* Increase DNS timeout from 1 second to 5 seconds for MX check 1 seconds is rather short when using a recursive DNS resolver which hasn't got a cached result already available. Use 5 seconds instead, which is the timeout value we use for outgoing HTTP queries. * Add more precise error messages for invalid e-mail addresses
		
			
				
	
	
		
			55 lines
		
	
	
		
			1.3 KiB
		
	
	
	
		
			Ruby
		
	
	
	
	
	
			
		
		
	
	
			55 lines
		
	
	
		
			1.3 KiB
		
	
	
	
		
			Ruby
		
	
	
	
	
	
# frozen_string_literal: true
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require 'resolv'
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class EmailMxValidator < ActiveModel::Validator
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  def validate(user)
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    domain = get_domain(user.email)
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    if domain.nil?
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      user.errors.add(:email, I18n.t('users.invalid_email'))
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    else
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      ips, hostnames = resolve_mx(domain)
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      if ips.empty?
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        user.errors.add(:email, I18n.t('users.invalid_email_mx'))
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      elsif on_blacklist?(hostnames + ips)
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        user.errors.add(:email, I18n.t('users.blocked_email_provider'))
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      end
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    end
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  end
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  private
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  def get_domain(value)
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    _, domain = value.split('@', 2)
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    return nil if domain.nil?
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    TagManager.instance.normalize_domain(domain)
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  rescue Addressable::URI::InvalidURIError
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    nil
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  end
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  def resolve_mx(domain)
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    hostnames = []
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    ips       = []
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    Resolv::DNS.open do |dns|
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      dns.timeouts = 5
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      hostnames = dns.getresources(domain, Resolv::DNS::Resource::IN::MX).to_a.map { |e| e.exchange.to_s }
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      ([domain] + hostnames).uniq.each do |hostname|
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        ips.concat(dns.getresources(hostname, Resolv::DNS::Resource::IN::A).to_a.map { |e| e.address.to_s })
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        ips.concat(dns.getresources(hostname, Resolv::DNS::Resource::IN::AAAA).to_a.map { |e| e.address.to_s })
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      end
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    end
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    [ips, hostnames]
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  end
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  def on_blacklist?(values)
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    EmailDomainBlock.where(domain: values.uniq).any?
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  end
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end
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