Google Calendar API - Stop watching events notFound - php

Question

I am creating a web site to interact with Google Calendars and watching resources and I want to stop them, but I can't seem to do that, so Google sends the headers "X-Goog-Channel-Id" and "X-Goog-Resource-Id" with the webhook request which from the documentation seems like that's all that's needed to send back to stop them, but I just keep getting a:
Google\Service\Exception: {
"error": {
"errors": [
{
"domain": "global",
"reason": "notFound",
"message": "Channel '0PAA4Z9RXJYMA7YMAV6O' not found for project '309331158475'"
}
],
"code": 404,
"message": "Channel '0PAA4Z9RXJYMA7YMAV6O' not found for project '309331158475'"
}
}
But they should be found as that's what Google has just sent in the header of the webhook. What am I doing wrong?
$headers = getallheaders();
try{
$client = new Google_Client();
$client->setAccessToken(get_google_accesstoken());
$service = new Google_Service_Calendar($client);
$channel = new Google_Service_Calendar_Channel($service);
$channel->setId($headers['X-Goog-Channel-Id']);
$channel->setResourceId($headers['X-Goog-Resource-Id']);
$service->channels->stop($channel);
}catch(Exception $e){
echo $e->getMessage();
}
So the steps I have currently are registering the watch event for the calendar, all good here. Then when the calendar changes Google loads the URL /webhook/google/ on my site and just for concept on that page I have the code above to stop the webhook from happening again, but it shows the error.
I'm generating the watch event with the code below if that helps
$expire = time()+86400;
try {
$client = new Google_Client();
$client->setAccessToken(get_google_accesstoken());
$service = new Google_Service_Calendar($client);
$channel = new Google_Service_Calendar_Channel($client);
$channel->setId(generaterandomstring(20));
$optParams = array('ttl' => $expire);
$channel->setParams($optParams);
$channel->setType('web_hook');
$channel->setAddress($site_url.'/webhook/google/');
$watchEvent = $service->events->watch('email#mysite.com', $channel);
}catch(Exception $e) {
}

Answer 1

I'd guess it's because the channel has already expired.
The $expire = time()+86400 line makes it seem like you're making it expire in 86.4 seconds. Could it be that you're trying to stop the channel watch more than 86 seconds after it was created?