Here is a quick and easy way to automate the process :

Step #1 (we can have lots of fun)
I will consider that you use capistrano for deploying your app. The only thing you have to do in your capistrano recipe is to “touch” a dummy file to update its modification date.

namespace :deploy do
  desc 'Restart My App'
  task :restart, :roles => :app do
    run "touch #{current_path}/last_deploy"
  end
end

Step #2 (there’s so much we can do)
Now in application_controller, add a before_filter like this

before_filter :last_deploy

def last_deploy
  @last_deploy = File.new("last_deploy").atime rescue Time.now
end

Step #3 (it’s just you and me)
Display the date in the layout or in the view of your choice

<%= "Last deployment : #{@last_deploy}"%>

Edit : Oh, dear readers, I just want to let you know that RubyFleebie is now on Twitter.

For the past few months this blog has been pretty much dead. I could give you tons of excuses as for why it has been so but that’s all they would be, mere excuses! And I assure you that you would not find any of them very convincing.

I received several comments recently telling me that you liked my blog and asking me when I plan writing again and believe me, it always goes straight to my heart. For some time now I am in the expectation that most of you will give up on me and remove this blog from your list forever but for some reason… you don’t!

Since I am a bit rusty at writing blog posts, I chose the easy way : a numbered list of Rails Gems/Plugins that I like. Hmmm, I know… it’s soooooo 2007! But, interesting nonetheless. If you don’t mind, I’d like that you share in the comment section the plugins that you like the most as well. Perhaps this post could become a reference to discover great plugins. Oh btw, from now on I will use the terms plugins and gems like they were the same thing.

1. Paperclip by Thoughtbot

   Very easy to install & configure. I use it for thumbnails generation and it works wonder.

2. locale_routing by Perfectline

   If you are developing a multilingual app/website (with I18n), don’t miss this simple plugin. It auto inserts the locale in the url without messing with your routes.

3. thinking-sphinx by freelancing-gods

   A fast and reliable free-text search solution for your rails apps, using the Sphinx daemon. The only thing that is really unfortunate with sphinx is that is doesn’t index new database records live out of the box. Instead you have to build the index manually or setup a cronjob at a given interval. The workaround is to use delta indexes with the delayed-job plugin but it forces you to have a rake task always running on your server. I had so much problems with the rake task getting killed for no apparent reason that I decided that live indexing was not so important. Instead I have a cronjob running every X hours that rebuild the index from scratch

4. will_paginate by mislav

   I guess we all know and use this one but I had to put it in my list anyway. It is such a great and easy to use pagination plugin.

5. acts_as_state_machine by rubyist

This one I use all the time. Everytime an activerecord object can be in more than a single “state” (enabled, hidden, locked, whatever)… think about using it!

That’s it! Now, it’s your turn : what is your own top 5 list?

I’m sorry for not updating my blog more often. Now is the time to use the best excuse in the world that will make me look like a busy businessman and you will all be impressed. Here we go : I don’t have the time!

I know a lot of you are using GOD to keep your daemons / processes alive. I really don’t want to say bad things about GOD (I can’t because I never tried it)… but I DID read some really nasty things about it and somehow it convinced me to try an alternative : Monit.

The biggest advantage with Monit is that it is written in C instead of ruby… so it doesn’t leak and it appears to be faster. It is also pretty easy to configure. Here is a very basic monit configuration file:

set daemon 60

set httpd port 2812 address localhost
     allow localhost 

check process my_process
  with pidfile /home/apps/someapp/my_process.pid
  start program = "/home/apps/someapp/my_process start"
  stop program = "/home/apps/someapp/my_process stop"

Then, you start the monit daemon by typing : monit

It will poll the monit configuration file every minute (this is the set daemon 60 part) and will restart ‘my_process’ whenever it is not running. Of course this is an extremely simple use case and there are a lot more configuration options you can play with. Have a look at the documentation for more info.

As you might know already, the official ruby interpreter is written in pure C. This means that whenever you type a ruby instruction, the interpreter will call the corresponding C function for you. For example, if you do :

Ruby will call a C function (probably rb_ary_new) and a C structure will be created to hold the content of arr. When you will try to access arr later in your code, the interpreter will use that same C structure.

