index.php

<?php

// Load the Google API PHP Client Library.
require_once __DIR__ . '/vendor/autoload.php';

$analytics = initializeAnalytics();

// Reference https://developers.google.com/analytics/devguides/reporting/core/dimsmets

switch ($_GET['dimensions']) {
  case 'browser':
    $getDimensions = "ga:browser";
    break;

  case 'referrer':
    $getDimensions = "ga:fullReferrer";
    break;
  
  default:
    $getDimensions = "ga:userType";
    break;
}

$response = sample($analytics, $getDimensions);


header('Content-Type: application/json');
echo json_encode($response);


/**
 * Initializes an Analytics Reporting API V4 service object.
 *
 * @return An authorized Analytics Reporting API V4 service object.
 */
function initializeAnalytics()
{

  // Use the developers console and download your service account
  // credentials in JSON format. Place them in this directory or
  // change the key file location if necessary.
  $KEY_FILE_LOCATION = __DIR__ . '/service-account-credentials.json';

  // Create and configure a new client object.
  $client = new Google_Client();
  $client->setApplicationName("Hello Analytics Reporting");
  $client->setAuthConfig($KEY_FILE_LOCATION);
  $client->setScopes(['https://www.googleapis.com/auth/analytics.readonly']);
  $analytics = new Google_Service_AnalyticsReporting($client);

  return $analytics;
}


/**
 * Queries the Analytics Reporting API V4.
 *
 * @param service An authorized Analytics Reporting API V4 service object.
 * @return The Analytics Reporting API V4 response.
 */


function sample($analytics, $getDimensions)
{
  $VIEW_ID = "95444571";
  // Create the DateRange object.
  $dateRange = new Google_Service_AnalyticsReporting_DateRange();
  $dateRange->setStartDate("7daysAgo");
  $dateRange->setEndDate("today");

  // Create the Metrics object.
  $sessions = new Google_Service_AnalyticsReporting_Metric();
  $sessions->setExpression("ga:sessions");
  $sessions->setAlias("sessions");

  //Create the Dimensions object.
  $dimensions = new Google_Service_AnalyticsReporting_Dimension();
  $dimensions->setName($getDimensions);

  // Create the ReportRequest object.
  $request = new Google_Service_AnalyticsReporting_ReportRequest();
  $request->setViewId($VIEW_ID);
  $request->setDateRanges($dateRange);
  $request->setDimensions(array($dimensions));
  // $request->setDimensions(array($userType));
  $request->setMetrics(array($sessions));

  $body = new Google_Service_AnalyticsReporting_GetReportsRequest();
  $body->setReportRequests( array( $request) );
  return $analytics->reports->batchGet( $body );

}