Validating Email Addresses with Ruby

After my post on how to send email thru action mailer I thought of writing how to validate that email address and thought it would be useful for all.

Here it goes

In any application in which a user enters an email address, there is the very real possibility that the user will make a typo and your application will end up with an invalid address. You can have them enter it twice, but this seems clunky. And you can, of course, send an email with an activation link, which provides the only true validation, but there’s no need to bother sending the email if you know the address is no good. Furthermore, once you’re past the page where the user enters their email address, you’ve missed your chance to tell them there’s something wrong and they should correct it.

So you really should do what you can to validate the address when the user enters it. I recently made a simple addition to my applications that helps a lot: verify that the domain name is valid.

It’s surprisingly easy to do—especially with a little help from Peter Cooper’s excellent Beginning Ruby, which has a very useful chapter on network programming. The following code is adapted from his examples:

require ‘resolv’
def validate_email_domain(email)
domain = email.match(/\@(.+)/)[1] do |dns|
@mx = dns.getresources(domain, Resolv::DNS::Resource::IN::MX)
@mx.size > 0 ? true : false

This example makes use of the Ruby standard library “resolv”, so you need to require it first.

The first step is to separate the domain name from the rest of the email address. The regular expression captures the part of the string that follows the @ symbol.

Then the code creates a new DNS resolver object and queries the resolver for an MX (mail exchanger) resource at the specified domain. This returns an array, which will be empty if there is no MX record for the domain.

(Note: In a previous version of this article, I used Resolv.getaddress to see if there is a DNS entry for the domain, instead of checking for an MX record. This approach works most of the time, but it rejects any domain for which there is no A record. If a domain is used only for email and not for a web server, there might not be an A record. Also, some domains have an A record only for, which will also fail the simple getaddress test.)

You can use something like the following in the validate method within the appropriate model:

unless email.blank?
unless email =~ /^[a-zA-Z][\w\.-]*[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$/
errors.add(:email, “Your email address does not appear to be valid”)
errors.add(:email, “Your email domain name appears to be incorrect”) unless validate_email_domain(email)

I first check to make sure the email address is not blank, because that’s detected by a simple validates_presence_of :email statement that produces a different error message.

Then I make sure that the email address is at least syntactically reasonable, with a rather ugly regular expression, before bothering to check the DNS.

It should be noted that the regex I use here isn’t designed to cover all of the RFC2822 cases, nor with other RFC drafts dealing with non-ASCII addressing.

An even better approach would be to use an observer to validate the address with an Ajax call before the user submits the form.

It is possible to take this a step further by sending the SMTP server referenced in the MX record a “RCPT TO:” command. In theory, this would check that the user name is valid as well as the domain name. This takes additional time, however, and I’ve read that the response from mail servers is often not reliable. If anyone has tried this, I’d appreciate any feedback on how well it worked.

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Action Mailer is the Rails component that enables applications to send and receive e-mail. In this chapter we will see how to send an email using Rails. So lets start with creating a emails project using following command.

C:\ruby\> rails emails

This will create required framework to proceed. Now we will start with configuring Action Mailer.

Action Mailer – Configuration

Following are the steps you have to follow to complete your configruation before proceeding with actual work:

Go into config folder of your emails project and open environment.rb file and add the following line at the bottom of this file.

ActionMailer::Base.delivery_method = :smtp

This tells ActionMailer that you want to user SMTP server. You can also set it to be :sendmail if you are using a Unix-based operating system such as Mac OS X or Linux.

Add the following lines of code to the bottom of your environment.rb as well.

ActionMailer::Base.server_settings = {

:address => “”,

:port => 25,

:domain => “”,

:authentication => :login,

:user_name => “username”,

:password => “password”,


The values given in double quotes will be different for your SMTP server. You can take this information from your Inernet Service Provider if you already don’t know. You don’t need to change port number 25 and authentication type if you ar eusing standard SMTP server.

