Unable to get Google OAuth Token - php

Question

I'm trying to add calendar events to my Google calendar from a php script. Note that I can do this successfully directly from a Google test page so I think that my calendar is set up correctly. However, when I attempt do this from a php script, I'm not able to get the OAuth2 token.
The following script, mostly taken from a Google example, runs without error, but it always winds up with a "Connect Me!" link. When I click on this link, it takes me to a validation screen that warns me that this app would like to manage my calendars. I click 'Accept' and a then see my calendar. A little inconvenient, but if this gets the OAuth token, fine.
I then go back and run the script again, hoping that the access token will now be available, but I get exactly the same result. No matter how many times I run this script, I never get the token, which I need in order to expand the script to add events to the calendar.
I've been at this for days, and I'm just not getting anywhere. Can anyone help? Thanks.
<?php
require_once '../../src/Google_Client.php';
require_once '../../src/contrib/Google_CalendarService.php';
require_once '../../src/auth/Google_OAuth2.php';
session_start();
$client = new Google_Client();
$client->setApplicationName("Add Google Calendar Entries");
// Visit https://code.google.com/apis/console?api=calendar to generate your
// client id, client secret, and to register your redirect uri.
$client->setClientId('843319906820-1s1d737e77o71a3vaskf434k3ape1fk5.apps.googleusercontent.com');
$client->setClientSecret('AP5imn3e0TEWNyLTCNm8YJj6');
$client->setRedirectUri('https://www.google.com/calendar/');
$client->setDeveloperKey('AIzaSyDIw3ks7AmrIrRxjO9y2gWBhQDYHFWd-uc');
$client->setUseObjects(true);
$cal = new Google_CalendarService($client);
if (isset($_GET['logout'])) {
unset($_SESSION['token']);
}
if (isset($_GET['code'])) {
$client->authenticate($_GET['code']);
$_SESSION['token'] = $client->getAccessToken();
header('Location: http://' . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF']);
}
if (isset($_SESSION['token'])) {
$client->setAccessToken($_SESSION['token']);
}
if ($client->getAccessToken()) {
$calList = $cal->calendarList->listCalendarList();
print "<h1>Calendar List</h1><pre>" . print_r($calList, true) . "</pre>";
$_SESSION['token'] = $client->getAccessToken();
} else {
$authUrl = $client->createAuthUrl();
print "<a class='login' href='$authUrl'>Connect Me!</a>";
}
?>
EDIT: Attempting to implement the suggestion from Vinicius Pinto. I've changed my redirect to point directly back to this script. Now I get this error:
Fatal error: Uncaught exception 'Google_ServiceException' with message
'Error calling GET
https://www.googleapis.com/calendar/v3/users/me/calendarList?key=AIzaSyDIw3ks7AmrIrRxjO9y2gWBhQDYHFWd-uc:
(403) Access Not Configured. Please use Google Developers Console to
activate the API for your project.' in
D:\Hosting\11347607\html\scripts\google-api-php-client\src\io\Google_REST.php:66
Stack trace: #0
D:\Hosting\11347607\html\scripts\google-api-php-client\src\io\Google_REST.php(36):
Google_REST::decodeHttpResponse(Object(Google_HttpRequest)) #1
D:\Hosting\11347607\html\scripts\google-api-php-client\src\service\Google_ServiceResource.php(186):
Google_REST::execute(Object(Google_HttpRequest)) #2
D:\Hosting\11347607\html\scripts\google-api-php-client\src\contrib\Google_CalendarService.php(205):
Google_ServiceResource->__call('list', Array) #3
D:\Hosting\11347607\html\scripts\google-api-php-client\examples\calendar\simple.php(43):
Google_CalendarListServiceResource->listCalen in
D:\Hosting\11347607\html\scripts\google-api-php-client\src\io\Google_REST.php
on line 66
It would appear that I don't have the correct APIs activated in the developer console. I have the Calendar API and the Google Cloud Storage JSON API activated and nothing else. I don't see any other APIs that would be relevant, and I don't think that this message is telling me which APIs it wants.
EDIT 2: Looks like I was using the wrong developer key. I've changed it to the key for server applications. Now my error is this:
Fatal error: Uncaught exception 'Google_AuthException' with message
'Error refreshing the OAuth2 token, message: '{ "error" :
"invalid_client" }'' in
D:\Hosting\11347607\html\scripts\google-api-php-client\src\auth\Google_OAuth2.php:288
Stack trace: #0
D:\Hosting\11347607\html\scripts\google-api-php-client\src\auth\Google_OAuth2.php(248):
Google_OAuth2->refreshTokenRequest(Array) #1
D:\Hosting\11347607\html\scripts\google-api-php-client\src\auth\Google_OAuth2.php(225):
Google_OAuth2->refreshToken('1/6ZdJyZALqcbwW...') #2
D:\Hosting\11347607\html\scripts\google-api-php-client\src\service\Google_ServiceResource.php(167):
Google_OAuth2->sign(Object(Google_HttpRequest)) #3
D:\Hosting\11347607\html\scripts\google-api-php-client\src\contrib\Google_CalendarService.php(205):
Google_ServiceResource->__call('list', Array) #4
D:\Hosting\11347607\html\scripts\google-api-php-client\examples\calendar\simple.php(47):
Google_CalendarListServiceResource->listCalendarList() in
D:\Hosting\11347607\html\scripts\google-api-php-client\src\auth\Google_OAuth2.php
on line 288

Answer 1

The $client->setRedirectUri() should receive a URL pointing to your application, because this is the URL that you'll be redirected to after you authorize the application in the Google page. That's why you are being redirect to the calendar, because you are using the calendar URL.
It seems like your script is already expecting a $_GET['code'], so try setting the redirect URL to the url of this script. You'll also need to set the same URL in the Developers Console, under API -> Credentials.
You only get a token when you call $client->authenticate($_GET['code']); with a value code.
Take a look at this lib I just commited to Github, it's an early version, but it's working fine (I'm using to access YouTube). It's using the new official library.
Update: as said in the comments, the developer key isn't actually required for this to work, even though all Google sample code sets it.