04. Declare block content
There are several types of modules: block modules and node modules are two. Block modules create abbreviated content that is typically (but not always, and not required to be) displayed along the left or right side of a page. Node modules generate full page content (such as blog, forum, or book pages).
We'll create a block content to start, and later discuss node content, as well as filtering content. A module can generate content for blocks and also for a full page (the blogs module is a good example of this). The hook for a block module is appropriately called "block", so let's start our next function:
<?php
/**
* Generate HTML for the onthisdate block
* @param op the operation from the URL
* @param delta offset
* @returns block HTML
*/
function onthisdate_block($op='list', $delta=0) {
} // end function onthisdate_block
?>The block function takes two parameters: the operation and the offset, or delta. The offset allows you to create different content for different blocks, all within the same block function. We'll just worry about the operation at this point. In particular, we care about the specific case where the block is being listed in the blocks page. In all other situations, we'll display the block content.
When the module will be listed on the blocks page, the $op parameter's value will be 'list':
<?php
/**
* Generate HTML for the onthisdate block
* @param op the operation from the URL
* @param delta offset
* @returns block HTML
*/
function onthisdate_block($op='list', $delta=0) {
// listing of blocks, such as on the admin/block page
if ($op == "list") {
$block[0]["info"] = t('On This Date');
return $block;
}
} // end onthisdate_block
?>Next, we'll generate the block content.
More information about the block hook:
Download the code so far, (4.7 version) renaming to onthisdate.module before saving in your Drupal installation.
For more information see: Hook Block API documentation.