{% show_simple_captcha_tag %}

Showing simple captcha in liquid template

	module Liquid
	module Tags
	module SimpleCaptcha
	class HumanTest < ::Liquid::Tag
	include ::ActionView::Helpers::FormTagHelper
	include ::SimpleCaptcha::ViewHelper

	attr_accessor :request, :session

	def render(context)
	controller = context.registers[:controller]
	self.request = controller.request
	self.session = controller.session
	context.registers[:controller].send(:render_to_string, :partial => ::SimpleCaptcha.partial_path, :locals => { :registers => context.registers, :simple_captcha_options => simple_captcha_options({}) })
	end
	end
	end

	::Liquid::Template.register_tag('show_simple_captcha_tag', SimpleCaptcha::HumanTest)
	end
	end

view raw

simple_captcha.rb

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activerecord GROUPed BY in batches

We are all familiar with activerecord .find_in_batches. The main idea behind it is not allowing to load thousands of ActiveRecord objects in memory which would cause tear down the server. I looked at this method and I looked at `.group` which applies GROUP BY clause. Just for fun, I thought what if I receive these “grouped_by” data in batches, something like

 scope.grouped_by_in_batches(group_by_column) do |batch, value|
  batch is an array same as we get in case of `find_in_batches`
  value is the grouped value of the column
 end

Hence I worked on this idea, made a pull request which obliviously did not work, as this was not a common use case, thats all fine. I agree to it. Even I never got to use it till date. However in attempt to do so, I really enjoyed writing test cases for it, getting interacted with a couple of ruby/rails expertise. Feeling happy about it.

rspec STDOUT

I happened to write some rspec for one ruby program which was accepting some input text in some form, and then it was expected to print the output to the console, or perhaps I did not want to separate the logic of printing. Anyways, that made me expect rspec should check the console output of my program, and after some googling(thanks to many rubyist) I got to work the following

	require 'spec_helper'

	describe "Transaction" do
	it "should handle dummy numerals" do
	transaction_input(%{
	x1 is I
	x5 is V
	x10 is X
	x50 is L
	x100 is C
	x500 is D
	x1000 is M
	how much is x1000 x100 ?
	how much is x1 x1 ?
	how much is x1 x5 ?
	}
	).should_output(%{
	x1000 x100 is 1100
	x1 x1 is 2
	x1 x5 is 4
	})
	end
	end

view raw

transaction_spec.rb

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Wow, I liked it.

And the spec_helper made it for me

	require "#{File.dirname(__FILE__)}/../lib/transactions.rb"
	include Transactions

	def capture_stdout(&block)
	original_stdout = $stdout
	$stdout = fake = StringIO.new
	begin
	yield
	ensure
	$stdout = original_stdout
	end
	fake.string
	end

	class TransactionInput
	def initialize output
	@output = output
	end

	def should_output output
	@output.split("\n").should == output.split("\n")[1..-2].collect{\|line\| line.strip}
	end
	end

	def transaction_input input
	TransactionInput.new capture_stdout{ input.split("\n")[1..-2].each{\|line\| Message.new(line).process} }
	end

view raw

spec_helper.rb

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Writing Code For Others

Highlight changes being made on ActiveRecord object inside email

I simply needed one helper method which would help me highlight changes being made on any ActiveRecord object inside email. Below is one example of that I have come up with and would like to extend it in my future projects too.

It gave me some insights into ActiveRecord::Base#previous_changes and ActiveRecord::Base#reflections. Nice to learn such ActiveRecord features.

samg/diffy also helped me out decorating text changes

Adding to my MailerHelper

	module MailerHelper
	def highligh_changes_made_to object, options={}
	html = ""
	attrs = options[:attrs] \|\| object.class.attribute_names
	html << "<br/><p>"

	attrs.each do \|attr\|
	html << "<p> #{attr.to_s.humanize} : "

	if object.previous_changes.include? attr.to_s
	if object.class.columns_hash[attr.to_s].type==:text
	html << "<br/>"
	html << text_changes(object.previous_changes[attr.to_s][0], object.previous_changes[attr.to_s][1])

	else
	html << "<font color='gray'>#{object_attr object, attr, object.previous_changes[attr.to_s][0]}</font> => "
	html << "<b>#{object_attr object, attr, object.previous_changes[attr.to_s][1]}</b>"
	end

