Mail

Introduction

Mail is an internet library for Ruby that is designed to handle email
generation, parsing and sending in a simple, rubyesque manner.

The purpose of this library is to provide a single point of access to handle
all email functions, including sending and receiving email. All network
type actions are done through proxy methods to Net::SMTP, Net::POP3 etc.

Built from my experience with TMail, it is designed to be a pure ruby
implementation that makes generating, sending and parsing email a no
brainer.

It is also designed from the ground up to work with the more modern versions
of Ruby. Modern Rubies handle text encodings much more wonderfully than before
so these features have been taken full advantage of in this library allowing
Mail to handle a lot more messages more cleanly than TMail.

Finally, Mail has been designed with a very simple object oriented system
that really opens up the email messages you are parsing, if you know what
you are doing, you can fiddle with every last bit of your email directly.

You can contribute to this library

Yes, you! Mail is used in countless apps by people around the world. It is,
like all open source software, a labour of love borne from our free time.
If you would like to say thanks, please dig in and contribute alongside us!
Triage and fix GitHub issues, improve
our documentation, add new features—up to you! Thank you for pitching in.

Compatibility
Discussion
Current Capabilities of Mail
Roadmap
Testing Policy
API Policy
Installation
Encodings
Contributing
Usage
Excerpts from TREC Span Corpus 2005
License

Compatibility

Mail is tested against:

Ruby: 2.5
Ruby: 2.6
Ruby: 2.7
Ruby: 3.0
Ruby: 3.1
Ruby: 3.2
JRuby: 9.2
JRuby: 9.3
JRuby: 9.4
JRuby: stable
JRuby: head
Truffleruby: stable
Truffleruby: head

As new versions of Ruby are released, Mail will be compatible with support for the “preview” and all “normal maintenance”, “security maintenance” and the two most recent “end of life” versions listed at the Ruby Maintenance Branches page. Pull requests to assist in adding support for new preview releases are more than welcome.

Every Mail commit is tested by GitHub Actions on all supported Ruby versions.

Discussion

If you want to discuss mail with like minded individuals, please subscribe to
the Google Group.

Current Capabilities of Mail

RFC5322 Support, Reading and Writing
RFC6532 Support, reading UTF-8 headers
RFC2045-2049 Support for multipart email
Support for creating multipart alternate email
Support for reading multipart/report email & getting details from such
Wrappers for File, Net/POP3, Net/SMTP
Auto-encoding of non-US-ASCII bodies and header fields

Mail is RFC5322 and RFC6532 compliant now, that is, it can parse US-ASCII and UTF-8
email and generate US-ASCII email. There are a few obsoleted email syntax that
it will have problems with, but it also is quite robust, meaning, if it finds something
it doesn’t understand it will not crash, instead, it will skip the problem and keep
parsing. In the case of a header it doesn’t understand, it will initialise the header
as an optional unstructured field and continue parsing.

This means Mail won’t (ever) crunch your data (I think).

You can also create MIME emails. There are helper methods for making a
multipart/alternate email for text/plain and text/html (the most common pair)
and you can manually create any other type of MIME email.

Roadmap

Next TODO:

Improve MIME support for character sets in headers, currently works, mostly, needs refinement.

Testing Policy

Basically… we do BDD on Mail. No method gets written in Mail without a
corresponding or covering spec. We expect as a minimum 100% coverage
measured by RCov. While this is not perfect by any measure, it is pretty
good. Additionally, all functional tests from TMail are to be passing before
the gem gets released.

It also means you can be sure Mail will behave correctly.

You can run tests locally by running bundle exec rspec.

You can run tests on all supported Ruby versions by using act.

API Policy

No API removals within a single point release. All removals to be deprecated with
warnings for at least one MINOR point release before removal.

Also, all private or protected methods to be declared as such - though this is still I/P.

Installation

Installation is fairly simple, I host mail on rubygems, so you can just do:

# gem install mail

Encodings

If you didn’t know, handling encodings in Emails is not as straight forward as you
would hope.

