WEBVTT

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AKIRA MATSUDA: So. Welcome to Ruby on Rails
internal talk.

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This is titled Ruby on Rails Hacking Guide,

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which is deeply inspired by Minero Alki's
Legendary Ruby

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book titles Rails- for, Ruby Hacking Guide.

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So, before I get started, let me just introduce

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myself. I am Akira Matsuda - amatsuda on GitHub

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and Twitter. I'm a committer of Ruby and Ruby

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on Rails projects and I'm from Japan.

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As a individual on GitHub, I created a pagination

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library called kaminari and active_decoractor,
action_args and et cetera,

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et cetera. Such libraries.

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As a Rails committer, ranked in here, in the

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bottom, like, twenty-seventh. I've done 374
commits so far

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and, since I made my first commit about six

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years ago.

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I initially titled this talk as Ruby on Rails

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Hacking Guide, but I slightly changed my mind
after

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I listened to DHH's keynote. This talk should
be

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titled like Ruby on Rails Reading Guide. Since
we're

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actually gonna spend the whole forty minutes
just for

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reading the whole framework code.

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And, not gonna talk anything about, like,
science. But

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it's like, reading a novel, reading a story.
So,

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why should we, why should we read Rails? I

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think we have three big reasons here.

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Firstly, as DHH defined, we're software writers,
and you

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need to read a lot in order to be

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a good writer, right. This is obvious. So,
we

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need to read Rails to be a good Rails

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programmer. And if you don't understand any
piece of

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code in your application, that means you don't
really

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understand your application.

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So, don't let a magical piece of code exist

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in your app. I know that Rails applications
are

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filled with such magics like, for example,
like this.

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It's such simple, just one line of Ruby code,

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in just one method. But it, it really does

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a lot of things for you, right. But we

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need to be able to explain why, why is

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this controller inheriting from ApplicationController
inheriting from ActionController::Base? We.

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Or, how the http request actually calls this
in

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index Ruby method. Or why are we setting this

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u- users relation into a controller instance
variable. Et

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cetera, et cetera.

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Or, think about this example. This, this,
this is

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a typical Rails-ish DSL. This reads good.
It's pretty

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straight forward for readers, as a documentation.
But, you're

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not an application reader, right. We, we're
application writer.

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So you have to write this. And as a

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writer, you don't, don't usually write when
you don't

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understand what it means, right.

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So, so a question. What, what, what is this

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Rails.application.routes.draw, or get in the
second line. Looks like

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a method call taking a hash parameter. What
is

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it doing? Who actually knows, who here actually
knows

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what's gonna happen with this code? Can explain?

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Right. So, if you think, if you think you

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can explain how this define a route, if, if

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you cannot explain. Sorry. If you cannot explain
that

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means for, it's just a magic. And that's why

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you're, you're in this room now, right. So,
you'll

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soon get to know what the get means.

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And as the third reason to read Rails code

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is because Rails.has_many :bugs. So, as I
told you,

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I patched a lot. And mostly I, I patch

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Rails because I hit bugs in my production
application.

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And I guess, you all have the same experience.

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I'm sure. Rails is basically buggy. And we
need

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to deal with them. With the bugs.

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So, naturally, Rails programmer job is not
just to

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maintain the application, but you also need
to maintain

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Rails framework as well. It's our job. And
it's

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your job. So we need to be familiar with

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the code base.

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And strangely, this talk is kind of categorized
as

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a novice talk. But, I'm not sure. I'm, I'm

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gonna talk about the Rails internal. So. I
hope

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you enjoy.

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Let's begin. This is what I'm gonna talk.
So,

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first of all, Ruby on Rails is a open-source

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software on GitHub. There's no C-extension
inside. So. I

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mean, there's, there's no C-code. 100% Ruby.
That means,

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if you're a Ruby programmer, you just can
read

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it and, and you can write it if necessary.

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You can get its source code here, by git

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cloning from GitHub. By the way, here's a
tiny

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tip. How you can find the GitHub repository
for

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the gem you use. You can use, you can

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use a gem named gem-src. It's on, it's here

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on GitHub. And please take a look at this

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repository. This is how you can install it
and

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how you can use it.

