One product page has different cookie from others - php

Question

I want to save product id in an array when user opens a product page, and then save that array in a cookie. This is my code:
if(is_product()) {
if(isset($_COOKIE['recent'])) {
$data = unserialize($_COOKIE['recent']);
$product_id = get_the_ID();
if(!in_array($product_id, $data)) {
array_unshift($data, $product_id);
if(count($data) > 8) {
array_pop($data);
}
setcookie('recent', serialize($data), time()+(3600*24*7), "/");
}
echo "SET";
}else{
$data = array();
$product_id = get_the_ID();
array_unshift($data, $product_id);
setcookie('recent', serialize($data), time()+(3600*24*7), "/");
echo "DIDNT SET";
}
print_r($data);
}
Those echos and print_r is for debugging purposes. So if it is a product page, I check whether cookie is already set, if yes, then I just want to add product ID to the array if it is already there and update the value. And if cookie is not set, I'm creating a new array and then printing content of $data.
The problem is, that all, except one product page works fine. For example I can browse through products and see that it prints out the same array over and over again, but one product page has its own array of IDs, which is array of one element - that product element. That product page has no different URL from others. same pattern: website.com/product/productname/
It seems like it has its own scope. Even tough I used "/" for the domain, so I guess it should be the same across all the website?
What is wrong here?

Answer 1

I tested this locally and had similar results. The reason you were getting the output errors in your header was because you were trying to set the initial cookie with an integer instead of a string. That and the WP headers were initialized but the query had not fully processed.
I made a plugin that will run on the template_redirect hook which will allow you to debug much easier. There's also a [recently_viewed] shortcode that'll let you do something with your actual result.
You can drop this in your theme or create a recently_viewed.php in your plugins folder:
https://gist.github.com/simplethemes/4f9b6f969bcc0a0a6668aeed75491a15
/*
Plugin Name: Set Shop Cookie
Description: Adds a cookie for most recently viewed products
Version: 0.1
Author: Casey Lee
Author URL: https://simplethemes.com
*/
class SetWpShopCookie {
/**
* #var string API URL
*/
public static $instance;
public $recent_cookie;
public $cookie_name = 'recent';
public $recent_products;
/** Hook WordPress
* #return void
*/
public function __construct()
{
self::$instance = $this;
add_action( 'template_redirect', array( $this, 'get_recent_cookie') );
add_action( 'template_redirect', array( $this, 'set_post_cookie') );
add_shortcode( 'recently_viewed', array( $this, 'recent_products') );
}
/**
* Gets the 'recent' cookie
* #return array or null
*/
public function get_recent_cookie()
{
$recent_cookie = null;
$cookies = array();
foreach ( $_COOKIE as $name => $value ) {
$cookies[] = new WP_Http_Cookie( array( 'name' => $name, 'value' => $value ) );
}
foreach($cookies as $cookie) {
if ($this->cookie_name == $cookie->name) {
$recent_cookie = $cookie;
break;
}
}
$this->recent_cookie = $recent_cookie;
}
/**
* Load scripts when plugin is executed
* #see https://developer.wordpress.org/reference/classes/wp_http_cookie/
*/
public function set_post_cookie()
{
global $post;
$product_id = $post->ID;
$cookie_time = time() + 60 * 60 * 24 * 7;
// nothing to do here if we're not in a product single
if (!is_product())
return;
// create the cookie
if(!$this->recent_cookie) {
$data = array();
array_unshift($data, $product_id);
setcookie($this->cookie_name, serialize($data), $cookie_time, COOKIEPATH, COOKIE_DOMAIN);
// update existing cookie
} else {
$data = unserialize($this->recent_cookie->value);
if(!in_array($product_id, $data)) {
array_unshift($data, $product_id);
if(count($data) > 8) {
array_pop($data);
}
// Use WP globals for portable cookie settings
setcookie($this->cookie_name, serialize($data), $cookie_time, COOKIEPATH, COOKIE_DOMAIN);
}
}
// Debug
// var_dump($this->recent_cookie);
}
// Recently viewed products shortcode
function recent_products( $atts ) {
// Attributes
$atts = shortcode_atts(
array(
'count' => '5',
),
$atts,
'recently_viewed'
);
$product_data = unserialize($this->recent_cookie->value);
$str = '';
if ($product_data) {
foreach ($product_data as $products_viewed) {
$str .= $products_viewed .' ,';
}
return 'You recently viewed these products: ' . rtrim($str,',');
} else {
return 'Why don\'t you visit our shop?';
}
}
}
new SetWpShopCookie;

Answer 2

It's difficult to say without seeing your output. Try posting a dump of your $data in the context you mention. get_the_ID() is a proxy through get_post(), so you might try setting the ID more reliably with the below. At least then you'll see an error if you don't have a proper object.
global $product;
$product_id = $product->id;