Upload Image using CKeditor - Rails

Hello Guys,

   Today i've configure CKeditor (https://github.com/galetahub/ckeditor) to my Rails application and i found there is no upload button along with Image insert dialog.
So i've modified the ckeditor/config.js to below and it then show new tab called 'Upload' in Image insert dialog.

See. config.js

CKEDITOR.editorConfig = function (config) {

  // ... other configuration ...
  config.language = 'en';
  config.toolbar_regular = [
    { name: 'document', items: ['Source'] },
    { name: 'clipboard', groups: [ 'clipboard', 'undo' ], items: [ 'Cut', 'Copy', 'Paste', 'PasteText', 'PasteFromWord', '-', 'Undo', 'Redo' ] },
    { name: 'basicstyles', groups: [ 'basicstyles', 'cleanup' ], items: [ 'Bold', 'Italic', 'Underline', 'Strike', 'Subscript', 'Superscript', '-', 'RemoveFormat' ] },
    '/',
    { name: 'paragraph', groups: [ 'list', 'indent', 'blocks', 'align', 'bidi' ], items: [ 'NumberedList', 'BulletedList', '-', 'Outdent', 'Indent', '-', 'Blockquote', 'CreateDiv', '-', 'JustifyLeft', 'JustifyCenter', 'JustifyRight', 'JustifyBlock' ] },
    { name: 'links', items: [ 'Link', 'Unlink', 'Anchor' ] },
    { name: 'insert', items: ['Table', 'Image', 'HorizontalRule', 'SpecialChar' ] },
    '/',
    { name: 'styles', items: [ 'Styles', 'Format', 'Font', 'FontSize' ] },
    { name: 'colors', items: [ 'TextColor', 'BGColor' ] },
    { name: 'tools', items: [ 'Maximize'] },
    { name: 'plugins', items: ['CodeSnippet', 'Cite'] }
  ];
  config.toolbar_lite = config.toolbar_regular.concat({ name: "lite", items: ["lite_ToggleShow", "lite_AcceptAll", "lite_RejectAll"] });
    config.toolbar = 'regular';
  config.allowedContent = true;
   /* Filebrowser routes */
  // The location of an external file browser, that should be launched when "Browse Server" button is pressed.
  config.filebrowserBrowseUrl = "/ckeditor/attachment_files";
  // The location of an external file browser, that should be launched when "Browse Server" button is pressed in the Flash dialog.
  config.filebrowserFlashBrowseUrl = "/ckeditor/attachment_files";
  // The location of a script that handles file uploads in the Flash dialog.
  config.filebrowserFlashUploadUrl = "/ckeditor/attachment_files";
  // The location of an external file browser, that should be launched when "Browse Server" button is pressed in the Link tab of Image dialog.
  config.filebrowserImageBrowseLinkUrl = "/ckeditor/pictures";
  // The location of an external file browser, that should be launched when "Browse Server" button is pressed in the Image dialog.
  config.filebrowserImageBrowseUrl = "/ckeditor/pictures";
  // The location of a script that handles file uploads in the Image dialog.
  config.filebrowserImageUploadUrl = "/ckeditor/pictures";
  // The location of a script that handles file uploads.
  config.filebrowserUploadUrl = "/ckeditor/attachment_files";
  // Rails CSRF token
  config.filebrowserParams = function(){
    var csrf_token, csrf_param, meta,
        metas = document.getElementsByTagName('meta'),
        params = new Object();
    for ( var i = 0 ; i < metas.length ; i++ ){
      meta = metas[i];
      switch(meta.name) {
        case "csrf-token":
          csrf_token = meta.content;
          break;
        case "csrf-param":
          csrf_param = meta.content;
          break;
        default:
          continue;
      }
    }
    if (csrf_param !== undefined && csrf_token !== undefined) {
      params[csrf_param] = csrf_token;
    }
    return params;
  };
  config.addQueryString = function( url, params ){
    var queryString = [];
    if ( !params ) {
      return url;
    } else {
      for ( var i in params )
        queryString.push( i + "=" + encodeURIComponent( params[ i ] ) );
    }
    return url + ( ( url.indexOf( "?" ) != -1 ) ? "&" : "?" ) + queryString.join( "&" );
  };
  // Integrate Rails CSRF token into file upload dialogs (link, image, attachment and flash)
  CKEDITOR.on( 'dialogDefinition', function( ev ){
    // Take the dialog name and its definition from the event data.
    var dialogName = ev.data.name;
    var dialogDefinition = ev.data.definition;
    var content, upload;
    if (CKEDITOR.tools.indexOf(['link', 'image', 'attachment', 'flash'], dialogName) > -1) {
      content = (dialogDefinition.getContents('Upload') || dialogDefinition.getContents('upload'));
      upload = (content == null ? null : content.get('upload'));
      if (upload && upload.filebrowser && upload.filebrowser['params'] === undefined) {
        upload.filebrowser['params'] = config.filebrowserParams();
        upload.action = config.addQueryString(upload.action, upload.filebrowser['params']);
      }
    }
  });
};

