DZone Snippets: rails code

Simple cacher module for Rails

remvee (Remco van 't Veer) — Tue, 01 Apr 2008 09:12:56 GMT

Illustration of a simple cacher module for Rails.



# lib/cacher.rb

module Cacher

  STORE = {}

  

  def cache(*args)

    STORE[args.inspect] ||= yield

  end



  def flush!

    STORE.clear

  end

  module_function :flush!

end



# app/models/person.rb

class Person < AR::Base

  include Cacher



  def finger

    cache(:finger, email) do

      `finger #{email}`

    end

  end

end



# app/controller/application.rb

class ApplicationController < AC::Base

  after_filter { Cacher.flush! }

end

Persistent Rails cookie session

remvee (Remco van 't Veer) — Mon, 25 Feb 2008 12:23:27 GMT

Session cookies, the Rails-2 kind, are transient because that's safer. In some applications safety isn't important. The following makes the session cookies persist for a year.



class ApplicationController < ActionController::Base

  before_filter :update_session_expiration_date



private

  def update_session_expiration_date

    unless ActionController::Base.session_options[:session_expires]

      ActionController::Base.session_options[:session_expires] = 1.year.from_now

    end

  end

end

load all fixtures

remvee (Remco van 't Veer) — Fri, 18 Jan 2008 19:01:16 GMT

In some test cases I need all my fixtures to be loaded. To make this easier, add the following to test/test_helper.rb:



class Test::Unit::TestCase

  def self.all_fixtures

    Dir[File.dirname(__FILE__) + "/fixtures/*.yml"].each do |f|

      fixtures File.basename(f, '.yml')

    end

  end



  ..

end

and in your tests use it as follows:



class FooTest < Test::Unit::TestCase

  all_fixtures



  ..

end

Happy testing!

Disable protected attributes in ActiveRecordHelper forms

remvee (Remco van 't Veer) — Mon, 28 Aug 2006 20:48:51 GMT

To make the form method in ActiveRecordHelper disable protected attribute, place the following in your application_help.rb:



def attr_protected?(record, column)

  o = instance_variable_get("@#{record}")

  o && o.class.protected_attributes &&

      o.class.protected_attributes.include?(column.name.to_sym)

end



def default_input_block

  Proc.new { |record, column|

    options = attr_protected?(record, column) ? {:disabled => true} : {}

    <<-"end_html" 

      

        #{column.human_name}

        


        #{input(record, column.name, options)}

      

    end_html

  }

end

And mark some attributes protected, for example:



class Item < ActiveRecord::Base

  attr_protected :created_at

end

The created_at attribute will be rendered but won't be editable. This will work for "dynamic scaffolds" too!

give focus to first input field or textarea on page

remvee (Remco van 't Veer) — Thu, 15 Jun 2006 12:05:55 GMT

Place the following in your application.js file and make sure your layout includes "javascript_include_tag :defaults".



Event.observe(window, 'load', function() {

  var e = $A(document.getElementsByTagName('*')).find(function(e) {

    return (e.tagName.toUpperCase() == 'INPUT' && (e.type == 'text' || e.type == 'password'))

        || e.tagName.toUpperCase() == 'TEXTAREA' || e.tagName.toUpperCase() == 'SELECT';

  });

  if (e) e.focus();

});

non persistent ActiveRecord

remvee (Remco van 't Veer) — Thu, 27 Apr 2006 11:52:06 GMT



# = ActiveForm - non persistent ActiveRecord

#

# Simple base class to make AR objects without a corresponding database

# table.  These objects can still use AR validations but can't be saved

# to the database.  Use the +valid?+ method to validate.

#

# == Example

#

#   class FeedbackForm < ActiveForm

#     column :email

#     column :message

#     validates_presence_of :email, :message

#   end

#

class ActiveForm < ActiveRecord::Base

  def self.columns() @columns ||= []; end # :nodoc:

  

  # Define an attribute, takes the same arguments as

  # ActiveRecord::ConnectionAdapters::Column.new only in a

  # slightly different order.

  def self.column(name, sql_type = nil, default = nil, null = true)

    columns << ActiveRecord::ConnectionAdapters::Column.new(

        name.to_s, default, sql_type.to_s, null)

  end

end

url and xml encode to fool naive web spiders

remvee (Remco van 't Veer) — Sun, 26 Feb 2006 16:31:17 GMT

Encode all characters to XML entities:



  def xml_encode(text)

    text.unpack('c*').map{|c|"&\##{c};"}.join

  end

Encode all characters to %00%00.. url ecoding:



  def url_encode(text)

    text.split('').map{|c|"%#{c.unpack('H2')}"}.join

  end

The following:



  ">mail somebody

yields:



  mail somebody

which works fine in a browser.