Google Analytics Reporting API usage example

ga_reporting.php

<?php

// composer require google/apiclient

require __DIR__ . '/vendor/autoload.php';

// This is the file obtained from Google during the service account creation process
// see these links: 
// 1. https://console.developers.google.com/apis/credentials/serviceaccountkey
// 2. https://console.developers.google.com/iam-admin/serviceaccounts/create
$secrets = __DIR__ . '/secrets.json';

$client = new Google_Client();
$client->setApplicationName('Test App');
$client->setAuthConfig($secrets);
$client->setScopes([
    'https://www.googleapis.com/auth/analytics.readonly'
]);

$analytics = new Google_Service_AnalyticsReporting($client);
$dateRange = new Google_Service_AnalyticsReporting_DateRange();
$dateRange->setStartDate('2009-01-01');
$dateRange->setEndDate('2019-07-16');

$pageViews = new Google_Service_AnalyticsReporting_Metric();
$pageViews->setExpression("ga:pageviews");
$pageViews->setAlias('pageviews');

$filter = new Google_Service_AnalyticsReporting_DimensionFilter();
$filter->setOperator('EXACT');
$filter->setDimensionName('ga:pagePath');
$filter->setExpressions([
    '/path/to/a/page/'
]);

$filterClause = new Google_Service_AnalyticsReporting_DimensionFilterClause();
$filterClause->setFilters([$filter]);

$request = new Google_Service_AnalyticsReporting_ReportRequest();

// View ID has to be taken from the View Settings of your Google Analytics account
// Note: Reporting API will fail unless View ID is a string
$request->setViewId('01234567890');
$request->setDateRanges($dateRange);
$request->setMetrics([$pageViews]);
$request->setDimensionFilterClauses([$filterClause]);

$body = new Google_Service_AnalyticsReporting_GetReportsRequest();
$body->setReportRequests([$request]);

/**
 * Here and below we have to deal with incorrect type hints in the generated PHP code 
 *
 * @var Google_Service_AnalyticsReporting_Report $report
 */
$report = $analytics->reports->batchGet($body)->getReports()[0];

/**
 * @var Google_Service_AnalyticsReporting_DateRangeValues $total
 */
$total = $report->getData()->getTotals()[0];

// This is the desired page views amount
echo $total->current();

It works. Thank you