Hope this article helps you.

Unlock ReadOnly Model Object

Phasing some interesting problem after creating record for model which has HasMany relationship.

I have class say 'Category' & 'CategoryOptions'.

Category Has Many CategoryOptions

When i create record for CategoryOption using below syntax it locks the newly created object.

category = Category.first

category_option = category.category_options.create(params[:category_option])

If i do 

category_option.readonly?

=> true

Now i'm trying to update category_option using

category_option.update_attributes(params[:category_option])

but it raises Exception like 

ActiveRecord::ReadOnlyRecord

To remove readonly lock from object use below method

category_option.send(:instance_variable_set, :@readonly, false)

Now try

category_option.readonly?

=> false

category_option.update_attributes(params[:category_option]) works perfectly.

Hope this article will help you to remove Readonly lock from Model Object.

Install WKHTMLTOPDF

Hello Guys,

        Here i'm providing steps to install Wkhtmltopdf.

1. Download WKHTMLTOPDF source from http://wkhtmltopdf.org/downloads.html

2. Dobule click on downloaded source.

3. Go to terminal and type : which wkhtmltopdf. That gives you path like below.   /usr/local/bin/wkhtmltopdf4. wkhtmltopdf --version : gives you version no of installed wkhtmltopdf.

Delayed job to use specific connection via ruby

Hello Guys,
           Yesterday  i was phasing one interesting problem. Sharing single database between 2 rails application but now i've requirement to use application specific table for delayed jobs.

Lets assume i've application called DemoApp & TestApp. And both sharing single DB called 'demo_app_prod'. Now for TestApp i required separate DB called 'test_app_prod' which has single table called 'delayed_jobs'.

Step1:

at TestApp you have database.yaml like
 login: &login
  adapter: mysql
  username: admin
  host: localhost  
  password:
 
development:
  <<: *login
  database: demo_app_dev

test:
  <<: *login
  database: demo_app_test
 
production:
  <<: *login
  database: demo_app_prod  

staging:
  <<: *login
  database: test_app_prod

Step2:
at TestApp added migration called 
   rails generate migration add_delayed_job

  class AddDelayedJob < ActiveRecord::Migration
  def connection
    ActiveRecord::Base.establish_connection(Rails.env).connection
  end
 
  def up
    oldEnv = Rails.env
    Rails.env = 'staging' #set environment variable from your database.yml
    ActiveRecord::Base.establish_connection(Rails.env)   
    create_table :delayed_jobs, :force => true do |table|
      table.integer  :priority, :default => 0 
      table.integer  :attempts, :default => 0  
      table.text     :handler                      
      table.text     :last_error                  
      table.datetime :run_at                       
      table.datetime :locked_at                    
      table.datetime :failed_at                    
      table.string   :locked_by          
      table.timestamps
    end
    Rails.env = oldEnv
    ActiveRecord::Base.establish_connection ActiveRecord::Base.configurations[Rails.env]
  end
 
  def down   
    oldEnv = Rails.env
    Rails.env = 'staging'
    ActiveRecord::Base.establish_connection(Rails.env).connection
    drop_table :delayed_jobs
    Rails.env = oldEnv
    ActiveRecord::Base.establish_connection ActiveRecord::Base.configurations[Rails.env]
  end
end

Step3:

 In initializers/delayed_job.rb add below lines

Delayed::Job.class_eval do
  establish_connection ActiveRecord::Base.configurations["local"]
end

This the easy way to establish multiple db connection via ruby for delayed job.

