DZone Snippets: helpers code

Rails helpers for A List Apart No. 256

sporkyy (Todd Sayre) — Sun, 27 Apr 2008 23:01:52 GMT

I cooked up some Ruby on Rails helpers for testing the techniques in the article Accessible Data Visualization with Web Standards from A List Apart No. 256. If you want to know more about Rails, check out No. 257. If you want to be smarter, read A List Apart every week.

def chartlist(data)

  total = data.inject(0.0) { |sum, datum| sum + datum[:count] }

  bars = ''



  data.each do |datum|

    link  = content_tag 'a', datum[:name], :href => datum[:href]

    count = content_tag 'span', datum[:count], :class => 'count'

    index = content_tag 'span', "(#{(datum[:count]/total*100).to_i}%)", :class => 'index', :style => "width: #{(datum[:count]/total*100).to_i}%"

    bars << content_tag('li', link << count << index)

  end



  content_tag 'ul', bars, :class => 'chartlist'

end

Sample data for a chartlist (example)

data = [{ :name => 'Apples',   :count => 420, :href => 'http://www.example.com/fruits/apples/' },

        { :name => 'Bananas',  :count => 280, :href => 'http://www.example.com/fruits/bananas/' },

        { :name => 'Cherries', :count => 200, :href => 'http://www.example.com/fruits/cherries/' },

        { :name => 'Dates',    :count => 100, :href => 'http://www.example.com/fruits/dates/' }]

def sparkline(data)

  max = data.sort.last.to_f

  sparklines = ''



  data.each_with_index do |datum, index|

    count_string = datum.to_s

    '(' << count_string if index == 0

    count_string << ',' if index != data.length

    count_string << ')' if index == data.length

    count = content_tag 'span', count_string, :class => 'count', :style => "height: #{(datum/max*100).to_i}%"

    index = content_tag 'span', count << ' ', :class => 'index'

    sparklines << index

  end



  content_tag('span', sparklines, :class => 'sparkline')

end

Sample data for sparklines (example)

data = [60, 220, 140, 80, 110, 90, 180, 140, 120, 160, 175, 225, 175, 125]

def timeline(data)

  max = data.sort { |a, b| a[:count] <=> b[:count] }.last[:count]

  bars = ''



  data.each do |datum|

    label = content_tag 'span', datum[:label], :class => 'label'

    count = content_tag 'span', "(#{datum[:count]})", :class => 'count', :style => "height: #{(datum[:count]/max.to_f*100).to_i}%"

    link  = content_tag 'a', label << count, :href => datum[:href], :title => "#{datum[:label]}: #{datum[:count]}"

    bars << content_tag('li', link, :style => "width: #{(100.0/data.length).to_i}%")

  end



  content_tag 'ul', bars, :class => 'timeline'

end

Sample data for a timeline (example)

data = [{ :date => '2007-12-01', :count =>  40, label => '1' },

        { :date => '2007-12-02', :count => 100, label => '2' },

        { :date => '2007-12-03', :count => 150, label => '3' }]

PHP Select Form Helper

nathancarnes (Nathan Carnes) — Fri, 25 Jan 2008 02:13:40 GMT

// takes an array of values and a value to match, and outputs formatted

Mask all but last 4 digits

jrm02t () — Tue, 28 Nov 2006 08:51:41 GMT

If you need to mask all but the last 4 digits of a nubmer - like a credit card number - this helper works nicely.

Just pass it a number or string.



def mask_number(number)

  number.to_s.size < 5 ? number.to_s : (('*' * number.to_s[0..-5].length) + number.to_s[-4..-1])

end

Block to Partial Rails Helper

err (Chris Wanstrath) — Mon, 28 Aug 2006 05:49:13 GMT

From http://errtheblog.com/post/13.
Create a helper which takes a block and renders that block within the context of a partial.