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I'm not gonna explain here. But. So, what
this

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does is after this gem installed, it will
automatically

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git, git clone this source from GitHub repository.
So,

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you, you need not to memorize the author's
name

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or you can not, you don't need to search

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on GitHub. As a gem install, it automatically
gets

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the code from GitHub. It's so useful for social

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coders.

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Anyway. Let's go back to the Rails source.
Firstly,

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let's see what's included in the gem. To know

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what's included in gem, take a look at the

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gemspec. So this is taken from the file rails.gemspec.

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Here it defines the files included. It looks
like

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it doesn't really include any program. It's
just documents,

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right.

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And you can find these declarations. A bunch
of

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add_dependencies. So that means Rails has
no code inside,

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but instead if defines several dependencies.
It means that

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this is a meta, meta-gem, meta-package, to
install these

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seven gems, right.

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And these seven gems are in the Rails repository.

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And Rails is a full-stack framework, a full-stack
MVC

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framework. And all these M and V and C

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are included in this one repository. So we
have

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model, view, and controller.

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And we have these gems. I'm sorry it's, can

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you read it? I'm sorry it's hard to read.

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Anyway. We have ActiveRecord, ActionPack and
ActionView. And this

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is something called model, and these are views,
and

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these are controllers.

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So, Rails gem is a meta-package that depends
on

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these seven gems.

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So let's take a look at the Rails server

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command and, and let me explain how, how the

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Rails actually boots. For, starting up the
Rails server,

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you just need to run Rails server command.
So,

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what's happening internally when you execute
this command?

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When I hit the Rails command it actually executes

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bin slash rails in your application. So, let's
read

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that file first. That file should look like
this.

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It requires config/boot inside your application
first, and then

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requires rails/commands.

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Rails/boot looks like this. It just bundles
something. I'm

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gonna skip the bundler part, because it's,
it's out

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of today's scope, but it, it, it kind of

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tweaks the $LOAD_PATH nicely.

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And so the second line. Rails/commands. It
requires rails/commands.

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So where is "rails" directory? You can find
"rails"

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directory in the railties gem. There's a gem
called

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railties, which I, I didn't explain. So, next
chapter

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is about railties.

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What, what actually railties is? Railties
is a very

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wisely-crafted tiny library, initially created
by Yehuda Katz and

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Carl, Carl Lerche. So let's dive into it.

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Here's the gemspec. The gemspec says this
is about

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Rails internals. And the gemspec shows that
now this

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gem includes some libraries. Ruby files. Actually,
it includes

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like this. So, when you step inside the railties

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lib directory, you'll see these. One directory
and one

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file called rails dot rb.

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So these's the rails directory. And this is
how

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Rails/commands dot rb looks like in the railties
gem.

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It requires commands_tasks, and then invokes
a CommandTask with

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a given command name. ARGV, right.

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In this case, so, in this case server, right.

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So this is the file named commands_tasks dot
rb.

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It requires rails/commands/server first. So
let's take a look

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at rails/commands/server. And this is rails/commands/server.
It requires, at

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very top, it requires rails. So, then jump
to

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rails dot rb. Rails dot rb was at the

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very top of the repository, right.

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So this is how rails dot rb looks like.

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It requires rails/application. So, let's go
to rails/application. And

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it defines a top-level module named Rails.

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So rails/application, it requires rails/engine,
and it defines a

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Rails Application class, inheriting Rails
Engine.

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So, jump to rails/engine. Now, rails/engine
requires rails/railtie and

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it, Rails Engine class inherits from Rails
Railtie. So,

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next file is rails/railtie.

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Railtie, it looks like this. It requires rails/initializable
and

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rails/configuration. And defines Rails Railtie
class, that includes Rails

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Initializable. So next follow the, next file
is rails/initializable.

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It defines a Rails Initizable- Initializer.

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So, what we learned so far is, railties defines

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these core classes, like Application, Engine,
Railtie, Initializable. Which

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are very, very important. Actually, the core
of Rails.

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So railties is like this. It's the core of

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Rails, in the middle.

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And we had something called Plugin as well,
but

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it was gone since Rails 4.

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So, let's skip it. So railties is a library

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providing something underneath the Rails Application.
And I have

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another answer for you. Railties is, according
to Wikipedia,

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this is the definition of something called
Railroad tie.

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It's a rectangular piece of wood which is
laid

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underneath the rails, sometimes called sleeper,
railway sleeper.

