Android Question MailParser / POP3 Problem handling attachments sent via SMTP

[MFfromGermany]

Hey guys,

I've written a windows-forms-application in VB. This application sends mails via SMTP and I receive them with the android app I've written in B4A. So far it works.

But when I add an attachment (test.txt for example) to the mail in VB, the B4A MailParser does not seem to recognize this attachment. However, when I send an email via Gmail directly from their homepage, MailParser recognizes the txt-file and I can read from it.

I've read about this problem before but couldn't find any solution for it. Maybe you guys have an idea how to solve that.

Best regards

 

[Erel]

Can you upload the raw message (as it arrives on the device)?

 

[MFfromGermany]

Well, I guess the raw message is "MessageText" in POP_DownloadCompleted Sub. If so, then here you got:

file saved: attachment1 (3 bytes)
Delivered-To: rm2314fzg01@gmail.com
Received: by 10.36.91.200 with SMTP id g191csp369010itb;
        Thu, 10 Dec 2015 01:24:52 -0800 (PST)
X-Received: by 10.194.118.74 with SMTP id kk10mr11274275wjb.5.1449739492867;
        Thu, 10 Dec 2015 01:24:52 -0800 (PST)
Return-Path: <rm2309nfp01@gmail.com>
Received: from mail-wm0-x243.google.com (mail-wm0-x243.google.com. [2a00:1450:400c:c09::243])
        by mx.google.com with ESMTPS id s204si16488891wmf.121.2015.12.10.01.24.52
        for <rm2314fzg01@gmail.com>
        (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
        Thu, 10 Dec 2015 01:24:52 -0800 (PST)
Received-SPF: pass (google.com: domain of rm2309nfp01@gmail.com designates 2a00:1450:400c:c09::243 as permitted sender) client-ip=2a00:1450:400c:c09::243;
Authentication-Results: mx.google.com;
       spf=pass (google.com: domain of rm2309nfp01@gmail.com designates 2a00:1450:400c:c09::243 as permitted sender) smtp.mailfrom=rm2309nfp01@gmail.com;
       dkim=pass header.i=@gmail.com;
       dmarc=pass (p=NONE dis=NONE) header.from=gmail.com
Received: by mail-wm0-x243.google.com with SMTP id c201so2118784wme.3
        for <rm2314fzg01@gmail.com>; Thu, 10 Dec 2015 01:24:52 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=20120113;
        h=message-id:date:mime-version:from:to:subject:content-type;
        bh=hIt5VF0Dl2dqHtnKzEqXKjT5LjhPMfMgfDkP9ZL4Jgk=;
        b=oNBgAgDO1ICHmLRvt8m4knF4JoXZT5ctJUBJPVxqG+x9oOu9Yu9KhA8xK/NtB8zIKg
         Z06uC3x9wN3HLhk4osOxkDbBIv8/6/IgT2d+jdzUzJIXwAv6U+jxqzP6T1MFY5H46AEM
         uI52o6IV/Z+Lb6O6kbn8p4vDRaZQcAunkxvR+70EpQEWllziqm5SNqFHqBtMIhhk+S+5
         Gi7o05FlvdYL3zK6jAr/k7K3PuHYnbB0nusOFxz04fVWKPSCg4bz34T/HKYv9z1B5Zj8
         eRghfhPSqhtpySMu6j8Y80jtP4+DN+kTw0BXw7q7EWRI4GnqGxilhf7jKMvaw+a8CrOy
         BqBA==
X-Received: by 10.194.79.37 with SMTP id g5mr11378653wjx.107.1449739492659;
        Thu, 10 Dec 2015 01:24:52 -0800 (PST)
Return-Path: <rm2309nfp01@gmail.com>
Received: from Desktop-PC ([2a02:8070:6182:5300:49a:2653:b6b4:f349])
        by smtp.gmail.com with ESMTPSA id ft4sm11406825wjb.37.2015.12.10.01.24.51
        for <rm2314fzg01@gmail.com>
        (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128);
        Thu, 10 Dec 2015 01:24:51 -0800 (PST)
Message-ID: <566944e3.2467c20a.2e612.ffffd022@mx.google.com>
Date: Thu, 10 Dec 2015 01:24:51 -0800 (PST)
X-Google-Original-Date: 10 Dec 2015 10:24:52 +0100
MIME-Version: 1.0
From: "rm2309nfp01@gmail.com" <rm2309nfp01@gmail.com>
To: rm2314fzg01@gmail.com
Subject: Test
Content-Type: multipart/mixed;
boundary=--boundary_2_6e2820fd-15b6-413f-98ac-7deafba0a178
----boundary_2_6e2820fd-15b6-413f-98ac-7deafba0a178
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: quoted-printable
Test
----boundary_2_6e2820fd-15b6-413f-98ac-7deafba0a178
Content-Type: application/octet-stream; name=test.txt
Content-Transfer-Encoding: base64
Content-Disposition: attachment
VGVzdA0K
----boundary_2_6e2820fd-15b6-413f-98ac-7deafba0a178--

This seems to me that the attachment is both recognized and saved, but how come I can neither read from it nor find it on my smartphone?

 

[Erel]

I think that the format got broken when you posted it. Please save it with File.WriteString and then upload the file.

 

[MFfromGermany]

Here you got the raw message in an txt-File.

Meanwhile I tried changing the directory the attachment should be saved to - problem's still remaining.

By the way, when I send an email trough B4J it doesn't work neither.

Thank you for your help so far.

 

[Erel]

Change ParseMultipartBody to:

Sub ParseMultipartBody (Mail As String, Msg As Message)
   'find first boundary
   index = Mail.IndexOf2("--" & boundary, index)
   ReadNextLine(Mail)
   Dim headers As StringBuilder
   headers.Initialize
   Do While index < Mail.Length
     Dim line As String
     line = ReadNextLine(Mail)
     If line.Length > 0 Then
       headers.Append(line).Append(" ")
     Else If index < Mail.Length Then
       Dim nextPart As Int
       nextPart = Mail.IndexOf2("--" & boundary, index)
       If nextPart = -1 Then nextPart = Mail.Length + 2
       If nextPart-2 > index Then
         HandlePart(headers.ToString, Mail.SubString2(index, nextPart-2), Msg)
       End If
       index = nextPart
       ReadNextLine(Mail)
       headers.Initialize
     End If
   Loop
End Sub

It will return the attachment as attachment1. You can try it with this code:

Dim m As Message = MailParser.ParseMail(File.ReadString(File.DirAssets, "MsgTxt.txt"), File.DirRootExternal)
Log($"Number of attachments ${m.Attachments.Size}"$)
Log($"Attachment 1: ${File.ReadString(File.DirRootExternal, m.Attachments.Get(0))}"$)

 

[MFfromGermany]

Thank you very much, I'm going to try it tomorrow and report if it has worked.

 

[MFfromGermany]

It works perfectly, you're a genius. To say 'thank you' is hardly enough.