Question

在.Net中使用GMail API。使用Net.Mail.MailMessage创建消息传递。然后使用MimeKit创建MimeMessage（使用此方法发送附件+ HTML消息）。将MimeMessage.ToString传递给Base64编码器。没有API错误。代码运行正常。我可以在GMail的已发送页面中看到该消息。邮件看起来很完美（发送实际返回消息ID）。但是，在Gmail中，此邮件附加了以下附加邮件。

Bounce <nobody@gmail.com>

An error occurred. Your message was not sent.

像往常一样，Google没有其他信息。如何解决这个问题？

        Dim msg = New Net.Mail.MailMessage
        msg.Subject = subject
        msg.To.Add(New MailAddress(ToEmail))
        msg.From = New MailAddress(FromEmail, SenderName)
        msg.ReplyTo = New MailAddress(FromEmail, SenderName)
        msg.Body = bodyText
        msg.IsBodyHtml = True

        If Not String.IsNullOrWhiteSpace(fileAttachment) Then
            If System.IO.File.Exists(fileAttachment) Then
                Dim Attachment As New Net.Mail.Attachment(fileAttachment, "application/pdf")
                msg.Attachments.Add(Attachment)
            End If
        End If
       Dim message As MimeMessage = MimeMessage.CreateFromMailMessage(msg)
       Dim newMsg = New Google.Apis.Gmail.v1.Data.Message()
       newMsg.Raw = Base64UrlEncode(message.ToString)
       GmailService.Users.Messages.Send(newMsg, "me").Execute()



Private Function Base64UrlEncode(ByVal input As String) As String
            Dim inputBytes = System.Text.Encoding.UTF8.GetBytes(input)
            'Special "url-safe" base64 encode.
            Return Convert.ToBase64String(inputBytes).Replace("+", "-").Replace("/", "_").Replace("=", "")
        End Function

这是返回消息。你可以看到一切看起来都不错。使用Google API是最令人沮丧的事情。

200 OK

- Hide headers -

cache-control:  no-cache, no-store, max-age=0, must-revalidate
content-encoding:  gzip
content-length:  85
content-type:  application/json; charset=UTF-8
date:  Sat, 24 Jan 2015 05:57:21 GMT
etag:  "96Z6JVARoyR8skov3RseF4DCFpA/mFWFskkdSFxyjIhRJHJuhDCBvfY"
expires:  Fri, 01 Jan 1990 00:00:00 GMT
pragma:  no-cache
server:  GSE
vary:  Origin, X-Origin

{
 "id": "14b1a841e4fff910",
 "threadId": "14b1a841e4fff910",
 "labelIds": [
  "SENT"
 ]
}

Answer 1

这很疯狂。这就是问题所在。

这一行

msg.ReplyTo = New MailAddress(FromEmail, SenderName)

出于任何原因（我猜当FromEmail和ReplyTo是相同的电子邮件时）将RFC2822 Reply-To参数留空。即使注释msg.ReplyTo，参数仍为空白。毋庸置疑，GMail API似乎存在回复问题留空的问题。绝对是一个编程错误。

所以我必须在最终的RFC2882消息中做这个黑客。

inputTxt = Replace(inputTxt, "Reply-To:", "Reply-To: " & FromEmail)

现在有效。

*********如下面的评论所指出，您可以使用MailMessage.ReplyToList.Add()来解决此问题。因此，问题是Gmail API中需要ReplyTo地址（尽管有人可能会认为ReplyTo应默认为From电子邮件）。 **********

Answer 2

以防万一有人偶然发现并希望获得C＃答案，以下是MimeKit使用上一个答案作为指南的原因。

public void SendEmail(MyInternalSystemEmailMessage email)
{
    var mailMessage = new System.Net.Mail.MailMessage();
    mailMessage.From = new System.Net.Mail.MailAddress(email.FromAddress);
    mailMessage.To.Add(email.ToRecipients);
    mailMessage.ReplyToList.Add(email.FromAddress);
    mailMessage.Subject = email.Subject;
    mailMessage.Body = email.Body;
    mailMessage.IsBodyHtml = email.IsHtml;

    foreach (System.Net.Mail.Attachment attachment in email.Attachments)
    {
        mailMessage.Attachments.Add(attachment);
    }

    var mimeMessage = MimeKit.MimeMessage.CreateFromMailMessage(mailMessage);

    var gmailMessage = new Google.Apis.Gmail.v1.Data.Message {
        Raw = Encode(mimeMessage.ToString())
    };

    Google.Apis.Gmail.v1.UsersResource.MessagesResource.SendRequest request = service.Users.Messages.Send(gmailMessage, ServiceEmail);

    request.Execute();
}

public static string Encode(string text)
{
    byte[] bytes = System.Text.Encoding.UTF8.GetBytes(text);

    return System.Convert.ToBase64String(bytes)
        .Replace('+', '-')
        .Replace('/', '_')
        .Replace("=", "");
}

GMail API电子邮件弹跳

2 个答案: