nateinaction/segment-cache-for-wp-engine

<?php
/**
 * This file defines the class that creates the set-segment shortcode
 *
 * @package segment-cache-for-wp-engine
 */

namespace SegmentCacheWPE\Shortcode;

// Prevent direct access.
defined( 'ABSPATH' ) || exit;

/**
 * Class Set_Segment
 *
 * Add a WordPress shortcode to set a cache segment
 */
class Set_Segment {

    /**
     * Name of the WP Engine cookie that creates the segment
     *
     * @const string
     */
    const COOKIE_NAME = 'wpe-us';

    /**
     * Default attributes for set_segment shortcode
     *
     * @var array
     */
    public $default_atts = array(
        self::COOKIE_NAME => 'default',
        'path'            => '/',
        'max-age'         => '31536000',
        'secure'          => 'false',
        'samesite'        => 'lax',
    );

    /**
     * All valid attributes for set_segment shortcode
     * https://developer.mozilla.org/en-US/docs/Web/API/Document/cookie
     *
     * @var array
     */
    public $valid_atts = array(
        self::COOKIE_NAME,
        'path',
        'domain',
        'max-age',
        'expire',
        'secure',
        'samesite',
    );

    /**
     * Cookie string
     *
     * @var string
     */
    public $cookie_string = self::COOKIE_NAME . '=default';

    /**
     * Set Segment
     *
     * This function acts as a factory and orchestrates all cookie setting actions after shortcode is invoked
     *
     * @param array $atts Key/value store of shortcode attributes as input from user.
     */
    public function set_segment_cookie( $atts = [] ) {
        if ( isset( $atts['segment-name'] ) ) {
            $atts[ self::COOKIE_NAME ] = $atts['segment-name'];
            $atts                      = $this->validate_atts( $atts );
            $this->cookie_string       = $this->atts_to_cookie_string( $atts );
            $this->add_to_footer();
        }
    }

    /**
     * Validate set_segment attributes
     *
     * Provide valid and default options to cookie setter
     *
     * @param array $atts Key/value store of shortcode attributes as input from user.
     * @return array $atts Key/value store of valid attributes to be used by setcookie.
     */
    public function validate_atts( $atts = [] ) {
        $validated_atts = $this->default_atts;
        foreach ( $this->valid_atts as $key ) {
            if ( array_key_exists( $key, $atts ) ) {
                $validated_atts[ $key ] = esc_html( $atts[ $key ] );
            }
        }
        return $validated_atts;
    }

    /**
     * Convert atts array to javascript cookie param string
     *
     * @param array $atts Key/value store of valid attributes.
     * @return string Javascript cookie param string
     */
    public function atts_to_cookie_string( $atts = [] ) {
        return implode(
            ';',
            array_map(
                function ( $val, $key ) {
                    return "{$key}={$val}";
                },
                $atts,
                array_keys( $atts )
            )
        );
    }

    /**
     * Hook WordPress to add the inline JS cookie setter to the footer
     */
    public function add_to_footer() {
        add_action( 'wp_footer', array( $this, 'set_cookie' ) );
    }

    /**
     * Set cookie via inline js
     *
     * Enqueue and localize are great options but I could not bring myself to
     * add an extra http request for a one line js file so this is inline.
     */
    public function set_cookie() {
        echo '<script type="text/javascript">';
        echo 'document.cookie = "' . esc_attr( $this->cookie_string ) . '";';
        echo '</script>';
    }

    /**
     * Hook WordPress to add shortcode
     */
    public static function add_shortcode() {
        $set_segment = new Set_Segment();
        add_shortcode( 'segment-cache-set', array( $set_segment, 'set_segment_cookie' ) );
    }
}