I have tried to simplify it some:

All objects that can render into an email, have an #encoded method. Encoded will
return the object as a complete string ready to send in the mail system, that is,
it will include the header field and value and CRLF at the end and wrapped as
needed.
All objects that can render into an email, have a #decoded method. Decoded will
return the object’s “value” only as a string. This means it will not include
the header fields (like ‘To:’ or ‘Subject:’).
By default, calling #to_s on a container object will call its encoded
method, while #to_s on a field object will call its decoded method.
So calling #to_s on a Mail object will return the mail, all encoded
ready to send, while calling #to_s on the From field or the body will
return the decoded value of the object. The header object of Mail is considered a
container. If you are in doubt, call #encoded, or #decoded
explicitly, this is safer if you are not sure.
Structured fields that have parameter values that can be encoded (e.g. Content-Type) will
provide decoded parameter values when you call the parameter names as methods against
the object.
Structured fields that have parameter values that can be encoded (e.g. Content-Type) will
provide encoded parameter values when you call the parameter names through the
object.parameters[''] method call.

Contributing

Please do! Contributing is easy in Mail. Please read the CONTRIBUTING.md document for more info.

Usage

All major mail functions should be able to happen from the Mail module.
So, you should be able to just require 'mail' to get started.

mail is pretty well documented in its Ruby code. You can look it up e.g. at rubydoc.info.

Making an email

mail = Mail.new do
  from    'mikel@test.lindsaar.net'
  to      'you@test.lindsaar.net'
  subject 'This is a test email'
  body    File.read('body.txt')
end

mail.to_s #=&gt; "From: mikel@test.lindsaar.net\r\nTo: you@...

Making an email, have it your way:

mail = Mail.new do
  body File.read('body.txt')
end

mail['from'] = 'mikel@test.lindsaar.net'
mail[:to]    = 'you@test.lindsaar.net'
mail.subject = 'This is a test email'

mail.header['X-Custom-Header'] = 'custom value'

mail.to_s #=&gt; "From: mikel@test.lindsaar.net\r\nTo: you@...

Don’t Worry About Message IDs:

mail = Mail.new do
  to   'you@test.lindsaar.net'
  body 'Some simple body'
end

mail.to_s =~ /Message\-ID: &lt;[\d\w_]+@.+.mail/ #=&gt; 27

Mail will automatically add a Message-ID field if it is missing and
give it a unique, random Message-ID along the lines of:

<4a7ff76d7016_13a81ab802e1@local.host.mail>

Or do worry about Message-IDs:

mail = Mail.new do
  to         'you@test.lindsaar.net'
  message_id ''
  body       'Some simple body'
end

mail.to_s =~ /Message\-ID: / #=&gt; 27

Mail will take the message_id you assign to it trusting that you know
what you are doing.

Sending an email:

Mail defaults to sending via SMTP to local host port 25. If you have a
sendmail or postfix daemon running on this port, sending email is as
easy as:

Mail.deliver do
  from     'me@test.lindsaar.net'
  to       'you@test.lindsaar.net'
  subject  'Here is the image you wanted'
  body     File.read('body.txt')
  add_file '/full/path/to/somefile.png'
end

mail = Mail.new do
  from     'me@test.lindsaar.net'
  to       'you@test.lindsaar.net'
  subject  'Here is the image you wanted'
  body     File.read('body.txt')
  add_file :filename =&gt; 'somefile.png', :content =&gt; File.read('/somefile.png')
end

mail.deliver!

Sending via sendmail can be done like so:

mail = Mail.new do
  from     'me@test.lindsaar.net'
  to       'you@test.lindsaar.net'
  subject  'Here is the image you wanted'
  body     File.read('body.txt')
  add_file :filename =&gt; 'somefile.png', :content =&gt; File.read('/somefile.png')
end

mail.delivery_method :sendmail

mail.deliver

Sending via smtp (for example to mailcatcher)

Mail.defaults do
  delivery_method :smtp, address: "localhost", port: 1025
end

Exim requires its own delivery manager, and can be used like so:

mail.delivery_method :exim, :location =&gt; "/usr/bin/exim"

mail.deliver

Mail may be “delivered” to a logfile, too, for development and testing:

