Morshed Alam

How to rename Rails3 application

noreply@blogger.com (Morshed Alam) — Wed, 04 Apr 2012 10:55:00 +0000

A Rails3 application name are using as a Ruby name space for entire application and throughout the project tree as well. So, If anyone later decide to change the project name, then have to replace the name in the following files:

Rakefile
config.ru
config/routes.rb
config/application.rb
config/environment.rb
config/environments/development.rb
config/environments/test.rb
config/environments/production.rb
initializers/secret_token.rb
initializers/session_store.rb

You can run following command in your project root, to find out the list of files containing project name(assume you are using linux):

grep -Ri 'AppName' * | cut -f1 -d':' | sort | uniq

You can use following gem to rename rails3 application without any hassle:

https://github.com/morshedalam/rename

Multiple login in google talk

noreply@blogger.com (Morshed Alam) — Tue, 10 Jan 2012 08:07:00 +0000

Most of us have multiple google talk IDs and used third party software to login at a time. But, anyone can do multiple login to gtalk by using a simple trick below:

Right click gtalk icon and select properties

Add /nomutex at the end of target property like following way

"C:\Users\Morshed\AppData\Roaming\Google\Google Talk\googletalk.exe" /startmenu /nomutex

Click to Apply and Ok

Done! Now click on gtalk icon and open as many as gtalk windows you want. Cheers!!

HTTP basic authentication using email address

noreply@blogger.com (Morshed Alam) — Sat, 31 Dec 2011 08:18:00 +0000

In my previous article, I have written about HTTP basic authentication in rails using a plain user access YML.

Last few days ago, I have modified the logic to log-in using email address and password. So that anyone don't need to remember another new password. Hope it might help you...

Written a news private method

def login_by_email(user_name, password)
    is_logged_in = false
    if (user_name.match(/.+\b@yourdomain.com$\b/i))
      require 'net/imap'
      require 'openssl'
      client = Net::IMAP.new(host, port, true, nil, false)
      begin
        client.login(user_name, password)
        client.logout
        is_logged_in = true
      rescue Exception => error
        logger.error "Unable to log-in :: #{error.message}"
      end
      client.disconnect
    end
    return is_logged_in
  end

On line#3 I have checked the domain name to provide access for a specific domain. After that modified the authentication method following way:

def authenticate_for_staging_server
    authenticate_or_request_with_http_basic do |user_name, password|
      login_by_email(user_name, password) == true
    end
  end

HTTP basic authentication in rails to protect staging server

noreply@blogger.com (Morshed Alam) — Sun, 04 Dec 2011 04:59:00 +0000

Sometimes, you may need to protect your staging server from outside world. It can be done easily by using http basic authentication in rails3.

I did following things to use HTTP basic authentication to protect my staging server:

YML file with username and password pair:

devuser: devpass
testuser: testuserpass

Loaded YML data from application initializer:

HTTP_AUTH_USERS = YAML.load_file("#{Rails.root.to_s}/config/staging_server_users.yml")

Callback and authentication in the application controller:

before_filter :authenticate_for_staging_server, :if => lambda { Rails.env.development? }

private
def authenticate_for_staging_server
  authenticate_or_request_with_http_basic do |user_name, password|
    password == HTTP_AUTH_USERS[user_name]
  end
end

Hope it will help a lot who wants to protect their staging server.

XForms in PHP

noreply@blogger.com (Morshed Alam) — Sat, 19 Nov 2011 18:00:00 +0000

The next generation of HTML form is XForms which is more flexible than the HTML forms and saves a lot of time and effort. It enables the separation of data and logic from presentation as well.

In the XForms, XML used to define forms data, stores and transports data in the XML documents and has two different parts:

XForm model - defines the form, what it should do, what data it contains
XForm user interface - defines the input fields and how it will displayed

You can see a basic hello world example here - XForms/HelloWorld. You must have to install XForms extension for your Firefox version.

Some more resources are given below:

How to deactivate facebook account

noreply@blogger.com (Morshed Alam) — Sat, 19 Nov 2011 12:57:00 +0000

Now a days Facebook became part of our busy life and couldn't think without it. But, if you need to deactivate your account then can do that by following steps below:

Once, you deactivate your account, your profile and information will be instantly inactivated. But, information will not be lost however, and will be available to recover whenever you want within 14 days.

Steps are given below to deactivate the Facebook account:

Go to Account menu on top right corner of the page and select Account Settings.
Click to Security from right side menu
Click to Deactivate your account link from bottom
And, then select reason and click to Confirm button
System will open a pop-up box for your password and captcha text. Enter those and click on the confirm button.

After confirmation system will redirect to Facebook's home page, where you will see a message confirming that your account has been deactivated.

To cancel deactivation, log-in again and choose cancel deactivation within 14 days.

