Google Drive API：使用服务账户进行无用户认证访问指南

// backend/googleDrive.js (Wix Velo 后端模块示例)
import { GoogleAuth } from 'google-auth-library';
import { getSecret } from 'wix-secrets-backend'; // 假设 Wix Velo 提供了获取 Secret 的方法

// 异步函数，用于获取 Google 服务账户的访问令牌
async function getServiceAccountAccessToken() {
  const clientEmail = await getSecret('GOOGLE_SERVICE_ACCOUNT_EMAIL');
  // 私钥可能包含换行符，从 Secret Manager 获取后需要确保格式正确
  const privateKey = (await getSecret('GOOGLE_PRIVATE_KEY')).replace(/\n/g, '
');

  if (!clientEmail || !privateKey) {
    throw new Error('Google Service Account credentials not found in Secrets Manager.');
  }

  const credentials = {
    client_email: clientEmail,
    private_key: privateKey,
  };

  // 定义服务账户需要访问的范围
  // https://www.googleapis.com/auth/drive.readonly 仅读取权限
  // https://www.googleapis.com/auth/drive 可以读写
  const auth = new GoogleAuth({
    credentials,
    scopes: ['https://www.googleapis.com/auth/drive.readonly'],
  });

  const client = await auth.getClient();
  const accessTokenResponse = await client.getAccessToken();

  if (!accessTokenResponse || !accessTokenResponse.token) {
    throw new Error('Failed to retrieve access token from Google Service Account.');
  }

  return accessTokenResponse.token;
}

export { getServiceAccountAccessToken };

// backend/googleDrive.js (Wix Velo 后端模块示例)
import { fetch } from 'wix-fetch';
import { getServiceAccountAccessToken } from './googleDrive'; // 导入上面定义的函数

// 异步函数，用于从 Google Drive 获取照片
async function fetchPhotosFromGoogleDrive() {
  const apiUrl = 'https://www.googleapis.com/drive/v3/files';
  const fields = 'files(id,name,mimeType,thumbnailLink)'; // 定义需要获取的文件字段

  try {
    const accessToken = await getServiceAccountAccessToken(); // 获取服务账户访问令牌

    const response = await fetch(`${apiUrl}?fields=${fields}`, {
      method: 'GET',
      headers: {
        'Authorization': `Bearer ${accessToken}` // 使用获取到的访问令牌
      }
    });
    const data = await response.json();

    if (!response.ok) {
      // 记录详细错误信息，包括 Google API 返回的错误
      console.error('Google Drive API Error:', data);
      throw new Error(`Failed to fetch photos from Google Drive: ${data.error?.message || response.statusText}`);
    }

    if (!data.files) {
      return []; // 如果没有文件数据，返回空数组
    }

    // 过滤出图片文件
    const imageFiles = data.files.filter(file => file.mimeType.startsWith('image/'));

    return imageFiles;
  } catch (error) {
    console.error('Error in fetchPhotosFromGoogleDrive:', error);
    throw error; // 重新抛出错误以便上层处理
  }
}

// 辅助函数，用于生成缩略图 URL (如果 thumbnailLink 不直接可用)
// 注意：Google Drive API v3 通常会直接提供 thumbnailLink
function getThumbnailUrl(fileId) {
  const timestamp = Date.now(); // 添加时间戳以避免缓存问题
  return `https://drive.google.com/thumbnail?id=${fileId}&timestamp=${timestamp}`;
}

// 导出函数供前端调用
export { fetchPhotosFromGoogleDrive, getThumbnailUrl };

// pages/yourPage.js (Wix Velo 客户端代码示例)
import { fetchPhotosFromGoogleDrive } from 'backend/googleDrive'; // 导入后端函数

$w.onReady(function () {
  displayPhotos();
});

async function displayPhotos() {
  const myGallery = $w('#myGallery'); // 假设页面上有一个 ID 为 'myGallery' 的画廊组件

  try {
    const photos = await fetchPhotosFromGoogleDrive();

    if (photos.length === 0) {
      console.warn('No photos found in Google Drive.');
      myGallery.items = [];
      return;
    }

    const galleryItems = photos.map(photo => ({
      type: 'image',
      src: photo.thumbnailLink || getThumbnailUrl(photo.id), // 优先使用 thumbnailLink
      title: photo.name,
      description: photo.name, // 可选：添加描述
    }));

    myGallery.items = galleryItems;
  } catch (error) {
    console.error('Error fetching and displaying photos:', error);
    // 可以在这里显示用户友好的错误消息
  }
}