Rebuild the corrupted legacy data.

Hello Guys,
        Yesterday i phase one problem regarding positioning with legacy database. For my rails application i have used the awesome_nested_set to manage nesting/threading. Case is to rearrange the position and for that i have used pretty nice method called 'rebuild!'.

Assume i have model called 'Post' and have nesting per Category .

# id: integer
# category_id: integer
# lft :integer
# parent_id :integer
# position :integer
# rgt :integer
class Post < ActiveRecord::Base
  acts_as_nested_set :scope => :category
end

In the legacy database, having 3 categories called 'Alpha', 'Beta', 'Gama'. In which category Alpha's data mess out.
To over come this problem invoke command on console.
> script/console
> category = Category.find_by_name('Alpha')
> category.posts.rebuild!

Now cross check the data and it results as per need. Hope this post is helpful to you guys. Cheers!!

Preventing Recursive Method Calls in Salesforce

Hello Guys,

        Yesterday i was playing with salesforce custom object. I had task to update the object once particular field get updated /inserted (for same object). 

Eg. I have Student__c is custom object on salesforce.

Structure of Student__c object is like:

Id, Name__c, Score_in_maths__c, Score_in_science__c, Total_score__c

So when trying to update any score value required to update Total_score__c  accordingly.  To fulfill  this i have added trigger on Student__c (after update) but it results as recursive loop.

To overcome above issue just followed the steps mention in http://blog.jeffdouglas.com/2009/10/02/preventing-recursive-future-method-calls-in-salesforce/. And it works for me.

Free feel to leave comment or ask queries. :)

Generate chart using axlsx gem

Hello Rubies,

        I have generated the graph via axlsx gem of ruby. Follow the easy steps to generate 3D stacked bar graph.

Install axlsx gem via

   gem install axlsx

Lets, generate graph.rb file and than run ruby graph.rb

require "rubygems"

require "axlsx"

 p = Axlsx::Package.new
 wb = p.workbook

 wb.styles do |s|

    wb.add_worksheet(:name => "Bar graph demo") do |sheet|

        sheet.add_row ["A Simple Bar Chart"]

        sheet.add_chart(Axlsx::Bar3DChart, :start_at => "A1", :end_at => "F27", :grouping => :stacked, :show_legend => false, :shape => :box, :barDir => :col) do |chart|
         chart.valAxis.title = "Volumes"
         chart.catAxis.title = "Periods"
         chart.add_series :data => [1,2,3], :labels => ['Mar', 'Apr','May'], :colors => ['92D050', '92D050', '92D050']
         chart.add_series :data => [4,2,6], :labels => ['Mar', 'Apr', 'May'], :colors => ['FFFF00', 'FFFF00','FFFF00']

       end

   end  

end

file = File.open('/home/Desktop/graph.xlsx', 'w')
p.serialize(file)

Lets invoke ruby graph.rb on console and get the stacked bar chart.

Axlsx to support line break (\n)

Hello Rubies,
      Yesterday when i was playing with axlsx gem find something interesting. Requirement is need to allow line break in content. And current axlsx gem does not support that feature. So add this patch to your existing gem or either point directly to git repository b'coze that patch is unpublished as for now.

Add this line to axlsx1.2.3/lib/axlsx/workbook/worksheet/worksheet.rb

Remove line #500  

str.gsub(/[[:cntrl:]]/,'')

and Replace with

  if RUBY_VERSION == "1.8.7"
    nasty_control_char_matcher = Regexp.new("[\x01\x02\x03\x04\x05\x06\x07\x08\x1F\v\xE2]")
  else
    nasty_control_char_matcher = Regexp.new("[\x01\x02\x03\x04\x05\x06\x07\x08\x1F\v\u2028]")
  end

  str.gsub(nasty_control_char_matcher,'')

or

gem 'axlsx', '1.2.3', :git => 'git://github.com/randym/axlsx.git'

Hope this post is useful to you folks :).

Replace double space with in javascript

Hello Guys,

        Last time when i was playing with double spaces.. found the interesting thing. When passing the double space string from javascript (view) to controller , it converts the valid space to non-breaking space.

Lets see the eg.