On the ruby side of things we say that everything is an object. On the C side of things we say that everything is a VALUE

You also already know that everything in ruby is an object. To represent this reality on the C side of things, a custom type (typedef) has been created and has been given the name of VALUE. This type is a pointer (well, in fact it is not really a pointer but we won’t go into this right now) that can reference any kind of data type. When C defines something as a VALUE, you know that it is dealing with something that either A) comes from the ruby side of things, B) will be returned to the ruby side of things or C) is usable on the ruby side of things in one way or another. In all other situations, C is just C and doesn’t need the VALUE data type. When you see C using VALUE, what you are really seeing is ruby from the inside, and ruby from the inside is an ugly beast. It is not pretty, not elegant, not easy, not cool and honestly not that interesting. The thing is, it can save you a lot of work if you want to bridge an existing C library into your ruby application instead of having to rewrite the whole thing in plain ruby. That, in part, is why it can be very useful to know a little bit of ruby’s ugly side.

Let’s move on. We said that VALUE was the C way to represent a ruby object. If you open one of the source file of the ruby interpreter (array.c, string.c, etc.), you will find that the word VALUE is used everywhere :

Since everything in ruby is an object (or a VALUE), the C functions that are responsible of returning something ready to use on the ruby side of things always have to return a VALUE. If they would return something else (int, char, char *, long), ruby would complain because it can understand objects and only objects.

A Fixnum is not a int, it is a VALUE. A Bignum is not a long, it is a VALUE. A String is not a char *, it is a VALUE, and so on.

VALUE is not really a pointer, you say?

Ok the following is not really important for the sake of this post but if you’re curious it will interest you. I said earlier that VALUE wasn’t really a pointer. Time has come to explain what it is and why. VALUE is in fact an unsigned long.

There is only one reason why VALUE is an unsigned long and not a pointer : efficiency.

Remember what a pointer is? It is a variable that contains an address to some structure in memory. It is perfect for complex objects like arrays, hashes and custom objects… but it is a bit overkill for more primitive objects like Fixnums, booleans (TrueClass and FalseClass instances) and nil (NilClass instance). Ruby inventor thought that it would be great if in some cases the VALUE object could BE the data instead of POINTING TO the data. I mean, why having a VALUE that points to a structure that contains an integer that contains the number 1 when you could simply have a VALUE that contains the number 1?

So instead of being a pointer, VALUE is an unsigned long that can contain either A) an address to some structure that contains the data or B) the data itself (immediate value).

The data in a VALUE is stored in such a way that it is possible to know if it contains an address to some structure in memory or an immediate value. Ingenious, ain’t it?

In my next post, I will try to explain how you can use the ugly side of ruby to bridge an existing C library into your ruby (or rubyonrails) application.

I’m struggling since day #1 to find a good code editor for ruby. Mac users are happy with their textmate… but what’s left for us linux users? I tried gedit, vim, scribes and eclipse (with the aptana plugin) but wasn’t happy enough with any of them. I thought I found a real gem in Komodo edit, but that’s just not doing it for me anymore. Komodo is a great editor but it is plagued with a huge problem : it is slow and unresponsive. Sometime you start typing code and you won’t see what you just typed on the screen. Wait a few seconds and boom, here is your code… full of typos.

Now that my honey moon with Komodo is over, I searched the web and found Geany, a light-weight code editor that works for linux and windows. I’m very satisfied with it so far. Instead of making a half-assed review of the editor, I think you should try it by yourself and decide if you like it or not.

Off topic note :

Those who liked the “in depth” posts I was doing in the early days of this blog might be disappointed with the kind of posts I’m doing now. I’m thinking about this for some time and I can say that I am planning to start writing like those early days. Why? Well, simply because I found it more enjoyable. The problem however is finding the time to write longer and more in-depth posts. I am currently quite busy with TimmyOnTime and other projects so unfortunately RubyFleebie is suffering from it. I want to thank you for your patience… it amazes me that I still have all those subscribers and daily readers.

The following is a guest post from Dan Simard

Sometimes, you have to reinvent the wheel. It’s really sad to say and you will probably hate me for saying that (and I know that you’ll do because I hate myself for it). I’ve written a new globalization plugin for Rails.

Why did I reinvented the wheel?

I searched and tried a lot of other globalisation plugins… and I really tried them. I spent hours with Globalize. It was just too much. I tried the gettext_Localize that works with the good ol’ gettext command. Fuck it. Too complicated. It just didn’t fit my needs at all.

All I wanted was a wheel that you can put a wood-pole in the middle and then it could start spinning. I made one.

You can go on the simplyglobal project homepage to learn on to install it and use it.

In fact, this is not really a globalization plugin because there’s no localization handling or anything that can look like it. The name should have been simplytranslated but I already created the project with the name simplyglobal and it was an hassle to change it.

