Use of dirty objects

Some times we wanted to know what are the previous values for an object.
We can track the unsaved attribute changes in Rails.
These can be used before save only.

The below are the methods you can use.
* changed
* changed?
* changes

Eg:
Before Assigning:
user = User.find(1)
user.first_name # => "Naga"
user.last_name # => "Harish"
user.changed? # => false
user.changed # => []

After Assigning:
user.first_name = "Turvi"
user.last_name = "Sri"
user.changed? # => true
user.changes # => {"first_name"=>["Naga", "Turvi"], "last_name"=>["Harish", "Sri"]}
user.changed # => ["first_name", "last_name"]

You can also you the dirty suffixes.
DIRTY_SUFFIXES = ['_changed?', '_change', '_will_change!', '_was']

user.first_name_changed? # => true
user.first_name_change # => ["Naga", "Turvi"]
user.first_name_was # => "Naga"
user.first_name_will_change! # => "Turvi"

NOTE: Once you save this record changed? will become false.

So you can have History as one more table or one more column called update_history as column to store all the changes.

About to launch Simplybus.com

Book Bus Tickets Online
We are developing a new product www.simplybus.com. This is mainly for the frequent travellers. Frequent travellers can get discounted tickets through out the life by booking on this website.

Here are the features.
Get your BUS tickets at discounted rate anytime, anywhere to all destinations on all operators...

Book online using credit, debit cards and net banking

Get confirmations by email and SMS

Book bus tickets online with over 500+ bus travel operators

Book bus tickets online for over 5000+ routes across India

Return bus tickets reservation

Stay Tuned.. We will release on November 6th 2009, 12:14 PM. (Auspicious Time. :))

BitlaSoft 2nd Year Anniversary

This year too we had a great celebrations in our office for Bitlasoft's 2nd year Anniversary. This year we had a dark blue Jacket with a logo on the front side and punch line on the back side.

We had party with our family too. Nice enjoyment with all the quiz, Tambola, some silly questions, silly games :) .

We discussed all the cool things about the company. We wish all the best to all of us for a bright future of bitlasoft.

Clone in Ruby

Clone is help ful for the values changed in the object but not the complete object change.

Let me explain with an example.

take an array
arr1 = ["a", "b", "c", "d"]
let me initiliza arr1 to arr2
arr2 = arr1
puts arr2
=> ["a", "b", "c", "d"]


If I change arr1 values i.e.,
arr1[1] = "z"
puts arr1
=> ["a", "z", "c", "d"]

then see arr2
puts arr2
=> ["a", "z", "c", "d"]

#This wil get changed because the whole arr1 is pointed to one block of memory and the same arr2 is also pointing to the same block. You can check this.
arr1.id and arr2.id which will be same.
puts arr1.id
=> 40972250
puts arr2.id
=> 40972250

Suppose if you want arr2 as the previuos arr1 and arr1 should get changed?

Do this:

arr1 = ["a", "b", "c", "d"]
arr2 = arr1.clone
puts arr2
=> ["a", "b", "c", "d"]

arr1[1] = "z"
puts arr1
=> ["a", "z", "c", "d"]

puts arr2
=> ["a", "b", "c", "d"]



But if you change the whole arr1 to some other values then arr2 will not change.
Eg:
arr1 = ["a", "b", "c"]
arr2 = arr1
puts arr2
=> ["a", "b", "c"]

arr1 = ["z", "y", "x"]
puts arr2
=> ["a", "b", "c"]
arr2 will be same as old arr1 because arr1 memory locaton will be different after the new initilaization.

You can check this by arr1.id and arr2.id
In this case clone is not needed.



More about clone (copied from Ruby book(Dave Thomas, The Pragmatic Programmers))---

clone obj.clone -> anObject

Produces a shallow copy of obj---the instance variables of obj are copied, but not the objects they reference. Copies the frozen and tainted state of obj. See also the discussion under Object#dup .

class Klass
attr_accessor :str
end
s1 = Klass.new » #
s1.str = "Hello" » "Hello"
s2 = s1.clone » #
s2.str[1,4] = "i" » "i"
s1.inspect » "#"
s2.inspect » "#"

Sending Email with attachment in Ruby on Rails using Gmail Account

Its very important to send an email with attachment in Ruby on Rails. Generally most of the applications use this.

I'll write you step by step procedure.

For sending an email you need to to specify the mailer details in environment.rb

require 'smtp_tls' #this is used for GMAIL . click here to get this file. Copy this file in your lib folder.

# ActionMailer Settings
ActionMailer::Base.delivery_method = :smtp
ActionMailer::Base.perform_deliveries = true
ActionMailer::Base.raise_delivery_errors = true
ActionMailer::Base.default_charset = "utf-8"
ActionMailer::Base.logger = nil #this will prevent you by printing in the log.


ActionMailer::Base.smtp_settings = {
:address => "smtp.gmail.com",
:port => 587,
:domain => "gmail.com",
:authentication => :login,
:user_name => "username@gmail.com",
:password => "your assword",
}

To use ActionMailer, you need to create a mailer model.

$ script/generate mailer SendMail

This will create the model file app/models/send_mail.rb

Where ever you want to call the mailer method,
SendMail.deliver_send_attachment(subject, message, document)

"deliver_ " will deliver the email specified with the method.
"send_attachment" method should be in send_mail.rb (model)
In you models app/models/send_mail.rb
class SendMail < ActionMailer::Base
def send_mail(subject, message, document)
@from = "your email"
@subject = subject
@body['message'] = message #@body["message"] here @message will be the instance variable
@recipients = "some email" #recipient email
content_type "text/html"
@sent_on = Time.now
unless document.nil?
part :content_type => document.content_type do |p|
p.attachment :content_type => document.content_type,
:body => File.open("./public/#{your file name}", 'rb') { |f| f.read },
:filename => document.filename
end
end
@layout = :some layout
end
end

In the above code for the attachment I passed document object, in which content type (image, doc, pdf etc.,)is saved.
generally the content type will be
"application/msword" -> for MSword
"application/pdf" -> for MSword
"image/gif" -> for gif images

Instead of document.content_type you hard code it by the type mentioned above.
eg:
part :content_type => "application/pdf" do |p|
p.attachment :content_type => "application/pdf",
:body => File.open("./public/#{your file name}", 'rb') { |f| f.read },
:filename => "file_name"
end

In your views app/views/send_mail/send_attachment.rhtml
Hi some name,
This is the message <%= @message %>

Yours truly,
blah blah.

This will send an email with the attachment using Gmail.

mobee.in @ Barcampbangalore7

Yesterday I attended Barcampbangalore7 at IIMB. This is the first barcamp I ever attended. Very interesting and I was excited to see the people talking on different things. I decided to give a talk for the next barcamp on any technical issues. :)

Our CEO Dashrath has given a talk on mobee.in . It was very interesting talk and the response is also very good. There was also some few issues and requirements came from the people. We may finish those requirements in another 2 or 3 days.. :)

Other than mobee.in discussion I attended few more discussions which are very interesting and its a very good sunday with all these discussions. The campus (IIMB) itself is very nice with lot of trees.
The lunch arranged by bcb7 is very nice and tasty. :)

1 year celebrations in Bitlasoft

Officially Bitlasoft has celebrated 1 year completion on June 29th.
We had Black T-shirts with a logo. Its really awesome.
we had a long meeting with our CEO Dashrath Bitla and some of our colleagues with the PAST, PRESENT and FUTURE of the company.
we are looking more for the company from our beloved product ticketSimply. :)