Drupal 7 Module Development

Chapter 4
Our single_blog_block_info() function is a simple hook_block_info()
implementation as described in Chapter 2. We return an array of information that
describes the blocks that our module provides. Each key in the array is the "delta"
for that block. The delta, when combined with the name of the module, creates
the unique block ID for a block which is stored in the block.tpl.php file's
$block_html_id. For example, we've defined our "recent blog posts" block as
having a delta of recent, so its full block ID is single-blog-recent. The block ID
is used by Drupal to assign blocks to regions. The "info" returned by our
single_blog_block_info() function defines the block "name" that you see
on the block administration page.
The single_blog_block_view() function implements hook_block_view().
When Drupal wants to render a particular block, it calls the hook_block_view()
implementation of the module responsible for the block, passing in the block's
$delta as a parameter. Our function first checks the $delta given to it and then
returns the requested block's data as an array containing the block title in the
subject key and its contents in the content key. First, we're going to set the block
title using the t() function. From Chapter 2, you should recall that t() translates
English language strings into other languages. Then our function checks that the
user viewing the page can access the website's content via user_access('access
content'); this call checks if the current user has the access content permission. If
the current user doesn't have the proper permission, you'll notice that our function
returns an empty content key; this signals to Drupal that the requested block should
not be rendered.
The last thing we're going to do before we finally start theming is to call our API
function, single_blog_list(), in order to get the raw data from the database.
Actually, single_blog_list() returns a result set object, but we haven't learned
any special Database API functions to retrieve each row from the result set object. If
we just iterate over this object using foreach, we'll get a series of objects that contain
each row's data.
foreach ($result as $node) { }
Specifically, each time through the foreach loop, $node will be an object with
properties for each database field we requested, nid, title, created, and uid.
When the $result object has processed all the rows, the foreach loop will
automatically end.
[ 97 ]