How to set up gmail push notification

Question

I tried to understand how this works since more than a day, and I'm totally confused right now.

Here is my (very simple) goal: make a GET request on a URL when I receive a new email.

• I have created a topic as they asked (named new-email)
• I have a subscription in that topic (named new-email-inbox), with delivery type push, and setting my endpoint URL.
• I gave my subscription authorization to this account: gmail-api-push@system.gserviceaccount.com (Editor & Editor Pub/Sub)

How do I set up the rest ? I don't understand what to do now..

Answer 1

Thanks to the reply from @antoine-nedelec I was also create a watcher in Laravel.

I installed the package google/apiclient (composer require google/apiclient)

However I to implement some modifications, as otherwise this did not work for me:

• Enable domain wide delegation for this service account: https://developers.google.com/identity/protocols/oauth2/service-account?hl=en#delegatingauthority (https://admin.google.com/ac/owl/domainwidedelegation?hl=de needed to use the id, and not the email and used the scope https://mail.google.com/) or I would have received an error Client is unauthorized to retrieve access tokens using this method, or client not authorized for any of the scopes requested.
• Use my email instead of "me" (otherwise received Precondition check failed. error).
• I already had a credentials for pub/sub notifications, so I used that file
• Enabled GMail Api (that one was easy).

Of course this code has just dd for seeing an output. For production you could handle the exception and just ignore the $messagesResponse.

<?php
    
use Google_Client;
use Google_Service_Gmail;
use Google_Service_Gmail_WatchRequest;

define('MY_EMAIL', 'myemail@example.com');
define('PROJECT', 'pivotal-destruction-123456');
define('TOPIC', 'my_topic');

function watch()
{

    $client = new Google_Client();
    $client->setAuthConfig(resource_path('mycredentials.json'));
    $client->setSubject(MY_EMAIL);
    $client->addScope("https://mail.google.com/");
    $client->setAccessType("offline");
    $client->setApprovalPrompt('force');
    $service = new Google_Service_Gmail($client);
    try {
        $watch = new Google_Service_Gmail_WatchRequest($client);
        $watch->setTopicName("projects/" . PROJECT . "/topics/" . TOPIC);
        $messagesResponse = $service->users->watch(MY_EMAIL, $watch);
    } catch(\Exception $e) {
        dd("EXCEPTION", $e);
    }

    dd("WATCHED!!!", $messagesResponse);
}

BTW I tried to log the output from the webhook, but first missed to disable the CSRF check (VerifyCsrfToken.php), so did not get any notifications.

Answer 2

I did a Symfony4 command, executed everyday like a cron:

class WatchGoogleClient extends Command {

    private $kernel;
    private $gmailService;

    public function __construct(GmailService $gmailService, Kernel $kernel)
    {
        parent::__construct();
        $this->gmailService = $gmailService;
        $this->kernel = $kernel;
    }

    protected function configure()
    {
        $this->setName('app:watch-google-client')
            ->setDescription('watch-google-client')
            ->setHelp('Reset the google watch timer');
    }

    protected function execute(InputInterface $input, OutputInterface $output)
    {
        // This getClient function is basically what is given by the google API tutorial
        $client = $this->gmailService->getClient($this->kernel);
        $service = new \Google_Service_Gmail($client);
        $watchreq = new \Google_Service_Gmail_WatchRequest();
        $watchreq->setLabelIds(array('INBOX'));
        $watchreq->setTopicName('YOUR_TOPIC_NAME');
        $msg = $service->users->watch('me', $watchreq);

        var_dump($msg);
        // DO WHAT YOU WANT WITH THIS RESPONSE BUT THE WATCH REQUEST IS SET
    }
}