Month: November 2012

How To Generate Barcode Using Barby Gem In Rails 2.3.8

Posted on by Jay

A barcode is a series of vertical black lines with white spaces in between. This series of lines and spaces can be read by a device that can decode them. This would be a barcode reader.

In Ruby on Rails there is a gem called “barby” which generates the barcode with various format.

Here is an example to create barcode using barby & Rails 2.3.8.

Step#1

Include the barby gems in your config/environment.rb file

config.gem'barby'
config.gem 'barby-chunky_png'
config.gem 'png''RubyInline'

Install the gems by running the commandrake gems:install. Restart the Rails server.

You might face problem to start the server after the gems installed.Comment out the gems “png” & “RubyInline” in the “config/environment.rb” to get the server started.

Step#2

Create a folder named “Barcodes” to store the barcode images in your “Public” folder.

Step#3

Add the below lines of code in your controller

require'barby'
'barby/outputter/png_outputter'

Step#4

The following method will generate the barcode images and store in the “/public/Barcodes” path. Place this method inside the controller.

The “symbology” is the format in which the barcode will be generated. Default is “Code128B”, If you want to generate in different format you can set the “symbology” according to it.

def generate_barcodes(data) # check to see if we don't already have this barcode image uri = CGI.escape(symbology) + '_' + CGI.escape(data) + '.jpg' fname = RAILS_ROOT + '/public/Barcodes/' + uri #fname = '/var/www/html/arc_cloud/arcdevelopment/' + uri
 
# if the barcode image doesn't already exist then generate and save it
if ! File.exists?(fname)
 
str = 'Barby::'+symbology+'.new("'+data+'")'
 
begin
barcode = eval str
rescue Exception => exc
barcode = Barby::Code128B.new(data) # fall back to Code128 type B
end
 
File.open(fname, 'w') do |f|
f.write barcode.to_jpg
end
 
end
uri
end

Step#5

Following lines of code will call to generate your dynamic barcode
generate_barcodes(@item_id)

Step#6

To show the Barcode images call the following lines of code

<img src="/Barcodes/<%= @job_info.job_number %>.jpg" >

How to shorten URL using “bitly.com” in Rails 3.x

Posted on by Jay

rorURL shortening is a technique on the World Wide Web (WWW) in which a Uniform Resource Locator (URL) may be made substantially shorter in length and still direct to the required page.

This is achieved by using an HTTP Redirect on a domain name that is short, which links to the web page that has a long URL. This is especially convenient for messaging technologies such as Twitter and Identical which severely limit the number of characters that may be used in a message.

Many web developers pass descriptive attributes in the URL to represent data hierarchies, command structures, transaction paths or session information. This can result in URLs that are hundreds of characters long and that contain complex character patterns. Such URLs are difficult to memorize and manually reproduce. As a result, long URLs must be copied-and-pasted for reliability. Thus, short URLs are more convenient for websites.

Step# 1

  • To begin with, create an account at bit.ly “
  • Get your API key by the following URL

“http://bit.ly/account/your_api_key/”

Step# 2

  • In rails 3.x

Write the following gems in your gemfile

gem 'bitly'
  • Run “bundle install”

Step# 3

Add the following code in your controller

require 'bitly'

Step# 4

Bitly recently released their version 3 API. From this 0.5.0 release, the gem will continue to work the same but also provide a V3 module, using the version 3 API. The standard module will become deprecated, as Bitly do not plan to keep the version 2 API around f orever.

To move to using the version 3 API, call in you top of the controller:

Bitly.use_api_version_3

Step# 5

To shorten a URL

bitly = Bitly.new('your-bitly-user-id','your-bitly-api-key') page_url = bitly.shorten('your-url') shorten_url = page_url.short_url

It will generate the bitly URL similar to “http://bit.ly/7BWXcQ”

Creating an Engine on Refinery CMS

Posted on by Jay

Refinerycms

‘Engines’ are nothing but ‘plug-ins’ which adds up extended functionality to the existing Refinery application. Engines installs in the “vendor/extensions” folder in a refinery app.

Engines will create a tab in the Admin panel of the Refinery CMS to control the information on the engine.This example demonstrates creating an engine in an existing refinery app. The environments used are Ruby 1.9.3, Rails 3.2.8 & Refinery cms 2.0.8.

Step#1

To create an engine, just execute the below command

rails generate refinery:engine engine_name attribute:type attribute:name

NB: The engine name should be in singular which will generate the structure in plural form.
For example we want a FAQ engine for our CMS which will be controlled by CMS admin

rails generate refinery:engine MyFaq question:string answer:text

Running the above command will create a new folder “extensions” under “vendor” directory and in the “extensions” the new engine “my_faqs” will be created.

Step#2

After that run the below commands to make it executable

bundle install
rails generate refinery:my_faqs
rake db:migrate
rake db:seed

Step#3

Restart the server to get the effect. You will find the new tab “My Faqs” has been added both in the menu section of the user section and admin section.

Login as Admin to manage your FAQs

How to customize an engine during creation?

Creating the engine with a namespace

rails g refinery:engine MyFaq title description:text --namespace FAQ

Creating the engine by skipping the frontend pages

It will add menu and form page in the admin section only. User section will be omitted

rails g refinery:engine MyFaq title description:text --skip-frontend