Next step will be to create a mailer

Generate a mailer:

Use the following command to generate a mailer as follows:

C:\ruby\> cd emails

C:\ruby\emails> ruby script/generate mailer Emailer

This will create a file emailer.rb in app\models directory. Check the content of this file is as follows:

class Emailer > ActionMailer::Base


Let’s create one method as follows.

class Emailer > ActionMailer::Base

def contact(recipient, subject, message, sent_at =

@subject = subject

@recipients = recipient

@from = ‘’

@sent_on = sent_at

@body[“title”] = ‘This is title’

@body[“email”] = ‘’

@body[“message”] = message

@headers = {}



The contact method has four parameters a recipient, subject, message and a sent_at, which defines when the e-mail is sent. The method also defines six standard parameters that are a part of every ActionMailer method:

@subject defines the e-mail subject.

@body is a Ruby hash that contains values with which you can populate the mail template. You created three key-value pairs: title, email, and message

@recipients is a list of the people to whom the message is being sent.

@from defines who the e-mail is from.

@sent_on takes the sent_at parameter and sets the timestamp of the e-mail.

@headers is another hash that enables you to modify the e-mail headers. For example, you can set the MIME type of the e-mail if you want to send either plain text or HTML e-mail.

Now we will create a mailer template which is just text with standard Rails placeholders scattered throughout.

Put following code in app/views/contact.rhtml file


You are having one email message from with a tilte

and following is the message:


Next we will create a controller for this application as follows:

C:\ruby\emails> ruby script/generate controller Emailer

Now lets define a controller method in emailer_controller.rb which will call Model method to send actual email as follows:

class EmailerController < email =” @params[” recipient =” email[” subject =” email[” message =” email[” text =””> ‘Message sent successfully’



To deliver e-mail using the mailer.s contact method, you have to add deliver_ to the beginningof the method name. You add a return if request.xhr? line so that you can escape to Rails Java Scripr (RJS) if the browser does not support JavaScript and then tell the method to render a text message.

You are almost done except to prepare a screen from where you will get user information to send email. So lets define one screen method index in controller and corresponding view:

Add following code in emailer_controller.rb file

def index

render :file => ‘app\views\emailer\index.rhtml’


Now let’s define our view in app\views\emails\index.rhtml

Send Email


bracket %= text_field ’email’, ‘subject’ %bracket bracket /pbracket

bracket pbracket bracket label for=”email_recipient”bracket Recipientbracket /labelbracket :

bracket %= text_field ’email’, ‘recipient’ %bracket bracket /pbracket

bracket pbracket bracket label for=”email_message”bracket Messagebracket /labelbracket

bracket %= text_area ’email’, ‘message’ %bracket bracket /pbracket

Now test your application by using This displays following screen and by using this screen now you will be able to send your message to anybody.

This will send your message and will display text message that “Message sent successfully”

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Rmagick installation/configuration with rails on Ubuntu or fedora

Rmagick installation on Ubuntu

I have seen many times that people are facing a lot of problem in installing RMagick and Image Magick on ubuntu…….The same problem was faced by me and i got it solve by following the steps given below

Download RMagick and Imagemagick..

put RMagick in the vendors folder where u want it to run from and Image Magick on Desktop

Go to the Path where Image Magick is stored and follow the steps

1) ./configure

2) make

3) make install

if you get an error while doing this task

type the following command in terminal

apt-get install build-essential (make sure that ruby dev is installed)

once you have done this follow the above 3 steps and things should start working

So thats all about ImageMagick

now come RMagick installation

move the the RMagick installation path and follow the steps

1) ./configure

Thats things should work..

You may even try doing this

sudo apt-get install imagemagick
sudo apt-get install libmagick9-dev
sudo gem install rmagick

I dont think u will get any error. If you get any post ur errors as comment and get it solved..