# Delivers by logging the encoded message to $stdout
mail.delivery_method :logger

# Delivers to an existing logger at :debug severity
mail.delivery_method :logger, logger: other_logger, severity: :debug

Getting Emails from a POP or IMAP Server:

You can configure Mail to receive email using retriever_method
within Mail.defaults:

# e.g. POP3
Mail.defaults do
  retriever_method :pop3, :address    =&gt; "pop.gmail.com",
                          :port       =&gt; 995,
                          :user_name  =&gt; '',
                          :password   =&gt; '',
                          :enable_ssl =&gt; true
end

# IMAP
Mail.defaults do
  retriever_method :imap, :address    =&gt; "imap.mailbox.org",
                          :port       =&gt; 993,
                          :user_name  =&gt; '',
                          :password   =&gt; '',
                          :enable_ssl =&gt; true
end

You can access incoming email in a number of ways.

The most recent email:

Mail.all    #=&gt; Returns an array of all emails
Mail.first  #=&gt; Returns the first unread email
Mail.last   #=&gt; Returns the last unread email

The first 10 emails sorted by date in ascending order:

emails = Mail.find(:what =&gt; :first, :count =&gt; 10, :order =&gt; :asc)
emails.length #=&gt; 10

Or even all emails:

emails = Mail.all
emails.length #=&gt; LOTS!

Reading an Email

mail = Mail.read('/path/to/message.eml')

mail.envelope_from   #=&gt; 'mikel@test.lindsaar.net'
mail.from.addresses  #=&gt; ['mikel@test.lindsaar.net', 'ada@test.lindsaar.net']
mail.sender.address  #=&gt; 'mikel@test.lindsaar.net'
mail.to              #=&gt; 'bob@test.lindsaar.net'
mail.cc              #=&gt; 'sam@test.lindsaar.net'
mail.subject         #=&gt; "This is the subject"
mail.date.to_s       #=&gt; '21 Nov 1997 09:55:06 -0600'
mail.message_id      #=&gt; '&lt;4D6AA7EB.6490534@xxx.xxx&gt;'
mail.decoded         #=&gt; 'This is the body of the email...

Many more methods available.

Reading a Multipart Email

mail = Mail.read('multipart_email')

mail.multipart?          #=&gt; true
mail.parts.length        #=&gt; 2
mail.body.preamble       #=&gt; "Text before the first part"
mail.body.epilogue       #=&gt; "Text after the last part"
mail.parts.map { |p| p.content_type }  #=&gt; ['text/plain', 'application/pdf']
mail.parts.map { |p| p.class }         #=&gt; [Mail::Message, Mail::Message]
mail.parts[0].content_type_parameters  #=&gt; {'charset' =&gt; 'ISO-8859-1'}
mail.parts[1].content_type_parameters  #=&gt; {'name' =&gt; 'my.pdf'}

Mail generates a tree of parts. Each message has many or no parts. Each part
is another message which can have many or no parts.

A message will only have parts if it is a multipart/mixed or multipart/related
content type and has a boundary defined.

Testing and Extracting Attachments

mail.attachments.each do | attachment |
  # Attachments is an AttachmentsList object containing a
  # number of Part objects
  if (attachment.content_type.start_with?('image/'))
    # extracting images for example...
    filename = attachment.filename
    begin
      File.open(images_dir + filename, "w+b", 0644) {|f| f.write attachment.decoded}
    rescue =&gt; e
      puts "Unable to save data for #{filename} because #{e.message}"
    end
  end
end

Writing and Sending a Multipart/Alternative (HTML and Text) Email

Mail makes some basic assumptions and makes doing the common thing as
simple as possible…. (asking a lot from a mail library)

mail = Mail.deliver do
  to      'nicolas@test.lindsaar.net.au'
  from    'Mikel Lindsaar '
  subject 'First multipart email sent with Mail'

  text_part do
    body 'This is plain text'
  end

  html_part do
    content_type 'text/html; charset=UTF-8'
    body '<h1>This is HTML</h1>'
  end
end

Mail then delivers the email at the end of the block and returns the
resulting Mail::Message object, which you can then inspect if you
so desire…

puts mail.to_s #=&gt;

