Question

I am creating functions in my code to clean it up, one of them is for working out the offset for pagination.

The function is

function pageOffSet($page, $count, $resultsPerPage) {
     // WORK OUT HIGHEST PAGE NUMBER
     $pageCount = ceil($count / $resultsPerPage);
     // IF GET PAGE VARIABLE IS HIGHER THAN MAX PAGE POSSIBLE
     if (isset($page) && $page > $pageCount) {
          $page = $pageCount;
     // IF VALID GET PAGE VARIABLE
     } elseif (isset($page) && is_numeric($page) && $page > 1) { 
          $page = $page;
     // IF PAGE GET VARIABLE NOT SET
     } else { 
          $page = 1;
     }
     // OFFSET FOR POST RESULTS
     $offSet = ($page - 1) * $resultsPerPage;
     return array('offSet' => $offSet, 'resultsPerPage' => $resultsPerPage);
}

And I call it like,

$page = pageOffSet($_GET['page'], $count, 15);

Except $_GET['page'] may be set or unset? I check inside the function to see if it is set or not, but is it ok to do this? I get no errors but I just want to check?

Answer 1

An error will not occur, but a warning will probably be generated, depending on your error reporting settings. However, a better approach may be using an default argument:

function pageOffSet($count, $resultsPerPage, $page = NULL) { ... }

Then to check if $page is there, use:

if ($page)

Or to check if it’s not there, use:

if (!$page)

This way, you can use the first two arguments without needing to provide the last; or you can provide all three. To use $page, check if it is NULL or not and use it accordingly.