Google Drive API IAuthenticator

Question

我正在嘗試將我的ASP.NET C＃應用程序與Google Drive API集成。我們已經成功地將文檔存儲爲我們的驅動器存儲帳戶的pdf文件，但現在我們正在嘗試檢索並下載文件。

我們打電話給我們返回數據。我的問題是，它給了我幾個下載鏈接，並且這些鏈接中的每一個（當用於檢索文檔時）都會給出一個錯誤，說明「未經授權」。

在文檔中提到了ICredentials，但是我找不到有關如何從我們的ServiceAccountCredential創建這個ICredentials對象的任何內容。

我也在文檔中看到了一種允許公共訪問檢索文檔的方式，但我試過這個，但它也沒有工作。奇怪的是我們可以下載縮略圖，但不是實際的文檔。

任何人都可以幫助我知道如何獲得這些鏈接的授權嗎？

Answer 1

使用服務帳戶創建驅動器服務Credential與Oauth2幾乎相同。

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; 

      } 

上述方法將返回可用於進行其他調用的驅動器服務。這是我用來下載文件的方法。一旦你從files.list獲得文件資源

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

正如你可以看到它使用downloadURL來下載文件。

/// <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; 
      } 
     } 

代碼來自教程撕開Google Drive api C# download