if (file_exists(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.'.php'))
{
$name = config_item('subclass_prefix').$class;
if (class_exists($name, FALSE) === FALSE)
{
require_once(APPPATH.$directory.'/'.$name.'.php');
}
}
// Did we find the class?
if ($name === FALSE)
{
// Note: We use exit() rather than show_error() in order to avoid a
// self-referencing loop with the Exceptions class
set_status_header(503);
echo 'Unable to locate the specified class: '.$class.'.php';
exit(5); // EXIT_UNK_CLASS
}
// Keep track of what we just loaded
is_loaded($class);
$_classes[$class] = isset($param)
? new $name($param)
: new $name();
return $_classes[$class];
}
如果我运行函数 $ CI =& load_class（'Custom_library'）; 会找到正确的文件，但会查找带有前缀 CI_的Class。并因此引发并显示错误消息：
If I run the function $CI =& load_class('Custom_library'); it finds the right file but than is looking for the Class with a prefix "CI_" and thus throws and error message:
Fatal error: Uncaught Error: Class 'CI_Custom_library' not found in /home/gp/public_html/system/core/Common.php:196 Stack trace: #0 /home/gp/public_html/application/core/MY_Log.php(14): load_class('Custom_library') #1 /home/gp/public_html/system/core/Common.php(478): MY_Log->write_log('error', 'Severity: error...') #2 /home/gp/public_html/system/core/Exceptions.php(105): log_message('error', 'Severity: error...') #3 /home/gp/public_html/system/core/Common.php(662): CI_Exceptions->log_exception('error', 'Exception: Clas...', '/home/gp/public...', 196) #4 [internal function]: _exception_handler(Object(Error)) #5 {main} thrown in /home/gp/public_html/system/core/Common.php on line 196
推荐答案
扩展 CI_Log 不起作用。原因是在创建返回。 $ CI 之前创建 CI_Log 很久，因此对于<$ c $没有可用的实例 c>& get_instance（）
Extending CI_Log is not going to work if you need to access other libraries. The reason is CI_Log is created long before $CI is created so no "instance" is available for &get_instance() to return.
$ this->加载不起作用，因为 $ this 不是控制器（ $ this 和 $ CI 指向同一对象）和类 load （'CI_Loader'）尚未创建。
$this->load doesn't work because $this is not a controller ($this and $CI point to the same object) and the class load ('CI_Loader') hasn't been created yet either.
解决这个问题的方法可能不止一种。在我看来，最不容易破解的方法是使您的记录器类使用 CI_Log 而不是扩展。
There might be more than one way around this. Seems to me the least hacked way is to make your logger class utilize CI_Log instead of extend it.
应用程序/库/Logger.php
class Logger
{
protected $CI;
public function __construct()
{
$this->CI = & get_instance();
$this->CI->load->library('custom_library');
}
public function write_log($level, $msg)
{
//do stuff with "custom_library"
$this->CI->custom_library->some_function();
//use the built-in logging mechanism, a.k.a. CI_Log
return log_message($level, $msg);
}
}
您的记录器将需要与其他任何库一样加载到Controller中。
Your `logger' will need to be loaded in a Controller the same as any other library.
$this->load->library('logger');
使用示例可能是这样的
$this->logger->write_log('error', "This is FUBAR");
在您呼叫 $ this-> load-> library时（'logger'）; log 类已创建，并且是 $ CI （又名 $ this ）。因此，此行
By the time you call $this->load->library('logger'); the log class has been created and is part of $CI (a.k.a. $this). So this line
//use the built-in logging mechanism, a.k.a. CI_Log
return log_message($level, $msg);
可以用这种方式完成
//use the built-in logging mechanism, a.k.a. CI_Log
return $this->CI->log->write_log($level, $msg);
由于所有 log_message 确实还是调用 log-> write_log 。我没有看到任何问题，而不是使用 log_message 。
That would be marginally more efficient since all log_message does is call log->write_log anyway. I don't see any problem doing this instead of using log_message.
有趣的问题，我学到了很多看着它。谢谢。
Interesting question and I learned a bunch by looking into it. Thanks.
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