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存储应用专属数据

“应用数据文件夹”是一个特殊的隐藏文件夹，应用可以使用它来存储特定于应用的数据，如配置文件。当您尝试在应用数据文件夹中创建文件时，系统会自动创建该文件夹。使用此文件夹存储用户不应直接与之互动的任何文件。此文件夹仅供您的应用访问，且其内容对用户和其他云端硬盘应用是隐藏的。

appDataFolder 中的文件无法在存储位置（聊天室）之间移动。如需了解详情，请参阅文件组织。

当用户从其“我的云端硬盘”中卸载您的应用时，应用数据文件夹会被删除。用户也可以手动删除应用的数据文件夹。

应用数据文件夹范围

您必须先请求访问 https://www.googleapis.com/auth/drive.appdata 范围，然后才能访问应用数据文件夹。如需详细了解范围以及如何请求对这些范围的访问权限，请参阅 API 专属授权和身份验证信息。如需详细了解特定 OAuth 2.0 范围，请参阅适用于 Google API 的 OAuth 2.0 范围。

在应用数据文件夹中创建文件

如需在应用数据文件夹中创建文件，请在文件的 parents 属性中指定 appDataFolder，然后使用 files.create 方法将文件上传到该文件夹。以下代码示例展示了如何使用客户端库将文件插入文件夹。

Java

drive/snippets/drive_v3/src/main/java/UploadAppData.java

在 GitHub 上查看

import com.google.api.client.googleapis.json.GoogleJsonResponseException;
import com.google.api.client.http.FileContent;
import com.google.api.client.http.HttpRequestInitializer;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.services.drive.Drive;
import com.google.api.services.drive.DriveScopes;
import com.google.api.services.drive.model.File;
import com.google.auth.http.HttpCredentialsAdapter;
import com.google.auth.oauth2.GoogleCredentials;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collections;

/**
 * Class to demonstrate use-case of create file in the application data folder.
 */
public class UploadAppData {

  /**
   * Creates a file in the application data folder.
   *
   * @return Created file's Id.
   */
  public static String uploadAppData() throws IOException {
        /*Load pre-authorized user credentials from the environment.
        TODO(developer) - See https://developers.google.com/identity for
        guides on implementing OAuth2 for your application.*/
    GoogleCredentials credentials = null;
    try {
      credentials = GoogleCredentials.getApplicationDefault()
          .createScoped(Arrays.asList(DriveScopes.DRIVE_APPDATA));
    } catch (IOException e) {
      e.printStackTrace();
    }
    HttpRequestInitializer requestInitializer = new HttpCredentialsAdapter(
        credentials);

    // Build a new authorized API client service.
    Drive service = new Drive.Builder(new NetHttpTransport(),
        GsonFactory.getDefaultInstance(),
        requestInitializer)
        .setApplicationName("Drive samples")
        .build();
    try {
      // File's metadata.
      File fileMetadata = new File();
      fileMetadata.setName("config.json");
      fileMetadata.setParents(Collections.singletonList("appDataFolder"));
      java.io.File filePath = new java.io.File("files/config.json");
      FileContent mediaContent = new FileContent("application/json", filePath);
      File file = service.files().create(fileMetadata, mediaContent)
          .setFields("id")
          .execute();
      System.out.println("File ID: " + file.getId());
      return file.getId();
    } catch (GoogleJsonResponseException e) {
      // TODO(developer) - handle error appropriately
      System.err.println("Unable to create file: " + e.getDetails());
      throw e;
    }
  }

}

Python

drive/snippets/drive-v3/app_data_snippet/upload_appdata.py

在 GitHub 上查看

import google.auth
from googleapiclient.discovery import build
from googleapiclient.errors import HttpError
from googleapiclient.http import MediaFileUpload


def upload_appdata():
  """Insert a file in the application data folder and prints file Id.
  Returns : ID's of the inserted files

