Class: Dkim::SignedMail

Inherits:
Object
  • Object
show all
Includes:
Options
Defined in:
lib/dkim/signed_mail.rb

Instance Attribute Summary

Attributes included from Options

#body_canonicalization, #domain, #expire, #header_canonicalization, #identity, #options, #private_key, #selector, #signable_headers, #signing_algorithm, #time

Instance Method Summary collapse

Constructor Details

#initialize(message, options = {}) ⇒ SignedMail

A new instance of SignedMail

Parameters:

  • message (String, #to_s) —

    mail message to be signed

  • options (Hash) (defaults to: {}) —

    hash of options for signing. Defaults are taken from Dkim. See Options for details.



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# File 'lib/dkim/signed_mail.rb', line 17

def initialize message, options={}
  message = message.to_s.gsub(/\r?\n/, "\r\n")
  headers, body = message.split(/\r?\n\r?\n/, 2)
  @original_message = message
  @headers = Header.parse headers
  @body    = Body.new body

  # default options from Dkim.options
  @options = Dkim.options.merge(options)
end

Instance Method Details

#canonical_body ⇒ String

Returns Body of message in its canonical form.

Returns:

  • (String) —

    Body of message in its canonical form



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# File 'lib/dkim/signed_mail.rb', line 45

def canonical_body
  @body.to_s(body_canonicalization)
end

#canonical_header ⇒ String

Returns Signed headers of message in their canonical forms.

Returns:

  • (String) —

    Signed headers of message in their canonical forms



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# File 'lib/dkim/signed_mail.rb', line 40

def canonical_header
  canonicalized_headers.to_s(header_canonicalization)
end

#canonicalized_headers ⇒ Object 



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# File 'lib/dkim/signed_mail.rb', line 28

def canonicalized_headers
  CanonicalizedHeaders.new(@headers, signed_headers)
end

#dkim_header ⇒ DkimHeader

Returns Constructed signature for the mail message.

Returns:

  • (DkimHeader) —

    Constructed signature for the mail message



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# File 'lib/dkim/signed_mail.rb', line 50

def dkim_header
  dkim_header = DkimHeader.new

  raise "A private key is required" unless private_key
  raise "A domain is required"      unless domain
  raise "A selector is required"    unless selector

  # Add basic DKIM info
  dkim_header['v'] = '1'
  dkim_header['a'] = signing_algorithm
  dkim_header['c'] = "#{header_canonicalization}/#{body_canonicalization}"
  dkim_header['d'] = domain
  dkim_header['i'] = identity if identity
  dkim_header['q'] = 'dns/txt'
  dkim_header['s'] = selector
  dkim_header['t'] = (time || Time.now).to_i
  dkim_header['x'] = expire.to_i if expire

  # Add body hash and blank signature
  dkim_header['bh']= digest_alg.digest(canonical_body)
  dkim_header['h'] = signed_headers.join(':')
  dkim_header['b'] = ''

  # Calculate signature based on intermediate signature header
  headers = canonical_header
  headers << dkim_header.to_s(header_canonicalization)
  dkim_header['b'] = private_key.sign(digest_alg, headers)

  dkim_header
end

#signed_headers ⇒ Array<String>

Returns lowercased names of headers in the order they are signed.

Returns:

  • (Array<String>) —

    lowercased names of headers in the order they are signed



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# File 'lib/dkim/signed_mail.rb', line 33

def signed_headers
  @headers.map(&:relaxed_key).select do |key|
    signable_headers.map(&:downcase).include?(key)
  end
end

#to_s ⇒ String

Returns Message combined with calculated dkim header signature.

Returns:

  • (String) —

    Message combined with calculated dkim header signature



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# File 'lib/dkim/signed_mail.rb', line 82

def to_s
  dkim_header.to_s + "\r\n" + @original_message
end