// 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.
// [START drive_download_file]
using Google.Apis.Auth.OAuth2;
using Google.Apis.Download;
using Google.Apis.Drive.v3;
using Google.Apis.Services;
namespace DriveV3Snippets
{
// Class to demonstrate use-case of drive's download file.
public class DownloadFile
{
///
/// Download a Document file in PDF format.
///
/// file ID of any workspace document format file.
/// byte array stream if successful, null otherwise.
public static MemoryStream DriveDownloadFile(string fileId)
{
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.Drive);
// Create Drive API service.
var service = new DriveService(new BaseClientService.Initializer
{
HttpClientInitializer = credential,
ApplicationName = "Drive API Snippets"
});
var request = service.Files.Get(fileId);
var stream = new MemoryStream();
// Add a handler which will be notified on progress changes.
// It will notify on each chunk download and when the
// download is completed or failed.
request.MediaDownloader.ProgressChanged +=
progress =>
{
switch (progress.Status)
{
case DownloadStatus.Downloading:
{
Console.WriteLine(progress.BytesDownloaded);
break;
}
case DownloadStatus.Completed:
{
Console.WriteLine("Download complete.");
break;
}
case DownloadStatus.Failed:
{
Console.WriteLine("Download failed.");
break;
}
}
};
request.Download(stream);
return stream;
}
catch (Exception e)
{
// TODO(developer) - handle error appropriately
if (e is AggregateException)
{
Console.WriteLine("Credential Not found");
}
else
{
throw;
}
}
return null;
}
}
}
// [END drive_download_file]