  Load pre-authorized user credentials from the environment.
  TODO(developer) - See https://developers.google.com/identity
  for guides on implementing OAuth2 for the application.
  """
  creds, _ = google.auth.default()

  try:
    # call drive api client
    service = build("drive", "v3", credentials=creds)

    # pylint: disable=maybe-no-member
    file_metadata = {"name": "abc.txt", "parents": ["appDataFolder"]}
    media = MediaFileUpload("abc.txt", mimetype="text/txt", resumable=True)
    file = (
        service.files()
        .create(body=file_metadata, media_body=media, fields="id")
        .execute()
    )
    print(f'File ID: {file.get("id")}')

  except HttpError as error:
    print(f"An error occurred: {error}")
    file = None

  return file.get("id")


if __name__ == "__main__":
  upload_appdata()

Node.js

drive/snippets/drive_v3/appdata_snippets/upload_appdata.js

在 GitHub 上查看

/**
 * Insert a file in the application data folder and prints file Id
 * */
async function uploadAppdata() {
  // Get credentials and build service
  // TODO (developer) - Use appropriate auth mechanism for your app

  const {GoogleAuth} = require('google-auth-library');
  const {google} = require('googleapis');
  const fs = require('fs');

  const auth = new GoogleAuth({
    scopes: 'https://www.googleapis.com/auth/drive.appdata',
  });
  const service = google.drive({version: 'v3', auth});
  const fileMetadata = {
    name: 'config.json',
    parents: ['appDataFolder'],
  };
  const media = {
    mimeType: 'application/json',
    body: fs.createReadStream('files/config.json'),
  };
  try {
    const file = await service.files.create({
      requestBody: fileMetadata,
      media: media,
      fields: 'id',
    });
    console.log('File Id:', file.data.id);
    return file.data.id;
  } catch (err) {
    // TODO(developer) - Handle error
    throw err;
  }
}

PHP

drive/snippets/drive_v3/src/DriveUploadAppData.php

在 GitHub 上查看

use Google\Client;
use Google\Service\Drive;
function uploadAppData()
{
   try {
    $client = new Client();
    $client->useApplicationDefaultCredentials();
    $client->addScope(Drive::DRIVE);
    $client->addScope(Drive::DRIVE_APPDATA);
    $driveService = new Drive($client);
    $fileMetadata = new Drive\DriveFile(array(
        'name' => 'config.json',
        'parents' => array('appDataFolder')
    ));
    $content = file_get_contents('../files/config.json');
    $file = $driveService->files->create($fileMetadata, array(
        'data' => $content,
        'mimeType' => 'application/json',
        'uploadType' => 'multipart',
        'fields' => 'id'));
    printf("File ID: %s\n", $file->id);
    return $file->id;

   } catch(Exception $e) {
     echo "Error Message: ".$e;
   }  
}

.NET

drive/snippets/drive_v3/DriveV3Snippets/UploadAppData.cs

在 GitHub 上查看

using Google.Apis.Auth.OAuth2;
using Google.Apis.Drive.v3;
using Google.Apis.Services;

namespace DriveV3Snippets
{
    // Class of demonstrate the use of Drive upload app data. 
    public class UploadAppData
    {
        /// <summary>
        /// Insert a file in the application data folder and prints file Id.
        /// </summary>
        /// <param name="filePath">File path to upload.</param>
        /// <returns>ID's of the inserted files, null otherwise.</returns>
        public static string DriveUploadAppData(string filePath)
        {
            try
            {
                /* Load pre-authorized user credentials from the environment.
                 TODO(developer) - See https://developers.google.com/identity for
                 guides on implementing OAuth2 for your application. */
                GoogleCredential credential = GoogleCredential.GetApplicationDefault()
                    .CreateScoped(DriveService.Scope.DriveAppdata);