View: index.rhtml

a = "This  is the pen"

a.gsub("  ", "&nbsp;&nsbsp;")

<script language='javascript/text'>

 

  /* Now assign the value to input element by */

  $('txtid').value = <%= a %>;

 // Get value back encodeURIComponent($('txtid'))

</script>
 

at controller

def any_method

   # replace '\xC2\xA0' or '&nbsp;' with ' '

   params[:a].gsub("\xC2\xA0", " ").gsub("&nbsp;", " ")

end

Hope above article is helpful to you guys.

For more info follow: http://www.javascripter.net/faq/mathsymbols.htm

http://erisds.co.uk/code/getting-rid-of-non-breaking-spaces-nbsp

Arbitrary precision decimal floating-point type for Ruby

Hello Rubies,

           Accurately convert numbers  to decimal or exact precision point. Use the Flt gem do discover the below scenario. 

Flt::DecNum is a standards-compliant arbitrary precision decimal floating-point type for Ruby. It is based on the Python Decimal class. 

Usage:

sudo gem install flt

require 'flt'

include Flt

 

x = 0.00000020586

y = Flt::DecNum(x.to_s)

Flt::DecNum.context.precision = 2

puts y/Flt::DecNum(1)

result should be 2.1E-7

For more information just follow the http://flt.rubyforge.org/.

Generate Rss feed with rails application

  Hey guys,
      Lets today we create the rss feed with our existing rails application. Consider we have controller called post and have index method to show all the available posts. Now meanwhile we need to create feed for available posts as well.

controller:

def index
  @posts = Post.find(:all, :order => "created_at desc")
  respond_to do |format|
     format.html { render :template => 'posts/index.rhtml' }
     format.xml { render :template => 'posts/index.rxml', :layout => false
        headers["Content-Type"] = "application/rss+xml"
     }
  end
end

view:

index.rxml

xml.instruct!
xml.rss "version" => "2.0", "xmlns:dc" => "http://purl.org/dc/elements/1.1/" do
  xml.channel do
    xml.title 'Available Posts'
    xml.description h("Here is the posts ... blah blah")
   
    @posts.each do |post|
      xml.item do
        xml.title post.title
        xml.link url_for(:only_path => false,
          :controller => 'posts',
          :action => 'show',
          :fishery => post.id)
        xml.description post.description
        xml.pubDate CGI.rfc1123_date(post.created_at)
      end
    end
  end
end

index.rhtml

# Add auto discovery tag to access rss feed

<%= auto_discovery_link_tag :rss, {:controller => "posts", :action => "index"}%>

See your rss feed for posts is ready!! Whenever auto discovery tag found it enables the rss icon on browser. Keep in mind Either you have to use predefined xml node or need to create XSL template. You can also emend the stylesheet into XSL template.

Get the Date difference in days

Hello guys,

        Wanna to get the date difference in terms of days?

eg.

date_x = Time.now.to_date

date_y = Date.parse('2012-05-20')

passed_days = (date_x.to_date - date_y.to_date).to_i

passed_days should give the date difference in days.

Convert string to serialize hash

Hello Rubies,

        Do you phase the problem ? - sometime  when we are retrieving the serialized hash field from table we might get string as response. So in that case you can use one of the below solutions.

Eg. 

Model - User.rb

class User < ActiveRecord::Base

   serialize :content, Hash

end

convert string to serialize hash format by 

# get the one of the record from users table

user = User.first

either using

    user.content.to_yaml

or

    YAML.parse(user.content)

or

    YAML.load(user.content)

Ajax request via javascript

Hello Rubies,
      Have you tried AJAX request via javascript? Lets see the eg.

<script type="text/javascript">

  // Ajax without update parameter:
  function ajax_request(id){
    window._token = '<%= form_authenticity_token %>';
    var url = '/controller/action';
    var pars = 'id=' + id + '&authenticity_token=' + window._token;
    var myAjax = new Ajax.Request(url, {method: 'post', parameters: pars, onFailure: showFailure(), onSuccess: showSuccess() });
  }

  // Ajax with update parameter:
  function ajax_update_request(id){
    window._token = '<%= form_authenticity_token %>';
    var url = '/controller/action';
    var pars = 'id=' + id + '&authenticity_token=' + window._token;
    var myAjax = new Ajax.Updater('update_div_id', url, {method: 'get', parameters: pars, onFailure: showFailure(), onSuccess: showSuccess()});
  }

  function showSuccess(){
  }

  function showFailure(){
  }

</script>

rake jobs:work fails - delayed_job

 Hello Guys,

       Do you stuck with the problem to execute rake jobs:work during delayed_job implementation? than follow the below steps.