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So this is rail ties. Consider this. The applications

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are the trains that run on Rails, and railties,

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Rails is the framework, and railties is something
lies

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underneath the Rails framework. This is why
they named

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it railties, I guess. This is a beautiful
metaphor,

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isn't it?

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So how does it work? Or, how can we

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use it? This is how, how, how it's work.

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We can git grep the whole railtie repository,
and

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you can find some uses of railtie. These are

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in, not only in railties, they're actually,
these are

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in mailers, ActiveRecord, ActionPack, blah,
blah, blah.

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We're gonna take it. So, so let's take a,

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take a look at it, like this. So, each

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component has its own railtie, inheriting
from Rails::Railtie, like

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this. This is how we use railtie.

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So, railtie is not only in the core, but

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in, we can find railties everywhere. Railtie.
It's inside

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each component, right. And, so, this is what's
written

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inside the railtie class.

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It has some, mainly we, we see two kinds

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of class method calls, config and initializer,
right. These

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are class method calls to railtie class. So,
what's

00:18:22.799 --> 00:18:24.299
config?

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This is the definition. Railtie config create
something. Instantiates

00:18:31.679 --> 00:18:38.679
something like Railtie::Configuration. And
so config is a instance

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of Railtie::Configuration. Railtie::Configuration
is something like this. It, it

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has one method_missing method. And it accepts
any method

00:18:52.220 --> 00:18:55.860
call and just stores the given name and arguments

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and block into a class-level hash.

00:19:02.570 --> 00:19:09.570
So, what is initializer? Initializer looks
like this. The,

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it just keeps the given block as a proc

00:19:15.600 --> 00:19:22.600
instance, with a name, with a given name,
right.

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So, this is everything. This is what railties
is

00:19:32.610 --> 00:19:38.019
doing. It, it sets something, some values
via config

00:19:38.019 --> 00:19:42.950
method call and initializer method call. And
to, to

00:19:42.950 --> 00:19:49.950
use them for the later use.

00:19:51.299 --> 00:19:54.370
And railties is actually class, but it's prohibited
to

00:19:54.370 --> 00:19:59.610
instantiate. So, you cannot make a instance
of the

00:19:59.610 --> 00:20:06.610
railtie class. Instead, you just can inherit
and, when

00:20:07.809 --> 00:20:13.960
inherited, it, it kind of memorizes the, the
children

00:20:13.960 --> 00:20:17.889
class names.

00:20:17.889 --> 00:20:24.759
So, this is a summary what, of what railties

00:20:24.759 --> 00:20:27.759
is doing. Railties is a core of Rails that

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provides Railtie, Engine, Application, et
cetera, and we can

00:20:30.779 --> 00:20:34.870
find Railtie in other Rails components like
ActiveRecord, ActionPack.

00:20:34.870 --> 00:20:38.580
And a railtie can keep config and initializer
values.

00:20:38.580 --> 00:20:43.499
And Railtie ties up these railties, all right.

00:20:43.499 --> 00:20:47.009
So, let's see how, how actually Rails server
ties

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these up. And how, how Rails server boots.
So,

00:20:53.999 --> 00:20:58.169
let's go back to rails/commands/commands_tasks
dot rb. After it

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requiring rails/commands/server, it executes,
it requires the application and

00:21:03.929 --> 00:21:07.340
then executes server dot start.

00:21:07.340 --> 00:21:14.340
Server dot start is defined here, because
it was

00:21:15.909 --> 00:21:22.909
defined in Rails/commands/server. Server dot
start calls, just calls

00:21:23.870 --> 00:21:28.470
super. And super is, super class of this class

00:21:28.470 --> 00:21:30.669
is Rack::Server.

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So, welcome to the Rack world. Now, now we

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need to read the Rack code. Oh my god.

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This is not Rack hacking guide, so I'm just

00:21:51.970 --> 00:21:58.970
gonna skip it. It. Anyway. Finally calls something
like

00:22:04.019 --> 00:22:11.019
this, via rack/builder. It evaluates this
Ruby string. Like,

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Rack::Builder dot new taking contents of config
dot ru

00:22:22.549 --> 00:22:26.610
in your application.

00:22:26.610 --> 00:22:33.610
And Rack::Builder just instance_evals the
given block. So, this

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is what's written inside your application's
config dot ru.