                // Create Drive API service.
                var service = new DriveService(new BaseClientService.Initializer
                {
                    HttpClientInitializer = credential,
                    ApplicationName = "Drive API Snippets"
                });
                var fileMetadata = new Google.Apis.Drive.v3.Data.File()
                {
                    Name = "config.json",
                    Parents = new List<string>()
                    {
                        "appDataFolder"
                    }
                };
                FilesResource.CreateMediaUpload request;
                using (var stream = new FileStream(filePath,
                           FileMode.Open))
                {
                    request = service.Files.Create(
                        fileMetadata, stream, "application/json");
                    request.Fields = "id";
                    request.Upload();
                }

                var file = request.ResponseBody;
                // Prints the file id.
                Console.WriteLine("File ID: " + file.Id);
                return file.Id;
            }
            catch (Exception e)
            {
                // TODO(developer) - handle error appropriately
                if (e is AggregateException)
                {
                    Console.WriteLine("Credential Not found");
                }
                else
                {
                    throw;
                }
            }
            return null;
        }
    }
}

如需详细了解如何在文件夹中创建文件，请参阅创建和填充文件夹。

在应用数据文件夹中搜索文件

如需在应用数据文件夹中搜索文件，请将 spaces 字段设置为 appDataFolder，然后使用 files.list 方法。以下代码示例展示了如何使用客户端库搜索应用数据文件夹中的文件。

Java

drive/snippets/drive_v3/src/main/java/ListAppData.java

在 GitHub 上查看

import com.google.api.client.googleapis.json.GoogleJsonResponseException;
import com.google.api.client.http.HttpRequestInitializer;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.services.drive.Drive;
import com.google.api.services.drive.DriveScopes;
import com.google.api.services.drive.model.File;
import com.google.api.services.drive.model.FileList;
import com.google.auth.http.HttpCredentialsAdapter;
import com.google.auth.oauth2.GoogleCredentials;
import java.io.IOException;
import java.util.Arrays;

/**
 * Class to demonstrate use-case of list 10 files in the application data folder.
 */
public class ListAppData {

  /**
   * list down files in the application data folder.
   *
   * @return list of 10 files.
   */
  public static FileList listAppData() throws IOException {
        /*Load pre-authorized user credentials from the environment.
        TODO(developer) - See https://developers.google.com/identity for
        guides on implementing OAuth2 for your application.*/
    GoogleCredentials credentials = null;
    try {
      credentials = GoogleCredentials.getApplicationDefault()
          .createScoped(Arrays.asList(DriveScopes.DRIVE_APPDATA));
    } catch (IOException e) {
      e.printStackTrace();
    }
    HttpRequestInitializer requestInitializer = new HttpCredentialsAdapter(
        credentials);

    // Build a new authorized API client service.
    Drive service = new Drive.Builder(new NetHttpTransport(),
        GsonFactory.getDefaultInstance(),
        requestInitializer)
        .setApplicationName("Drive samples")
        .build();
    try {
      FileList files = service.files().list()
          .setSpaces("appDataFolder")
          .setFields("nextPageToken, files(id, name)")
          .setPageSize(10)
          .execute();
      for (File file : files.getFiles()) {
        System.out.printf("Found file: %s (%s)\n",
            file.getName(), file.getId());
      }

      return files;
    } catch (GoogleJsonResponseException e) {
      // TODO(developer) - handle error appropriately
      System.err.println("Unable to list files: " + e.getDetails());
      throw e;
    }
  }

}

Python

drive/snippets/drive-v3/app_data_snippet/list_appdata.py

在 GitHub 上查看

import google.auth
from googleapiclient.discovery import build
from googleapiclient.errors import HttpError


def list_appdata():
  """List all files inserted in the application data folder
  prints file titles with Ids.
  Returns : List of items

  Load pre-authorized user credentials from the environment.
  TODO(developer) - See https://developers.google.com/identity
  for guides on implementing OAuth2 for the application.
  """
  creds, _ = google.auth.default()

  try:
    # call drive api client
    service = build("drive", "v3", credentials=creds)