To: nicolas@test.lindsaar.net.au
From: Mikel Lindsaar 
Subject: First multipart email sent with Mail
Content-Type: multipart/alternative;
  boundary=--==_mimepart_4a914f0c911be_6f0f1ab8026659
Message-ID: &lt;4a914f12ac7e_6f0f1ab80267d1@baci.local.mail&gt;
Date: Mon, 24 Aug 2009 00:15:46 +1000
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit


----==_mimepart_4a914f0c911be_6f0f1ab8026659
Content-ID: &lt;4a914f12c8c4_6f0f1ab80268d6@baci.local.mail&gt;
Date: Mon, 24 Aug 2009 00:15:46 +1000
Mime-Version: 1.0
Content-Type: text/plain
Content-Transfer-Encoding: 7bit

This is plain text
----==_mimepart_4a914f0c911be_6f0f1ab8026659
Content-Type: text/html; charset=UTF-8
Content-ID: &lt;4a914f12cf86_6f0f1ab802692c@baci.local.mail&gt;
Date: Mon, 24 Aug 2009 00:15:46 +1000
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit

<h1>This is HTML</h1>
----==_mimepart_4a914f0c911be_6f0f1ab8026659--

Mail inserts the content transfer encoding, the mime version,
the content-IDs and handles the content-type and boundary.

Mail assumes that if your text in the body is only us-ascii, that your
transfer encoding is 7bit and it is text/plain. You can override this
by explicitly declaring it.

Making Multipart/Alternate, Without a Block

You don’t have to use a block with the text and html part included, you
can just do it declaratively. However, you need to add Mail::Parts to
an email, not Mail::Messages.

mail = Mail.new do
  to      'nicolas@test.lindsaar.net.au'
  from    'Mikel Lindsaar '
  subject 'First multipart email sent with Mail'
end

text_part = Mail::Part.new do
  body 'This is plain text'
end

html_part = Mail::Part.new do
  content_type 'text/html; charset=UTF-8'
  body '<h1>This is HTML</h1>'
end

mail.text_part = text_part
mail.html_part = html_part

Results in the same email as done using the block form

Getting Error Reports from an Email:

@mail = Mail.read('/path/to/bounce_message.eml')

@mail.bounced?         #=&gt; true
@mail.final_recipient  #=&gt; rfc822;mikel@dont.exist.com
@mail.action           #=&gt; failed
@mail.error_status     #=&gt; 5.5.0
@mail.diagnostic_code  #=&gt; smtp;550 Requested action not taken: mailbox unavailable
@mail.retryable?       #=&gt; false

Attaching and Detaching Files

You can just read the file off an absolute path, Mail will try
to guess the mime_type and will encode the file in Base64 for you.

@mail = Mail.new
@mail.add_file("/path/to/file.jpg")
@mail.parts.first.attachment? #=&gt; true
@mail.parts.first.content_transfer_encoding.to_s #=&gt; 'base64'
@mail.attachments.first.mime_type #=&gt; 'image/jpg'
@mail.attachments.first.filename #=&gt; 'file.jpg'
@mail.attachments.first.decoded == File.read('/path/to/file.jpg') #=&gt; true

Or You can pass in file_data and give it a filename, again, mail
will try and guess the mime_type for you.

@mail = Mail.new
@mail.attachments['myfile.pdf'] = File.read('path/to/myfile.pdf')
@mail.parts.first.attachment? #=&gt; true
@mail.attachments.first.mime_type #=&gt; 'application/pdf'
@mail.attachments.first.decoded == File.read('path/to/myfile.pdf') #=&gt; true

You can also override the guessed MIME media type if you really know better
than mail (this should be rarely needed)

@mail = Mail.new
@mail.attachments['myfile.pdf'] = { :mime_type =&gt; 'application/x-pdf',
                                    :content =&gt; File.read('path/to/myfile.pdf') }
@mail.parts.first.mime_type #=&gt; 'application/x-pdf'

Of course… Mail will round trip an attachment as well

@mail = Mail.new do
  to      'nicolas@test.lindsaar.net.au'
  from    'Mikel Lindsaar '
  subject 'First multipart email sent with Mail'

  text_part do
    body 'Here is the attachment you wanted'
  end

  html_part do
    content_type 'text/html; charset=UTF-8'
    body '<h1>Funky Title</h1><p>Here is the attachment you wanted</p>'
  end

  add_file '/path/to/myfile.pdf'
end

@round_tripped_mail = Mail.new(@mail.encoded)

@round_tripped_mail.attachments.length #=&gt; 1
@round_tripped_mail.attachments.first.filename #=&gt; 'myfile.pdf'

See “Testing and extracting attachments” above for more details.

