DZone Snippets: rubyonrails code

Custom Rails Callback

onkis (Mike Ball) — Thu, 13 Mar 2008 16:28:28 GMT

// This shows you how to extend active record to allow a custom callback.



#ever needed to add your own callback into the active record callback chain?

#here's how...

module ActiveRecord

  

  #to keep things clean we'll define our own module

  module SweetCustomCallbacks

    

    #this is the ruby method that is called when you call include on a module

    #the method passed, base in our case, is the class your including yourself in

    def self.included(base)

      

      #this clas_eval method takes a block that will be added to base, which is ActiveRecord::Base

      #basically this is like writing code directly into the class ActiveRecord::Base

      base.class_eval do

        

        #alias_method_chain is very cool

        #it allows us override a method without removing the original and without the original knowing its been changed

        #here's how it works:

        # 1st argument is the name of the method you're overriding

        # 2nd argument is feature you want to add

        # so if create_or_update is called it will actually call create_or_update_with_sweet_custom_callbacks

        # the original is still avaliable at create_or_update_without_custom_callbacks

        

        alias_method_chain :create_or_update, :sweet_custom_callbacks

        #the method create_or_update is an internals method to ActiveRecord that is called whenever you call .save or .update

        

        #this is the class method that allows the cool syntax:

        # class Article < ActiveRecord::Base

        # before_before_save :add_authors_name

        #private

        #def add_authors_name

        #.....

        def self.before_before_save(*callbacks, &block)

          callbacks << block if block_given? #add the block to the array of callback functions if a block was passed

          write_inheritable_array(:before_before_save,callbacks) 

        end

      end

    end

    

    #the instance method, although not recomended is avaliable for overriding

    #also if you wanted to have a callback that always did something say add the users's id to the object 

    #you could always code that in here and remove the class above

    def before_before_save() end



    #ok this is the method that is now called instead of create_or_update

    #it calls a method callback on 

    def create_or_update_with_sweet_custom_callbacks

      return false if callback(:before_before_save) == false  #this method does all the real work and calls the callback function in callbacks.rb that gets the methods and runs them 

      create_or_update_without_sweet_custom_callbacks

    end

    

   end

 

   class Base    

     include SweetCustomCallbacks #include our module in ActiveRecord::Base

   end

end

Convert a UTF-8 string to ISO-8859-1

drcorbeille (Christian Meichtry) — Mon, 21 Jan 2008 14:35:26 GMT

Convert a utf string to iso, used this when generating a pdf with pdf-writer in Rails, all my text is UTF8 but pdf-writer does not support this.



#add this to environment.rb

#call to_iso on any UTF8 string to get a ISO string back

#example : "Cédez le passage aux français".to_iso



class String

  require 'iconv' #this line is not needed in rails !

  def to_iso

    Iconv.conv('ISO-8859-1', 'utf-8', self)

  end

end

open_body_tag

jnewland (Jesse Newland) — Thu, 01 Nov 2007 19:24:01 GMT



  #creates a body tag uniquely indentifying this page

  #takes an options Hash with two keys:

  #

  #id::        string that will be used as the body's ID. defaults to controller.controller_name.singularize

  #classes::   an Array of class names. defaults to [params[:action]]

  #

  #Examples:

  #

  # in HomeController#index:

  #

  # <%= open_body_tag %>

  # => 

  #

  # <%= open_body_tag(:id => 'foo') %>

  # => 

  #

  # <%= open_body_tag(:id => 'foo', :classes => %w(one two)) %>

  # => 

  def open_body_tag(options = { :id => controller.controller_name.singularize, :classes => [params[:action]] })

    ""

  end

Convert .rhtml templates to .html.erb

whomwah (Duncan Robertson) — Fri, 12 Oct 2007 08:58:46 GMT

// run this shell command from within the dir you want to change. You will need to change the hg line to use which ever version control you are using, or if you're not use version control (naughty!) then leave out the hg letters altogether.



for f in $(find . -name '*.rhtml') ; do c=$(dirname $f)/$(basename $f .rhtml).html.erb ; hg mv $f $c ; done

Rails URL Validation

jnewland (Jesse Newland) — Wed, 12 Sep 2007 14:03:00 GMT

No regexes, allows URLs with ports or IPs. Inspiration from here



  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

Helper for testing default routes generated by a resource in Ruby on Rails

grantneufeld (Grant Neufeld) — Mon, 10 Sep 2007 12:46:23 GMT

These methods test that the routes for resources defined in routes.rb are working as expected. Call them from your functional (controller) tests.

Add the following 3 methods to test/test_helper.rb (updated for Rails 1.2.5 which no longer uses semicolons as a separator for the edit action):



# Test for routes generated by map.resource (singular).

def assert_routing_for_resource(controller, skip=[], nesting=[])

  routes = [

    ["new",'/new',{},:get], ["create",'',{},:post],

    ["show",'',{},:get], ["edit",'/edit',{},:get],

    ["update",'',{},:put], ["destroy",'',{},:delete]

    ]

  check_resource_routing(controller, routes, skip, nesting)

end

# Test for routes generated by map.resources (plural).

def assert_routing_for_resources(controller, skip=[], nesting=[])

  routes = [

    ["index",'',{},:get], ["new",'/new',{},:get], ["create",'',{},:post],

    ["show",'/1',{:id=>'1'},:get], ["edit",'/1/edit',{:id=>'1'},:get],

    ["update",'/1',{:id=>'1'},:put], ["destroy",'/1',{:id=>'1'},:delete]

    ]

  check_resource_routing(controller, routes, skip, nesting)

end



# Check that the expected paths will be generated by a resource, and that

# the expected params will be generated by paths defined by a resource.

# routes is array of [action, url string after controller, extra params].

def check_resource_routing(controller, routes, skip=[], nesting=[])

  # set a prefix for nested resources

  prefix = nesting.join('s/1/')

  unless prefix.blank?

    prefix += "s/1/"

  end

  # Add params for nested resources.

  # For each 'nest', include a ":nest_id=>'1'" param.

  params = {}

  nesting.each do |param|

    params["#{param}_id".to_sym] = '1'

  end

  # Test each of the standard resource routes.

  routes.each do |pair|

    unless skip.include? pair[0]

      assert_generates("/#{prefix}#{controller}#{pair[1]}",

        {:controller=>controller,

        :action=>pair[0]}.merge(pair[2]).merge(params), {}, {},

        "Failed generation of resource route for action #{pair[0]} /#{prefix}#{controller}#{pair[1]}")

      assert_recognizes(

        {:controller=>controller,

          :action=>pair[0]}.merge(pair[2]).merge(params),

        {:path=>"/#{prefix}#{controller}#{pair[1]}", :method=>pair[3]},

        {}, "Failed to recognize resource route for path #{pair[3]}:/#{prefix}#{controller}#{pair[1]}")

    end

  end

end

EXAMPLES

You can specify actions to 'skip' (if you have a special route for that action).
If using nested resources, set the nesting array (use singular strings).

So, if you have the following in routes.rb:



map.make_thing '/make', :controller=>'things', :action=>'new'

map.resources :nests do |nest|

  nest.resources :things

end

map.resource :foo

then you can use the following in things_controller_test.rb:



def test_resource_routing

  assert_routing_for_resources 'things', ['new'], ['nest']

  assert_routing_for_resource 'foo'

end

Modified Growl support for Ruby autotest

grantneufeld (Grant Neufeld) — Sun, 09 Sep 2007 13:22:55 GMT

# This code is a different approach to using Growl notifications (Mac OS X)
# with autotest for Ruby.
# The code can be added to ~/.autotest
# Be sure to comment out "require 'autotest/growl'" if you have that line
# in your .autotest file.
# Based on ZenTest-3.6.1/lib/autotest/growl.rb
# Requires the 2 rails png graphics found at:
# http://blog.internautdesign.com/2006/11/12/autotest-growl-goodness



module Autotest::Growl

  # save the name of the working directory (e.g., the app name)

  # to be used as a key to identify this particular run of autotest

  # so the same growl notification will be reused for updates,

  # instead of a new growl window for every posting.

  @@current_directory_name = Dir.pwd.match(/([^\/]+)\z/).to_s

  def self.growl title, msg, pri=0

    title += " in #{@@current_directory_name}"

    msg += " at #{Time.now}"

    # ### change the path to the directory for the png graphics:

    system "growlnotify -n autotest #{pri > 0 ? '-s ' : ''}--image /Users/grant/Pictures/rails_#{pri > 0 ? 'fail' : 'ok'}.png -p #{pri} -d '#{Dir.pwd}' -m #{msg.inspect} #{title}"

  end



  Autotest.add_hook :run do  |at|

    growl "autotest running", "Started"

  end

  Autotest.add_hook :red do |at|

    growl "Tests Failed", "#{at.files_to_test.size} tests failed", 2

  end

  Autotest.add_hook :green do |at|

    growl "Tests Passed", "Tests passed", -2 if at.tainted

  end

  Autotest.add_hook :all_good do |at|

    growl "Tests Passed", "All tests passed", -2 if at.tainted

  end

end

Using POP3 to Retrieve Email for Rails App

timmorgan (Tim Morgan) — Tue, 26 Jun 2007 17:40:30 GMT

Put this in a file called "inbox" in the scripts/ directory of your Rails app. change the host, username, and password to match.

Set up a cron job to run this script every so often (frequency depends on your needs).



#!/usr/bin/env ruby



require 'net/pop'

require File.dirname(__FILE__) + '/../config/environment'



logger = RAILS_DEFAULT_LOGGER



logger.info "Running Mail Importer..." 

Net::POP3.start("localhost", nil, "username", "password") do |pop|

  if pop.mails.empty?

    logger.info "NO MAIL" 

  else

    pop.mails.each do |email|

      begin

        logger.info "receiving mail..." 

        Notifier.receive(email.pop)

        email.delete

      rescue Exception => e

        logger.error "Error receiving email at " + Time.now.to_s + "::: " + e.message

      end

    end

  end

end

logger.info "Finished Mail Importer."

Setting up Ruby On Rails with PostgreSQL on Mac OS X 10.4.9

ntk () — Thu, 21 Jun 2007 21:25:53 GMT

This is a modified version of the Ruby on Rails Tutorial (TutorialStepOne, TutorialStepOnePostgresql, ...).

Log in to an admin user account and, if necessary, fix your command search path in $HOME/.bash_profile, $HOME/.bash_login or $HOME/.profile to include "/usr/local" and "/usr/local/sbin" (cf. Using /usr/local > Set The Path; echo $PATH | tr ":" "\n"). If there are no such files, just create them: touch $HOME/.bash_login && touch $HOME/.bashrc (ls -a | grep \.bash).

To avoid RubyGems loading issues it's no bad idea to add export RUBYOPT=rubygems to your $HOME/.bash_login file as well.

If you want your system path changes to take effect not only for you you can modify the global system path settings in the systemwide initialization files /private/etc/profile and /private/etc/bashrc accordingly.

To fix the paths of installed manual pages add the lines "MANPATH /usr/local/share/man" and "MANPATH /usr/local/man" to sudo nano +45 /usr/share/misc/man.conf (man -w | tr ":" "\n").

(USE THE FOLLOWING AT YOUR OWN RISK!)

REQUIREMENTS:

I. Xcode

II. PostgreSQL Database Server

Install this PostgreSQL Database Server package.



# test after installation

which psql     # /usr/local/bin/psql

psql --version     # psql (PostgreSQL) 8.2.3, contains support for command-line editing

Alternative installation: Getting PostgreSQL running for Rails on a Mac

III. Ruby 1.8.6, Ruby On Rails 1.2.3 & Mongrel 1.0.1

Building Ruby, Rails, Subversion, Mongrel, and MySQL on Mac OS X

To install both Mongrel & Mongrel Cluster use: sudo gem install -y mongrel mongrel_cluster (cf. Using Mongrel Cluster).



# test after installation

ruby -v     # ruby 1.8.6

rails -v     # Rails 1.2.3

gem list     # ... mongrel (1.0.1) ...

IV. ruby-postgres 0.7.1



sudo gem install -y ruby-postgres

As an alternative you may try Ruby on rails installer script for Mac OSX or choose to install via MacPorts as described in Installing Ruby on Rails and PostgreSQL on OS X, Second Edition or Installing Rails on Mac OS X Tiger (10.4.8). However, you then may have to change your system paths mentioned above accordingly.

1. create a database server





# first create a directory called PostgreSQL-db on your Desktop

mkdir -p $HOME/Desktop/PostgreSQL-db



# create a new db server called railsdb

/usr/local/bin/initdb -E UTF8 -D $HOME/Desktop/PostgreSQL-db/railsdb



# START DB SERVER

dir="$HOME/Desktop/PostgreSQL-db"; /usr/local/bin/pg_ctl -D $dir/railsdb -l $dir/railsdb/postgres.log start



# STOP DB SERVER

#dir="$HOME/Desktop/PostgreSQL-db"; /usr/local/bin/pg_ctl -D $dir/railsdb -l $dir/railsdb/postgres.log stop -m smart



# check

cat $HOME/Desktop/PostgreSQL-db/railsdb/pg_hba.conf



   ...

   # TYPE  DATABASE    USER        CIDR-ADDRESS          METHOD



   # "local" is for Unix domain socket connections only

   local   all         all                               trust

   # IPv4 local connections:

   host    all         all         127.0.0.1/32          trust

   # IPv6 local connections:

   host    all         all         ::1/128               trust

2. create PostgreSQL database





createdb `whoami`_development

#dropdb `whoami`_development



createdb `whoami`_test

#dropdb `whoami`_test



#createdb `whoami`_production

#dropdb `whoami`_production

3. set up your Rails project





cd $HOME/Desktop/RubyOnRails-projects

rails -d postgresql `whoami`

cd `whoami`

4. edit /config/database.yml





open -e $HOME/Desktop/RubyOnRails-projects/`whoami`/config/database.yml



# just uncomment the following line

#encoding: UTF8

5. make Rails & PostgreSQL work together





cd $HOME/Desktop/RubyOnRails-projects/`whoami`



ruby script/generate migration People



# edit /db/migrate/001_people.rb

# cf. http://wiki.rubyonrails.org/rails/pages/TutorialStepOneMigrations



open -e $HOME/Desktop/RubyOnRails-projects/`whoami`/db/migrate/001_people.rb



 class People < ActiveRecord::Migration



    def self.up

      create_table :people do |table|

      # note that "id" is added implicitly, by default

        table.column :name, :string

        table.column :street1, :string

        table.column :street2, :string

        table.column :city, :string

        table.column :state, :string

        table.column :zip, :string

     end

    end



    def self.down

      drop_table :people 

    end

  end







rake db:migrate



ruby script/generate model Person  



#open -e $HOME/Desktop/RubyOnRails-projects/`whoami`/app/models/person.rb  # file will be explained below



ruby script/console



>> ...

        entry = Person.new

        entry.name = "Name" 

        entry.street1 = "123 Somwhere" 

        entry.street2 = "" 

        entry.city = "Smallville" 

        entry.state = "KS" 

        entry.zip = "123456" 

        entry.save

        exit





# check newly created db table



psql `whoami`_development

SELECT * FROM people;

\q





# test

rake      # ... 0 failures, 0 errors



# create new controller

ruby script/generate controller People list view new edit





# edit /app/controllers/people_controller.rb

open -e $HOME/Desktop/RubyOnRails-projects/`whoami`/app/controllers/people_controller.rb



  def view

   @person = Person.find(1)

  end







# edit /app/views/people/view.rhtml

open -e $HOME/Desktop/RubyOnRails-projects/`whoami`/app/views/people/view.rhtml



# copy & paste & uncomment the following lines



#

#  

#    People#view

#    This page will display one person.

#    

#    <%= @person.name %>


#    <%= @person.street1 %>


#    <%= @person.street2 %>


#    <%= @person.city %>


#    <%= @person.state %>


#    <%= @person.zip %>


#    

#  

#





# the file /app/models/person.rb explained (see above)

# open -e $HOME/Desktop/RubyOnRails-projects/`whoami`/app/models/person.rb



# class Person < ActiveRecord::Base

# end



# How does this know to map to the people table we created? ActiveRecord pluralizes the class name and looks for that 

# table in the database. This doesn’t just mean adding an ’s’. Irregular plural forms are also handled, so Rails knows 

# that the plural of ‘person’ is ‘people’. The rules for how it does this are described in the documentation

# (see http://wiki.rubyonrails.org/rails/pages/TutorialStepSix).



# test

rake



# start your Rails app

cd $HOME/Desktop/RubyOnRails-projects/`whoami`



ruby script/server

#ruby script/server --environment=development



# open a second shell window and go to ...  

open -a Safari http://localhost:3000/people/view

Print and preselect checkboxes

vkeesari (VK) — Sun, 03 Jun 2007 21:45:23 GMT

Create a selection box list and preselect with previously assigned Roles



def createCheckBoxList(user)

    

    userRolesID = Hash.new

    user.roles.each do | ur |

      userRolesID[ur.name] = ur.id   

    end

 

    @roles = Role.find(:all)

    

    html_output = String.new

    # first create the checkbox

      for role in @roles

        if userRolesID.has_key?(role.name)

          html_output << check_box("roles_user", role.id, :checked => 'checked')

        else

          html_output << check_box("roles_user", role.id)

        end

        # then print the role name

        html_output << " " + role.name + "
"

      end

      

      return html_output

    

  end