Rails application deployment using shell script

noreply@blogger.com (Morshed Alam) — Mon, 31 Oct 2011 06:51:00 +0000

I have used following shell script to deploy one of my Ruby on Rails applications:

DATES=`date +%Y%m%d%H%I%S`
service apache2 stop &&
mysqldump -u[user] -p[pass] [yourdbname] > "your backup directory"[yourdbname]_${DATES}.sql
git pull &&
bundle install --path [your bundle path] &&
bundle exec rake db:migrate RAILS_ENV=production &&
mv [your application's production log file] [your application's production log backup path]/production_${DATES}.log &&
touch [your application's production log path]/production.log &&
chown [user]:[group] [your application's production log file] &&
service apache2 start

In the above code snippet,

Line 01: Used to get the current date time
Line 02: Stopped the Apache server
Line 03: Used to take database backup in the backup directory
Line 04: Getting update source from repository
Line 05: Bundle install to update gem list
Line 06: Run database migration to migrate latest script if any
Line 07: Rotating log in every deployment
Line 08: Creating new production log file
Line 09: Providing proper user access to write log
Line 10: And, then start the server again

That's all. Your application should run without any issue if you configure third bracket's([]) information perfectly.

But, now a days - Capistrano allows you to deploy a Rails applications easily. You can try that and can customize if you need to.

Using helper method from action mailer views

noreply@blogger.com (Morshed Alam) — Mon, 17 Oct 2011 04:48:00 +0000

Action Mailer of Ruby on Rails(RoR) allows you to send emails from application using a mailer model and views. Sometimes you may need to use any helper method though it does not allow by default. In that case you have to include helper(module) in the Mailer class.

Say, you may need to use method(s) from ProductsHelper module, then you need to write following line in the Mailer file which will provide accessibility to use all methods written in ProductsHelper

add_template_helper(ProductsHelper)

Cheers!!

Disable a user account in Linux

noreply@blogger.com (Morshed Alam) — Thu, 29 Sep 2011 06:46:00 +0000

There are some different approaches to do that. The easy way to disable a user account is to alter stored password which is stored to /etc/shadow. In that case password will be lost unless you save save the password in different file.

You can alter the password by using following command:

passwd {username} {new password}

It might better to lock a account rather than change password if you need to re-activate again. By following command a user account can be lock easily:

passwd {username} -l

If you will ever need to re-enable the account just unlock using following command:

passwd {username} -u

If you don't need to keep the account anymore then use following command to delete a user permanently.

userdel {username}

The above operation will keep his home directory, mails, etc. Use following command to delete all his files on the system.

userdel -r {username}

Be careful to do that, your mistake may destroy all files of the server.

Note: User still will be able to connect using ssh via key-based auth on changing the user password or locking. If this is used, then the user’s authorized_keys must me moved to a different location.

How to resize Facebook UI dialog

noreply@blogger.com (Morshed Alam) — Mon, 26 Sep 2011 06:54:00 +0000

Once, I had to re-size the facebook UI dialog while working on friends invitation widget for greenarrow.com The widget was loaded under a popup which was wrapped up by an iframe as well. In this case it was not showing properly, the widget was not accommodate in that popup. That's why had to re-size the widget. I did that by following way..

var old_size = FB.UIServer.Methods["apprequests"].size;
FB.UIServer.Methods["apprequests"].size = {
 width:320,
 height:430
};
FB.ui({
 method: 'apprequests',
 message: 'A nice customizable first page application, visit - http://www.greearrow.com'
}, function() { });
FB.UIServer.Methods["apprequests"].size = old_size;

I have stored the old size first and then assign the size which i was needed. After that re-assign the old size again so that it does not broke my another UI dialog. Because in other case i have used default size.

Ruby interpreter has stopped working

noreply@blogger.com (Morshed Alam) — Sat, 24 Sep 2011 03:27:00 +0000

From last couple of days, I was facing a problem with my ruby interpreter. It was crashing continuously after few page requests and getting message:

Ruby interpreter (CUI) 1.9.2p180 [i386-mingw32] has stopped working

I have tried to find out the reason and frequency to stopped but couldn't find the actual reason. After googling got a suggestion about css media link. But it does not solved the problem as well.

Finally, I have identified that it happens for missing file. The ruby interpreter was crashed after two request for me if the file missing exists, it may differ for others.

Install mysql2 gem on Windows 7

noreply@blogger.com (Morshed Alam) — Tue, 26 Jul 2011 14:22:00 +0000

Last couple of days ago, I was stuck to install mysql2 gem on windows7 for rails3 and tried lots of instructions by googling. Unfortunately, those were not worked for me.

