我一直面临着一个持续的问题，而试图设置谷歌分析数据API（GA 4）使用谷歌提供的快速入门指南（快速入门指南）。
当我设置GOOGLE_APPLICATION_CREDENTIALS时出现了特定的问题。我已经正确地将credentials.json文件放在quickstart.php文件旁边，并使用PHP putenv函数设置变量，如下所示：

putenv('GOOGLE_APPLICATION_CREDENTIALS="'.__DIR__.'/credentials.json"');

不幸的是，每次我运行我的测试时，我都会遇到这个错误消息：

Fatal error: Uncaught DomainException: Unable to read the credential file specified by GOOGLE_APPLICATION_CREDENTIALS: file "/google/credentials.json" does not exist in /google/vendor/google/auth/src/CredentialsLoader.php:81 Stack trace: #0 /google/vendor/google/auth/src/ApplicationDefaultCredentials.php(160): Google\Auth\CredentialsLoader::fromEnv() #1 /google/vendor/google/gax/src/CredentialsWrapper.php(267): Google\Auth\ApplicationDefaultCredentials::getCredentials() #2 /google/vendor/google/gax/src/CredentialsWrapper.php(136): Google\ApiCore\CredentialsWrapper::buildApplicationDefaultCredentials() #3 /google/vendor/google/gax/src/GapicClientTrait in /google/vendor/google/gax/src/CredentialsWrapper.php on line 275

我三次检查了文件路径，一切似乎都很正常，但错误仍然存在。
有没有人遇到过这个问题，或者有没有人对如何解决这个问题有见解？任何帮助都非常感谢。
附加信息：

• 语言：PHP
• API：Google Analytics数据API（GA 4）

在此先谢谢您！
参考代码：

<?php
header("Cache-Control: no-store, no-cache, must-revalidate, max-age=0");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");
date_default_timezone_set('Europe/London');
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

putenv('GOOGLE_APPLICATION_CREDENTIALS="'.__DIR__.'/credentials.json"');

require 'vendor/autoload.php';

use Google\Analytics\Data\V1beta\BetaAnalyticsDataClient;
use Google\Analytics\Data\V1beta\DateRange;
use Google\Analytics\Data\V1beta\Dimension;
use Google\Analytics\Data\V1beta\Metric;

/**
 * TODO(developer): Replace this variable with your Google Analytics 4
 *   property ID before running the sample.
 */
$property_id = 'YOUR-GA4-PROPERTY-ID';

// Using a default constructor instructs the client to use the credentials
// specified in GOOGLE_APPLICATION_CREDENTIALS environment variable.
$client = new BetaAnalyticsDataClient();

// Make an API call.
$response = $client->runReport([
    'property' => 'properties/' . $property_id,
    'dateRanges' => [
        new DateRange([
            'start_date' => '2020-03-31',
            'end_date' => 'today',
        ]),
    ],
    'dimensions' => [new Dimension(
        [
            'name' => 'city',
        ]
    ),
    ],
    'metrics' => [new Metric(
        [
            'name' => 'activeUsers',
        ]
    )
    ]
]);

// Print results of an API call.
print 'Report result: ' . PHP_EOL;

foreach ($response->getRows() as $row) {
    print $row->getDimensionValues()[0]->getValue()
        . ' ' . $row->getMetricValues()[0]->getValue() . PHP_EOL;
}