Adding Meta Boxes

functions.php

/* 
3 steps
1. Create the meta field
2. Display is in the admin area
3. Add a save feature that checks the nonce created in the display function
*/


// add homepage meta box

function add_home_awesome_box() {

    if( in_array($_GET['post'], array('17') ) ) { // if the page id is in this array
	
	add_meta_box('home_awesome_text', 'Awesome Text Section', 'show_home_awesome_in_admin', 'page');
	
	} // end if in array

}

add_action('add_meta_boxes', 'add_home_awesome_box');


// show that home meta box on the homepage

function show_home_awesome_in_admin($post) {

	$valueHomeAwesome = get_post_meta($post->ID, '_home_awesomeness_value', true);

	wp_nonce_field( basename( __FILE__ ), 'home_awesome_nonce_field'); 
	?>

	<label for="home_awesome_text">Your awesome text will go here</label>
	<input type="text" name="home_awesome_text" value="<?php echo $valueHomeAwesome; ?>" />


<?php

} // end showing home awesome only on homepage



// save home meta box 

function save_my_awesome_text_box($post_id) {

	$isAutosave = wp_is_post_autosave($post_id);
	$isRevision = wp_is_post_revision($post_id);

	$isValidNonce = false;


	if ( isset( $_POST[ 'home_awesome_nonce_field' ] ) )  { // if the nonce is set in the post

		if (wp_verify_nonce($_POST['home_awesome_nonce_field'], basename( __FILE__ ))) { // check if valid nonce
			$isValidNonce = true;
		}

	}

	// dont save if autosave, revision, or is nonce is false
	if ($isAutosave || $isRevision || !$isValidNonce) {
		return;  // end this function
	}


	// if the key exists
	if (array_key_exists('home_awesome_text', $_POST)) { // check if it is in the save post data

		update_post_meta ($post_id, '_home_awesomeness_value', sanitize_text_field($_POST['home_awesome_text'])	);

	}




} // end save my aweome meta box