Infinite token for Google Api Service?

Question

Google

Guys, I'm using google/apiclient in a project. To work with this api, you need to log in and get a token with which the library will work. It looks like this:

protected function getClient()
    {
        $client = new Google_Client();
        $client->setApplicationName(APPLICATION_NAME);
        $client->setScopes(SCOPES);
        $client->setAuthConfig(CLIENT_SECRET_PATH);
        $client->setAccessType('offline');

        // Load previously authorized credentials from a file.
        $credentialsPath = CREDENTIALS_PATH;
        if (file_exists($credentialsPath)) {
            $accessToken = json_decode(file_get_contents($credentialsPath), true);
        } else {
            // Request authorization from the user.
            $authUrl = $client->createAuthUrl();
            printf("Open the following link in your browser:\n%s\n", $authUrl);
            print 'Enter verification code: ';
            $authCode = trim(fgets(STDIN));

            // Exchange authorization code for an access token.
            $accessToken = $client->fetchAccessTokenWithAuthCode($authCode);

            // Store the credentials to disk.
            if (!file_exists(dirname($credentialsPath))) {
                mkdir(dirname($credentialsPath), 0700, true);
            }
            file_put_contents($credentialsPath, json_encode($accessToken));
            printf("Credentials saved to %s\n", $credentialsPath);
        }
        $client->setAccessToken($accessToken);


        // Refresh the token if it's expired.
        if ($client->getRefreshToken()) {
            $client->fetchAccessTokenWithRefreshToken($client->getRefreshToken());
            file_put_contents($credentialsPath, json_encode($client->getAccessToken()));

        }
        return $client;
    }

After that, the authorization data will be written to $credentialsPath . But! After expires_in expires , the client will refresh its token by sending a refresh_token to the server . After updating the token, everything works again until you need to update it again.
I also noticed that after:

// Refresh the token if it's expired.
        if ($client->getRefreshToken()) {
            $client->fetchAccessTokenWithRefreshToken($client->getRefreshToken());
            file_put_contents($credentialsPath, json_encode($client->getAccessToken()));
        }

Refresh_token is not written to the file . That is, when you need to update, this token is not in the file.
Who faced similar?
File on first login:

{"access_token":"ya29.Ci9IA7H-*******-*********","token_type":"Bearer","expires_in":3600,"refresh_token":"1\/**********-*******","created":1471990656}

The file after the first refresh of the token:

{"access_token":"ya29.Ci9IA7H-*******-*********","token_type":"Bearer","expires_in":3600,"created":1471990987}

Answer 1

Yes, I did. For Google, this is normal. It sends refresh_token only once. If the refresh_token has already been issued to you, then do not wait for it anymore. Just don't overwrite the previous one and use it.