5
function menufun_menu() {
  $items['menufun/%/bar/baz'] = array(
    'title' => 'Hi',
    'page callback' => 'menufun_hello',
    'page arguments' => array(1), // The matched wildcard.
    'access callback' => TRUE,
  );

  return $items;
}

/**
* Page callback.
*/
function menufun_hello($a = NULL, $b = NULL) {
  return t('Hello. $a is @a and $b is @b', array('@a' => $a, '@b' => $b));
}

In the menufun_menu() function, the page argument for the menufun_hello callback is only one. Why does menufun_hello() have two parameters?

2 Answers 2

7

Menu callbacks are passed first the arguments defined in page arguments then excess arguments from the url.

So in the above example:

menufun/1/bar/baz

Will provide these vars:

$a = 1;
$b = NULL;

If you however provide an extra argument in the url:

menufun/1/bar/baz/2

You will transfer it to the menu callback:

$a = 1;
$b = 2;

The other advantedge is like tim writes, that it allows reuse of the same code for various cases, making the module more maintainable.

3
  • in this url menufun/1/bar/baz/2, why it transfer 2 to the $b?
    – enjoylife
    Commented Mar 30, 2011 at 15:41
  • 1
    @enjoylife because it's the first non required argument. If baz was left out, the url wouldn't match, so it's not included, unless included under 'page arguments'
    – googletorp
    Commented Mar 30, 2011 at 17:03
  • You can have an unlimited number of arguments after the required ones - eg menufun/1/bar/baz/2/arg3/arg4 will pass 4 arguments to your page callback - 1, 2, arg3, and arg4.
    – cam8001
    Commented Mar 31, 2011 at 9:16
1

In this case, menufun_hello() takes up to two arguments, but as little as zero, since it provides defaults. This means that menufun_menu() could later pass another argument, and the function signature wouldn't have to change.

1
  • 1
    The function will always be called with at least one argument, because that is required in the menu definition. So the = NULL part is unecessary (unless that function is re-used in another menu definition for example)
    – Berdir
    Commented Mar 30, 2011 at 15:33

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