Class: Mailcheck

Inherits:
Object
  • Object
show all
Defined in:
lib/mailcheck.rb,
lib/mailcheck/version.rb

Constant Summary collapse

THRESHOLD = 
3
DOMAINS = 
['yahoo.com', 'google.com', 'hotmail.com', 'gmail.com', 'me.com', 'aol.com', 'mac.com', 'live.com', 'comcast.net', 'googlemail.com', 'msn.com', 'hotmail.co.uk', 'yahoo.co.uk', 'facebook.com', 'verizon.net', 'sbcglobal.net', 'att.net', 'gmx.com', 'mail.com']
TOP_LEVEL_DOMAINS = 
['co.uk', 'com', 'net', 'org', 'info', 'edu', 'gov', 'mil']
VERSION = 
"0.0.2"

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}) ⇒ Mailcheck

Returns a new instance of Mailcheck.



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# File 'lib/mailcheck.rb', line 11

def initialize(opts={})
  @domains = opts[:domains] || DOMAINS
  @top_level_domains = opts[:top_level_domains] || TOP_LEVEL_DOMAINS
end

Instance Method Details

#find_closest_domain(domain, domains) ⇒ Object 



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# File 'lib/mailcheck.rb', line 44

def find_closest_domain(domain, domains)
  min_dist = 99

  for i in 0...domains.length do
    if domain === domains[i]
      return domain
    end
    dist = sift_3distance(domain, domains[i])
    if dist < min_dist
      min_dist = dist
      closest_domain = domains[i]
    end
  end

  if min_dist <= THRESHOLD && closest_domain
    closest_domain
  else
    false
  end
end

#sift_3distance(s1, s2) ⇒ Object 



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# File 'lib/mailcheck.rb', line 65

def sift_3distance(s1, s2)
  # sift3: http:#siderite.blogspot.com/2007/04/super-fast-and-accurate-string-distance.html

  c = 0
  offset1 = 0
  offset2 = 0
  lcs = 0
  max_offset = 5

  while (c + offset1 < s1.length) && (c + offset2 < s2.length) do
    if s1[c + offset1] == s2[c + offset2]
      lcs += 1
    else
      offset1 = 0
      offset2 = 0
      for i in 0...max_offset do
        if c + i < s1.length && s1[c + i] == s2[c]
          offset1 = i
          break
        end
        if c + i < s2.length && s1[c] == s2[c + i]
          offset2 = i
          break
        end
      end
    end
    c += 1
  end
  return (s1.length + s2.length) / 2 - lcs
end

#split_email(email) ⇒ Object 



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# File 'lib/mailcheck.rb', line 96

def split_email(email)

  parts = email.split('@')

  if parts.length < 2
    return false
  end

  for i in 0...parts.length do
    if parts[i] === ''
      return false
    end
  end

  domain = parts.pop
  domain_parts = domain.split('.')
  tld = ''

  if domain_parts.length == 0
    # The address does not have a top-level domain
    return false
  elsif domain_parts.length == 1
    # The address has only a top-level domain (valid under RFC)
    tld = domain_parts[0]
  else
    # The address has a domain and a top-level domain
    for i in 1...domain_parts.length do
      tld << "#{domain_parts[i]}."
    end
    if domain_parts.length >= 2
      tld = tld[0, tld.length - 1]
    end
  end

  {
    :top_level_domain => tld,
    :domain => domain,
    :address => parts.join('@')
  }
end

#suggest(email) ⇒ Object 



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# File 'lib/mailcheck.rb', line 16

def suggest(email)
  email_parts = split_email(email.downcase)

  return false if email_parts == false

  closest_domain = find_closest_domain(email_parts[:domain], @domains)

  if closest_domain
    if closest_domain != email_parts[:domain]
      # The email address closely matches one of the supplied domains return a suggestion
      return { :address => email_parts[:address], :domain => closest_domain, :full => "#{email_parts[:address]}@#{closest_domain}" }
    end
  else
    # The email address does not closely match one of the supplied domains
    closest_top_level_domain = find_closest_domain(email_parts[:top_level_domain], @top_level_domains)
    if email_parts[:domain] && closest_top_level_domain && closest_top_level_domain != email_parts[:top_level_domain]
      # The email address may have a mispelled top-level domain return a suggestion
      domain = email_parts[:domain]
      closest_domain = domain[0, domain.rindex(email_parts[:top_level_domain])] + closest_top_level_domain
      return { :address => email_parts[:address], :domain => closest_domain, :full => "#{email_parts[:address]}@#{closest_domain}" }
    end
  end
  # The email address exactly matches one of the supplied domains, does not closely
  # match any domain and does not appear to simply have a mispelled top-level domain,
  # or is an invalid email address do not return a suggestion.
  false
end