Create this helper:



def block_to_partial(partial_name, options = {}, &block)

  options.merge!(:body => capture(&block))

  concat(render(:partial => partial_name, :locals => options), block.binding)

end

Create this helper, too:



def sidebar_module(title, options = {}, &block)

  block_to_partial('shared/sidebar_module', options.merge(:title => title), &block)

end

Create this partial (app/views/shared/_sidebar_module.rhtml):



 class="sidebar_module">

  <%= title %>

  <%= body %>

Use it in your views:



<% sidebar_module 'Recent Stories' do %>

  <%= render :partial => 'recent_stories', :collection => @recent_stories %>

<% end %>

Javascript Link Helper

rafee (Rafael Lima) — Thu, 20 Apr 2006 10:50:18 GMT

Ruby on Rails helper to create a link tag to 'name' wich execute the 'javascript' statement onclick event. The last both parameters are the same as for link_to.

Helper para o Ruby on Rails para criar um tag de link associado ao 'name' que executa o código 'javascript' no evento onclick. Os últimos dois parâmetros são os mesmos utilizados no link_to



	def javascript_link_to(name, javascript, html_options = nil, *parameters_for_method_reference)

		options = [ :action => @params["action"] ]

		html_options = { :onclick => javascript+"return false" }

		link_to(name, options, html_options, *parameters_for_method_reference)

	end

PNG-24 Alpha support for IE

Seb (Sébastien Grosjean) — Tue, 04 Apr 2006 02:03:26 GMT

What so much webdesigners dream about!
Get alpha channel on web, that's possible with PNG-24 images and this trick.
BE CAREFUL: that seem to work only for 10 images per page.



  # Display PNG-24 images with alpha channel on IE

  # BE CAREFUL: with this trick, only 10 PNGs seems to be supported by IE

  # Don't forget to set the size of your div

  def transpng(id, png)

    '

    '

  end

Using helpers inside a controller

Namor () — Wed, 29 Mar 2006 11:16:53 GMT

Ripped from
http://gabriel.gironda.org/articles/2006/02/08/using-helpers-inside-a-controller

This is incredibly straightforward and more of an occasional convenience, but I thought I'd throw it out there anyway. You may find that sometimes, even though the controller obviously isn't the view, that you want to use some of the helper methods available.

The only case I've come across so far is wanting to use pluralize() in a flash message and not have to do it by hand using the inflector. You could include ActionView::Helpers::TextHelper in the controller, but that fills your namespace with crap.

Put this in the class ApplicationController instead:



  def help

    Helper.instance

  end



  class Helper

    include Singleton

    include ActionView::Helpers::TextHelper

  end

Then you can just use it like so:



  def check_for_max_donkeys

    if Donkey.find_fit_donkeys.size == APP_SETTINGS['max_fit_donkeys']

      flash_error "The maximum of #{help.pluralize(APP_SETTINGS['max_fit_donkeys'], 'donkey')} has been reached."

      redirect_to_index

    end

  end

Update: Don't use the method name "helper" because Rails already uses that. Just "help" works fine.

Alternative zebra stripes approach using a helper

davidnorth (David North) — Wed, 22 Jun 2005 18:38:04 GMT

This is a tidy way of alternating classes on some element.

In the view:

In your application helper:



def alternate(str1 = "odd", str2 = "even")

   @alternate_odd_even_state = true if @alternate_odd_even_state.nil?

   @alternate_odd_even_state = !@alternate_odd_even_state

   @alternate_odd_even_state ? str2 : str1

end

Custom captures

mdaines (Michael Daines) — Fri, 17 Jun 2005 09:18:27 GMT

I made a layout with some slightly ugly code for making rounded boxes with CSS and HTML, and wanted a way to automate the boxes. I had thought of having two functions to print starting and ending code, but this seems nicer.

This goes with the other application helpers:



  def rounded_box(&block)

    concat '
' + capture(&block) + '
', block.binding

  end

This goes in a view:



<% rounded_box do %>



... stuff to put in the rounded box ...



<% end %>