Setting up ImageMagick & rmagick on Redhat

  1. sudo yum install libjpeg-devel libpng-devel glib2-devel fontconfig-devel zlib-devel libwmf-devel freetype-devel libtiff-devel
  2. wget
  3. tar zxzvf ImageMagick-6.3.2-9.tar.gz
  4. cd ImageMagick-6.3.2-9
  5. ./configure
  6. make
  7. sudo make install
  8. sudo gem install rmagick
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Radiant CMS

Radiant CMS

Its a powerful open source CMS (Content Management System) developed in ruby on rails. Radiant 0.6.4 has just been released! This version includes a powerful extension system so developers can tailor Radiant to their specific needs. Here i gave you some instructions to deploy it on your localhost.

First install the gem by

% gem install –include-dependencies radiant

Then create a radiant project of your own by

% radiant –database [mysql|postresql|sqlite3] path/to/project

for eg:
% radiant –database mysql my_radiant_application

Then you have to configure your database by edit your database.yml file like follows

adapter: mysql
database: my_radiant_development
username: root
password: admin
host: localhost

# Warning: The database defined as ‘test’ will be erased and
# re-generated from your development database when you run ‘rake’.
# Do not set this db to the same as development or production.
adapter: mysql
database: my_radiant_test
username: root
host: localhost

adapter: mysql
database: my_radiant_production
username: root
password: admin
host: localhost

you can use any of the database modes listed in database.yml. Then based on your database configuration
database schema should created by

% rake [environment] db:bootstrap

for eg: % rake production db:bootstrap if u r in production environment

Here u goes, start your server

% mongrel_rails start -e , where mongrel is your server (Mongrel server)

Type the http://localhost:3000/admin to login. The user name is password should be known to you because
while creating schema it asks for u the admin user name and password.
In the application you can’t see any model, controller or view files but its working
fine this is how possible is all those files are written along with the radiant gem that
u should installed before starting project. you can see those files in your local ruby gems folder.

Thats all , now you can go ahead with some other own radiant application.
if you want more explanation go and visit Radiant home page

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Implement Captcha in a rails application

Well with increase in spamming this facility of captcha has done the magic although people always find some or the other reason to crack a security but for the time being this can be implemented..

Captchator is a very good service which can be combined easily with RoR and implement captcha

Jst few lines of code does the magic for you

View :-
in img src call the follwing source$yoursessionid

Just like the one below

Write the above lines in views which will display a random captcha on the form or the page

Then$yoursessionid/$answer using this fetch the value which is entered by the user

If the answer is correct, the result is “1”, if not, it is “0”.

You can check the same in ur browser

Try it in your Browser:

1. Go to you like) and read the text from the picture.
2. Go to you like)/(text from the picture). If you entered the text correctly, you will see “1”.

Thats it..Captcha Ready for ur site..Aviod spamming in 10 mins no more security and coding required.

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File Column Plugin in Rails

This is another plugin which i have implemented for File uploading. The main advantage of this is that we can integrate RMagick to it easily for generating thumbnails and giving other properties to the plugin.

The main thing after downloading the plugin from
you just need to put 2-3 lines of code and get things going

on the page from where u want to upload a file just write 1 line of code

    <%= file_column_field "entry", "image" %>

and on the page where you want to display that file write the following line

<%= image_tag url_for_file_column(“entry”, “image”) %>

You can use RMagick and make thumbnails of your image by adding the following line in the model

class Entry < ActiveRecord::Base
file_column :image, :magick => {
:versions => { “thumb” => “50×50”, “medium” => “640×480>” }


class Entry < ActiveRecord::Base
file_column :image, :magick => { :geometry => “640×480>” }

write this in the model of the page where u want to implement the plugin

Thats it.. njoi


The old version of file column plugin doesnt work in rails 2.2 …to get working in rails 2.2 then you need to modify file_coulmn.rb file.

Update the line #619 in vendor/plugins/file_column/lib/file_column.rb from


Or you can download the latest plugin from the

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