Deprecated function: explode(): Passing null to parameter #2 ($string) of type string is deprecated

@sah62, I have fixed the issue and created MR. please review it once.

Hi @sah62,

Thank you for reporting the bug. The visitor_id is generated client-side add stored in the cookie. It is used to track unique visitors. I am guessing the Google crawler does not set cookie values.

`[$visitor_id] = is_string($_pk_id) ? explode('.', $_pk_id) : [];`

Thanks for the quick replies. I can confirm that the approach described above eliminates the problem.

Sorry, but I just saw this in my watchdog log:

Warning: Undefined array key 0 in Drupal\visitors\Service\CookieService->getId() (line 40 of /var/www/mysite/web/modules/contrib/visitors/src/Service/CookieService.php)

I believe the code should be changed from this:

[$visitor_id] = is_string($_pk_id) ? explode('.', $_pk_id) : [];

return $visitor_id;

to this:

$visitor_id = is_string($_pk_id) ? explode('.', $_pk_id) : [];

return $visitor_id;

What about

[$visitor_id] = is_string($_pk_id) ? explode('.', $_pk_id) : [NULL];

return $visitor_id;

I don't know if more than the visitor_id could be in the _pk_id.

Looking a little deeper: as described in VisitorsCookieInterface.php, the getId() function is supposed to return a string. $visitor_id does not have an initial value. Doing this:

[$visitor_id] =...

sets the value of an array element with an undefined index. The function then returns $visitor_id, which has no value. Maybe this is the right thing to do:

$visitor_id = is_string($_pk_id) ? $_pk_id : "";

return $visitor_id;

This ensures that the value of $visitor_id is set to a string value.

Hi @sah62,

Thank you for reporting the warning. I was able to reproduce the 'Undefined array key 0' message. I added unit tests.

The javascript tracking code is from the Matomo project. I do not completely understand it.

This is the value in the cookie. 'fa522cfb5f93fbee' is the unique visitor id. I do not know what '1714423797' is.
"fa522cfb5f93fbee.1714423797."

Automatically closed - issue fixed for 2 weeks with no activity.

bluegeek9 → closed merge request !143