    # pylint: disable=maybe-no-member
    response = (
        service.files()
        .list(
            spaces="appDataFolder",
            fields="nextPageToken, files(id, name)",
            pageSize=10,
        )
        .execute()
    )
    for file in response.get("files", []):
      # Process change
      print(f'Found file: {file.get("name")}, {file.get("id")}')

  except HttpError as error:
    print(f"An error occurred: {error}")
    response = None

  return response.get("files")


if __name__ == "__main__":
  list_appdata()

Node.js

drive/snippets/drive_v3/appdata_snippets/list_appdata.js

在 GitHub 上查看

/**
 * Copyright 2022 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * List all files inserted in the application data folder
 * */
async function listAppdata() {
  // Get credentials and build service
  // TODO (developer) - Use appropriate auth mechanism for your app

  const {GoogleAuth} = require('google-auth-library');
  const {google} = require('googleapis');

  const auth = new GoogleAuth({
    scopes: 'https://www.googleapis.com/auth/drive.appdata',
  });
  const service = google.drive({version: 'v3', auth});
  try {
    const res = await service.files.list({
      spaces: 'appDataFolder',
      fields: 'nextPageToken, files(id, name)',
      pageSize: 100,
    });
    res.data.files.forEach(function(file) {
      console.log('Found file:', file.name, file.id);
    });
    return res.data.files;
  } catch (err) {
    // TODO(developer) - Handle error
    throw err;
  }
}

module.exports = listAppdata;

PHP

drive/snippets/drive_v3/src/DriveListAppData.php

在 GitHub 上查看

use Google\Client;
use Google\Service\Drive;
function listAppData()
{
    try {
        $client = new Client();
        $client->useApplicationDefaultCredentials();
        $client->addScope(Drive::DRIVE);
        $driveService = new Drive($client);
        $response = $driveService->files->listFiles(array(
            'spaces' => 'appDataFolder',
            'fields' => 'nextPageToken, files(id, name)',
            'pageSize' => 10
        ));
        foreach ($response->files as $file) {
            printf("Found file: %s (%s)", $file->name, $file->id);
        }
        return $response->files;

    }catch(Exception $e) {
        echo "Error Message: ".$e;
    }

}

.NET

drive/snippets/drive_v3/DriveV3Snippets/ListAppData.cs

在 GitHub 上查看

using Google.Apis.Auth.OAuth2;
using Google.Apis.Drive.v3;
using Google.Apis.Drive.v3.Data;
using Google.Apis.Services;

namespace DriveV3Snippets
{
    // Class to demonstrate use-case of Drive's list files in the application data folder.
    public class ListAppData
    {
        /// <summary>
        /// List down files in the application data folder.
        /// </summary>
        /// <returns>list of 10 files, null otherwise.</returns>
        public static FileList DriveListAppData()
        {
            try
            {
                /* Load pre-authorized user credentials from the environment.
                 TODO(developer) - See https://developers.google.com/identity for
                 guides on implementing OAuth2 for your application. */
                GoogleCredential credential = GoogleCredential.GetApplicationDefault()
                    .CreateScoped(DriveService.Scope.DriveAppdata);

                // Create Drive API service.
                var service = new DriveService(new BaseClientService.Initializer
                {
                    HttpClientInitializer = credential,
                    ApplicationName = "Drive API Snippets"
                });

                var request = service.Files.List();
                request.Spaces = "appDataFolder";
                request.Fields = "nextPageToken, files(id, name)";
                request.PageSize = 10;
                var result = request.Execute();
                foreach (var file in result.Files)
                {
                    // Prints the list of 10 file names.
                    Console.WriteLine("Found file: {0} ({1})", file.Name, file.Id);
                }
                return result;
            }
            catch (Exception e)
            {
                // TODO(developer) - handle error appropriately
                if (e is AggregateException)
                {
                    Console.WriteLine("Credential Not found");
                }
                else
                {
                    throw;
                }
            }
            return null;
        }
    }
}

从应用数据文件夹下载文件

如需从应用数据文件夹下载文件，请使用 files.get 方法。如需了解详情并查看代码示例，请参阅下载 blob 文件内容。