discourse/lib/email.rb

require 'mail'
require_dependency 'email/message_builder'
require_dependency 'email/renderer'
require_dependency 'email/sender'
require_dependency 'email/styles'

module Email

  def self.is_valid?(email)
    return false unless String === email
    !!(EmailValidator.email_regex =~ email)
  end

  def self.downcase(email)
    return email unless Email.is_valid?(email)
    email.downcase
  end

  def self.cleanup_alias(name)
    name ? name.gsub(/[:<>,"]/, '') : name
  end

  def self.extract_parts(raw)
    mail = Mail.new(raw)
    text = nil
    html = nil

    if mail.multipart?
      text = mail.text_part
      html = mail.html_part
    elsif mail.content_type.to_s["text/html"]
      html = mail
    else
      text = mail
    end

    [text&.decoded, html&.decoded]
  end

end