WordPress

Embed WordPress Functions Outside WordPress

Create a Sub directory on the wordpress and add the code

Programmatically login a user without a password:

Declaring WooCommerce support in themes(custom themes)

Passing Value from template file to header

Hooks

There are two types of hooks: actions and filters.

• Actions allow you to add extra functionality at a specific point in the processing of the page—for example, you might want to add extra widgets or menus, or add a promotional message to your page.
• Filters allow you to intercept and modify data as it is processed—for example, you might want to insert another CSS class in a WordPress HTML element, or modify some of your pages blocks.

In brief: actions do stuff; filters change stuff.

*Actions: 1. add_action 2. do_action 3. remove_action

do_action : Registers an action hook while add_action : adds a callback function to the registered hook.

do_action( ‘after_gill_arrives’ , $gill_has_keys = true , $gill_has_car = true );
This tells WordPress to create a hook called ‘after_gill_arrives’, run any actions that are attached to this hook, and pass the arguments $gill_has_keys and $gill_has_car to those actions (the 2 arguments we specified above).

*Filters: 1. add_filter 2. apply_filter

*Priority: add_action('init', 'run_me_early', 9);
add_action('init', 'run_me_normal'); // default value of 10 is used since a priority wasn't specified
add_action('init', 'run_me_late', 11);

The first function to run will be run_me_early(), followed by run_me_normal(), and finally the last one to run will be run_me_late().

Reference: https://docs.presscustomizr.com/article/26-wordpress-actions-filters-and-hooks-a-guide-for-non-developers

Taxonomy

Taxonomy is a way to group things together.

This will display all the categories of the current post.

In WordPress, terms refers to the items in a taxonomy.

For example, a website has categories books, politics, and blogging in it. While category itself is a taxonomy the items inside it are called terms.

Default Taxonomies: Category, Tag, ....

Pagination

Custom Query with Pagination

$current_page = ( get_query_var('paged') ) ? get_query_var('paged') : 1; //get current page no from URL

$about_post = new WP_Query(array('category_name' => 'about', 
				 'post_per_page' => 3,
				 'paged' => $current_page //get post from current page	));

if($about_post -> have_posts()): //check if it has post
	while($about_post -> have_posts()): //loop 
		$about_post -> the_post(); //we need to call "the_post" method to get details of each post
		the_title(); // displays the title of each post
	endwhile;
	
	$max_pages = $about_post->max_num_pages; //total no of pages
	
	next_posts_link('Next Page', $max_pages); //ordinary pagination
	
	previous_posts_link(); //ordinary pagination
	
	echo paginate_links(array('total' => $max_pages)); //numbered pagination
	
endif;

NOTE:
next_posts_link() and paginate_links() will not work as it is on custom query.
previous_posts_link() will work on custom query.

How to hide subcategory products from main category in Woocommerce?

Add the following lines of code at the end of your theme’s functions.php file.

function exclude_product_cat_children($wp_query) {
if ( isset ( $wp_query->query_vars['product_cat'] ) && $wp_query->is_main_query()) {
    $wp_query->set('tax_query', array( 
                                    array (
                                        'taxonomy' => 'product_cat',
                                        'field' => 'slug',
                                        'terms' => $wp_query->query_vars['product_cat'],
                                        'include_children' => false
                                    ) 
                                 )
    );
  }
}  
add_filter('pre_get_posts', 'exclude_product_cat_children');

Programmatically login a user without a password:

$username = "admin";
$user = get_user_by('login', $username );


if ( !is_wp_error( $user ) &&   !is_user_logged_in())
{
    wp_clear_auth_cookie();
    wp_set_current_user ( $user->ID );
    wp_set_auth_cookie  ( $user->ID );

}

$queried_object = get_queried_object();
 var_dump( $queried_object );

Ajax Cart Count Update on Cart Page

add_filter( 'woocommerce_add_to_cart_fragments', 'woocommerce_header_add_to_cart_fragment' );

function woocommerce_header_add_to_cart_fragment( $fragments ) {
	global $woocommerce;

	ob_start();
	?>
	CART (cart->cart_contents_count; ?>)
	

WordPress User Roles and Capabilities

Install wordpress in subdirectory

Logging

How to Use Shortcodes in your WordPress Sidebar Widgets