Hiç büyük bir değer ama oldukça düzgün izah değil hissediyorum bir öğretici tökezledi? Bu benim ikilem. I THIS TUTORIAL bazı değer biliyorum ama sadece bunu elde edemez.

1. Nereye her işlev diyorsunuz?
2. Which function should be called first and which next, and which third?
3. Tüm işlevler bir uygulamadaki tüm dosyalarda adı verilecek?
4. Herkes "Geri Düğmesi Blues" tedavi daha iyi bir yol biliyor mu?

Bu makalenin yazarı içeren bazı iyi konuşma heyecan olacak merak ediyorum. Ben özellikle ilgilendiğim kısmı geri düğmesine basıldığında bir veritabanına formu yinelenen girişleri önlemek için geri düğmesini kontrol edilir. Temelde, uygulamanızda komut yürütülmesi sırasında şu üç işlevi çağırarak geri düğmesini kontrol etmek istiyorum. Tam olarak ne (yukarıdaki soruya bakınız) işlevleri çağırmak amacıyla öğretici açık değildir.

All forwards movement is performed by using my scriptNext function. This is called within the current script in order to activate the new script.

function scriptNext($script_id)
// proceed forwards to a new script
{
   if (empty($script_id)) {
      trigger_error("script id is not defined", E_USER_ERROR);
   } // if

   // get list of screens used in this session
   $page_stack = $_SESSION['page_stack'];
   if (in_array($script_id, $page_stack)) {
      // remove this item and any following items from the stack array
      do {
         $last = array_pop($page_stack);
      } while ($last != $script_id);
   } // if

   // add next script to end of array and update session data
   $page_stack[] = $script_id;
   $_SESSION['page_stack'] = $page_stack;

   // now pass control to the designated script
   $location = 'http://' .$_SERVER['HTTP_HOST'] .$script_id;
   header('Location: ' .$location); 
   exit;

} // scriptNext

When any script has finished its processing it terminates by calling my scriptPrevious function. This will drop the current script from the end of the stack array and reactivate the previous script in the array.

function scriptPrevious()
// go back to the previous script (as defined in PAGE_STACK)
{
   // get id of current script
   $script_id = $_SERVER['PHP_SELF'];

   // get list of screens used in this session
   $page_stack = $_SESSION['page_stack'];
   if (in_array($script_id, $page_stack)) {
      // remove this item and any following items from the stack array
      do {
         $last = array_pop($page_stack);
      } while ($last != $script_id);
      // update session data
      $_SESSION['page_stack'] = $page_stack;
   } // if

   if (count($page_stack) > 0) {
      $previous = array_pop($page_stack);
      // reactivate previous script
      $location = 'http://' .$_SERVER['HTTP_HOST'] .$previous;
   } else {
      // no previous scripts, so terminate session
      session_unset();
      session_destroy();
      // revert to default start page
      $location = 'http://' .$_SERVER['HTTP_HOST'] .'/index.php';
   } // if

   header('Location: ' .$location); 
   exit;

} // scriptPrevious

Whenever a script is activated, which can be either through the scriptNext or scriptPrevious functions, or because of the BACK button in the browser, it will call the following function to verify that it is the current script according to the contents of the program stack and take appropriate action if it is not.

function initSession()
// initialise session data
{
   // get program stack
   if (isset($_SESSION['page_stack'])) {
      // use existing stack
      $page_stack = $_SESSION['page_stack'];
   } else {
      // create new stack which starts with current script
      $page_stack[] = $_SERVER['PHP_SELF'];
      $_SESSION['page_stack'] = $page_stack;
   } // if

   // check that this script is at the end of the current stack
   $actual = $_SERVER['PHP_SELF'];
   $expected = $page_stack[count($page_stack)-1];
   if ($expected != $actual) {
      if (in_array($actual, $page_stack)) {// script is within current stack, so remove anything which follows
      while ($page_stack[count($page_stack)-1] != $actual ) {
            $null = array_pop($page_stack);
         } // while
         $_SESSION['page_stack'] = $page_stack;
      } // if
      // set script id to last entry in program stack
      $actual = $page_stack[count($page_stack)-1];
      $location = 'http://' .$_SERVER['HTTP_HOST'] .$actual;
      header('Location: ' .$location);
      exit;
   } // if

   ... // continue processing

} // initSession

The action taken depends on whether the current script exists within the program stack or not. There are three possibilities:

• The current script is not in the $page_stack array, in which case it is not allowed to continue. Instead it is replaced by the script which is at the end of the array.
• The current script is in the $page_stack array, but it is not the last entry. In this case all following entries in the array are removed.
• The current script is the last entry in the $page_stack array. This is the expected situation. Drinks all round!