Question

当以下代码中的mailFromName包含“æ”，“ø”或“å”时，我们正面临通过Mandrill SMTP发送邮件时出现问题的无效问题。当我们使用另一个SMTP时，邮件发送得非常好。

Mail.ReplyToList.Add(New MailAddress(mailFromAddress, mailFromName, System.Text.Encoding.UTF8))

我们使用.NET smtpClient类。

Dim SmtpClient As New System.Net.Mail.SmtpClient
SmtpClient.Send(Mail)
SmtpClient.Dispose()

更新

正如评论中所建议的那样，我同意这看起来像编码问题，但无法看到我能为自己做些什么。

它似乎只连接到包含æ，ø和å而不是Mail.To的RepleyToList，我以类似的方式定义它：

Dim mTo As New MailAddress(mailToAddress, mailToName, System.Text.Encoding.UTF8)
Mail.To.Add(mTo)

mailToName可以包含æ，ø和å，并且发送完全没问题。

很难证明某些事情没有发生，但我确信邮件不会发送，我确信它已连接到replyToList中的sendername。

我怎么知道？

我在发送之前记录邮件。包含相关字符的邮件会被记录，但在https://mandrillapp.com/activity中永远不会显示，并且永远不会到达收件人。我删除了æ，ø或å - 所有这些都在Mandrill概述中可见，一切正常。

想看看我的完整代码吗？

请注意，发送失败的邮件不会产生异常。

  Public Sub sendMail(ByVal mailFromAddress As String, ByVal mailFromName As String, _
                      ByVal mailToAddress As String, ByVal mailToName As String, ByVal mailCcAddress As String, ByVal mailBCcAddress As String, _
                      ByVal mailPriority As Net.Mail.MailPriority, ByVal IsBodyHtml As Boolean, ByVal mailSubject As String, _
                      ByVal bodyPlain As String, ByVal bodyHTML As String)
    Const maxtry As Integer = 3
    Dim tries As Integer = 0
    Dim failed As Boolean = False

    ' mailFromName = mailFromName.Replace("æ", "ae")

    Do
      tries += 1

      Try

        failed = False
        Dim Mail As New MailMessage


        If mailFromAddress <> String.Empty Then
          'Mail.ReplyTo = New MailAddress(mailFromAddress, mailFromName, System.Text.Encoding.UTF8)
          Mail.ReplyToList.Add(New MailAddress(mailFromAddress, mailFromName, System.Text.Encoding.UTF8))
        Else
          'Mail.ReplyTo = New MailAddress(Me.MailAddressFrom, Me.MailAddressDisplayName, System.Text.Encoding.UTF8)
          Mail.ReplyToList.Add(New MailAddress(Me.MailAddressFrom, Me.MailAddressDisplayName, System.Text.Encoding.UTF8))
        End If
        Mail.From = New MailAddress(Me.MailAddressFrom, Me.MailAddressDisplayName, System.Text.Encoding.UTF8)
        Mail.Sender = New MailAddress(Me.MailAddressFrom, Me.MailAddressDisplayName, System.Text.Encoding.UTF8)

        If mailToAddress <> String.Empty Then
          Dim mTo As New MailAddress(mailToAddress, mailToName, System.Text.Encoding.UTF8) 'UTF8
          Mail.To.Add(mTo)
        End If
        If mailCcAddress <> String.Empty Then
          Dim mCc As New MailAddress(mailCcAddress)
          Mail.CC.Add(mCc)
        End If
        If mailBCcAddress <> String.Empty Then
          Dim mBCc As New MailAddress(mailBCcAddress)
          Mail.Bcc.Add(mBCc)
        End If

        Mail.Priority = mailPriority

        Mail.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure

        Mail.IsBodyHtml = IsBodyHtml 
        Mail.HeadersEncoding = Encoding.GetEncoding("utf-8")

        Mail.Subject = mailSubject
        Mail.SubjectEncoding = Encoding.GetEncoding("utf-8") ' = System.Text.Encoding.Default 'UTF8 'Default ' Test on all possible encodings

        If IsBodyHtml Then
          Mail.AlternateViews.Add(AlternateView.CreateAlternateViewFromString(bodyHTML, System.Text.Encoding.Default, "text/html"))
        End If
        Mail.BodyEncoding = Encoding.GetEncoding("utf-8")
        Mail.Body = bodyPlain

        ' Add to log
        addToMailLog(mailToAddress, mailCcAddress, mailSubject, bodyPlain)

        ' Send
        Dim SmtpClient As New System.Net.Mail.SmtpClient
        'SmtpClient.ServicePoint.MaxIdleTime = 1
        SmtpClient.Send(Mail)
        Me._status = EMailStatus.EOkay
        SmtpClient.Dispose()

      Catch ex As Exception
        Dim debugInfo As New CDebug("sendMail", "Try: " & tries.ToString & ", UserId: " & Me.UserId, ex.ToString, Me.UserId, String.Empty)
        Me._status = EMailStatus.EMailSendError
        failed = True
      End Try

    Loop Until (failed = False Or tries >= maxtry)

  End Sub

更新II

我现在使用WireShark跟踪SMTP通信。请参阅屏幕截图，其中显示了未交付但未显示在Mandrill活动列表中的邮件的通信 - 即使我们获得SMTP响应正常并排队ID。

我有三个例子：

送达：

mailFromName = "xxx xxxxxxxxx xxxx - xxxxxxxxxx xxxxxxx xxxxxxxxx"

未交付：

mailFromName = "xxx xxxxxxxxx xxxx - xxxxxxxxxx xxxxxxx xxxxxxæxx"

送达：

mailFromName = "æxx xxxxxxxxx xxxx - xxxxxxxxxx xxxxxxx xxxxxxxxx"

Answer 1

我相信我已经找到了解释。似乎smtpclient在约72个字符的主题和回复显示名称后添加一个新行。问题是这似乎是在字符串编码后发生的。因此，在某些情况下，在编码字符的中间添加一个新行字符，其中afaik是非法的。

我不确定为什么Mandrill SMTP服务器在没有返回错误的情况下失败，而其他SMTP服务器处理这种情况就好了。

既然我明白了发生了什么，我必须想办法解决它 - 最好的建议得到赏金。

使用带有Mandrill SMTP的SmtpClient进行.NET发送失败

1 个答案: