Plasticx Blog

I see in your example that you are decoding everything with base64_decode. What happens if it is encoded differently?

Good eyes. TMail auto-magically decodes the transfer encoding of a part’s body. So I updated my example. Thanks!

My TMail just returns a body of 2 bytes for any attachment (including the one in your .tar). It seems that it’s not decoding the attachment when I call body (and looking at the code for #body shows that a non-multipart returns unquoted_body(to_charset) … to_charset defaults to ‘utf-8’.

Do I have an old version of TMail somehow?

A simpler solution thanks to the attachment_fu plugin is:

class Attachment < ActiveRecord::Base
  has_attachment
end

def receive(email)
  email.attachments.each do |attachment|
    Attachment.create :uploaded_data => attachment
  end
end

That’s all there is to it.

I have tried your code on the latest tmail. it does not work. I modifed your code, here it is:

	
parser.rb

#
	
MIME multipart parsing test

#

require ‘tmail’

	
To get part’s filename
	
part is a TMail::Mail

  def part_filename(part)


	
print some useful informaion

    puts “….”

    puts “transfer_encoding: #{part.transfer_encoding}”

    puts “content loca: #{part[‘content-location’]}”

    puts “content type: #{part.content_type}”

    puts "   main type: #{part.main_type}"

    puts "    sub type: #{part.sub_type}"

    puts "  type param:"

    puts "     charset: #{part.type_param(‘charset’)}"

    puts "        name: #{part.type_param(‘name’)}"

    puts “disposition type : #{part.disposition}”

    puts "   param-filename: #{part.disposition_param(‘filename’)}"

    puts “….”


	
get filename

    if part[‘content-location’] != nil && part[‘content-location’].body.length != 0

      filename = part[‘content-location’].body

    elsif part.type_param(‘name’) != nil  && part.type_param(‘name’).length != 0

      filename = part.type_param(‘name’)

    elsif part.disposition_param(‘filename’) != nil && part.disposition_param(‘filename’).length != 0

      filename = part.disposition_param(‘filename’)

    else

      filename = nil

    end

  end

CTYPE_TO_EXT = {
‘image/jpeg’ => ‘jpg’,
‘image/gif’  => ‘gif’,
‘image/png’  => ‘png’,
‘image/tiff’ => ‘tif’
}
def ext( mail )
CTYPE_TO_EXT[mail.content_type] || ‘txt’
end

	
main function to parse email

def receive(email)

  #email.attachments are TMail::Attachment

  #but they ignore a text/mail parts.

  if email.multipart?

    tmp_dir = “/usr/local/portal/public/parts”

    idx = 1

    email.parts.each do |part|

      if part.multipart?

        receive(part)

      else

        puts “--#{idx}——”

        filename = part_filename(part)

        filename = “#{idx}.#{ext(part)}” if filename.nil?

        filepath = tmp_dir + ‘/’ + filename

        puts “#{filepath}”

        File.open(filepath,File::CREAT|File::TRUNC|File::WRONLY,0644) { |f|

          if part.transfer_encoding != “base64”

              f.write( part.body )

          elsif

              f.write( TMail::Base64.decode(part.body) )

          end

        }

      puts "  " 

      idx += 1

      end # end if

    end # end email.parts.

  end  # end if

end  # end def


	
main entrance, parse the email content recursively

email = TMail::Mail.load( ARGV0 || ‘email.dat’ )

receive(email)

to parse all parts of email, recursively. All images & text will be sperated from the email properly.

sorry for so many postings..

I cleaned up the posts DANG, thanks for taking the time to clean up the code and present it so that others can learn from it.

Hmmm, this is exactly what I need to do!! Extract a jpeg from an email. However, using Mr/Ms Dang’s version which gives lots of great feedback – however my jpeg attachment is resolved to a 2 byte file (the plain text and html parts of the multipart message are saved fine). The attachment is show with the right filename, base64 encoding and the right MIME type.

Am on Rails 1.2.3.7116.

Any thoughts or ideas on how to get past this hurdle?

Cheers, —Kip

OK, I’ve worked it out. Apply the patch at http://dev.rubyonrails.org/attachment/ticket/7861/base64_decoding.patch, which means you don’t have to check for a part being in base64 (all back to automatic).

And then make sure the file is opened in binary mode (the code here doesn’t do that, at least for this windows machine).

Now all is good.

—Kip

@KipCole did you say automatic or automagic? :)

And my original code has of the fresh smell of noob all over it, you get a free index on Enumerable’s with enum.each_with_index, so I updated the original code see the “update 08/01/2007” comments.

decode automagically decodes the transfer encoding of mime parts now (again). This blog post was before TMail was fixed in Rails 1.2.2 back in around March of 2007. Also the official TMail with all of the Rails patches is being maintained again at Rubyforge
http://rubyforge.org/projects/tmail/

Decoding mail via Rails is one of the neatest features I’ve seen.