Overview-approach to block visibility

Note: As of 5.x you can specify what roles can see a block through the block admin UI, but using PHP gives you extra flexibility.

1. Go to administer >> access control and ensure “administer blocks “ and “use PHP for block visibility” are checked for your role.
2. Go to administer >> blocks and find the block you want to set the visibility for.
3. Click “configure” next to that block.
4. Under the section entitled, “Page specific visibility settings”, click the radio button for “Show if the following PHP code returns TRUE”
5. In the text box provided, enter whichever of the following snippets meets your needs:

Show block only to logged in users:

Variation: “if (!$user->uid){“ will show block only to anonymous users.

Show block only to a particular role:

Variations: Replace "Approved Role" with whichever role you want to view it. Or use !in_array to hide it for that role.

Show block set of roles:

(Thanks Chris Herberte)

Don't show block set of roles:

Show block only to a particular user:

Variations: Replace the “1” with any UID.

Show block only for specific content type:

Variations: This example would show the block on all 'story' and 'page' type nodes. Just change line 2 - the $types array - to indicate which node types you want your block to appear on. Use the format 'nodetype' => 1 for each type you need. And yes, the array can hold single type only.

Combining PHP visibility control with specific page visibility:

When you choose the option to control visibility by PHP, you lose the ability to have Drupal automatically show/not show based on path. This workaround is a bit complex and clunky, but it works.

1. On the page administer >> blocks, hover over the configure link to view the URL. Most of the URLs will end in “configure/sometext/somenumber”. Make a note of the “sometext” and the “somenumber”.
2. Go to administer >> blocks >> add block (tab) . This new block will become the block that is shown so title it appropriately.
3. Set the block body input type to PHP.
4. Start out with this shell in the block body text area:
<?php
global $user;
$output = '';

return $output;
?>
5. Paste in just the “if” part from one of the snippets above. We’ll use the first snippet as an example. You should have something like this:
<?php
global $user;
$output = '';

if ($user->uid){
}

return $output;
?>
6. Add in the block calling code so it looks like this:
<?php
global $user;
$output = '';

if ($user->uid){
$block = SOMETEXT_block('view', SOMENUMBER);
$output =  $block['content'];
}

return $output;
?>
7. Replace with the “SOMETEXT” and “SOMENUMBER” that you noted in step 1.
8. The final result should look something like this:
<?php
global $user;
$output = '';

if ($user->uid){
$block = menu_block('view', 10);
$output =  $block['content'];
}

return $output;
?>
9. That takes care of showing the block only to logged in users (or whatever snippet you used). Next go to the “Page specific visibility settings” section and set one of the first two radio buttons as normal.
10. Enable and place this new block and disable the old one. You may find it helpful to change the title on the original block to differentiate them.