WooCommerce force SSL entire shop

functions.php

<?php

/*
Author: Doug Edgington
Description: modified version of Woocomemrce SSL functionality, forces ssl on Woocommerce pages and two additional custom pages
*/
function dee_ssl_template_redirect() {
  if ( ! is_ssl() ) {
		
		if ( is_checkout() || is_account_page() || is_woocommerce() ) {
			if ( 0 === strpos( $_SERVER['REQUEST_URI'], 'http' ) ) {
				wp_safe_redirect( preg_replace( '|^http://|', 'https://', $_SERVER['REQUEST_URI'] ) );
				exit;
			} else {
				wp_safe_redirect( 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'] );
				exit;
			}
		}
	}
	// Break out of SSL if we leave woocommerce pages or custom pages
	elseif ( is_ssl() && $_SERVER['REQUEST_URI'] && ! is_checkout() && ! is_page( woocommerce_get_page_id('thanks') ) && ! is_ajax() && ! is_account_page()) {

		if ( 0 === strpos( $_SERVER['REQUEST_URI'], 'http' ) ) {
			wp_safe_redirect( preg_replace( '|^https://|', 'http://', $_SERVER['REQUEST_URI'] ) );
			exit;
		} else {
			wp_safe_redirect( 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'] );
			exit;
		}
	}
} //end function
add_action( 'template_redirect', 'dee_ssl_template_redirect', 1 );

?>

If you want to force SSL on your entire WooCommerce shop.