PHP OOP - 如何定义带有变量或函数输出的 CONST？

Question

我的具体情况是，我正在尝试将路径定义为常量。现在我这样硬编码:

class Cache
{
   const PATH_TO_CACHE = '/home/site/public_html/wp-content/themes/theme/cache/';

但我需要定义是可移植的。所以可以检测路径，放入变量，然后放入类。本质上，我想要完成的是:

$somepath = {code to get path};

class Cache 
{
const PATH_TO_CACHE = $somepath;

Answer 1

我喜欢为此使用依赖注入(inject)。例如:

class Cache {

  private $path_to_cache;

  function __construct($cache_path) {
    $this->path_to_cache = $cache_path;
  } 

}

然后您可以使用定义的设置:

$cache = new Cache($GLOBALS['config']['cache_path']);
$cache = new Cache($_SERVER['cache_path']);
$cache = new Cache($some_other_way_to_get_cache_path);

等等

您也可以在开发/调试时轻松更改路径:

$cache = new Cache('path/to/folder/that/is/being/problematic');