	else
	html << "#{object_attr object, attr, (object.send attr.to_sym)}"
	end

	html << "</p>"
	end
	html << "<p/><br/>"
	html.html_safe
	end

	def object_attr object, attr, foreign_key_value
	return foreign_key_value unless attr.ends_with? "_id"

	assoc = object.class.reflections.values.select{ \|assoc\| assoc.foreign_key==attr }.first
	return "<NotFound>" unless assoc

	assoc.klass.where(:id => foreign_key_value).first \|\| '""'
	end

	def text_changes str1, str2
	Diffy::Diff.new( str1, str2).collect do \|line\|
	case line
	when /^\+/ then
	"<b>#{line[1..-1]}</b>"

	when /^-/ then
	"<font color='gray'>#{line[1..-1]}</font>"

	when /^\// then

	else
	line

	end
	end.join("<br/>").to_s
	end
	end

	class ActionMailer::Base
	helper MailerHelper
	end

view raw

mailer_helper.rb

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My rails mailer knows request and current_user

How about accessing @request and @current_user in your mailer

	# config/initializers/mailer_knows.rb

	module MailerBefore
	def before(hash)
	hash.keys.each do \|key\|
	define_method key.to_sym do
	eval " @#{key} = hash[key] "
	end
	end
	end
	end

	class ActionMailer::Base
	extend MailerBefore
	end

	class ActionController::Base
	before_filter :mailer_knows
	def mailer_knows
	ActionMailer::Base.before({
	:request => request,
	:current_user => (current_user and current_user.dup)
	})
	end
	end

view raw

mailer_knows.rb

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a quick javascript lightbox

I had to develop some feature which required some javascript lightbox,
I really not needed a fancy one, but a small or medium one
it was for some small confirmation and in addition a couple of inputs on confirmation
so you can imagine a small html form being poped up
I had to add one then, and I guessed tomorrow there might be couple of more coming

I found very nice options when googled
but I thought of implementing one of my own just for fun, and I got this a quick one

admin.lightbox.show(
  html: "my html goes here"
  title: "my title"
).done(->
  alert "Am done"

And it really took a very less time to build this one as follows

view raw

admin.lightbox.js.coffee

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The most interesting part here is to be able to define callbacks like done and cancel.

view raw

admin.lightbox.css.scss

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And I welcome all suggestions :)

smallest thread pool in ruby

	class ThreadPool
	attr_accessor :threads, :max_size

	def initialize max_size=4
	@max_size = max_size
	@threads = []
	end

	def start *args, &block
	while(threads.count>=max_size) do
	threads.select!{ \|thr\| !thr.stop? }
	sleep(0.1)
	end

	threads << Thread.new(args) do \|args\|
	begin
	args = args[0] if args.length==1
	yield args

	rescue Exception => e
	puts e.message
	puts e.backtrace

	end
	end
	end

	def join
	threads.map(&:join)
	end
	end


	# p = ThreadPool.new

	# 1.upto(10) do \|i\|
	# p.start(i) do \|a\|
	# $stdout.flush
	# puts "p #{a}"
	# end
	# end
	# p.join

view raw

thread_pool.rb

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activeadmin cool tweaks

tweak 1: Make some column quick-editable on the index list page

Ok… so I want to be quickly able to edit few names, here on the same list page, something like below

Thats simply great!

Now it makes me quickly update any name there itself on the list page, <enter> will make it, <escape> will ignore it, and <tab> will move to the next one. awesome.

And to make it work I just need to have one line of code change

All I need to say is `editable_test_column`, and its done.

	ActiveAdmin.register Article do
	index do
	selectable_column
	id_column
	column :name, :sortable => :name do \|resource\|
	editable_text_column resource, :name
	end
	column :article_type
	column :created_at
	column :updated_at
	default_actions
	end
	end

view raw

article.rb

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And here how it works, you will need to define a couple of things

You need to define editable_text_column, this you could place inside app/admin/lib/

	module ActiveAdmin
	module Views
	class IndexAsTable < ActiveAdmin::Component
	def editable_text_column resource, attr
	val = resource.send(attr)
	val = " " if val.blank?

	html = %{
	<div id='editable_text_column_#{resource.id}'
	class='editable_text_column'
	ondblclick='admin.editable_text_column_do(this)' >
	#{val}
	</div>

