RubyRegex is a nice collection of regular expressions in Ruby
RubyRegex::Url
RubyRegex::Domain
RubyRegex::Email
RubyRegex::Username
RubyRegex::USSocialSecurity
RubyRegex::GeneralPostalCode
RubyRegex::ZIPCode
RubyRegex::CreditCard
RubyRegex::MasterCard
RubyRegex::Visa
RubyRegex::TwitterUsername
RubyRegex::DeliciousUsername
RubyRegex::SlideshareUsername
RubyRegex::GithubUsername
RubyRegex::UUID
RubyRegex::DBDate
RubyRegex::DBDatetime
RubyRegex::SpanishBankAccountNumber
RubyRegex::Dni
Add to your Gemfile
gem 'ruby_regex'
In the models
validates_format_of :email, :with => RubyRegex::Email
Of course, contributions will be apreciated.
If you want to contribute send me a pull request with new regular expressions (and their tests) or send me an email with your desired regular expression to emili@eparreno.com
RubyRegex is released under the MIT-License and is Copyright (c)2010 Emili Parreño.