Error sending Multipart messages

[scorredoira]

Hi,

I am trying to send an email with attachments but I only receive one part:

• If I add both parts I get only the text without the attachment.
• If I add only part1 I get the text.
• If I add only part2 I get the text attached as "noname".

this is the code:

package main

import (
    "bytes"
    "errors"
    "github.com/sloonz/go-mime-message"
    "github.com/sloonz/go-qprintable"
    "log"
    "net/smtp"
)

func main() {
    m := message.NewMultipartMessage("alternative", "")
    m.SetHeader("Subject", message.EncodeWord("test"))

    m1 := message.NewTextMessage(qprintable.UnixTextEncoding, bytes.NewBufferString("this is the text body."))
    m1.SetHeader("Content-Type", "text/plain")
    m.AddPart(m1)

    m2 := message.NewBinaryMessage(bytes.NewBufferString("this is some text as attachment."))
    m2.SetHeader("Content-Type", "application/octet-stream")
    m.AddPart(m2)

    var buf bytes.Buffer
    buf.ReadFrom(m)

    erri := smtp.SendMail(
        "mail.padelclick.com:25",
        smtp.PlainAuth("", "test", "test", "mail.example.com"),
        "test@example.com",
        []string{"test@example.com"},
        buf.Bytes())
}

[sloonz]

With the attached source code, I get a mail with two parts. My MUA show me the text attachment, and I can download the text attachment. This is the source code of the received mail :

Return-Path: <xxx@xxx.xxx>
X-Original-To: xxx@xxx.xxx.xxx
Delivered-To: xxx@xxx.xxx.xxx
Received: <snipped>
Received: <snipped>
MIME-Version: 1.0
Subject: test
Content-Type: multipart/alternative; boundary="==GoMultipartBoundary:0."
Message-Id: <20120619145207.5AEAD3FB0B@xxx.localdomain>
Date: Tue, 19 Jun 2012 16:52:07 +0200 (CEST)
From: xxx@xxx.xxx.xxx

--==GoMultipartBoundary:0.
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain

this is the text body.
--==GoMultipartBoundary:0.
Content-Transfer-Encoding: base64
Content-Type: application/octet-stream

dGhpcyBpcyBzb21lIHRleHQgYXMgYXR0YWNobWVudC4=
--==GoMultipartBoundary:0.--

Which seems correct to me. What you can do :

1. Check the source code of your received mail. Check that it is similar to the above one.
2. Compare it with a mail you know it works (send it with gmail for example) and compare the differences

[scorredoira]

My source is the same, but it seems that not all email clients parse in the same way. I am getting different results from Gmail and Thunderbird.

From the tests I have been doing, the problem seems to be NewMultipartMessage("alternative", ""). In order to send it as an attachment you need to set it as NewMultipartMessage("mixed", "")

http://en.wikipedia.org/wiki/MIME

The multipart/alternative subtype indicates that each part is an "alternative" version of the same (or similar) content, each in a different format denoted by its "Content-Type" header.

Multipart/mixed is used for sending files with different "Content-Type" headers inline (or as attachments).

[scorredoira]

I have uploaded a very basic version that works fine with gmail: https://github.com/scorredoira/email