c# - 在 Google Drive API 中使用服务帐户下载文件时出现未经授权的响应

Question

我正在使用以下代码从 Google 的身份验证服务器获取 凭据 以访问 Google drive API

 public static Google.Apis.Services.BaseClientService.Initializer getCredentials()
    {

        String serviceAccountEmail = "xxx@developer.gserviceaccount.com";

        var certificate = new X509Certificate2(@"xxx.p12", "notasecret", X509KeyStorageFlags.Exportable);

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



        return new BaseClientService.Initializer()
        {
            HttpClientInitializer = credential,
            ApplicationName = "AppName",
        };



    }

然后从文件元数据中检索下载 url 并尝试使用以下代码下载该文件:

 public static System.IO.Stream DownloadFile(Google.Apis.Drive.v2.Data.File file, Google.Apis.Drive.v2.DriveService service)
   {



       if (!String.IsNullOrEmpty(file.DownloadUrl))
       {
           try
           {
               HttpWebRequest request = (HttpWebRequest)WebRequest.Create(
                   new Uri(file.DownloadUrl));
              // authenticator.ApplyAuthenticationToRequest(request);
               HttpWebResponse response = (HttpWebResponse)request.GetResponse();
               if (response.StatusCode == HttpStatusCode.OK)
               {
                   return response.GetResponseStream();
               }
               else
               {
                   Console.WriteLine(
                       "An error occurred: " + response.StatusDescription);
                   return null;
               }
           }
           catch (Exception e)
           {
               Console.WriteLine("An error occurred: " + e.Message);
               return null;
           }
       }
       else
       {
           // The file doesn't have any content stored on Drive.
           return null;
       }
   }

但是我收到了 401 unauthorized 响应。我假设我需要在 Authorization: Bearer {ACCESS_TOKEN} 行的请求中添加授权 header ，但 HttpClientInitializer.Token 属性为空。是否可以使用 ServiceAccountCredential 验证此请求？

Answer 1

我今天遇到了同样的问题。使用您的方法发出请求时未提供身份验证 header 。我需要以不同的方式构建请求。你在哪里:

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(
               new Uri(file.DownloadUrl));

你应该有:

HttpResponseMessage response = await service.HttpClient.GetAsync(new Uri(file.DownloadUrl));

这可确保请求得到正确验证。