Untitled Snippet

class Program_Meta {

	public function __construct() {

		if ( is_admin() ) {
			add_action( 'load-post.php',     array( $this, 'init_metabox' ) );
			add_action( 'load-post-new.php', array( $this, 'init_metabox' ) );
		}

	}

	public function init_metabox() {

		add_action( 'add_meta_boxes',        array( $this, 'add_metabox' )         );
		add_action( 'save_post',             array( $this, 'save_metabox' ), 10, 2 );

	}

	public function add_metabox() {

		add_meta_box(
			'program-meta',
			__( 'Program Information', 'omd-programs' ),
			array( $this, 'render_metabox' ),
			'omd-programs',
			'side',
			'high'
		);

	}

	public function render_metabox( $post ) {

		// Add nonce for security and authentication.
		wp_nonce_field( 'omdp_nonce_action', 'omdp_nonce' );

		// Retrieve an existing value from the database.
		$omdp_learn_more_link = get_post_meta( $post->ID, 'omdp_learn_more_link', true );
		$omdp_logged_in_only = get_post_meta( $post->ID, 'omdp_logged_in_only', true );

		// Set default values.
		if( empty( $omdp_learn_more_link ) ) $omdp_learn_more_link = '';
		if( empty( $omdp_logged_in_only ) ) $omdp_logged_in_only = '1';

		// Form fields.
		echo '<table class="form-table">';

		echo '	<tr>';
		echo '		<th><label for="omdp_learn_more_link" class="omdp_learn_more_link_label">' . __( 'URL for "Learn More" Button', 'omd-programs' ) . '</label></th>';
		echo '		<td>';
		echo '			<input type="url" id="omdp_learn_more_link" name="omdp_learn_more_link" class="omdp_learn_more_link_field" placeholder="' . esc_attr__( '', 'omd-programs' ) . '" value="' . esc_attr( $omdp_learn_more_link ) . '">';
		echo '		</td>';
		echo '	</tr>';

		echo '	<tr>';
		echo '		<th><label for="omdp_logged_in_only" class="omdp_logged_in_only_label">' . __( 'User must be logged in to request program?', 'omd-programs' ) . '</label></th>';
		echo '		<td>';
		echo '			<label><input type="checkbox" id="omdp_logged_in_only" name="omdp_logged_in_only" class="omdp_logged_in_only_field" value="checked" ' . checked( $omdp_logged_in_only, 'checked', false ) . '> ' . __( '', 'omd-programs' ) . '</label>';
		echo '		</td>';
		echo '	</tr>';

		echo '</table>';

	}

	public function save_metabox( $post_id, $post ) {

		// Add nonce for security and authentication.
		$nonce_name   = isset( $_POST['omdp_nonce'] ) ? $_POST['omdp_nonce'] : '';
		$nonce_action = 'omdp_nonce_action';

		// Check if a nonce is set.
		if ( ! isset( $nonce_name ) )
			return;

		// Check if a nonce is valid.
		if ( ! wp_verify_nonce( $nonce_name, $nonce_action ) )
			return;

		// Check if the user has permissions to save data.
		if ( ! current_user_can( 'edit_post', $post_id ) )
			return;

		// Check if it's not an autosave.
		if ( wp_is_post_autosave( $post_id ) )
			return;

		// Sanitize user input.
		$omdp_new_learn_more_link = isset( $_POST[ 'omdp_learn_more_link' ] ) ? esc_url( $_POST[ 'omdp_learn_more_link' ] ) : '';
		$omdp_new_logged_in_only = isset( $_POST[ 'omdp_logged_in_only' ] ) ? 'checked'  : '';

		// Update the meta field in the database.
		update_post_meta( $post_id, 'omdp_learn_more_link', $omdp_new_learn_more_link );
		update_post_meta( $post_id, 'omdp_logged_in_only', $omdp_new_logged_in_only );

	}

}

new Program_Meta;