Freebusy Google Calendar API PHP without user authentication - php

Question

I am creating a booking engine which uses Google calendar.
Needed:
Get all events in time frame (day, week, month)
Check availability for time frame, freebusy (30 min, hour)
Post event if #2 was true
Currently I can get the events and check availability using the command line app I created following this tutorial by Google. But it still asks me to authenticate in browser, which is not what I want, as the calendar would always be the same and user won't have access to it.
My code so far:
<?php
require_once 'vendor/autoload.php';
define('APPLICATION_NAME', 'Google Calendar API PHP Quickstart');
define('CREDENTIALS_PATH', '~/.credentials/calendar-php-quickstart.json');
define('CLIENT_SECRET_PATH', 'client_secret.json');
// If modifying these scopes, delete your previously saved credentials
// at ~/.credentials/calendar-php-quickstart.json
define('SCOPES', implode(' ', array(
Google_Service_Calendar::CALENDAR_READONLY)
));
if (php_sapi_name() != 'cli') {
throw new Exception('This application must be run on the command line.');
}
/**
* Returns an authorized API client.
* #return Google_Client the authorized client object
*/
function getClient() {
$client = new Google_Client();
$client->setApplicationName(APPLICATION_NAME);
$client->setScopes(SCOPES);
$client->setAuthConfigFile(CLIENT_SECRET_PATH);
$client->setAccessType('offline');
// Load previously authorized credentials from a file.
$credentialsPath = expandHomeDirectory(CREDENTIALS_PATH);
if (file_exists($credentialsPath)) {
$accessToken = file_get_contents($credentialsPath);
} 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 = $client->authenticate($authCode);
// Store the credentials to disk.
if(!file_exists(dirname($credentialsPath))) {
mkdir(dirname($credentialsPath), 0700, true);
}
file_put_contents($credentialsPath, $accessToken);
printf("Credentials saved to %s\n", $credentialsPath);
}
$client->setAccessToken($accessToken);
// Refresh the token if it's expired.
if ($client->isAccessTokenExpired()) {
$client->refreshToken($client->getRefreshToken());
file_put_contents($credentialsPath, $client->getAccessToken());
}
return $client;
}
/**
* Expands the home directory alias '~' to the full path.
* #param string $path the path to expand.
* #return string the expanded path.
*/
function expandHomeDirectory($path) {
$homeDirectory = getenv('HOME');
if (empty($homeDirectory)) {
$homeDirectory = getenv("HOMEDRIVE") . getenv("HOMEPATH");
}
return str_replace('~', realpath($homeDirectory), $path);
}
// Get the API client and construct the service object.
$client = getClient();
$service = new Google_Service_Calendar($client);
// Print the next 10 events on the user's calendar.
$calendarId = 'pgsgh5dp4a5seur91fvn86bn3o#group.calendar.google.com';
$optParams = array(
'maxResults' => 10,
'orderBy' => 'startTime',
'singleEvents' => TRUE,
'timeMin' => '2005-08-15T15:52:01+0000',
);
$results = $service->events->listEvents($calendarId, $optParams);
if (count($results->getItems()) == 0) {
print "No upcoming events found.\n";
} else {
print "Upcoming events:\n";
foreach ($results->getItems() as $event) {
$start = $event->start->dateTime;
if (empty($start)) {
$start = $event->start->date;
}
printf("%s (%s)\n", $event->getSummary(), $start);
}
}
?>
Next steps:
How to skip the client side authentication?
How to turn everything into a web application instead of command line one?