Finally, I have specified a older version of mysql2 during installation which worked for me. Following are the steps which i did:

Install Mysql 5.5

Open command prompt and run following command

gem install mysql2 --version=0.2.6 --platform=ruby -- '--with-mysql-include="C:\Program Files\MySQL\MySQL Server 5.5\include" --with-mysql-lib="C:\Program Files\MySQL\MySQL Server 5.5\lib"'

Copy libmysql.dll from C:\Program Files\MySQL\MySQL Server 5.5\lib to [Ruby Installation Directory]\bin\
Specify mysql2 version to you gem file
Run bundle install

How to disable logging in Rails application

noreply@blogger.com (Morshed Alam) — Thu, 24 Feb 2011 16:34:00 +0000

It's not a good practice to do though depends on your needs. It can be done by two ways, one is to disable for whole application and another is to disable for specific environments. You're probably looking for some or all of the following settings:

config.logger
config.active_record.logger
config.action_controller.logger
config.action_view.logger
config.action_mailer.logger
config.active_resource.logger

If you set any of them to nil like following way:

config.active_record.logger = nil

It should disable logging for that specific component. You can experiment with these to disable logging for specific components or set all of them to nil to get no logging.

How to use mutliple ruby version on windows

noreply@blogger.com (Morshed Alam) — Mon, 14 Feb 2011 11:00:00 +0000

I have found a nice ruby version manager for windows named pik. It's pretty easy to install and manage multiple ruby versions.

First install the pik gem:

gem install pik

After installing the pik, you have to use pik_install script to install the pik executable. You must install pik in a different directory other than your ruby\bin directory.

pik_install C:\Windows\System32

If the installation gone smooth, you should see like ..

pik is installed

if you want to use pik with git bash, add the following line to your ~/.bashrc:

  [[ -s $USERPROFILE/.pik/.pikrc ]] && source $USERPROFILE/.pik/.pikrc

Now you can see the list of available ruby versions by using following commands:

pik list

Add, you can install a ruby version and add to version manager using below command:

pik add C:\Ruby192\bin

To switch the ruby version use command:

pik switch [Version Name]

That's all to use multiple version of ruby on windows machine.

Click here to know more about pik

LF will be replaced by CRLF

noreply@blogger.com (Morshed Alam) — Mon, 31 Jan 2011 10:01:00 +0000

I was getting following message while trying to add files to GIT index:

Warning: LF will be replaced by CRLF ....

By google search I found that - whenever tried to add files to the repository, git thinks that, the file is a text file and all files automatically will have their LF line endings converted to CRLF endings.

It's an important warning for a binary file because git incorrectly assesses a binary file to be a text file but it's OK for text file.

The line-ending conversion can be prevent by setting false of core.autocrlf attribute. By default it remains true.

The command is as follows(in Bash mode):

git config core.autocrlf false

Unpacked gem has no specification file

noreply@blogger.com (Morshed Alam) — Sat, 22 Jan 2011 06:43:00 +0000

I started working on a new rails project and in every time from command line operation getting this type of irritating message:

config.gem: Unpacked gem ..... in vendor/gems has no specification file. Run 'rake gems:refresh_specs' to fix this.

I run rake gems:refresh_specs but the problem isn't fixed. Moreover, tried by creating specification file as well.

After that, removed the irritating message by a single line of code to place in the environment file:

# Bootstrap the Rails environment, frameworks, and default configuration
require File.join(File.dirname(__FILE__), 'boot')

Rails::VendorGemSourceIndex.silence_spec_warnings = true

Rails::Initializer.run do |config|

’rails’ is not recognized as an internal or external command, operable program or batch file

noreply@blogger.com (Morshed Alam) — Thu, 20 Jan 2011 05:55:00 +0000

You might experience the problem due to the following reasons:

You haven’t installed Rails
Rails path cannot be found
Installed Rails using a ‘special’ installer

To resolve the issue, uninstall rails installation from your PC and try a normal installation through command prompt by using following command:

gem install rails –include-dependencies

Note: Be sure, you are connected with internet

Remote mysql backups on windows

noreply@blogger.com (Morshed Alam) — Tue, 18 Jan 2011 11:34:00 +0000

In our day to day job needs to backup remote mysql database and sometimes may needs to synchronize with another one.

It can be done by using following code snippet, no matter the remote server is windows or Linux.

Save the following code snippet as a batch(.bat) file and setup a task scheduler.

set DATET=%date:~-4%_%date:~7,2%
"your mysql bin directory\mysqldump" --host="remote-host" --user="remote-database-user" --password="remote database password" remote-database-name > "backup-directory"backup_%DATET%_csv.sql
"your mysql bin directory\mysql" -uuser -ppassword -t csv < "backup-directory"backup_%DATET%_csv.sql

‘nmake’ is not recognized as an internal or external command, operable program or batch file

noreply@blogger.com (Morshed Alam) — Tue, 11 Jan 2011 05:32:00 +0000

I have experienced the problem due to the version difference of rubygems installed on my developer PC with gems.

