Primary Category

WordPress Plugin that allows publishers/users to designate a primary category for posts/custom post types and query posts/custom post types based on their primary categories

Installation

1. Copy the primary-category folder into your wp-content/plugins folder
2. Activate the Primary Category plugin via the plugin admin page

Settings

Enable primary category feature?

1. Open the settings page from your dashboard Settings > Primary Category.
2. Select the taxonomies what you want to enable the feature.
3. After selecting taxonomies, click in the save changes button.

Settings > Primary Category

Settings Page

Set as Primary Category

After enabling a taxonomy from settings, select primary categories from post-edit or post-new screen.

Functions

Name	Argument(s)
the_primary_category	$taxonomy required support mixed ( int, WP_Term, object, string ) ----- $post_id required support mixed ( int, WP_Post, NULL ) default value: NULL ----- string $output optional default value: "link" others values: "name" ----- $echo optional default value: true

Basic example

$args = array(
	'post_type' => 'product',
);

$query = new WP_Query( $args );
if ( $query->have_posts() ) {
	while ( $query->have_posts() ) {
		$query->the_post();
		echo the_title();
		echo "<br/>"
		the_primary_category( 'product_cat', get_the_ID(), 'link' );
	}
}

Note:

-- $taxonomy and $post_id are required parameters and must be used when using the function
-- $output can be link or name
-- Function can be used with or without echo

Filters

Filter	Argument(s)
primary_category_html	string $html mixed ( int, WP_Term, object, string ) $taxonomy required mixed ( int, WP_Post, NULL ) $post_id required string $output

Shortcode

Tag	Attribute(s)
primary_category	mixed ( int, WP_Term, object, string ) taxonomy required -- mixed ( int, WP_Post, NULL ) post-id default value: NULL required -- string output default value: "link" others values: "name" optional

How to use

[primary_category taxonomy="category"]

[primary_category taxonomy="category" post-id="12"]

[primary_category taxonomy="category" post-id="12" output="link"]

WP_Query

See below how get posts with product_cat taxonomy selected primary category of with terms-ids 18 & 21

$taxonomy = 'product_cat';
$args = array(
       	'post_type' => 'product',
         'meta_query' => array(
         	array(
		  'key'     => '_primary_category_' . $taxonomy,
		  'value'   => array( 18,21 ),  // terms id
		  'compare' => 'IN',
    		)
	),
);

$query = new WP_Query( $args );

if ( $query->have_posts() ) {
      while ( $query->have_posts() ) {
	    $query->the_post();
	    the_title();
      }
}

https://developer.wordpress.org/reference/classes/wp_query/#custom-field-post-meta-parameters

TODO: Gutenberg Compatibility Issue

In order to make this plugin compatible with gutenberg, there was an issue with post-edit/post-new panels. I was unable to find a class to target the panels and display ‘set as primary’ button ahead terms. The reason was all panels were having the same class and gutenberg still doesn’t provide any method to add custom class/id.

Reference Link: WordPress/gutenberg#12082