From: Matt Armstrong <matt@...>
Date: 2004-11-22T16:44:04+09:00
Subject: Re: dealing with email attachments (photos)

ptkwt@aracnet.com (Phil Tomson) writes:

> What I want to do:
>
> I'm setting up a photo blog (probably using Hobix, but that's not
> final yet).  I want to be able to send an email to a certain email
> address and have that email posted to the blog if it meets certain
> criteria.  I also want to be able to attach photos to the email
> message.  When the script finds that there are attached photos it
> should read those attachements, de-encode them and copy them to a
> specified photo directory.
>
> It would be great if someone already has a script for doing this
> sort of thing that they would be willing to share.  If not, perhaps
> someone could point me in the right direction - which would be
> better for this: rubymail or TMail?

Hi Phil,

Disclaimer: I wrote and maintain RubyMail.  :-)

RubyMail and its companion package RubyFilter are geared toward this
kind of problem -- you really have to consider the features they
provide as a unit.  I wrote them to replace my use of "procmail" and
they have been handling all of my incoming email for years.

TMail has some definite advantages over RubyMail: support for Japanse
encodings in email addresses, subject lines, etc.; better support for
reading/writing mail from mailboxes; supports more of the MIME
standards, etc.  Despite RubyMail being 3+ years old, TMail is even
more mature.  As a downside, I don't think it is as well documented
(at least in English) and I find it harder to figure out how to use it
(but clearly *my* opinion on this means nothing).  I also wrote
RubyMail with efficiency in mind.  It has been a while since I ran any
benchmarks, but it was faster than TMail at parsing messages at the
time.

Last week I made some noise about soon introducing lots of
incompatible changes to RubyMail, but I am going to back away from
that and make the changes much more incremental and more compatible.
Though, I do plan to fold RubyFilter into RubyMail itself.

RubyMail+RubyFilter have been used successfully in a few real world
applications (that I know of):

- One of the more minor top level country code domain registrars uses
  it to process their abuse@ mailbox.

- There is http://www.merlin.org/ruby/ rbmhshow -- a MIME aware
  message viewer for the ancient MH mail system.  I think this is
  really cool!  I'm actually working on folding in some of the
  features he had to hack into RubyMail back into the main package.

- A few folks have mailed me about RubyFilter setup issues, etc.

What the package lacks are recipes for things like you describe.
Kevin's skeleton code below is pretty good:

> msg = RMail::Parser.read( file_handle )
> if msg.multipart?
> 	msg.each_part do | part |
> 		if part.header.media_type == 'image'
> 			# decode image and write to directory
> 		elsif part.header.media_type == 'text'
> 			# add part.body to the text of your posting,
> however you're storing it
> 		end
> 	end
> end

Once you have a part that stores the .jpg or whatever, you can call

    part.decode

and you'll get the un-base64 encoded version of the data.

----------------------------------------

If you go with RubyFilter, included in the package is an rdeliver
script that can handle the processing of the incoming message in a
pretty "safe" way (reduced chance for bouncing the message, etc.).

When set up, you'd have an .rdeliver script that looked something like
this obviously over-simplified script:

def main
  if message.multipart?
    message.each_part do | part |
      case part.header.media_type
      when 'image'
        File.open(some_unique_file_name, 'w') { |f|
          f.write(part.decode)
        }
      end
  end
end

Anyway, I'd be happy to walk you through any rough patches with
RubyMail/RubyFilter.


-- 
matt