Detailed explanation of CodeIgniter extended core class examples, detailed explanation of codeigniter_PHP tutorial

Detailed explanation of CodeIgniter extended core class examples, detailed explanation of codeigniter

The example in this article describes the method of CodeIgniter extending core class. Share it with everyone for your reference, the details are as follows:

The extension of core classes, auxiliary classes and functions in CI is quite convenient. The subclass_prefix extension prefix is ​​specified in the configuration file. The default is MY_. This configuration needs to be used as the prefix when extending. The extension methods are summarized below.

1. Extend core classes

The core classes are located under system/core, and most of them will be automatically loaded during initialization. There are two ways to extend core classes: replacing core classes and inheriting core classes.

Replace core classes

When a file with the same name as system/core exists in the application/core directory, the core class will be automatically replaced. Taking Loader.php as an example, this class will be automatically loaded after application/core/Loader.php is created. Since this class is the core class of the system, if Loader.php does not implement the methods in the CI_Loader class, an error will be reported, such as:

class CI_Loader
{
  ...
}

Replacing the core class requires rewriting all methods in it to avoid affecting the core functionality. But most of the time, there is no need to rewrite the entire core. Basically, it is just to add certain methods. In this case, inheritance can be used.

Inherit core classes

Inheriting the core class needs to be prefixed with subclass_prefix. If you extend the Input class, you need to create application/core/MY_Input.php, and MY_Input needs to inherit the CI_Input class, such as:

<&#63;php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class MY_Input extends CI_Input
{
  function _clean_input_keys($str)
  {
    $config = &get_config('config');
    if ( ! preg_match("/^[".$config['permitted_uri_chars']."]+$/i", rawurlencode($str))) {
      exit('Disallowed Key Characters.');
    }
    // Clean UTF-8 if supported
    if (UTF8_ENABLED === TRUE) {
      $str = $this->uni->clean_string($str);
    }
    return $str;
  }
}
/* End of file MY_Input.php */
/* Location: ./application/core/MY_Input.php */

2. Extended CI library

Some auxiliary classes are implemented under system/libraries. When it is necessary to extend these classes, the processing method is the same as the core class, except that the directory becomes application/libraries

3. Extended auxiliary functions

The auxiliary functions are stored in the application/helpers directory. The "inheritance" method of the auxiliary functions is the same as above. Because CI's auxiliary functions all use function_exists to determine whether they exist, the purpose of "rewriting" can also be achieved. For example, add an array sorting method in array:

<&#63;php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * 对二维数组进行排序
 * 
 * @param array $data 需要排序的字段
 * @param array $sort_field 按哪个键进行排序，如果不是所有键中都含有该字段则返回原数组
 * @param array $sort_type 排序方式 SORT_ASC 升序 SORT_DESC 降序
 * @return array
 */
function array_field_sort($data, $sort_field, $sort_type = SORT_ASC)
{
  if(! is_array($data)) {
    return false;
  }
  $sort_arr = array();
  foreach($data as $key => $val) {
    if(isset($val[$sort_field])) {
      $sort_arr[$key] = $val[$sort_field];
    }
  }
  if(count($sort_arr) == count($data)) {
    array_multisort($sort_arr, $sort_type, $data);
  }
  return $data;
}
/* End of file MY_array_helper.php */
/* Location: ./application/helpers/MY_array_helper.php */

In general, most of the content in the system directory of the CI framework can be rewritten, which is very flexible and easy to expand. But sometimes you need to pay attention. The more extensions, the better. Ensure that the functions that CI cannot be implemented are expanded. Finally, since CI provides extended functions, do not modify the content under system directly.

Readers who are interested in more codeigniter related content can check out the special topics on this site: "Introduction to codeigniter tutorial" and "CI (CodeIgniter) framework advanced tutorial"

I hope this article will be helpful to everyone’s PHP program design based on the CodeIgniter framework.

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