Google Analytics API on Codeigniter website

I've been trying to get Google API to work on my website for days now, but not getting it to work. Everywhere I search I find outdated examples... I need it to work with codeigniter and all I want to do is to fetch data from Google Analytics to show in the admin dashboard on my codeigniter website.

I understand that I need a Service Account, if I don't want to be authenticating everytime I look at the dashboard(?)

Can anyone please help me with getting this to work? Thank you so much in advance!

What I want done is: Fetch data from google analytics, return that data as maybe json, then I guess I can make a chart out of it with a plugin (perhaps some jQuery plugin already exists, or can I use googles own chart drawers?) and show this to administrators. I just want really simple data, as for example, how many users the last month...

After about a week - and of course, on the same day I post this question, I finally manage to fix this myself.

This is how I go about:

I downloaded the latest Google Client API (for php) from their github.

I added the Google folder (src) in my application/third_party folder.

Inside my controller I included the required files by doing:

require_once(BASEPATH . '../application/third_party/Google/Client.php');
require_once(BASEPATH . '../application/third_party/Google/Service/Analytics.php');

Then I added the following code below that for authorization with Service Account (which you get from the Google Console and selecting your project > APIs & auth > Credentials > Then create a new Client ID, select Service Account, when done, press "Generate new p12 key" and add that key to your third_party/Google folder:

session_start();

$client_id = '<YOUR_CLIENT_ID>'; //Client ID
$service_account_name = '<YOUR_CLIENT_EMAIL>'; //Email Address 
$key_file_location = BASEPATH . '../application/third_party/Google/<YOUR KEY.p12>'; //key.p12

$client = new Google_Client();
$client->setApplicationName("ApplicationName");
$service = new Google_Service_Analytics($client);

if (isset($_SESSION['service_token'])) {
  $client->setAccessToken($_SESSION['service_token']);
}

$key = file_get_contents($key_file_location);
$cred = new Google_Auth_AssertionCredentials(
    $service_account_name,
    array(
        'https://www.googleapis.com/auth/analytics',
    ),
    $key,
    'notasecret'
);
$client->setAssertionCredentials($cred);
if($client->getAuth()->isAccessTokenExpired()) {
  $client->getAuth()->refreshTokenWithAssertion($cred);
}
$_SESSION['service_token'] = $client->getAccessToken();

The code below is for getting sessions (page visits) from the last 31 days

$analytics = new Google_Service_Analytics($client);

$profileId = "ga:<YOUR_PROFILE_ID>";
$startDate = date('Y-m-d', strtotime('-31 days')); // 31 days from now
$endDate = date('Y-m-d'); // todays date

$metrics = "ga:sessions";

$optParams = array("dimensions" => "ga:date");
$results = $analytics->data_ga->get($profileId, $startDate, $endDate, $metrics, $optParams);

$data['report'] = $results->rows; //To send it to the view later

To get all the dimensions and metrics that you can use, use this link. Example on how to send it to the view: