Write Your Own! posted by Fora User @ Sun, 05 Aug 2007 16:34:38 -0000

Fora User — Sun, 05 Aug 2007 16:34:38 -0000

Great post, Maxim.

To take it even further, you can use any partial to act as a layout:

application_helper.rb


def inside(partial, AMPERSANDblock)
  instance_variable_set(:@content_for_layout, capture(AMPERSANDblock))
  concat(render(:partial => partial), block.binding)
end

_wrapper.rhtml (the outer layout partial)


<div id="wrapper">
  <%= yield %>
<div>

content.rhtml (the actual template)


<% inside "wrapper" do -%>
  Inside the wrapper
<% end -%>

Result:


<div id="wrapper">
  Inside the wrapper
</div>

This is completely compatible with the standard Rails layouts. They’ll work like they did before.

However, I don’t know if this plays well with page caching. Testing this is left as an exercise for the reader :)

—Andy

Write Your Own! posted by Fora User @ Tue, 13 Mar 2007 15:40:38 -0000

Fora User — Tue, 13 Mar 2007 15:40:38 -0000

Thanks for the post, helped a lot.

A little tough to follow though, here is the result that worked for me:

http://pastie.caboo.se/46627

Write Your Own! posted by Fora User @ Fri, 02 Mar 2007 06:55:43 -0000

Fora User — Fri, 02 Mar 2007 06:55:43 -0000

Hi all I am new(beginner) to rails…. where should i start from… please guide me…. suggest me some books…. thank u

Write Your Own! posted by Fora User @ Thu, 08 Feb 2007 21:14:21 -0000

Fora User — Thu, 08 Feb 2007 21:14:21 -0000

Very useful post! A good addition to help newbies like me would be to say that the skeleton for the plugin can be generated through

./script/generate plugin validates_write_once_of

Then you can paste into these skeleton files the parts of this recipe

I added a quick note on this on my site http://jcandkimmita.info/jc/?p=63

Write Your Own! posted by Fora User @ Wed, 31 Jan 2007 16:40:19 -0000

Fora User — Wed, 31 Jan 2007 16:40:19 -0000

Hello i’m new on rails, i will post here anyways think will help some one. the comments above i did this inf helper/application_helper.rb i added this module ApplicationHelper in_place_collection_editor_field(object,method,container) tag = ::ActionView::Helpers::InstanceTag.new(object, method, self) url = url_for( :action => “set_#{object}_#{method}”, :id => tag.object.id ) function = “new Ajax.InPlaceCollectionEditor(” function << ”’#{method}’,” function << ”’#{url}’,” collection = container.inject([]) do |options, element| options << “[ ’#{html_escape(element.last.to_s)}’, ’#{html_escape(element.first.to_s)}’]” end function << “{collection: [#{collection.join(’,’)}]});” javascript_tag(function) end on the view i added like this and that works for me <=@user.sex ><%= in_place_collection_editor_field :user,’sex’, Sex.find_all.collect{|x| [x.id,x.english]} -%>

def

where Sex is a object storage on the db so Also there is a catch that i figured out later from the main solution text you will find this line function << “{collection: [#{collection.join(’,’)}],}); i have to change it to function << “{collection: [#{collection.join(’,’)}]}); so it works with IE now

Write Your Own! posted by Fora User @ Mon, 04 Dec 2006 21:19:19 -0000

Fora User — Mon, 04 Dec 2006 21:19:19 -0000

Is there a reason why you would use both Bluecloth and RedCloth? Would just one or the other suffice?

Write Your Own! posted by Fora User @ Tue, 07 Nov 2006 22:41:14 -0000

Fora User — Tue, 07 Nov 2006 22:41:14 -0000

I’m totally lost as to what the complete code is supposed to look like or in which files each of your code snippets live? Can you possibly provide a little more detail? It sounds exactly like what I need. ie.values along with the option tags.

Write Your Own! posted by Fora User @ Sun, 08 Oct 2006 16:49:01 -0000

Fora User — Sun, 08 Oct 2006 16:49:01 -0000

I’ve written an update to this recipe that allows you to safely filter attributes/tags and define “profiles” that let you create different levels of filtering for different users.

Details here:

http://www.kookdujour.com/blog/details/11

Write Your Own! posted by Fora User @ Sun, 10 Sep 2006 14:15:56 -0000

Fora User — Sun, 10 Sep 2006 14:15:56 -0000

One big problem with this recipe:

It doesn’t do anything about tag attributes. A false sense of security is worse than none at all.

This means I can submit javascript handlers on allowed tags, a pretty big no-no. Other pre-santizing factors come into play as well.

The way around this is simple, but annoyingly so because you can’t write to the attributes attribute of an HTML::Tag node.


# stuff . . .
 if ALLOWED_TAGS.include?(node.name)
                             new_node=HTML::Tag.new(node.parent, node.line, node.position, node.name, [], node.closing)
                             new_node.to_s
                           else
# stuff . . .

Write Your Own! posted by Fora User @ Sun, 27 Aug 2006 06:48:20 -0000

Fora User — Sun, 27 Aug 2006 06:48:20 -0000

hello,

i am not new to rails but i am new to ajax. when i try to run the in_place_editor_field recipe i get a weird error.

this is what it says.

Error communicating with the server:

Action Controller: Exception caught

body { background-color: #fff; color: #333; }

body, p, ol, ul, td {
  font-family: verdana, arial, helvetica, sans-serif;
  font-size:   13px;
  line-height: 18px;
}

pre {
  background-color: #eee;
  padding: 10px;
  font-size: 11px;
}

a { color: #000; }
a:visited { color: #666; }
a:hover { color: #fff; background-color:#000; }

Unknown action No action responded to set_client_contact_first_name

i generated my app with scaffolding, and include the default javascript files. this error comes up after i make a change and press OK. then the area where i was editing the field says saving, then the error pops up in a javascript alert window.

any help would be greatly appreciated.

thanks.

Write Your Own! posted by Fora User @ Tue, 20 Jun 2006 16:36:57 -0000

Fora User — Tue, 20 Jun 2006 16:36:57 -0000

The last method above, load_from_yaml, doesn’t work anymore as written with ruby 1.8.4 . I’ve patched the restore.rake file. The link above also reflects the changes.

Write Your Own! posted by Fora User @ Fri, 09 Jun 2006 20:49:31 -0000

Fora User — Fri, 09 Jun 2006 20:49:31 -0000

Problem

You want to share instance variables across methods, or controllers.

Extra Ingredients

None

Credits

Taken from a post by Ezra Zygmuntowicz on the rails mailing list.

Solution

Put this in the top of your controller where you want to have a shared var. Assuming the var is @foo

MyController < ApplicationController

before_filter :setup_foo
 attr_reader :foo

def setup_foo
    @foo = "Whatever you want @foo to contain" 
end

end

Now @foo will be available to every action method in your controller and also in your views for that controller. If you want @foo to be available in all your controllers and view, put that code in your application.rb ApplicationController.

Discussion

You can also use a CONSTANT of course, defined in application.rb, for a variable whose contents will not change, and which will be available to the entire application.

Write Your Own! posted by Fora User @ Wed, 07 Jun 2006 00:47:26 -0000

Fora User — Wed, 07 Jun 2006 00:47:26 -0000

I understand where you’re coming from, resty, but that’s not what “recipe” books are about, in general. It’s an established genre, and it’s pretty much what it sounds like—how to make a specific thing, be it chocolate chip cookies or in-place editing.

To carry the analogy, if you’re holding your recipe book in one hand, and looking worryingly at what you’ve been assured is an “oven,” the recipe book is best perused after you read a book of the “How To Cook” genre.

I would suggest Agile Web Development with Rails, by Dave Thomas and DHH, which is available from Pragmatic Bookshelf. Once you’ve got your head wrapped around that, try Ruby For Rails, by David Black, from Manning Press.

Write Your Own! posted by Fora User @ Sun, 28 May 2006 03:52:03 -0000

Fora User — Sun, 28 May 2006 03:52:03 -0000

Problem

You’ve got your software running. You’re using Capistrano to deploy it. But there are several people working on the project who can deploy to production. You want all of the developers to be notified when your software gets deployed to production, including knowing which version of the software was deployed.

Extra Ingredients

Because this hooks into the deployment, this assumes you’ll already be including Capistrano

Solution

Generate a mailer :


 ruby script/generate mailer Notifier deployed
      exists  app/models/
      create  app/views/notifier
      exists  test/unit/
      create  test/fixtures/notifier
      create  app/models/notifier.rb
      create  test/unit/notifier_test.rb
      create  app/views/notifier/deployed.rhtml
      create  test/fixtures/notifier/deployed

In the capistrano deploy recipe (config/deploy.rb), create an “after_deploy” task :


desc "After the deploy is done, let people know about it" 
task :after_deploy do
  #  The mailer needs the environment configured for it - otherwise it doesn't 
  #  find the templates, and it doesn't know how to send email.
  require File.join(File.dirname(__FILE__), 'environment')
  Notifier.deliver_deployed("#{revision}")
end  

task :after_deploy_with_migrations do
  #  The same stuff that we want to do after a "regular" deploy
  after_deploy
end

Let the Notifier model handle the information sent to it :


  def deployed(version)
    @subject    = "Software Deployed!" 
    body(:version => version)
    @recipients = 'geeks@example.com'
    @from       = 'deployer@example.com'
    @sent_at    = Time.now
    @sent_on    = Time.now
  end

Finally, modify the view (app/views/notifier/deployed.rhtml) to have some important information.


Hello Geeks,

We just deployed to production with version <%= @version %> of the baseline.

It is now <%= Time.now %>.  Have a nice day.

Thank you, 

"The Deployer"

Now, whenever someone deploys your software to production, you will receive a nice email letting you know about it.

Discussion

This example uses the version that was deployed to production, but there are several variables that the deployment has available to it. Maybe including the user who did the deployment would be important to you, or the machines that were included in the deployment. See information in the deploy.rb along with documentation on Capistrano.

Including the “environment” in the require means that you will have access to all of the information in your application (and all of the database connections). That means you could also do different things than just sending an email – you could update a column in one of your models, insert information into your database, or just list all the users in your system.

Write Your Own! posted by Fora User @ Thu, 04 May 2006 15:48:38 -0000

Fora User — Thu, 04 May 2006 15:48:38 -0000

Problem

A model requires that one or more of its attributes be write once only. In other words, these protected attributes may only be set when the model is first save dto the database and are immutable thereafter.

Credits

In order to write my unit tests for this code I referred to Ezra Zygmuntowicz’s ez_where plugin

Solution

The code that you are going to have to write needs to do the following :

Only run on an update. This validation doesn’t apply to record creations.
Retrieve a copy of the model form the database.
Compare each protected attribute of the current model to that of the copy.
Add an error to the model’s errors collection for each protected attribute that differs.

You could situate this code within the model’s validate_on_update method. But if you created your own validation as a plugin, validates_write_once_of, you could reuse this validation on other models and you’d gain the benefit of making your code more descriptive. Rails makes this easy (of course) – we’ll just model the new vaidation on an existing one.

Validations are located in lib/active_record/validations.rb

Examining the method validates_presence_of for example, shows that it takes the following options

message – a cusom error message (default is “can’t be blank”)
on – Specifies when this validation is active (default is :save, other options are :create, :update)
if – Specifies a method, proc or string to call to determine if the validation should occur

The new validation will take all those options except for ‘on’. It only makes sense for this validation to be active on an update. The default message will be “can’t be changed”.

Here’s the code for write_once_of.rb


module WriteOnceOf
  def validates_write_once_of(*attr_names)
    configuration = { :message => "can't be changed" }
    configuration.merge!(attr_names.pop) if attr_names.last.is_a?(Hash)
    send( validation_method(:update) ) do |record|
      unless configuration[:if] and not evaluate_condition(configuration[:if], record)
        previous = self.find record.id
        attr_names.each do |attr_name|
          record.errors.add( attr_name, configuration[:message] ) if record.respond_to?(attr_name) and previous.send(attr_name) != record.send(attr_name)
          # replace the 'and' above with a double ampersand 
        end
      end
    end
  end
end

To get the validation to work as a plugin package it as follows

validates_write_once_of/
  init.rb
  lib/
    write_once_of.rb

The code for init.rb is


require 'write_once_of'
ActiveRecord::Base.extend WriteOnceOf

The validates_write_once_of folder should be placed in the /vendor/plugins folder of your rails application.

Use as follows


class SomeClass < ActiveRecord::Base
  validates_write_once_of :some_attribute, { :message => "can't be changed ... ever" }
end

Discussion

Rails ships with a very full and flexible set of validations. But being able to create your own validations enables you to write code that is very declarative and specific to your application domain. Its certainly worth doing so given how easily it can be done.

Write Your Own! posted by Fora User @ Sat, 29 Apr 2006 09:13:10 -0000

Fora User — Sat, 29 Apr 2006 09:13:10 -0000

Bold phrase

Write Your Own! posted by Fora User @ Sat, 22 Apr 2006 20:35:53 -0000

Fora User — Sat, 22 Apr 2006 20:35:53 -0000

Hello,

I’m afraid the very first recipe, InPlaceEditing, stumped me. How do I ‘cook’ this recipe? Don’t I have to create a database first? What’s the name of the database to create? I know I have to run some scripts sometime in the process.

Could we, at least for the first few recipes, be as detailed as can be, with one recipe that starts from the very, very beginning?

Thanks! frustrated

Write Your Own! posted by Fora User @ Sun, 16 Apr 2006 09:07:01 -0000

Fora User — Sun, 16 Apr 2006 09:07:01 -0000

That’s right! Thanks :)

Write Your Own! posted by Fora User @ Sat, 15 Apr 2006 19:20:18 -0000

Fora User — Sat, 15 Apr 2006 19:20:18 -0000

This is almost certainly not the correct place to post this, so apologies in advance. Update Its definately the wrong place :-(.

Paragraph four in “The Console is Your Friend” ends with the following line:

“Who needs and IDE?!”

My guess is that this was meant to be “Who needs an IDE?!”

Keith

Write Your Own! posted by Fora User @ Sat, 08 Apr 2006 18:49:29 -0000

Fora User — Sat, 08 Apr 2006 18:49:29 -0000

Problem

You want to use AJAX on a field that isn’t free text, but is a list of things that your user can choose.

Extra Ingredients

Rails 1.1

Solution

As of script.aculo.us version 1.5.3, a control called Ajax.InPlaceCollectionEditor deals with precisely this issue. This function works identically to Ajax.InPlaceEditor, except that it takes an array of arrays consisting of option names and values.

A Rails-oriented solution, however, should work similarly to the way select options are generated. Define a function in your application_helper.rb file:

def in_place_collection_editor_field(object,method,container)

The final parameter, container, contains the options for the drop-down box. First, resolve a tag and create the submit URL:

tag = ::ActionView::Helpers::InstanceTag.new(object, method, self)
url = url_for( :action => "set_#{object}_#{method}", :id => tag.object.id )

On the controller side, you will need to define a method set_object_method to handle the input. Next, start the definition of the function:

function =  "new Ajax.InPlaceCollectionEditor(" 
function << "'#{method}'," 
function << "'#{url}',"

Then, process the options:

collection = container.inject([]) do |options, element|
  options << "[ '#{html_escape(element.last.to_s)}', '#{html_escape(element.first.to_s)}']" 
end

Finally, add the collection to the final Javascript:

function << "{collection: [#{collection.join(',')}]," 
  function << "});" 
end

javascript_tag(function)

For example, in a list.rhtml file, the following defines an editor for a field called custom_field that has a number of options taken from the FieldType model:

<%= in_place_collection_editor_field 'custom_field', 'field_type', 
                           FieldType.find_all.collect{|x| [x.name,x.id]} %>

The x.name is the plaintext description, to be displayed to the user, while the x.id is the internal id. Given that the selected object id will be passed to the controller, along with the id of the object to process, the controller is simply defined as:

def set_custom_field_field_type
  @i = CustomField.find(params[:id])
  f  = FieldType.find(params[:value])
  @i.update_attribute( :field_type, f )
  render :text => f.name
end

Discussion

While this example also by-passes model validation, this can easily be built into the controller action. Logical extensions to this approach might include the other approaches used in ActionView::Helpers::FormOptionsHelper.

Write Your Own! posted by Fora User @ Mon, 03 Apr 2006 17:33:31 -0000

Fora User — Mon, 03 Apr 2006 17:33:31 -0000

There doesn’t seem to be any actual source code in the Authentication folder (or any other folder)?

Write Your Own! posted by Fora User @ Tue, 28 Mar 2006 08:13:36 -0000

Fora User — Tue, 28 Mar 2006 08:13:36 -0000

Can’t wait for the book fellas…another great Rails resource. I made you famous by adding your topics RSS to Rails-a-Rama!. Yes I am pimping it…because its a good thing like Martha Stewart said! I think… ;-)

Write Your Own! posted by Fora User @ Tue, 21 Mar 2006 16:58:51 -0000

Fora User — Tue, 21 Mar 2006 16:58:51 -0000

Note that to be able to use fixtures, we also need to define the reset_pk_sequence! for our MysqlAdapter. This function is called when all the fixtures are loaded to set the value of the sequence table accordingly (otherwise it will have a perhaps inconsistent value).

In our case, we have to get the last id value of our table, and set or update the id value of our sequence table accordingly:


      def reset_pk_sequence!( table, pk = nil, sequence = nil )                                                                                                                      
        sequence_name = table + "_sequence"                                                                                
        max_pk = select_value("SELECT MAX(id) FROM #{table}").to_i + 1                                                    
        sql = "INSERT INTO #{sequence_name} (`id`) VALUES (#{max_pk})"                                                         
        begin                                                                                                                  
          insert( sql )                                                                                                        
        rescue ActiveRecord::StatementInvalid                                                                                  
          sql = "UPDATE #{sequence_name} SET id=#{max_pk}"                                                                     
          nb = update( sql ,"Update Sequence")                                                                                 
        end

Write Your Own! posted by Fora User @ Sun, 19 Mar 2006 10:29:40 -0000

Fora User — Sun, 19 Mar 2006 10:29:40 -0000

Problem

You have a rails application with lots of controllers / views. All your pages have common structure elements (like header, footer etc.) through usage of layouts.

Rails allows one level of layouts. Most of the time it is sufficient, but sometimes you feel uncofortable with having pages sharing common elements. For example, all pages of a particular controller should have a common “submenu”. You end up using the same particles on every controller view.

Solution

Most of modern frameworks have an ability to embed pages in a layout, and then embed the result in another layout and so on. With a little trick you can do the equal thing in Rails.

First, add the following method into your ApplicationHelper:


def inside_layout(layout, AMPERSANDblock)
  @template.instance_variable_set("@content_for_layout", capture(AMPERSANDblock))

  layout = layout.include?("/") ? layout : "layouts/#{layout}" if layout
  buffer = eval("_erbout", block.binding)
  buffer.concat(@template.render_file(layout, true))
end

Then, design your views to use e.g. ‘inner_layout’.

In ‘layouts/inner_layout.rhtml’ write:

<% inside_layout 'outer_layout' do %>

  <div id="common_elements">
  </div>

  <%= @content_for_layout %>

<% end %>

The ‘outer_layout.rhtml’ will go as ussual layout (unless it needs to be nested in other higher level layout)

NOTE: Due to a limitation in textile (used in this forum) I had to remove the ampersands from the code above, so you’ll need to re-insert those before “block” variable. So the code should look like “capture(AMPERSANDblock) where AMPERSAND is replaced by the ampersand character.

Write Your Own! posted by Fora User @ Fri, 17 Mar 2006 19:31:32 -0000

Fora User — Fri, 17 Mar 2006 19:31:32 -0000

Problem

You want to allow your users to use certain HTML tags in their input
while restricting all other HTML tags.

Extra Ingredients

None

Credits

The idea for this recipe comes from Koen Eijsvogels and his post in
the Request a
Recipe forum.

Solution

Modify config/environment.rb by adding the following line at the end:


require_dependency 'rails_patch/text_helper'

Add a new subdirectory rails_patch to your application lib directory.

Add text_helper.rb to your lib/rails_patch directory and ensure it
looks as follows:


module ActionView
  module Helpers
    module TextHelper
      ALLOWED_TAGS = %w(a img) unless defined?(ALLOWED_TAGS)

      def whitelist(html)
        # only do this if absolutely necessary
        if html.index("<")
          tokenizer = HTML::Tokenizer.new(html)
          new_text = "" 

          while token = tokenizer.next
            node = HTML::Node.parse(nil, 0, 0, token, false)
            new_text << case node
                        when HTML::Tag
                          if ALLOWED_TAGS.include?(node.name)
                            node.to_s
                          else
                            node.to_s.gsub(/</, "lt")
                          end
                        else
                          node.to_s.gsub(/</, "lt")
                        end
          end

          html = new_text
        end

        html
      end
    end
  end
end

Then in your views you can simply do the following:


  <%= whitelist(@post.body) %>

NOTE: Due to a limitation in textile (used in this forum) I had to remove the ampersands and semi-colons from the code above, so you’ll need to re-insert those in the gsub calls. So the code should look like node.to_s.gsub(/LESS-THAN/, “AMPERSANDltSEMI-COLON”) where LESS-THAN, AMPERSAND and SEMI-COLON are replaced by their respective characters.

Discussion

Obviously we are taking advantage of the fact that classes (and
modules, in this case) in Ruby are open by patching our own method
into Rail’s TextHelper module.

If you want to allow more tags than just anchors and images, add
the additional tags to the %w() in following line:


ALLOWED_TAGS = %w(a img) unless defined?(ALLOWED_TAGS)

Recent Posts in 'Write Your Own!' | Pragmatic Forums

Write Your Own! posted by Fora User @ Sun, 05 Aug 2007 16:34:38 -0000

Write Your Own! posted by Fora User @ Tue, 13 Mar 2007 15:40:38 -0000

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Write Your Own! posted by Fora User @ Sun, 27 Aug 2006 06:48:20 -0000

Write Your Own! posted by Fora User @ Tue, 20 Jun 2006 16:36:57 -0000

Write Your Own! posted by Fora User @ Fri, 09 Jun 2006 20:49:31 -0000

Problem

Extra Ingredients

Credits

Solution

Discussion

Write Your Own! posted by Fora User @ Wed, 07 Jun 2006 00:47:26 -0000

Write Your Own! posted by Fora User @ Sun, 28 May 2006 03:52:03 -0000

Problem

Extra Ingredients

Solution

Discussion

Write Your Own! posted by Fora User @ Thu, 04 May 2006 15:48:38 -0000

Write Your Own! posted by Fora User @ Sat, 29 Apr 2006 09:13:10 -0000

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Write Your Own! posted by Fora User @ Sun, 16 Apr 2006 09:07:01 -0000

Write Your Own! posted by Fora User @ Sat, 15 Apr 2006 19:20:18 -0000

Write Your Own! posted by Fora User @ Sat, 08 Apr 2006 18:49:29 -0000

Problem

Extra Ingredients

Solution

Discussion

Further Reading

Write Your Own! posted by Fora User @ Mon, 03 Apr 2006 17:33:31 -0000

Write Your Own! posted by Fora User @ Tue, 28 Mar 2006 08:13:36 -0000

Write Your Own! posted by Fora User @ Tue, 21 Mar 2006 16:58:51 -0000

Write Your Own! posted by Fora User @ Sun, 19 Mar 2006 10:29:40 -0000

Problem

Solution

Write Your Own! posted by Fora User @ Fri, 17 Mar 2006 19:31:32 -0000

Problem

Extra Ingredients

Credits

Solution

Discussion

Further Reading