Google Drive API IAuthenticator

Question

我正在尝试将我的ASP.NET C＃应用程序与Google Drive API集成。我们已经成功地将文档存储为我们的驱动器存储帐户的pdf文件，但现在我们正在尝试检索并下载文件。

我们打电话给我们返回数据。我的问题是，它给了我几个下载链接，并且这些链接中的每一个（当用于检索文档时）都会给出一个错误，说明“未经授权”。

在文档中提到了ICredentials，但是我找不到有关如何从我们的ServiceAccountCredential创建这个ICredentials对象的任何内容。

我也在文档中看到了一种允许公共访问检索文档的方式，但我试过这个，但它也没有工作。奇怪的是我们可以下载缩略图，但不是实际的文档。

任何人都可以帮助我知道如何获得这些链接的授权吗？

Answer 1

使用服务帐户创建驱动器服务Credential与Oauth2几乎相同。

var service = AuthenticationHelper.AuthenticateServiceAccount("1046123799103-6v9cj8jbub068jgmss54m9gkuk4q2qu8@developer.gserviceaccount.com",@"C:\Users\HPUser\Downloads\e8bf61cc9963.p12"); 

/// <summary> 
     /// Authenticating to Google using a Service account 
     /// Documentation: https://developers.google.com/accounts/docs/OAuth2#serviceaccount 
     /// </summary> 
     /// <param name="serviceAccountEmail">From Google Developer console https://console.developers.google.com</param> 
     /// <param name="keyFilePath">Location of the Service account key file downloaded from Google Developer console https://console.developers.google.com</param> 
     /// <returns></returns> 
     public static DriveService AuthenticateServiceAccount(string serviceAccountEmail, string keyFilePath) 
     { 

      // check the file exists 
      if (!File.Exists(keyFilePath)) 
      { 
       Console.WriteLine("An Error occurred - Key file does not exist"); 
       return null; 
      } 

      string[] scopes = new string[] { DriveService.Scope.Drive };  // View analytics data    

      var certificate = new X509Certificate2(keyFilePath, "notasecret", X509KeyStorageFlags.Exportable); 
      try 
      { 
       ServiceAccountCredential credential = new ServiceAccountCredential(
        new ServiceAccountCredential.Initializer(serviceAccountEmail) 
        { 
         Scopes = scopes 
        }.FromCertificate(certificate)); 

       // Create the service. 
       DriveService service = new DriveService(new BaseClientService.Initializer() 
       { 
        HttpClientInitializer = credential, 
        ApplicationName = "Drive API Sample", 
       }); 
       return service; 
      } 
      catch (Exception ex) 
      { 

       Console.WriteLine(ex.InnerException); 
       return null; 

      } 

上述方法将返回可用于进行其他调用的驱动器服务。这是我用来下载文件的方法。一旦你从files.list获得文件资源

var m = service.Files.List().Execute(); 

正如你可以看到它使用downloadURL来下载文件。

/// <summary> 
     /// Download a file 
     /// Documentation: https://developers.google.com/drive/v2/reference/files/get 
     /// </summary> 
     /// <param name="_service">a Valid authenticated DriveService</param> 
     /// <param name="_fileResource">File resource of the file to download</param> 
     /// <param name="_saveTo">location of where to save the file including the file name to save it as.</param> 
     /// <returns></returns> 
     public static Boolean downloadFile(DriveService _service, File _fileResource, string _saveTo) 
     { 

      if (!String.IsNullOrEmpty(_fileResource.DownloadUrl)) 
      { 
       try 
       { 
        var x = _service.HttpClient.GetByteArrayAsync(_fileResource.DownloadUrl); 
        byte[] arrBytes = x.Result; 
        System.IO.File.WriteAllBytes(_saveTo, arrBytes); 
        return true;     
       } 
       catch (Exception e) 
       { 
        Console.WriteLine("An error occurred: " + e.Message); 
        return false; 
       } 
      } 
      else 
      { 
       // The file doesn't have any content stored on Drive. 
       return false; 
      } 
     } 

代码来自教程撕开Google Drive api C# download