使用.NET的Google API从gDrive下载文件时出现问题

时间:2019-03-16 06:28:58

标签: c# google-api google-drive-api google-api-dotnet-client

几年来,我有一个应用程序,用户可以使用它从gDrive加载数据。数据可以来自本地Google电子表格(gSheets)或txt,csv,xlsx等文件。突然以来,尽管本周没有任何变化,但本周有时突然无法下载文件。当我尝试下载文件时,我现在获得了html页面的内容,该页面基本上是一个登录屏幕。但是,仍然可以下载 gSheets的内容,所以这不可能是由于我正在使用的服务帐户的某些访问问题所致。我还可以确认文件仍与该服务帐户共享。 我正在使用以下代码下载文件:

        String serviceAccountEmail = this.apiConfig.ClientIdEmail;
        Byte[] keyFile = this.apiConfig.FileP12;

        var certificate = new X509Certificate2(keyFile, "notasecret", X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.PersistKeySet | X509KeyStorageFlags.Exportable);

        ServiceAccountCredential credential = new ServiceAccountCredential(
           new ServiceAccountCredential.Initializer(serviceAccountEmail)
           {
               Scopes = new[] { DriveService.Scope.Drive, DriveService.Scope.DriveFile }
           }.FromCertificate(certificate));

        DriveService service = new DriveService(new BaseClientService.Initializer()
        {
            HttpClientInitializer = credential,
            ApplicationName = "Drive Spotfire Datasource",
        });

        var response = service.HttpClient.GetByteArrayAsync(exportUrl).Result;
        Stream downloadStream = new MemoryStream(response);

“ exportUrl”的格式为

https://docs.google.com/a/<domain.com>/uc?id=<fileId>&export=download&gid=0

,当我在浏览器中尝试该网址时,可以毫无问题地下载文件。 在此期间,我尝试使用NuGet(版本1.38)中针对Google.Apis.Drive.v2和Google.Apis.Drive.v3的最新dll。 有谁知道为什么这些下载突然无法正常工作?

1 个答案:

答案 0 :(得分:0)

与此同时,我找到了解决方案。事实证明,下载文件时需要使用另一个URL:

    String serviceAccountEmail = this.apiConfig.ClientIdEmail;
    Byte[] keyFile = this.apiConfig.FileP12;

    var certificate = new X509Certificate2(keyFile, "notasecret", X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.PersistKeySet | X509KeyStorageFlags.Exportable);

    ServiceAccountCredential credential = new ServiceAccountCredential(
       new ServiceAccountCredential.Initializer(serviceAccountEmail)
       {
           Scopes = new[] { DriveService.Scope.Drive, DriveService.Scope.DriveFile }
       }.FromCertificate(certificate));

    DriveService service = new DriveService(new BaseClientService.Initializer()
    {
        HttpClientInitializer = credential,
        ApplicationName = "Drive Spotfire Datasource",
    });

    //get file handler
    Google.Apis.Drive.v2.Data.File file = service.Files.Get(this.uniqueKey).Execute();
    if (!file.MimeType.Equals("application/vnd.google-apps.spreadsheet"))
    {
        //for files use another Url
        exportUrl = file.DownloadUrl;
    }
    var response = service.HttpClient.GetByteArrayAsync(exportUrl).Result;
    Stream downloadStream = new MemoryStream(response);