# Build a condition array from the provided keywords and a specific set of fields to search on
# Take out any keywords that are 2 chars or less
def self.find_by_keywords(keywords)
  # Columns to do keyword searching on
  fields = %w{ user_name email }

  # Strip all words 2 chars or less, then split into an array
  keywords = keywords.gsub(/\b\S{1,2}\b/, "").strip.downcase.split(/\s+/)
  unless (keywords.nil? || keywords.empty?)

    # Build the initial conditional string with bindings in place,
    # then throw it into the newly created conditional array
    conditions = fields.collect {|f| ["LOWER(#{f}) LIKE ?"]*keywords.size }.join(" OR ").to_a

    # Loop number of fields, then each keyword, placing the actual bound parameter into the conditional array
    fields.size.times {|i| keywords.each {|kw| conditions << "%"+kw+"%" } }
    self.all(:conditions => conditions)
  else
    nil
  end
end

#-----

# Placing the above code in app/models/user.rb allows you to do safe keyword searching on the user table
class UsersController > ApplicationController
  ...
  def search
    @users = User.find_by_keywords(params[:keywords])
    ...
  end
  ...
end