Silence is Foo Mental notes on Ruby, Git, Rails and whatever geeky thing

My friend the Rails console – Part II

You can find the first part clicking here.

Despite all this Rails 3 thingy, we have to face it, we won't ditch Rails 2.3.x anytime soon, so I'm still in the mood to post things about Rails 2.3.x. This time I'll try to provide you guys with some Rails 3 version of the tricks or tips shown here.

Let's get it started.

Accessing helpers

When we fire up the Rails console automatically we have an instance of ActionView::Base called helper; if you have helper :all in your ApplicationController all the files in the app/helpers folder will be available in the helper object.

If we included all the helpers, using the Double-TAB trick (completion) would be a little bit annoying because we might have a lot of helpers starting with the same words. Let's fix it.

waza = ActionView::Base.new
waza.extend WazaHelper
waza.waza_helper_method(10) # => <waza>10</waza>

Remember that all the helpers are Ruby modules, and we can't instance modules, only mix them into classes

Now, let's say we haven't included all the helpers and we need to use one of those, say WazaHelper again.

helper.waza_helper_method # => method not found
include WazaHelper
waza.waza_helper_method(10) # => <waza>10</waza>

ActionController logging

In the first part of this post I spoke about calling controller actions from console, well, now I want to see what is being logged when I call those actions:

ActionController::Base.logger = Logger.new(STDOUT)
reload!

Or you can use a helper from my .irbrc:

log_ac_to STDOUT

Log your sessions to a separate log file

Let's say you have a buggy model and you are in one of those never-ending debugging sessions, and you'd like to send all the ActiveRecord logs to a separate file:

my_logger = Logger.new('log/my_logger.log')
my_logger.info('testing my logger') # go to see my_logger.log

ActiveRecord::Base.logger = my_logger
reload!

NOTE: Logger.new will create the log/my_logger.log if it doesn't exists, if it does, it'll use it.

Now, If you want to send the logs back to the console

ActiveRecord::Base.logger = Logger.new(STDOUT)
reload!

Or you can use a helper from my .irbrc:

log_ar_to :waza #ActiveRecord will log to log/waza.log
log_ar_to STDOUT #ActiveRecord will log to console

Environment shortcuts in Rails 2

There are several ways to specify the environment:

$ RAILS_ENV=production script/console

$ script/console production

but there are a shorter way to do it:

$ alias sc='script/console' # you can put this in your ~/.bash_profile or ~/.bashrc

$ sc p # => production
$ sc d # => development
$ sc t # => test

The "p", "d" and "e" shortcuts were implemented in Rails 2, you can see the implementation clicking here

Sadly, this won't work in Rails 3, these shortcuts have been deprecated and I haven't found either any documentation about the shortcuts nor any deprecation warning in Rails 3.

The good news is that Rails 3 comes with some predefined shortcuts by default

$ rails --help #it will show the list of commands and their shortcuts

console      Start the Rails console (short-cut alias: "c")
server       Start the Rails server (short-cut alias: "s")

Let's make it even shorter

$ alias r='rails' # you can put this in your ~/.bash_profile or ~/.bashrc
$ r c

Using different ruby versions in the console

$ script/console --irb ruby1.9

In Rails 3 the --irb option has been deprecated, if you use this option Rails 3 will respond with:

DEPRECATED: Invoke `/your/choice/of/ruby script/rails console` instead

so you have to do:

$ ruby1.9 script/rails console

The Rails Runner

Suppose you want to run some specific code in the Rails context, you can use script/console but sometimes you want to execute just a single line, that's what the runner was made for:

$ alias sr='script/runner'

$ sr 'MyJob.new.do_it'

You can send a file as argument too and specify an environment

$ sr -e production 'deploy.rb'

Want to send arguments to the deploy.rb file?

$ sr -e production 'deploy.rb' -- arg1 arg2

If you want to schedule a background job to run every 15 minutes:

0,15,30,45 * * * * PATH_TO_APP/script/runner -e production 'MyJob.new.perform'

The ~/.irbrc file

Everytime you fire the rails console or even just irb, this file is read. You can load gems, insert helpers, extend the ruby core, etc.

You can find my personal .irbrc file in this git repository http://github.com/rafmagana/irbrc

Hacking IRb

There's a number of gems that will help to make the console even better:

Utility Belt - http://utilitybelt.rubyforge.org/
Wirble - http://pablotron.org/software/wirble/
Pretty Print - http://is.gd/dAg40
Awesome Print - http://github.com/michaeldv/awesome_print

But, what if you don't find what you need in any library.? My first approach is to look for others .irbrc's and copy what I find useful, if I don't find what I need I make my own helpers.

Here I'll show you some simple examples.

Helpers

Sometimes I find myself writing 'clear' but that method doesn't exist in IRb, so

def clear
  system('clear')
end

The following is a very common trick among ruby developers

class Object
  def local_methods
    (methods - Object.instance_methods).sort
  end
end

it returns an array of methods defined in the parent class of the object

class Waza
   def say_hello(name)
      "hello, #{name}"
   end
end

w = Waza.new
w.local_methods # => ["say_hello"]

Nice!, let's get a little bit further

class Class
    def class_methods
       (methods - Class.instance_methods - Object.methods).sort
    end
end

class Waza
    def self.am_i_a_class?
       "yes, and an object too"
    end
end

Waza.class_methods # => ["am_i_a_class?"]

Interacting with the Mac pasteboard (clipboard)

Mac OS has some commands to access the pasteboard from terminal (http://is.gd/dAQjQ), pbcopy and pbpaste:

$ echo "http://download/file.zip" | pbcopy (or you can press Cmd-C in Safari or wherever)

$ wget `pbpaste` # wget http://download/file.zip (Cmd-V)

I really use these commands almost as a daily basis, but I wanted to use them in IRb, so I did it.

In my .irbrc you can find I extended the Object class with two methods:

Object#to_pb => copy text to the Mac OS's pasteboard
Object#paste => paste text from the Mac OS's pasteboard

UPDATE: I made a gem called PasterboaRb that adds these methods to the Object class.

"my text".to_pb

If you go to any Mac application and press Cmd-V the "my text" text will be pasted.

"ruby".to_pb
waza.say_hello paste # => "hello, ruby"

The Mac OS has 4 pasteboards: general, ruler, find and font.

"mac".to_pb	:general # default
"rails".to_pb :find
"ruby".to_pb :ruler
"rack".to_pb :font

waza.say_hello(paste :find) # => "hello, rails"
waza.say_hello(paste :ruler) # => "hello, ruby"
waza.say_hello(paste :general) # => "hello, mac"
waza.say_hello(paste :font) # => "hello, rack"

I really don't know what "ruler" and "font" are useful for, I couldn't find any documentation, but:

"general" - it's the default pasteboard; Cmd-C and Cmd-V use this pasteboard
"find" - Used by Cocoa applications to hold the value of the find field. (Whaaaat?)

Do the following:

"find rails".to_pb :find

Then open Safari or Textmate or whatever Cocoa application you want, now press Cmd-F and the text field will be automatically populated with the value of the "find" pasteboard, in this case, "find rails".

Real-life examples?

If I need to share an objects through several IRb sessions, I mean, in different terminals.

Terminal 1

w = Waza.new
w.name = "rails"
w.to_yaml.to_pb

Terminal 2

w = YAML::load paste
w.name # => "rails"

Sometimes I want to copy to the pasteboard something that a method returns, like usernames, email addresses, passwords, etc:

User.find(10).email.to_pb

Then I can paste the email pressing Cmd-V wherever I want. Yes, I'm that lazy.

That's it, hope it helps.