How to install

1. Execute ./script/plugin install http://simplyglobal.googlecode.com/svn/trunk/simplyglobal
2. Create a file named simplyglobal.rb in the config/initializers directory
3. In simplyglobal.rb, create hashes of language
Add the language hashes to the objectYou will end up with a file named simplyglobal.rb that looks like this :

In development, this file will be loaded every request. In production, it is loaded once.

How to use it with strings

After you installed it, you can use it in these various ways.

SimplyGlobal adds a t() method to all string objects that will return the translated string. Example, if you have defined a language hash that looks like this (note : normally, the languages hash are defined in config/initializers/simplyglobal.rb but I put it inline for the sake of the example) :

As simple as that!

You can use it like the % method of the String class.

You can also return all translations for a word. That is a special feature developed only for Frank.

Using it with views

Just create a view ending with _fr and simplyglobal will use it.

It also works for the partial.

will try to render _info_fr.html.erb rather than _info.html.erb.

Georges Brassens
- Les filles quand ça dit “je t’aime”, c’est comme un second baptême
- Aucune idée sur terre n’est digne d’un trépas

Billie Holiday
- Don’t threaten me with love, baby. Let’s just go walking in the rain.
- I never hurt nobody but myself and that’s nobody’s business but my own.

Assuming your recordset is ordered by author, you do something like this (remember, we’re in 1999) :

Ok welcome back in 2008. ASP is dead. You are coding in rails and you want to do the same thing. How will you do it? Storing the author name in a buffer variable like in 1999? Not too sure about it.

This is a job for Enumerable#group_by (Enumerable is a module that is mixed in the Array class)

Enumerable#group_by will create different sets of quotes based on the “author” values. Why the “&” sign? It’s because group_by expects a block. I could have done it this way : @authors = all_quotes.group_by{|quote| quote.author}

So @authors is now a hash that will look like this:

{”George Brassens” => [#<Quote id:131 …>, #<Quote id:331 …>], “Billie Holiday” => [#<Quote id:111 …>, #<Quote id:911 …>] }

Now you can iterate over it like this :

One more thing to note : @authors is a hash, and hashes cannot be ordered. If you want to display quotes by sorted author name, you could do this :

Note : Enumerable#group_by does not exist in ruby 1.8, it only exists in Rails. The method will be in ruby 1.9 however.

Fortunately, version 0.4 has been released on August 5th 2008. We’re going to try this new version internally and eventually use it for TimmyOnTime. I am personnally hoping for less memory consumption, more speed and more stability. This new version highlights are :

1. The beginning of ruby 1.9 support
2. Refactoring of error classes (I’m really looking forward to this)

Here is the full changelog :

XMPP4R 0.4 (05/08/2008)
=======================
* Initial support for Ruby 1.9 (see README_ruby19.txt)
* Complete PubSub API Change - more logical and better for
childclasses, support for collection node creation
* a Helper to assist with XEP-0115 Entity Capabilities
* SASL anonymous support
* File transfer fixes
* MUC room configuration fixes
* initial support for XEP-0118 User Tune
* fix for an xmlrpc exception-during-serialisation bug, which would cause
a hang
* Support auto-gem generation on GitHub with improved and DRY’er RakeFile and
gemspec.
* Add support for the old SSL protocol (needed to connect to GTalk)
* Changed API for Client, Component, Connection, Stream to remove
need for antiquated ‘threaded’ param in the initializer.
* Use a Logger instance instead of directly writing to stdout
* Re-factored & consolidated Error classes. See xmpp4r/errors.rb for all
custom errors that can be caught. All inherit from Jabber::Error which
itself inherits from Ruby’s StandardError. This is a first step in
re-factoring errors. The next step will be to convert all ‘raise’ calls to
raise a custom Jabber::Error or one of its children instead of anonymous
RuntimeErrors. This allows much more granularity in catching and handling
errors later.
If you were catching Jabber::ErrorException before you should probably
change that in your code to now catch Jabber::Error if you want to
catch everything or one of the custom children of Jabber::Error defined in
‘lib/xmpp4r/errors.rb’. Additionally, the Error class which encapsulated
the xmpp error response, has been renamed to ErrorResponse to reflect its
real usage. This free’s up ‘Jabber::Error’ for use as our base Error class.

Say I have these 2 arrays :

Now what if I want a new array that contains only the elements present in both arrays?

Have a nice weekend!

Cart model (as in : shopping cart)

Bill model

User

Basically, because the “through” table links the destination table with a has_one relationship, ActiveRecord complains with : Invalid source reflection macro :has_one for has_many :bills, :through => :carts. Use :source to specify the source reflection.

Someone on Rails Trac already created a ticket about this issue 2 years ago. Can we expect this feature to be officially supported in the future? Let’s hope so.