	<input

	data-path='#{resource.class.name.tableize}'
	data-attr='#{attr}'
	data-resource-id='#{resource.id}'
	class='editable_text_column admin-editable'
	id='editable_text_column_#{resource.id}'

	style='display:none;' />
	}
	html.html_safe
	end

view raw

custom_columns.rb

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Then you will need to add some javascript …


	var admin = {

	init: function(){
	admin.set_admin_editable_events();
	},

	set_admin_editable_events: function(){
	$(".admin-editable").live("keypress", function(e){
	if ( e.keyCode==27 )
	$( e.currentTarget ).hide();

	if ( e.keyCode==13 ){
	var path = $( e.currentTarget ).attr("data-path");
	var attr = $( e.currentTarget ).attr("data-attr");
	var resource_id = $( e.currentTarget ).attr("data-resource-id");
	var val = $( e.currentTarget ).val();

	val = $.trim(val)
	if (val.length==0)
	val = " ";

	$("div#"+$( e.currentTarget ).attr("id")).html(val);
	$( e.currentTarget ).hide();

	var payload = {}
	resource_class = path.slice(0,-1) // e.g. path = meters, resource_class = meter
	payload[resource_class] = {};
	payload[resource_class][attr] = val;

	$.put("/admin/"+path+"/"+resource_id, payload).done(function(result){
	console.log(result);
	});
	}
	});

	$(".admin-editable").live("blur", function(e){
	$( e.currentTarget ).hide();
	});
	},

	editable_text_column_do: function(el){
	var input = "input#"+$(el).attr("id")

	$(input).width( $(el).width()+4 ).height( $(el).height()+4 );
	$(input).css({top: ( $(el).offset().top-2 ), left: ( $(el).offset().left-2 ), position:'absolute'});

	val = $.trim( $(el).html() );
	if (val==" ")
	val = "";

	$(input).val( val );
	$(input).show();
	$(input).focus();
	}
	}

	$( document ).ready(function() {
	admin.init();
	});

view raw

active_admin.js

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and some css stuff


	input.editable_text_column {
	background-color: #FBFF8C;
	border: 1px none #FBFF8C;
	box-shadow: 0 2px 19px #AAAAAA;
	color: black;
	display: none;
	font-family: serif;
	font-size: 1em;
	font-style: italic;
	height: 30px;
	position: absolute;
	text-align: center;
	vertical-align: middle;
	width: 180px;
	z-index: 9090;
	}

	div.editable_text_column{
	padding:4px;
	background-color: #f9fbc2;
	}

view raw

active_admin.css.scss

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Thats it.

Next, I would love to quickly alter article type say having a dropdown there to save my time

tweak 2: quick editable dropdowns on list page

Ohh, now this is again great! … no? It actually updates the article type on value change. nice.

Let see the code behind

	ActiveAdmin.register Article do
	index do
	selectable_column
	id_column
	column :name, :sortable => :name do \|resource\|
	editable_text_column resource, :name
	end
	column 'Type', :sortable => :article_type do \|resource\|
	column_select(resource, :article_type, ["News", "Story", "Case Study", "Business"])
	end
	column :created_at
	column :updated_at
	default_actions
	end
	end

view raw

article.rb

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and to define `column_select`

	module ActiveAdmin
	module Views
	class IndexAsTable < ActiveAdmin::Component
	include CustomHelper

	def column_select resource, attr, list
	val = resource.send(attr)

	html = _select list, val, { "attrs" => %{
	data-path='#{resource.class.name.tableize}'
	data-attr='#{attr}'
	data-resource-id='#{resource.id}'
	class='admin-selectable'
	}
	}
	html.html_safe
	end

view raw

custom_columns.rb

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CustomHelper is one of my helper modules that really helps me render dropdown the way I need, and provides me some nice options, one may choose to use the default rails select helpers

	module CustomHelper
	def _select set, selected, options={}
	style = "margin:0;padding:0;#{options["style"]}"

	selected = options["default"] if selected.blank?
	cache = options["cache"] \|\| nil
	id = options["id"] \|\| nil

	id \|\|= "ch#{ch_uniq_id}" unless cache.blank?