00:22:43.940 --> 00:22:50.940
It requires config/environment dot rb first,
and runs Rails.application.

00:22:52.299 --> 00:22:55.220
Run is also a Rack command, I mean, Rack

00:22:55.220 --> 00:22:58.379
method.

00:22:58.379 --> 00:23:05.379
So, I just, I just, like, explained very fast,

00:23:07.519 --> 00:23:11.730
like, how the method, method call goes. How
method

00:23:11.730 --> 00:23:15.409
call graph looks like. So, I guess you find

00:23:15.409 --> 00:23:19.759
it difficult to follow, and how can it actually

00:23:19.759 --> 00:23:24.090
follow these method, method call graphs?

00:23:24.090 --> 00:23:30.929
Here's one tip. Just, puts caller from, in
a

00:23:30.929 --> 00:23:35.019
file inside your application. For, example,
in config dot

00:23:35.019 --> 00:23:39.919
ru file, like this. Just add a puts caller

00:23:39.919 --> 00:23:44.299
here. And run Rails server. Then, you'll get
an

00:23:44.299 --> 00:23:50.870
output like this in your console.

00:23:50.870 --> 00:23:55.730
And these, these are basically what I explained.
Like,

00:23:55.730 --> 00:24:02.730
we see commands/task and server and, like,
Rack::Builder.

00:24:05.919 --> 00:24:12.210
So, this is very useful. Like, when you get

00:24:12.210 --> 00:24:17.940
lost in the Ruby, Ruby jungle, use puts caller

00:24:17.940 --> 00:24:22.869
in caller locations, and that'll show you
the path

00:24:22.869 --> 00:24:25.690
to the place you are.

00:24:25.690 --> 00:24:32.690
All right. Anybody, but. The config dot ru
file

00:24:33.759 --> 00:24:39.039
requires config/environment.rb, and this is,
as you know, what's

00:24:39.039 --> 00:24:44.679
written inside the config/environment.rb.
It requires config/application dot rb

00:24:44.679 --> 00:24:47.610
and calls Rails.application.initialize!

00:24:47.610 --> 00:24:54.610
So, Rails.application.initialize! is the very,
very important method. As

00:24:57.809 --> 00:25:01.720
you may notice from, because it, it has an

00:25:01.720 --> 00:25:08.720
exclamation mark. This is what's written in
application.rb. Since,

00:25:09.220 --> 00:25:13.529
Rails 4 point 1, it, it really has nothing

00:25:13.529 --> 00:25:16.970
in its, in its class.

00:25:16.970 --> 00:25:23.970
But, but it defines a class called Application,
inheriting

00:25:24.360 --> 00:25:31.360
from Rails::Application.

00:25:33.499 --> 00:25:39.460
Before that, it requires rails/all and bundles
all the

00:25:39.460 --> 00:25:45.330
bundled gems. So this is rails dot, rails/all
dot

00:25:45.330 --> 00:25:51.759
rb. What it actually does is something like
this.

00:25:51.759 --> 00:25:57.909
It defines, so, it requires all these railties
that

00:25:57.909 --> 00:26:04.909
I showed you before. Railties defines configs
and initializers,

00:26:06.330 --> 00:26:10.879
as we have seen already.

00:26:10.879 --> 00:26:17.879
And then, we call Rails.application.initialize
exclamation. So, so we,

00:26:22.039 --> 00:26:27.929
we define initializers here and load all initializers
and

00:26:27.929 --> 00:26:33.049
then initialize exclamation, right.

00:26:33.049 --> 00:26:40.049
So, this is the initialize method. It run_initializers,
and

00:26:41.559 --> 00:26:48.559
run_initializers, it calls run, run method
for, for each

00:26:53.059 --> 00:26:59.830
initialize- initializable object in the initializers
collection.

00:26:59.830 --> 00:27:06.070
So initializable looks like this. Run just
executes the

00:27:06.070 --> 00:27:13.070
given argument. I mean, instance_exec through
stored proc inside

00:27:13.950 --> 00:27:20.950
the same context, right. I mean, in this case,

00:27:23.080 --> 00:27:27.119
at sign context is actually the application
instance, so

00:27:27.119 --> 00:27:34.119
it just instance_execs the stored procs in
the initializers.

