Google Classroom createCourse API调用出现401认证错误求助

问题背景 #

已完成以下操作：

• 创建外部模式的新项目
• 启用Google Classroom API
• 设置OAuth内容界面及凭证（生成含OAuth Client ID的credentials.json）
• 在CodeIgniter中通过composer安装google/apiclient:^2.0库

尝试使用如下CodeIgniter代码创建课程：

defined('BASEPATH') OR exit('No direct script access allowed');
require FCPATH . 'vendor/autoload.php';

use Google\Client;
use Google\Service\Classroom;
use Google\Service\Classroom\Course;
use Google\Service\Exception;

class Googleclassroom extends CI_Controller {
    
    function __construct()
    {       
        parent::__construct();      
    }
    
    public function createCourse()
    {       
        $client = new Google_Client();
        $client->setApplicationName('Google Classroom API PHP ');
        $client->setScopes(Google_Service_Classroom::CLASSROOM_COURSES_READONLY);
        $client->setAuthConfig('credentials.json');
        $client->setAccessType('offline');
        $client->setPrompt('select_account consent');
        
        $client->addScope("https://www.googleapis.com/auth/classroom.courses");
        $service = new Classroom($client);
        
        $course = new Course([
            'name' => '10th  Biology',
            'section' => 'Period 2',
            'descriptionHeading' => 'Welcome to 10th Grade Biology',
            'description' => 'hi',
            'room' => '301',
            'ownerId' => 'me',
            'courseState' => 'PROVISIONED'
        ]);
        $course = $service->courses->create($course);
        printf("Course created: %s (%s)\n", $course->name, $course->id);
    }
}

访问http://baseUrl/Googleclassroom/createCourse时触发401认证错误：

An uncaught Exception was encountered
Type: Google_Service_Exception
Message: { "error": { "code": 401, "message": "Request had invalid authentication credentials. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.", "errors": [ { "message": "Invalid Credentials", "domain": "global", "reason": "authError", "location": "Authorization", "locationType": "header" } ], "status": "UNAUTHENTICATED" } }

解决方案 #

1. 补充OAuth授权流程，获取有效访问令牌 #

当前代码仅初始化了客户端，但未处理OAuth授权流程，没有获取到有效的访问令牌。需添加完整的授权逻辑：

public function createCourse()
{       
    $client = new Google_Client();
    $client->setApplicationName('Google Classroom API PHP ');
    // 直接设置创建课程所需的权限，避免重复添加
    $client->setScopes([Google_Service_Classroom::CLASSROOM_COURSES]);
    // 使用FCPATH确保凭证文件路径正确
    $client->setAuthConfig(FCPATH . 'credentials.json');
    $client->setAccessType('offline');
    $client->setPrompt('select_account consent');

    $tokenPath = FCPATH . 'token.json';
    // 检查是否已有存储的令牌
    if (file_exists($tokenPath)) {
        $accessToken = json_decode(file_get_contents($tokenPath), true);
        $client->setAccessToken($accessToken);
    }

    // 处理令牌过期情况
    if ($client->isAccessTokenExpired()) {
        if ($client->getRefreshToken()) {
            // 刷新过期的令牌
            $client->fetchAccessTokenWithRefreshToken($client->getRefreshToken());
        } else {
            // 无刷新令牌，引导用户授权
            $authUrl = $client->createAuthUrl();
            redirect($authUrl);
        }
        // 保存更新后的令牌
        file_put_contents($tokenPath, json_encode($client->getAccessToken()));
    }

    $service = new Classroom($client);
    
    $course = new Course([
        'name' => '10th  Biology',
        'section' => 'Period 2',
        'descriptionHeading' => 'Welcome to 10th Grade Biology',
        'description' => 'hi',
        'room' => '301',
        'ownerId' => 'me',
        'courseState' => 'PROVISIONED'
    ]);
    try {
        $course = $service->courses->create($course);
        printf("Course created: %s (%s)\n", $course->name, $course->id);
    } catch (Exception $e) {
        echo 'Error creating course: ' . $e->getMessage();
    }
}

// 添加OAuth回调方法处理授权返回
public function oauth2callback()
{
    $client = new Google_Client();
    $client->setAuthConfig(FCPATH . 'credentials.json');
    $client->setScopes([Google_Service_Classroom::CLASSROOM_COURSES]);
    $client->setAccessType('offline');

    // 获取授权码并交换访问令牌
    $authCode = $this->input->get('code');
    $accessToken = $client->fetchAccessTokenWithAuthCode($authCode);
    $client->setAccessToken($accessToken);

    // 保存令牌到项目根目录
    $tokenPath = FCPATH . 'token.json';
    file_put_contents($tokenPath, json_encode($accessToken));

    // 重定向回创建课程的方法
    redirect('Googleclassroom/createCourse');
}

2. 修正权限配置 #

原代码先设置只读权限CLASSROOM_COURSES_READONLY，再添加创建权限，可能导致权限冲突。直接设置CLASSROOM_COURSES权限即可，无需重复添加。

3. 确保凭证文件路径正确 #

使用CodeIgniter的FCPATH常量指定credentials.json的完整路径，避免因相对路径问题无法读取文件。

4. 配置OAuth回调地址 #

在Google Cloud控制台的OAuth 2.0凭证设置中，添加回调地址http://baseUrl/Googleclassroom/oauth2callback，确保授权流程能正常完成。

5. 令牌存储说明 #

首次访问createCourse方法时，会自动跳转到Google授权页面，用户完成授权后，系统会将令牌保存为token.json到项目根目录，后续请求会自动使用该令牌进行认证，无需重复授权。

内容的提问来源于stack exchange，提问作者Rakesh Hiray