	html = ""
	html << "<select "
	html << " style='#{style}' "
	html << " #{options["attrs"]} "
	html << " data-cache='#{cache}' " unless cache.blank?
	html << " id='#{id}' " unless id.blank?
	html << ">"

	if options["blank"]
	html << "<option></option>"
	end

	unless cache.blank?
	options_html = Rails.cache.fetch("CustomHelper:#{cache}", expires_in: 1.minute ) { _select_options set, selected, options }
	else
	options_html = _select_options set, selected, options
	end

	html << options_html
	html << "</select>"

	unless cache.blank?
	html << %{
	<script type="text/javascript">
	$( document ).ready(function() {
	$("select##{id}").val("#{selected.to_s.strip}");
	});
	</script>
	}
	end

	html
	end

	def _select_options set, selected, options
	html = ""
	selected = selected.to_s.strip
	arr_match = options["arr_match"] \|\| 0

	set.each do \|option\|
	check = option
	value = option

	if option.is_a? Array
	check = option[arr_match]
	value = option[0]
	option = option[1]
	end

	if selected==check.to_s.strip
	html << "<option value='#{value}' selected>#{option}</option>"
	else
	html << "<option value='#{value}'>#{option}</option>"
	end
	end

	html
	end

	def ch_uniq_id
	@ch_uniq_id \|\|= Time.now.to_i
	@ch_uniq_id += 1
	end
	end

view raw

custom_helper.rb

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Then you need some javascript


	var admin = {

	init: function(){
	admin.set_admin_selectable_events();
	},

	set_admin_selectable_events: function(){
	$("select.admin-selectable").live("change", function(e){
	var path = $( e.currentTarget ).attr("data-path");
	var attr = $( e.currentTarget ).attr("data-attr");
	var resource_id = $( e.currentTarget ).attr("data-resource-id");
	var val = $( e.currentTarget ).val();

	val = $.trim(val)

	var payload = {}
	resource_class = path.slice(0,-1)
	payload[resource_class] = {};
	payload[resource_class][attr] = val;

	$.put("/admin/"+path+"/"+resource_id, payload).done(function(result){
	console.log(result);
	});
	});
	}
	}

	$( document ).ready(function() {
	admin.init();
	});

view raw

active_admin.js

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done.

I do have worked out several more tweaks like toggle button for boolean column, show/hide columns on the list page, auto-populate/suggest feature for string filters, one can make use ActiveAdmin icons too, then for one of my requirements I have set up the whole custom header and a dozens of custom pages. I would easily say that ActiveAdmin is just simple and awesome, one can really customize it to the extreme, the code structure will allow you to imagine and implement a number of custom scenarios.

rails user modifies email

I often thought of this, application user is actually modifying the email contents before mail gets delivered. And I just set one example of it

	# gem 'ckeditor_rails' # from https://github.com/tsechingho/ckeditor-rails

	# allow modifying existing template
	<textarea name="modified_email" class="ckeditor">
	<%= File.read "#{Rails.root.to_s}/app/views/user_mailer/do_email.html.erb"%>
	</textarea>

	<%= javascript_include_tag "ckeditor-jquery" %>
	<script type="text/javascript">
	$('.ckeditor').ckeditor({
	height: "800px",
	allowedContent: true,
	toolbar: [
	{ name: 'document', items : [ 'Source', '-', 'Undo','Redo', '-','SpellChecker'] },
	{ name: 'basicstyles', items : [ '-', 'Bold','Italic','Underline'] },
	{ name: 'colors', items : [ '-', 'TextColor','BGColor' ] },
	{ name: 'styles', items : [ '-', 'Styles','Format','Font','FontSize' ] },
	{ name: 'tools', items : [ '-', 'Maximize' ] }
	]
	});

	setTimeout(function(){
	$("a.cke_button").attr("style", "padding:8px;");
	$(".cke_chrome").attr("style", "width: 76% !important; overflow: hidden;");
	}, 500);
	</script>

	# in your mailer

	def do_email modified_contents
	body = ActionView::Base.new.render :inline => CGI.unescapeHTML(modified_contents), :locals => { :token => token }
	# you can have assigns as well

	mail :to => recipients,
	:subject => "Do Email",
	:content_type => "text/html",
	:body => body
	end

view raw

modify_emails.html.erb

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	window.admin \|\|= {}
	$.extend window.admin,

	lightbox:
	show: (options) ->
	options = {} unless options
	buttonDone = options.buttonDone or "Done"
	buttonCancel = options.buttonCancel or "Cancel"
	focus = options.focus or "input"

	$("body").append "<div id='modal_shadow'></div>" unless $("div#modal_shadow")[0]