Using Mail with Testing or Spec'ing Libraries

If mail is part of your system, you’ll need a way to test it without actually
sending emails, the TestMailer can do this for you.

require 'mail'
=&gt; true
Mail.defaults do
  delivery_method :test
end
=&gt; #
Mail::TestMailer.deliveries
=&gt; []
Mail.deliver do
  to 'mikel@me.com'
  from 'you@you.com'
  subject 'testing'
  body 'hello'
end
=&gt; # 1
Mail::TestMailer.deliveries.first
=&gt; # []

There is also a set of RSpec matchers stolen/inspired by Shoulda’s ActionMailer matchers (you’ll want to set delivery_method as above too):

Mail.defaults do
  delivery_method :test # in practice you'd do this in spec_helper.rb
end

describe "sending an email" do
  include Mail::Matchers

  before(:each) do
    Mail::TestMailer.deliveries.clear

    Mail.deliver do
      to ['mikel@me.com', 'mike2@me.com']
      from 'you@you.com'
      subject 'testing'
      body 'hello'
    end
  end

  it { is_expected.to have_sent_email } # passes if any email at all was sent

  it { is_expected.to have_sent_email.from('you@you.com') }
  it { is_expected.to have_sent_email.to('mike1@me.com') }

  # can specify a list of recipients...
  it { is_expected.to have_sent_email.to(['mike1@me.com', 'mike2@me.com']) }

  # ...or chain recipients together
  it { is_expected.to have_sent_email.to('mike1@me.com').to('mike2@me.com') }

  it { is_expected.to have_sent_email.with_subject('testing') }

  it { is_expected.to have_sent_email.with_body('hello') }

  # Can match subject or body with a regex
  # (or anything that responds_to? :match)

  it { is_expected.to have_sent_email.matching_subject(/test(ing)?/) }
  it { is_expected.to have_sent_email.matching_body(/h(a|e)llo/) }

  # Can chain together modifiers
  # Note that apart from recipients, repeating a modifier overwrites old value.

  it { is_expected.to have_sent_email.from('you@you.com').to('mike1@me.com').matching_body(/hell/)

  # test for attachments

  # ... by specific attachment
  it { is_expected.to have_sent_email.with_attachments(my_attachment) }

  # ... or any attachment
  it { is_expected.to have_sent_email.with_attachments(any_attachment) }

  # ... or attachment with filename
  it { is_expected.to have_sent_email.with_attachments(an_attachment_with_filename('file.txt')) }

  # ... or attachment with mime_type
  it { is_expected.to have_sent_email.with_attachments(an_attachment_with_mime_type('application/pdf')) }

  # ... by array of attachments
  it { is_expected.to have_sent_email.with_attachments([my_attachment1, my_attachment2]) } #note that order is important

  #... by presence
  it { is_expected.to have_sent_email.with_any_attachments }

  #... or by absence
  it { is_expected.to have_sent_email.with_no_attachments }

end

Excerpts from TREC Spam Corpus 2005

The spec fixture files in spec/fixtures/emails/from_trec_2005 are from the
2005 TREC Public Spam Corpus. They remain copyrighted under the terms of
that project and license agreement. They are used in this project to verify
and describe the development of this email parser implementation.

http://plg.uwaterloo.ca/~gvcormac/treccorpus/

They are used as allowed by ‘Permitted Uses, Clause 3’:

“Small excerpts of the information may be displayed to others
or published in a scientific or technical context, solely for
the purpose of describing the research and development and
related issues.”

– http://plg.uwaterloo.ca/~gvcormac/treccorpus/

License

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
‘Software’), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED ‘AS IS’, WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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