Setting custom cookies in Wordpress

Question

I am trying to set cookies to re-route returning users to my a specific page within my Wordpress site.

I'd like some advice with these 2 things:

1. Where in the Wordpress php files should cookies be checked before loading any content to handle a redirect? Is there a good file this should exist in over others?
2. How do I properly set a cookie within Wordpress? setcookie('cookie_name', 'cookie_value', time()+4000); doesn't seem to be saving any cookies to my system.

Answer 1

1 - You can check for cookies and do your redirect using hooks that are called before any output like the 'init' hook:

<?php

// Hook the function "redirect()" on to the "init" action
add_action('init', 'redirect');

// redirect() may redirect the user depending on the cookies he has
function redirect(){
  /* CODE */
}

?>

2 - The best way to set cookies would be using the 'init' hook like this:

<?php

add_action('init', 'my_setcookie');

// my_setcookie() set the cookie on the domain and directory WP is installed on
function my_setcookie(){
  $path = parse_url(get_option('siteurl'), PHP_URL_PATH);
  $host = parse_url(get_option('siteurl'), PHP_URL_HOST);
  $expiry = strtotime('+1 month');
  setcookie('my_cookie_name_1', 'my_cookie_value_1', $expiry, $path, $host);
  /* more cookies */
  setcookie('my_cookie_name_2', 'my_cookie_value_2', $expiry, $path, $host);
}

?>

This is more consistent, if you have a blog at www.example.com/blog, the coockie(s) will not be available at

• www.example.com
• www.example.com/store
• example.com
• www2.example.com
• ...

---

Update

you should also be able to use the COOKIE_PATH and COOKIEDOMAIN constants rather than figuring them out yourself, which I just noticed in Andre R Kohl's answer – drzaus

Answer 2

You probably should use the constants COOIKEPATH and COOKIE_DOMAIN, existing since WP 3.0

setcookie("your_cookie", $your_value, time()+3600, COOKIEPATH, COOKIE_DOMAIN);

Answer 3

Ah, realized I needed to hook this into the init().

SOLUTION: I created a function in functions.php that would set and check the cookie. for this to work properly, after defining the function, outside the function call this:

add_action('init', 'function-name'); 

Answer 4

This way worked :

    add_action( 'init', 'function-to-setcookie' ); 

    function function-to-setcookie(){

        //use condition here , in which page you eant to set cookie
        //choose a page where you want the cookie to be set
        $pageurl = get_option('siteurl').'/set-cookie-page'; 

       // use a function to get current page url and use condition 
       //to match it with the desired page where you want to set cookie 
       if ( $pageurl === current_page_url() ) {
           setcookie( 'cookie_name', 'cookie_value', $expiryTime, $cookiepath, $siteurl );
         }

    }

Answer 5

You will want to delete your cookie before any content is written to the page (before headers are sent).

To set the cookie, include the path, domain, and I also recommend setting the last 2 parameters to true ($secure and $httponly). You will also need to supply the same parameters to setcookie() when deleting, aside from the $expiry (which should be negative) and the $value (which should be empty '').

If you are passing json through the cookie, it seems like you need to base64_encode it as well, or it won't properly decode.

All of this should be done in a class so you can access the value of the cookie later on in your code. The class can be added to a plugin or functions.php.

Here is an example where we use a cookie to store an action response to then display it to the user after we redirect them:

class my_custom_class {

    const MY_COOKIE_NAME_JSON = 'my_cookie_name_json';
    const COOKIE_LIFETIME = 3600;

    private $cookie_value;

    function __construct() {
        // ensure you are deleting cookie before headers are sent
        add_action('init', [$this, 'process_cookie_json'], 10);
        // uses bootstrap alert to format return message
        add_filter('the_content', [$this, 'filter_the_content_in_the_main_loop'], 1);
    }
    
    static function some_action_that_sets_the_cookie($message, $response_type = 'success') {
        $responses = [];
        if (isset($_COOKIE[self::MY_COOKIE_NAME_JSON]))
            $responses = json_decode(base64_decode($_COOKIE[self::MY_COOKIE_NAME_JSON]));
        $responses[$response_type][] = $message;
        self::set_cookie_json($responses);
    }
    
    static function set_cookie_json(array $cookie_value) {
        setcookie(self::MY_COOKIE_NAME_JSON, base64_encode(json_encode($cookie_value)), time() + self::COOKIE_LIFETIME, "/", $_SERVER['HTTP_HOST'], true, true);
    }
    
    function process_cookie_json() {
        if (!isset($_COOKIE[self::MY_COOKIE_NAME_JSON]))
            return false;
        $this->cookie_value = json_decode(base64_decode($_COOKIE[self::MY_COOKIE_NAME_JSON]), true);
        setcookie(self::MY_COOKIE_NAME_JSON, '', -1, "/", $_SERVER['HTTP_HOST'], true, true);
        unset($_COOKIE[self::MY_COOKIE_NAME_JSON]);
    }

    function filter_the_content_in_the_main_loop($content) {
        if (!$this->cookie_value || !is_array($this->cookie_value))
            return $content;
        $alerts = [];
        foreach ($this->cookie_value as $response_type => $messages)
            $alerts[] = '<div class="alert alert-' . $response_type . '" role="alert">' . implode(PHP_EOL, $messages) . '</div>';
        return implode(null, $alerts) . $content;
    }

}

$my_custom_class = my_custom_class;

You can then set the cookie via:

my_custom_class::some_action_that_sets_the_cookie('the message');