I have downgraded the rubygems, to choose the right versions and solved the problem. After completing the installations, updated all of my gems which did not generate any errors.

If you still experience the problem then try the link below to resolve the problem:

‘nmake’ is not recognized as an internal or external command, operable program or batch file

Mysql backup on linux using ssh and cron

noreply@blogger.com (Morshed Alam) — Tue, 12 Oct 2010 12:45:00 +0000

Sometimes, we may need to backup and synchronize mysql on linux as a background process. Linux has a great program for this called cron. It allows tasks to be automatically run in the background at regular intervals.

Create a script file(.sh) using following code snippet to backup and restore database in to another database:

ssh user@remote-host "mysqldump -u my-remote-db-username --password=my-remote-db-password my-remote-db-name" | mysql -udb-username --password=db-password --host=host-name -C db-name

Open a terminal and run:
sudo crontab -l

To edit the list of cronjobs you can run following code which will open default editor to let us the crontab:
sudo crontab -e

You can configure your script in to crontab by following code:

* * * * * /bin/execute/this/script.sh

The above five stars represent different date parts in the following order:

minute (from 0 to 59)
hour (from 0 to 23)
day of month (from 1 to 31)
month (from 1 to 12)
day of week (from 0 to 6) (0=Sunday)

How to do custom redirection of a website

noreply@blogger.com (Morshed Alam) — Tue, 22 Jun 2010 17:35:00 +0000

Usually the redirection needs when a website changed/move to different location though it may use for lots of other purposes. In this post, I have explain how you can do it by using .htaccess

Say, your site has lots of URL and you want to redirect some of those which query string has a parameter name “option” and the value is “redirect”.

Below are the codes to redirect into new URL:

RewriteEngine on
RewriteCond %{QUERY_STRING} option=redirect
RewriteRule (.*) http://newsite.com/index.php?%{QUERY_STRING} [R=301,L]

Just copy above lines into .htaccess file and place it to root directory in your application.

Some helpful posts:

Change file extension in URL

noreply@blogger.com (Morshed Alam) — Sun, 20 Jun 2010 17:04:00 +0000

In my previous article I have shown how you can use different extension of a file instead of .php explicitly but in this post I have explain how to rewrite the URL instead of renaming the file extension explicitly.

To rewrite the URL you must add following lines in a .htaccess file and place it to root directory of your application.

Options +FollowSymlinks
RewriteEngine on
RewriteRule ^(.*)\.htm$ $1.php [nc]

The above code will rewrite the product.php to product.html.

And following is the code to pass parameters with URL

Options +FollowSymlinks
RewriteEngine on
RewriteRule ^(.*)\.html(.*)$ $1.php$2

Some related posts:

Hide the fact that web pages are written in PHP

noreply@blogger.com (Morshed Alam) — Sat, 19 Jun 2010 19:52:00 +0000

Sometimes you may want to hide the fact of your web site’s written language to visitors then you can do it easily by using .htaccess Say, you have developed your site by using PHP and wanted to show it as ASP then you can do it by using following tricks:

Just add following line in the .htaccess file and place it to application root directory.

AddType application/x-httpd-php .asp

Now everyone have to use all files of the application by using .asp though the application was written in PHP.

The bundled mysql.rb driver has been removed from Rails 2.2

noreply@blogger.com (Morshed Alam) — Sun, 21 Mar 2010 16:56:00 +0000

After two months, I have started working on rails again and upgraded Rails to 2.3.2 on my laptop. After upgraded when I have tried to run a sample rails application and got following errors:


=> Booting WEBrick
=> Rails 2.3.2 application starting on http://0.0.0.0:3000
!!! The bundled mysql.rb driver has been removed from Rails 2.2. Please install the mysql gem and try again: gem install mysql.
=> Call with -d to detach
[2010-03-21 04:39:09] INFO  WEBrick 1.3.1
[2010-03-21 04:39:09] INFO  ruby 1.8.6 (2007-09-24) [i386-mswin32]
[2010-03-21 04:39:09] INFO  WEBrick::HTTPServer#start: pid=5032 port=3000
=> Ctrl-C to shutdown server

After getting the above error I have installed newer version of mysql gem but problem was not solved. Then just copy the MySQL dll from mysql/bin/libmysql.dll to ruby/bin/libmysql.dll. And it worked perfectly.

Specify rendering engine of IE

noreply@blogger.com (Morshed Alam) — Mon, 15 Feb 2010 18:19:00 +0000

Internet Explorer 8 supports different document compatibility to ensure that your web pages have a consistent appearance in future versions.

If you are having trouble on a site in different IE, you can use specific rendering mode to display your web pages by using simple META tag. Below is the META tag to use IE7 rending in IE8:


<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />

Details of defining rendering engine in IE

Related link:

Most useful htaccess tips and tricks