Author: Vinny Panne

The following code example pulls out the last 5 published WordPress posts by their ID, extracts the first ID (which is the last published post ID) and then extracts the post’s tags into an array.

$return_tag_array is a list of the last published post’s tags.

  //Get list of past published posts, up to 5
  $args = array(
	'numberposts' => 5,
	'offset' => 0,
	'category' => 0,
	'orderby' => 'post_date',
	'order' => 'DESC',
	'include' => '',
	'exclude' => '',
	'meta_key' => '',
	'meta_value' =>'',
	'post_type' => 'post',
	'post_status' => 'publish',
	'suppress_filters' => true
);
	
  $published_posts = wp_get_recent_posts( $args, ARRAY_A );

  //Pull off the top most post, & retrieve the ID
  $last_published_post = reset($published_posts);
  $last_published_post_id = $last_published_post["ID"];

  //TAGS	
  //Use the post ID to pull off tags
  $tags = wp_get_post_tags($last_published_post_id);
  $return_tag_array = array();	
  foreach ($tags as $tag) {
	  $tag_name = $tag->name;
	  array_push($return_tag_array, $tag_name);
  }

I’ve been writing a custom WordPress plugin to accept emailed posts and insert them into a WordPress blog. One of the difficult issues I’ve encountered is that WordPress deals with tags and categories in different ways: it’s relatively easy to add and remove tags. It takes a bit of roundabout work to do the same with categories.

The below code fragment takes a string array of categories ( $to_post_categories ) and sets them onto a post (the ID of the post is in $created_post_id ).

	//Set post categories
	/**
	 * WP doesn't allow us to set categories as easily as tags. With tags we can simply declare 
	 * the names of the tags and be done with it. WP requires that we pass in the ID of the category, 
	 * and if the category doesn't exist, we need to create it. So we loop through the array of 
	 * category names, see if they exist (and if so, collect the ID) and if they don't exist, 
	 * create the category and map the ID to the post.
	 **/
	 foreach ($to_post_categories as $category_name) {
		 $category_id = get_category_by_slug($category_name);
		 if ($category_id == false) {
			 //Category doesn't exist, create it
			 $category_id = wp_create_category($category_name);
		 }
		 
		 //category_id now holds ID of right category or recently created category.
		 //Add category to post
		 wp_set_post_categories($created_post_id, array($category_id), true);
	 }//end looping through post categories sent to us