html email with inline images not rendered properly in iphone

Question

I was hoping someone could help me out what I'm doing wrong in the below code - my email get sent, with the image inlined properly in most email client (gmail web, android), but it does not render properly on an iphone/ipad: only the last attached picture is displayed, without any html content or text content displayed. I understand every email client interprets and renders the payload differently, I don't know how to make it work on an iphone.

Any help appreciated!

ruby code:

require 'mail'

def inline_body_with_attachments(html, attachments)
    attachments.each do |attachment|
        if (html =~ /#{attachment.filename}/)
            html = html.sub(attachment.filename, "cid:#{attachment.cid}")
        end
    end
    return html
end


mail = Mail.new({
    :from    => "[email protected]",
    :to      => "[email protected]",
    :subject => "html email with inline images"
})

text_part = Mail::Part.new do
    body "some text"
end

mail.text_part = text_part

# Load the attachments
attachment = "image.png"
mail.attachments[attachment] = File.read(attachment)

inline_html = inline_body_with_attachments("<b>An inline image</b><img src='image.png'/>", mail.attachments)

html_part = Mail::Part.new do
    content_type 'text/html; charset=UTF-8'
    body         inline_html
end

mail.html_part  = html_part
mail.deliver!

The email looks like:

Date: Fri, 24 May 2013 13:58:02 +0000
From: [email protected]
To: [email protected]
Message-ID: <[email protected]>
Subject: test mail with attachment- raw
Mime-Version: 1.0
Content-Type: multipart/alternative;
 boundary="--==_mimepart_519f71eab2260_2a1d9e076471d6";
 charset=UTF-8
Content-Transfer-Encoding: 7bit



----==_mimepart_519f71eab2260_2a1d9e076471d6
Date: Fri, 24 May 2013 13:58:02 +0000
Mime-Version: 1.0
Content-Type: text/plain;
 charset=UTF-8
Content-Transfer-Encoding: 7bit
Content-ID: <[email protected]>

some text

----==_mimepart_519f71eab2260_2a1d9e076471d6
Date: Fri, 24 May 2013 13:58:02 +0000
Mime-Version: 1.0
Content-Type: text/html;
 charset=UTF-8
Content-Transfer-Encoding: 7bit
Content-ID: <[email protected]>

<b>An inline image</b><img src='cid:[email protected]'/>

----==_mimepart_519f71eab2260_2a1d9e076471d6
Date: Fri, 24 May 2013 13:58:02 +0000
Mime-Version: 1.0
Content-Type: image/png;
 charset=UTF-8;
 filename=image.png
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
 filename=image.png
Content-ID: <[email protected]>

iVBORw0KGgoAAAANSUhEUgAAASwAAABaCAYAAAACcWsdAAAXUUlEQVR4nGJk
[.... more image encoding ...]
DhwFowAXGE0go2CQAAAAAAD//wMAFOkCtHNhXPkAAAAASUVORK5CYII=


----==_mimepart_519f71eab2260_2a1d9e076471d6--

Answer 1

In order to wrok on the iphone, I had to wrap the html content with the image into their own multipart/related part.

require 'mail'


def inline_body_with_attachments(html, attachments)
    attachments.each do |attachment|
        if (html =~ /#{attachment.filename}/)
            html = html.sub(attachment.filename, "cid:#{attachment.cid}")
        end
    end
    return html
end


mail = Mail.new({
    :from    => "[email protected]",
    :to      => "[email protected]",
    :subject => "test mail with attachment- raw4",
    :content_type => 'multipart/alternative'
})

text_part = Mail::Part.new do
    body "some text"
end

mail.add_part( text_part)

other_part = Mail::Part.new do
  content_type 'multipart/related;'
end

# Load the attachments
attachment = "image.png"
#mail.attachments[attachment] = File.read(attachment)
other_part.add_file(attachment)

inline_html = inline_body_with_attachments("<b>An inline image</b><img src='image.png'/>", other_part.attachments)
html_part = Mail::Part.new do
    content_type 'text/html; charset=UTF-8'
    body         inline_html
end
other_part.add_part(html_part)

mail.add_part(other_part)

mail.deliver!