Class: Predicates::Email

Inherits:
Base
  • Object
show all
Defined in:
lib/predicates/email.rb

Overview

Describes a regular expression pattern for email addresses, based on RFC2822 and RFC3696. Adapted from Alex Dunae’s validates_email_format_of plugin v1.2.2, available under MIT License at code.dunae.ca/validates_email_format_of.html

Options

  • :with_mx_record [boolean, default false] - whether to verify the email’s domain using a dns lookup for an mx record. This requires the Unix dig command. In Debian this is part of the dnsutils package. NOTE: RFC2821 states that when no MX records are listed, an A record may be used instead. This means that a missing MX record may not mean an invalid email address! Use at your own risk.

Example

field_is_an_email :with_mx_record => true

Constant Summary collapse

EmailAddressPattern = 
begin
  local_part_special_chars = Regexp.escape('!#$%&\'*-/=?+-^_`{|}~')
  local_part_unquoted = '(([[:alnum:]' + local_part_special_chars + ']+[\.\+]+))*[[:alnum:]' + local_part_special_chars + '+]+'
  local_part_quoted = '\"(([[:alnum:]' + local_part_special_chars + '\.\+]*|(\\\\[\x00-\xFF]))*)\"'
  Regexp.new(
    '^((' + local_part_unquoted + ')|(' + local_part_quoted + ')+)@(((\w+\-+)|(\w+\.))*\w{1,63}\.[a-z]{2,6}$)',
    Regexp::EXTENDED | Regexp::IGNORECASE, "n"
  )
end

Instance Attribute Summary collapse

Attributes inherited from Base

#full_message, #or_empty, #validate_if, #validate_on

Instance Method Summary collapse

Methods inherited from Base

#allow_empty?, #error, #error_binds, #initialize, #normalize, #to_human

Constructor Details

This class inherits a constructor from Predicates::Base

Instance Attribute Details

#with_mx_record ⇒ Object

Returns the value of attribute with_mx_record.



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# File 'lib/predicates/email.rb', line 10

def with_mx_record
  @with_mx_record
end

Instance Method Details

#error_message ⇒ Object 



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# File 'lib/predicates/email.rb', line 29

def error_message
  @error_message || :email
end

#validate(value, record) ⇒ Object 



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# File 'lib/predicates/email.rb', line 12

def validate(value, record)
  # local part max is 64 chars, domain part max is 255 chars
  domain, local = value.reverse.split('@', 2)

  valid = value.match(EmailAddressPattern)
  valid &&= !(value.match /\.\./)
  valid &&= (domain.length <= 255)
  valid &&= (local.length <= 64)

  if valid and self.with_mx_record
    mx_record = `dig #{value.split('@').last} mx +noall +short`
    valid &&= (!mx_record.empty?)
  end

  valid
end