# SixArm.com » Ruby » <br> Email address validation using RFC 822 pattern matching

* Docs: <http://sixarm.com/sixarm_ruby_email_address_validation/doc>
* Repo: <http://github.com/sixarm/sixarm_ruby_email_address_validation>
* Email: Joel Parker Henderson, <joel@sixarm.com>


## Introduction

Email address regular expression to validate an email address using RFC 822.

This is a gem wrapper around http://tfletcher.com/lib/rfc822.rb

For docs go to <http://sixarm.com/sixarm_ruby_email_address_validation/doc>

Want to help? We're happy to get pull requests.


## Quickstart

Install:

    gem install sixarm_ruby_email_address_validation

Bundler:

    gem "sixarm_ruby_email_address_validation", "=1.3.0"

Require:

    require "sixarm_ruby_email_address_validation"


## High Security (Optional)

To enable high security for all our gems:

    wget http://sixarm.com/sixarm.pem
    gem cert --add sixarm.pem
    gem sources --add http://sixarm.com

To install with high security:

    gem install sixarm_ruby_email_address_validation --test --trust-policy HighSecurity


## Example

    if EmailAddressValidation::Pattern=~"foo@bar.com"
      puts "present" 
    else
      puts "absent"
    end
    => "found"


## Pattern Match

To find an email address in a string, do the pattern match
then use the result, which is the match's string position:

Example of match position:
 
    match_position = EmailAddressValidation::Pattern=~'foo@bar.com'
    => 0

    match_position = EmailAddressValidation::Pattern=~'... foo@bar.com ...'
    => 4

    match_position = EmailAddressValidation::Pattern=~'... hello world ...'
    => nil


## Pattern Match Exact

To do a pattern match to the entire string, use the EmailAddressValidation::PatternExact.

The entire string must be one email address.

Example of pattern match:

    if EmailAddressValidation::PatternExact=~'foo@bar.com' 
      puts "present" 
    else
      puts "absent"
    end
    => found

    if EmailAddressValidation::PatternExact=~'... foo@bar.com ...' 
      puts "present" 
    else
      puts "absent"
    end
    => absent

This pattern is especialy useful to validate an email address.

Example to validate an email address:

    def valid?(email_address)
      EmailAddressValidation::PatternExact=~email_address ? true : false
    end


## Rails Validation

To add email address validation to a typical Ruby On Rails model:

    class User
      include EmailAddressValidation
      validates :email_address, :format => { :with => EmailAddressValidation::PatternExact }
    end


## Changes

* 2012-03-17 2.0.0 Upgrade for Ruby 1.9.3, minitest/spec, improved docs, new API.
* 2011-04-24 1.2.2 Upgrade for Ruby 1.9.2 and Rails 3.0.6


## License

You may choose any of these open source licenses:

  * Apache License
  * BSD License
  * CreativeCommons License, Non-commercial Share Alike
  * GNU General Public License Version 2 (GPL 2)
  * GNU Lesser General Public License (LGPL)
  * MIT License
  * Perl Artistic License
  * Ruby License

The software is provided "as is", without warranty of any kind, 
express or implied, including but not limited to the warranties of 
merchantability, fitness for a particular purpose and noninfringement. 

In no event shall the authors or copyright holders be liable for any 
claim, damages or other liability, whether in an action of contract, 
tort or otherwise, arising from, out of or in connection with the 
software or the use or other dealings in the software.

This license is for the included software that is created by SixArm;
some of the included software may have its own licenses, copyrights, 
authors, etc. and these do take precedence over the SixArm license.

Copyright (c) 2005-2013 Joel Parker Henderson