validates_length_of :phone, :is => 10, :message => 'must be 10 digits, excluding special characters such as spaces and dashes. No extension or country code allowed.', :if => Proc.new{|o| !o.phone.blank?}
  validates_length_of :fax, :is => 10, :message => 'must be 10 digits, excluding special characters such as spaces and dashes. No extension or country code allowed.', :if => Proc.new{|o| !o.fax.blank?}

  def directory_housekeeping()
    lifespan = 14
    format_mask = 'm_d_y'
    separator = format_mask.match(/[\_*\-]/).to_s
    
    earliest_date = Time.now + (60 * 60 * 24) * -lifespan
    cut_off_date = Date.new(y=earliest_date.year,m=earliest_date.month,d=earliest_date.day)
        
    a_format = Array.new
    a_format[0] = format_mask.match(/^[y,m,d]*/).to_s
    a_format[1] = format_mask.match(separator + '[y,m,d]*').to_s.gsub(separator,'')
    a_format[2] = format_mask.match('[y,m,d]$').to_s
    
    file = File.new('../housekeeping/webcam_pear/dir.xml')
    ddoc = REXML::Document.new(file)
    file.close
    
    file_delete = File.new('../housekeeping/webcam_pear/files2delete.xml', 'w')
    doc_delete = Document.new()
    doc_delete.add_element('files')
    
    ddoc.root.elements.each('file') do |file_node|
      sfile = file_node.text
      idate = Array.new
      idate[0] = sfile.match(/^\d*/).to_s.to_i
      idate[1] = sfile.match(/\_\d*/).to_s.gsub(separator,'').to_i
      idate[2] = sfile.match(/\_\d*\d$/).to_s.gsub(separator,'').to_i

      h = Hash.new
      0.upto(2) {|i| h[a_format[i]] = idate[i]}

      file_date = Date.new(y=h['y'], m=h['m'], d=h['d'])

      if file_date < cut_off_date
        o_file2delete = Element.new('file')
        o_file2delete.text = file_date.strftime(dformat)
        doc_delete.root.add_element o_file2delete
      end
    end
    file_delete.puts doc_delete
  end

<dir>
  <file>11_4_2007</file>
  <file>11_5_2007</file>
  <file>11_6_2007</file>
  <file>11_7_2007</file>
  <file>11_8_2007</file>
  <file>11_9_2007</file>
  <file>12_10_2007</file>
  <file>12_11_2007</file>
  <file>12_1_2007</file>
  <file>12_12_2007</file>
  <file>12_13_2007</file>
  <file>12_14_2007</file>
  <file>12_15_2007</file>
  <file>12_16_2007</file>
  <file>12_17_2007</file>
  <file>12_18_2007</file>
  <file>12_19_2007</file>
  <file>12_20_2007</file>
  <file>12_21_2007</file>
  <file>12_2_2007</file>
  <file>12_22_2007</file>
  <file>12_23_2007</file>
  <file>12_24_2007</file>
  <file>12_25_2007</file>
  <file>12_26_2007</file>
  <file>12_27_2007</file>
  <file>12_28_2007</file>
  <file>12_3_2007</file>
  <file>12_4_2007</file>
  <file>12_5_2007</file>
  <file>12_6_2007</file>
  <file>12_7_2007</file>
  <file>12_8_2007</file>
  <file>12_9_2007</file>
 </dir>

<files>
  <file>11_4_2007</file>
  <file>11_5_2007</file>
  <file>11_6_2007</file>
  <file>11_7_2007</file>
  <file>11_8_2007</file>
  <file>11_9_2007</file>
  <file>12_10_2007</file>
  <file>12_11_2007</file>
  <file>12_1_2007</file>
  <file>12_12_2007</file>
  <file>12_13_2007</file>
  <file>12_14_2007</file>
  <file>12_15_2007</file>
  <file>12_2_2007</file>
  <file>12_3_2007</file>
  <file>12_4_2007</file>
  <file>12_5_2007</file>
  <file>12_6_2007</file>
  <file>12_7_2007</file>
  <file>12_8_2007</file>
  <file>12_9_2007</file>
 </files>

a = '547'
/^\d\d\d$/ ~= a

a = '134323'
/^[0-9]*$/ =~ a
#result returns 0, indicating success

  validates_each :href, :on => :create do |record, attr, value|
    begin
      uri = URI.parse(value)
      if uri.class != URI::HTTP
        record.errors.add(attr, 'Only HTTP protocol addresses can be used')
      end
    rescue URI::InvalidURIError
      record.errors.add(attr, 'The format of the url is not valid.')
    end
  end

class Book < ActiveRecord::Base
  has_many :pages
end

class Pages < ActiveRecord::Base
  belongs_to :book
  
  validates_presence_of :page_id # this is not enough, anything can go in this field

  # we check if the parent object is valid or not
  validate do |page|
   if page.blank?
     unless page.book(true)
       errors.add(:page_id, "must be a valid Book id")
     end
   end
  end

end

  def url=(addr)
    super (addr.blank? || addr.starts_with?('http')) ? addr : "http://#{addr}"
  end

# Prevent user from joining group twice
def validate
	errors.add_to_base("You are already a member of the #{self.group.name} Group") unless Grouping.find(:all, :conditions => {:user_id => self.user_id, :group_id => self.group_id}).blank?
end

function isNumeric(value) {
  if (value == null || !value.toString().match(/^[-]?\d*\.?\d*$/)) return false;
  return true;
}

require 'chronic'

class Meeting < ActiveRecord::Base

  def validation
    errors.add :meeting_date, 'is not a valid date' if Chronic.parse(meeting_date.to_s).nil?
  end

end

gem install chronic

irb:>
Chronic.parse('tomorrow')
    #=> Mon Aug 28 12:00:00 PDT 2006

Chronic.parse('monday', :context => :past)
    #=> Mon Aug 21 12:00:00 PDT 2006

Chronic.parse('this tuesday 5:00')
    #=> Tue Aug 29 17:00:00 PDT 2006

Chronic.parse('this tuesday 5:00', :ambiguous_time_range => :none)
    #=> Tue Aug 29 05:00:00 PDT 2006

Chronic.parse('may 27th', :now => Time.local(2000, 1, 1))
    #=> Sat May 27 12:00:00 PDT 2000

Chronic.parse('may 27th', :guess => false)
    #=> Sun May 27 00:00:00 PDT 2007..Mon May 28 00:00:00 PDT 2007