 Rake.rb

In your rails application's Rakefile add few lines.

begin
  gem 'delayed_job', '~>2.0.5'
  require 'delayed/tasks'

rescue LoadError
  STDERR.puts "rake gems:install` to install delayed_job"
end

Also if you want to use the script/delayed_job start command than add delayed_job under lib folder of rails application.

lib/delayed_job

#!/usr/bin/env ruby

require File.expand_path(File.join(File.dirname(__FILE__), '.', 'config', 'environment'))
require 'delayed/command'
Delayed::Command.new(ARGV).daemonize

Now, you do the rake -T to see that delayed_job task are also embed. Hope you will find useful support via this post.

Dygraph fails on IE 8

Hello Guys,
      Just discover the problem while loading dygraph on IE 8. There are possible scenarios for dygraph failure.

case 1. instanceof is not support
           replace instanceof with Object.prototype.toString.call()
           Line 500 of dygraph-utils.js replace
              typeof Node === "object" ? o instanceof Node :
           with
              typeof Node === "object" ? Object.prototype.toString.call(o) === Node :

case 2. canvas can't load

<!DOCTYPE html>
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9">
<!--[if IE]><script src="excanvas.js"></script><![endif]-->
<!--[if lt IE 9]><script language="javascript" type="text/javascript" src="http://mycheckpoint.googlecode.com/svn-history/r95/trunk/dygraphs/excanvas.min.js"></script><![endif]-->

Hope above article will help you.

Configure mailer with ruby

Hello Rubies,

    As we have to send the mail from rails application for that it requires to set the mailer configuration with rails.

First you have to install the package called 'sendmail'

sudo apt-get install sendmail

Now in environment.rb file of rails application set below code:

ActionMailer::Base.delivery_method = :sendmail

config.action_mailer.smtp_settings = {
  :address => "smtp.gmail.com",
  :port => 587,
  :domain => 'test.com',
  :authentication => :plain,
  :user_name => 'XYZ@gmail.com',
  :password => 'PWD' 
}

Hope this post will help you.

Number of days between two dates

Hello Rubies,

    Get the days between two dates using below method of ruby date class.

Lets consider we have date range like

date1 = Date.today.to_date

date2 = 1.year.ago.to_date

no_of_days = date1.mjd - date2.mjd

Hope this simple method of ruby date class will help you out to find days between to dates.

Combination of array element

Hello Guys,

    Want the combination of array elements using ruby? than use the below custom method.

def arr_combine(arr_1, arr_2)
    return arr_1 if arr_2.empty?
    arr_3 = []
    arr_1.each do |e1|
      arr_2.each do |e2|
        arr_3 << [e1, e2].flatten
      end
    end
    return arr_3
  end

eg. we have array like arr = [[1,2], [3,4,5]]

we expect the result as [[1,3],[1,4],[1,5],[2,3],[2,4],[2,5]] than simply invoke the above method by passing each element of given array.

arr_combine(arr[0], arr[1]) gives you required outcome.

Hope this post will help you out.

Duck Typing in Ruby

Hello Rubies,

       Ruby is an object oriented programing language. we don't declare the data type of variables or methods - everything is treated as object. Ruby supports feature called 'duck typing'. Duck typing more concern about what's the behavior of method and what methods can be called on it.

For eg.

We create the simple method to do the multiplication of two arguments. As in ruby we didn't define the data type. So it return the output of method in requested method format.

def calculate(a, b)

  return a * b

end

case a. 

   Pass integer as argument

   calculate(2, 3) => 6

case b.

   Pass string as argument

   calculate('Ruby on ', 'Rails') => Ruby on Rails

So as per argument type it return back the result in requested format. So this is the concept of duck typing. 

If we have to implement same functionality using java than it requires to define methods as per requested type. so when we invoke the method than it first match argument type than return the appropriate result. 

So now you know how cool is ruby than java ;)