Category: PHP

Instructions:

1. Copy/paste this into your functions.php (TODO: convert it to a standalone php file, and make it into a plygin you can activte/deactivate)
2. Create a new menu item of type “custom URL”
3. Make your URL “http://#latestpost:category_name”
   • where “category_name” is the name of the category whose latest post you want to link to
4. Make the name whatver you want to appear on the menu
5. Profit!

Based on an idea (with some upgrading + bugfixes for latest WordPress in 2016) from http://www.viper007bond.com/2011/09/20/code-snippet-add-a-link-to-latest-post-to-wordpress-nav-menu/

[php]
/** Adam: add support for putting ‘latest post in category X’ to menu: */
// Front end only, don’t hack on the settings page
if ( ! is_admin() ) {
// Hook in early to modify the menu
// This is before the CSS "selected" classes are calculated
add_filter( ‘wp_get_nav_menu_items’, ‘replace_placeholder_nav_menu_item_with_latest_post’, 10, 3 );
}

// Replaces a custom URL placeholder with the URL to the latest post
function replace_placeholder_nav_menu_item_with_latest_post( $items, $menu, $args ) {

$key = ‘http://#latestpost:’;

// Loop through the menu items looking for placeholder(s)
foreach ( $items as $item ) {

// Is this the placeholder we’re looking for?
if ( 0 === strpos( $item->url, $key ) )
{

$catname = substr( $item->url, strlen($key) );
// Get the latest post
$latestpost = get_posts( array(
‘posts_per_page’ => 1,
‘category_name’ => $catname
) );

if ( empty( $latestpost ) )
continue;

// Replace the placeholder with the real URL
$item->url = get_permalink( $latestpost[0]->ID );
}
}

// Return the modified (or maybe unmodified) menu items array
return $items;
}
[/php]

(aka “why do my include/require/include_once/require_once files not work / seem NOT to be included, even though they are?”)

PHP has a mechanism for including files inside each other. The architects of PHP didn’t really think much about what they were doing with a lot of the core language features (witness the foolishness over Register Globals), and file import/include/require is a classic example.

This is one of the most fundamental features of the language, and it’s screwed up. It “seems” to work, so long as you write simplistic enough / small enough apps. The bigger your app, the more likely it is you’ll discover how poor this part of the language is.

Sadly, the code snippets on MySQL’s main website for PHP are mostly untested and buggy (try running them – half of them don’t execute because of silly mistakes).

After much trial and error, here’s one that *actually works*:

// Missing feature (?) from MySQL: find the list of valid ENUM values for a given ENUM
// (actually, returns all the value-arrays for ALL the enum fields in a given table, by name)
// ---------------------------------------------------------
function fetchEnumValuesForTable( $tablename )
{
	global $db; // assuming you're using PEAR:DB here, and throughout (I use it, or MDB, exclusively)
	
	$enumresult = $db->query("SHOW COLUMNS FROM $tablename");

	// Makes arrays out of all ENUM type fields.
	// Uses the field names as array names and skips non-ENUM fields
	while( $enumrow = $enumresult->fetchRow() )
	{
		extract($enumrow);
		if (substr($Type, 0, 4) != 'enum') continue;

		$Type = str_replace('enum', 'array', $Type);
		
		// Add to array
		eval( '$tmp = '."$Type;" ); // I'm not sure why, but I had to do this
		// intermediate step to get it to work
		
		$results[$Field] = $tmp;
	}
	
	return $results; // returns an array mapping each enum's "column name"
	// to "array of elements valid fo that ENUM"
}