我正在嘗試使用以下代碼從我的 google 作業區帳戶發送電子郵件：

using (var stream =
          new FileStream("credentials.json", FileMode.Open, FileAccess.Read))
{
    var credential = ServiceAccountCredential.FromServiceAccountData(stream);
    service = new GmailService(new BaseClientService.Initializer()
    {
        HttpClientInitializer = credential,
        ApplicationName = ApplicationName,
    });

    var email = MimeMessage.CreateFromMailMessage(new System.Net.Mail.MailMessage("EMAILADDRESS", destinationEmailAddress, "Verification code", $"Your verification code is {messageBody}"));

    Message message = new Message();

    byte[] blob;

    using (var memory = new MemoryStream())
    {
        email.WriteTo(memory);
        blob = memory.ToArray();
    }

    message.Raw = await credential.SignBlobAsync(blob);
    await service.Users.Messages.Send(message, "me").ExecuteAsync();
}

但我收到以下例外：

Google.Apis.Requests.RequestError\n先決條件檢查失敗。[400]\n錯誤 [\n\tMessage[Precondition check failed.] Location[ - ] Reason[failedPrecondition] Domain[global]\n]\n

我究竟做錯了什么？是否有直接的指南來正確地做到這一點？

uj5u.com熱心網友回復：

您遇到的問題是您使用的是帶有服務帳戶的 Gmail，并且您沒有正確配置對作業區帳戶上用戶的域范圍委派。按照本指南使用服務帳戶配置您的作業區帳戶。執行 Google Workspace 域范圍的授權

以下代碼應向您展示如何對其進行授權。請注意 CreateWithUser 方法，它設定了您希望將服務帳戶委派為的用戶。

class Program
    {
        private static readonly string[] Scopes = {GmailService.Scope.GmailSend};

        private static readonly string PathToServiceAccountKeyFile =
            @"C:\YouTube\workspaceserviceaccount-e4823a933ae3.json";

        private static readonly string workspaceAdmin = "[email protected]";
        private static readonly string sendEmailTo = "[email protected]";

        static async Task Main(string[] args)
        {
            Console.WriteLine("Hello World!");

            var credential = LoadGoogleCredentials();
            var service = CreateDirectoryService(credential);

            var mailMessage = new System.Net.Mail.MailMessage
            {
                From = new System.Net.Mail.MailAddress(workspaceAdmin),
                ReplyToList = {workspaceAdmin},
                To = {sendEmailTo},
                Subject = "Welcome",
                Body = "welcome new workspace user",
            };


            var mimeMessage = MimeMessage.CreateFromMailMessage(mailMessage);

            var gmailMessage = new Message
            {
                Raw = Encode(mimeMessage)
            };

            var request = await service.Users.Messages.Send(gmailMessage, workspaceAdmin).ExecuteAsync();

            Console.ReadLine();
        }

        public static string Encode(MimeMessage mimeMessage)
        {
            using (MemoryStream ms = new MemoryStream())
            {
                mimeMessage.WriteTo(ms);
                return Convert.ToBase64String(ms.GetBuffer())
                    .TrimEnd('=')
                    .Replace(' ', '-')
                    .Replace('/', '_');
            }
        }

        private static GmailService CreateDirectoryService(GoogleCredential credential)
        {
            return new(new BaseClientService.Initializer()
                {
                    HttpClientInitializer = credential,
                    ApplicationName = "Daimto Testing Workspace with service account"
                }
            );
        }

        private static GoogleCredential LoadGoogleCredentials()
        {
            return GoogleCredential.FromFile(PathToServiceAccountKeyFile)
                .CreateScoped(Scopes)
                .CreateWithUser(workspaceAdmin);
        }
    }

注意：即使我的測驗代碼是控制臺應用程式，此代碼對于所有型別的應用程式都是相同的，所使用的方法也適用于您的 asp .net 核心應用程式

來自評論

客戶端無權使用此方法檢索訪問令牌，或者客戶端未獲得任何請求范圍的授權

此錯誤訊息意味著您的 servcie 帳戶未獲得適當范圍的授權。gmail 發送方法需要一個允許訪問發送電子郵件的范圍，GmailService.Scope.GmailSend例如，因為我使用了 din 我的代碼記得將它添加到作業區中。

標籤：C＃ asp.net核心 谷歌API gmail-api google-api-dotnet-client

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