	$("body").append "<div id='admin-lightbox'></div>" unless $("div#admin-lightbox")[0]

	$("div#admin-lightbox").html "<div id='content'>" + options.html + "</div><div id='buttons'></div>"

	$("div#admin-lightbox div#buttons").append "<button onclick='admin.lightbox.do_done(); return false;'>" + buttonDone + "</button>"
	$("div#admin-lightbox div#buttons").append "<button onclick='admin.lightbox.do_cancel(); return false;'>" + buttonCancel + "</button>"

	$("div#admin-lightbox").prepend "<div id='title'>" + options.title + "</div>" if options.title

	$("div#modal_shadow").show()
	$("div#admin-lightbox").show()

	$($("div#admin-lightbox " + focus)[0]).focus()

	admin.lightbox

	callback_done: null
	done: (callback) ->
	admin.lightbox.callback_done = callback
	admin.lightbox
	do_done: ->
	try
	admin.lightbox.callback_done()
	admin.lightbox.hide()
	false

	callback_cancel: null
	cancel: (callback) ->
	admin.lightbox.callback_cancel = callback
	admin.lightbox
	do_cancel: ->
	try
	admin.lightbox.callback_cancel()
	admin.lightbox.hide()
	false

	hide: ->
	$("div#modal_shadow").hide()
	$("div#admin-lightbox").hide()
	admin.lightbox

	body.active_admin #modal_shadow{
	z-index: 999998;
	position:fixed;
	top: 0px; left: 0px;
	height:100%; width: 100%;
	background:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVQIW2NsampKAwAFAgHu04pC4AAAAABJRU5ErkJggg==) repeat;
	display:none;
	padding: 0; margin: 0;
	}

	body.active_admin #admin-layout{
	padding:10px;
	margin:10px;
	top: 100px;
	min-height:100px;min-width:200px;

	display:none;
	background-color:white;
	z-index:999999;

	-webkit-border-radius: 5px;
	-moz-border-radius: 5px;
	border-radius: 5px;

	box-shadow: 0px 5px 19px #777;
	-o-box-shadow: 0px 5px 19px #777;
	-webkit-box-shadow: 0px 5px 19px #777;
	-moz-box-shadow: 0px 5px 19px #777;

	position:fixed;
	top: 50%;
	left: 50%;
	margin-left: -200px;
	margin-top: -150px;
	}

	body.active_admin #admin-layout #title{
	padding:2px 5px;
	background-color: #efefef;
	font-weight: bold;
	color:#555;
	font-size: 1.1em;
	margin-bottom: 10px;

	-webkit-border-top-left-radius: 5px;
	-webkit-border-top-right-radius: 5px;
	-moz-border-radius-topleft: 5px;
	-moz-border-radius-topright: 5px;
	border-top-left-radius: 5px;
	border-top-right-radius: 5px;

	}

	body.active_admin #admin-layout #content{
	float:left;
	margin-bottom:10px;
	}

	body.active_admin #admin-layout #buttons{
	height:42px;
	width:96.5%;
	padding:5px;
	float:right;
	background-color: #efefef;
	float:right;

	border-bottom: 1px solid #eee;
	border-left: 1px solid #eee;
	border-right: 1px solid #eee;

	-webkit-border-bottom-right-radius: 5px;
	-webkit-border-bottom-left-radius: 5px;
	-moz-border-radius-bottomright: 5px;
	-moz-border-radius-bottomleft: 5px;
	border-bottom-right-radius: 5px;
	border-bottom-left-radius: 5px;

	}

	body.active_admin #admin-layout #buttons button{
	margin:8px;
	padding:8px;
	padding-top:6px;
	padding-bottom:6px;
	float:right;
	font-weight: bold;
	color:#555;
	font-size: 1.0em;

	}

keep it simple and standardized

amolnpujari

Menu

{% show_simple_captcha_tag %}

activerecord GROUPed BY in batches

rspec STDOUT

Writing Code For Others

Highlight changes being made on ActiveRecord object inside email

My rails mailer knows request and current_user

smallest thread pool in ruby

activeadmin cool tweaks

tweak 1: Make some column quick-editable on the index list page

tweak 2: quick editable dropdowns on list page

rails user modifies email

Menu

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tweak 1: Make some column quick-editable on the index list page

tweak 2: quick editable dropdowns on list page

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