Drupal PHP block visibility rules - drupal

Question

In a Drupal block's Page Visibility Settings I'd like to prevent a certain block from showing if the second value in the path is a number. This does not seem to be working for me. Cheers.
Show block ONLY when arguments are:
domain.com/video/one (arg 0 is 'video' and arg 1 is present and NOT a number)
Don't show:
domain.com/video
domain.com/video/1
<?php
if (arg(0) == 'video' && is_nan(arg(1)) && empty(arg(2))) {
return TRUE;
}
else {
return FALSE;
}
?>

Answer 1

I'm assuming this is in a hook_block/hook_block_view function? You could try a different approach:
if (preg_match('/^video\/[0-9]+$/', $_GET['q'])) {
// Path has matched, don't show the block. Are you sure you should be returning TRUE here?
return TRUE;
}
else {
// Path has matched, go ahead and show the block
return FALSE;
}

Answer 2

You can simply use the following code:
<?php
$arg1 = arg(1);
$arg2 = arg(2);
// Check arg(1) is not empty, or is_numeric() returns TRUE for NULL.
return (arg(0) == 'video' && !empty($arg1) && !is_numeric($arg1) && empty($arg2));
?>
As KingCrunch already said, is_nan() doesn't return TRUE when its argument is a number.
The code you reported contains another error too: empty() can be used only with variables, as reported in the PHP documentation.
empty() only checks variables as anything else will result in a parse error. In other words, the following will not work: empty(trim($name)).
The code I reported shows the block for paths like "video/video1"; if you want to show the block also for paths such as "video/video1/edit", then the following code should be used.
<?php
$arg1 = arg(1);
return (arg(0) == 'video' && !empty($arg1) && !is_numeric($arg1));
?>
Using arg() doesn't work if the path you are looking for is a path alias. Suppose that "video/video1" is a path alias for "node/10"; in that case arg(0) will return "node," and arg(1) will return "10." The same is true for $_GET['q'] that will be equal to "node/10."
This happens because Drupal, during its bootstrap, initialize $_GET['q'] with the following code:
// Drupal 6.
if (!empty($_GET['q'])) {
$_GET['q'] = drupal_get_normal_path(trim($_GET['q'], '/'));
}
else {
$_GET['q'] = drupal_get_normal_path(variable_get('site_frontpage', 'node'));
}
// Drupal 7.
if (!empty($_GET['q'])) {
$_GET['q'] = drupal_get_normal_path($_GET['q']);
}
else {
$_GET['q'] = drupal_get_normal_path(variable_get('site_frontpage', 'node'));
}
If you what you are checking is a path alias, then you should use the following code:
// Drupal 6.
$arg = explode('/', drupal_get_path_alias($_GET['q']);
return (arg[0] == 'video' && !empty($arg[1]) && !is_numeric(arg[1]) && empty($arg[2]));
// Drupal 7.
$arg = explode('/', drupal_get_path_alias();
return (arg[0] == 'video' && !empty($arg[1]) && !is_numeric(arg[1]) && empty($arg[2]));

Answer 3

Dont know, what your arguments looks like, but I assume you mixed up two kinds of types. is_nan() only works with numbers. If you want to test, if a value is a number,
var_dump(is_numeric(arg(1));
is_nan() tests, if a "numeric" value is a concrete value or "not a number" like "infinite" or the result of "0/0" or such.