PHP静态成员没有持有值

Question

Hi i have a strange problem with a WordPress plugin that i am writing, but this isnt about WordPress per se and more to do with PHP so please read on so I can explain. The WordPress plugin is hooked up so that the init() function gets called... this works i can confirm it gets called once.

class MyClass
{
   static $i=0;

   public static function init()
   {
     self::$i++;
   }

   public static function dosomething()
   {
     echo 'i is = ' . self::$i;
   }
}

When callinf dosomething() for the first time from within Wordpress it is ok. I then have another ajax-response.php file which includes the above class and again calls dosomething, which prints the i value = 1.

The problem is the i value when calling via the ajax-response.php script is back to 0?

Its as if it is executing in a totally different memory space and creating a new program, such that static member variables are only shared between same process as opposed to multiple web threads.

Any ideas?

Thanks in advance,

Chris

Answer 1

Its as if it is executing in a totally different memory space and creating a new program, such that static member variables are only shared between same process as opposed to multiple web threads.`

Exactly! :) That's 100% how this works. Each PHP request is a new one, with its own memory. The static keyword is not designed to work around that.

If you want to persist stuff across multiple processes / requests in a web application, you need to use sessions.