Gravity Forms Cookies // Saves the query string parameters from a users visit to a cookie and allows these values to be populated via Gravity Forms' Dynamic

gistfile1.php

<?php
/**
Plugin Name: Gravity Forms Cookies
Plugin URI: http://ounceoftalent.com/
Description: Saves the query string parameters from a users visit to a cookie and allows these values to be populated via Gravity Forms' Dynamic Population feature.
Version: 1.5
Author: David Smith
Author URI: http://ounceoftalent.com
License: GPL2
*/

class GFCookie {
    
    public static $cookie_prefix = 'gfc_';
    public static $session = false;
    public static $fresh_cookies = array();
    
    public static function init() {
        
        //GFCookie::delete_cookies(); exit;
        
        if(!is_admin()) {
            add_action('parse_request', array('GFCookie', 'save_cookie'), 9);
            add_action('gform_pre_render', array('GFCookie', 'load_cookie'));
        }
        
        add_shortcode('gf_cookied_link', array('GFCookie', 'cookied_link_shortcode'));
        
    }
    
    public static function save_cookie() {
        
        // if cookies are not enabled, default to session use
        // start the session regardless of $_GET being empty as session may have been previously populated
        if(!self::cookies_enabled()) {
            session_start();
        }
        
        // don't do anything with cookie if there is no data
        if(!empty($_GET))
            self::save_get_data();
        
        self::save_server_data();
        
    }
    
    public static function load_cookie($form = null) {
        
        $cookie = self::get_cookie_data(false);
        
        foreach($cookie as $key => $value) {
            
            // skip cookies that were not added by us
            if(strpos($key, self::$cookie_prefix) === false)
                continue;
            
            // load cookie value into $_GET for population into Gravity Forms
            $key = str_replace(self::$cookie_prefix, '', $key);
            $_GET[$key] = $value;
            
        }
        
        // if gfc referrer is set, find {referer} merge tag and replace
        if(self::get_cookie_data('HTTP_REFERER')) {
            foreach($form['fields'] as &$field) {
                if(strpos(rgar($field, 'defaultValue'), '{referer}') !== false)
                    $field['defaultValue'] = str_replace('{referer}', self::get_cookie_data('HTTP_REFERER'), $field['defaultValue']);
            }
        }
        
        return $form;
    }
    
    public static function get_cookie_data($key = false) {
        
        $session = isset($_SESSION) && is_array($_SESSION) ? $_SESSION : array();
        $cookie = self::cookies_enabled() ? $_COOKIE : $session;
        
        // cookies that have not yet been sent through the header are merged with existing cookies
        $cookie = array_merge($cookie, self::$fresh_cookies);
        
        if($key === false)
            return $cookie;
        
        $gfc_key = self::$cookie_prefix . $key;
        
        return rgar($cookie, $gfc_key);
    }
    
    public static function save_get_data() {
        
        $reserved_words = array('attachment_id', 'author', 'author_name', 'calendar', 'cat', 'category', 'category__and', 'category__in', 'category__not_in', 'category_name', 'comments_per_page', 'comments_popup', 'cpage', 'day', 'debug', 'error', 'exact', 'feed', 'hour', 'link_category', 'm', 'minute', 'monthnum', 'more', 'name', 'nav_menu', 'nopaging', 'offset', 'order', 'orderby', 'p', 'page', 'page_id', 'paged', 'pagename', 'pb', 'perm', 'post', 'post__in', 'post__not_in', 'post_format', 'post_mime_type', 'post_status', 'post_tag', 'post_type', 'posts', 'posts_per_archive_page', 'posts_per_page', 'preview', 'robots', 's', 'search', 'second', 'sentence', 'showposts', 'static', 'subpost', 'subpost_id', 'tag', 'tag__and', 'tag__in', 'tag__not_in', 'tag_id', 'tag_slug__and', 'tag_slug__in', 'taxonomy', 'tb', 'term', 'type', 'w', 'withcomments', 'withoutcomments', 'year', 'DBGSESSID');
        
        foreach($_GET as $key => $value) {
            if(!in_array($key, $reserved_words)) {
                self::save_data($key, $value);
            }
        }
        
    }
    
    public static function save_server_data() {
        
        $server_keys = array('HTTP_REFERER');
        
        foreach($_SERVER as $key => $value) { 
            if(in_array($key, $server_keys))
                self::save_data($key, $value);
        }
        
    }
    
    public static function save_data($key, $value) {
        
        $gfc_key = self::$cookie_prefix . $key;
        
        if(self::cookies_enabled()) {
            if(!rgar($_COOKIE, $gfc_key)) {
                setcookie($gfc_key, $value, time() + 60*60*24*60, '/');
                self::$fresh_cookies[$gfc_key] = $value;
            }
        } else {
            if(!rgar($_SESSION, $gfc_key)) {
                $_SESSION[$gfc_key] = $value;
                self::$fresh_cookies[$gfc_key] = $value;
            }
        }
        
    }
    
    /**
    * WP uses cookies by default so if $_COOKIES global is empty, cookies are likely not enabled
    * 
    */
    public static function cookies_enabled() {
        return !empty($_COOKIE);
    }
    
    public static function delete_cookies() {
        foreach($_COOKIE as $key => $value) {
            if(strpos($key, self::$cookie_prefix) !== false) {
                self::delete_cookie($key);
            }
        }
    }
    
    public static function delete_cookie($key) {
        setcookie($key, null, time() - 3600, '/');
    }
    
    public static function cookied_link_shortcode($atts) {
        
        extract( shortcode_atts( array(
            'url' => false
        ), $atts ) );
        
        return !$url ? '' : gf_get_cookied_link($url);
    }
       
}

GFCookie::init();

if(!function_exists('gf_get_cookied_link')) {
function gf_get_cookied_link($url) {
        
    $cookies = GFCookie::get_cookie_data();
    $gfc_cookies = array();
    
    foreach($cookies as $key => $value) {
        if(strpos($key, GFCookie::$cookie_prefix) !== false) {
            $key = str_replace('gfc_', '', $key);
            $gfc_cookies[$key] = str_replace(array('http://', 'https://'), '', $value);
        }
    }
    
    return add_query_arg($gfc_cookies, $url);
}
}

What type of cache exclusion do you recommend for implementing this on a wpengine hosted website? This seems to only work when you're logged during my testing.

@adonnan Does WP Engine support exempting any cookie with a prefix? If so, exempting any cookie with the "gfc_" prefix should do the trick.

@spivurno That did the trick, thanks! I've been trying to figure that one out for a while.

Glad to help, @adonnan!

@maan1234, I'm seeing the same issue with first time visitors. Your solution of returning true from cookies_enabled seems to fix the issue. Would this change introduce any new potential issues with how this is currently implemented?

@spivurno, thanks for the great snippet!

@taylor-onfido My pleasure!

Wow David, 10 years ago and still found useful your creations, like this one. One thing: how can implement a way to update the cookies created by query string when a new query string is created? I saw the part //GFCookie::delete_cookies(); exit; at beginning but how to use this function to clear the cokies created? Kind regards

@amar8105alva Glad you're still finding this useful!

You can call GFCookie::delete_cookies() anytime before content is being rendered to the screen to delete all cookies created by GFCookie. For example, you could do something like:

add_action( 'init', function() {
    GFCookie::delete_cookies();
}, 9 );