00:27:34.460 --> 00:27:38.190
In the application's context.

00:27:38.190 --> 00:27:45.190
So, I said initializers collection. Initializers
collection is this.

00:27:52.749 --> 00:27:59.749
And initializers, so, initializers, yeah.
In rai- railties initializers

00:28:02.239 --> 00:28:07.860
was created like this. So, what, what's in
the

00:28:07.860 --> 00:28:13.669
initializer's collection is instances of Rails
initializer, initializable initializer.

00:28:13.669 --> 00:28:20.320
Which, each initializer just, just holds a
proc instance,

00:28:20.320 --> 00:28:24.159
right.

00:28:24.159 --> 00:28:27.269
And as we've seen already these are called
from

00:28:27.269 --> 00:28:33.129
each Railtie classes.

00:28:33.129 --> 00:28:40.129
So. This is, this is what initialize do. And,

00:28:41.129 --> 00:28:45.659
so let's go back to the server. As we've

00:28:45.659 --> 00:28:52.659
seen, the start method calls super. I'm sorry.
I'll

00:28:52.730 --> 00:28:54.440
skip this.

00:28:54.440 --> 00:29:01.440
So. Summary. So, this is what we, what the

00:29:02.830 --> 00:29:08.210
railtie does for booting up the Rails server.
Finally,

00:29:08.210 --> 00:29:13.669
it runs Rails::Application in config dot ru.
Do you

00:29:13.669 --> 00:29:17.610
remember? It's written in config dot ru file.
Run.

00:29:17.610 --> 00:29:20.340
Run the application.

00:29:20.340 --> 00:29:26.539
So what is run? What is run method? It's

00:29:26.539 --> 00:29:31.499
defined like this. And with this, with this
definition,

00:29:31.499 --> 00:29:38.499
the Rack server calls Rails.application dot
call. Rails.application responds

00:29:41.129 --> 00:29:44.789
to call. So you can call this. That means

00:29:44.789 --> 00:29:47.850
Rails.application is a Rack application.

00:29:47.850 --> 00:29:54.489
And Rails.application as a Rack application,
it, it has

00:29:54.489 --> 00:29:58.759
a call method like this. It calls super. The

00:29:58.759 --> 00:30:05.759
super, the Rails.application super class was
Rails::Engine. So, so

00:30:07.429 --> 00:30:08.999
jump to Rails::Engine.

00:30:08.999 --> 00:30:15.999
Rails::Engine has this like call method. OK.
The call

00:30:16.080 --> 00:30:22.769
goes to app dot call. App is something like

00:30:22.769 --> 00:30:28.460
this. It's a config middleware that contains
default middleware

00:30:28.460 --> 00:30:35.460
stack, and the endpoint, something called
endpoint. Look at

00:30:36.039 --> 00:30:38.049
this.

00:30:38.049 --> 00:30:44.330
So, what's the end point? End point is a

00:30:44.330 --> 00:30:51.330
route. Route is a ActionDispatch::Routing::RouteSet
by default. OK.

00:30:56.169 --> 00:31:03.169
So. So, the next thing is routes. Route is

00:31:06.989 --> 00:31:13.989
usually defined in config/routes dot rb like
this. So,

00:31:14.379 --> 00:31:21.289
let's think of this simple route. Routes,
Rails.application.routes is,

00:31:21.289 --> 00:31:28.289
is ActionDispatch::Routing::RouteSet. It's
defined here in ActionDispatch gem, I'm

00:31:29.159 --> 00:31:33.749
sorry. ActionPack gem in action_dispatch directory.

00:31:33.749 --> 00:31:38.470
It, it also responds to call, as it's a

00:31:38.470 --> 00:31:45.470
Rack application. And call goes to router
dot call.

00:31:47.460 --> 00:31:54.460
Router is defined like this. Journey::Router.new.
So, so router

00:31:54.690 --> 00:31:57.059
is a Journey thing.

00:31:57.059 --> 00:32:04.059
Then, so Rails.application routes is also
a Rack application

00:32:14.080 --> 00:32:17.989
that defines endpoint, and it finally goes
to the

00:32:17.989 --> 00:32:20.679
Journey thing. But for now let's go back to

00:32:20.679 --> 00:32:25.590
the Routes.draw DSL.

00:32:25.590 --> 00:32:28.340
Here.

00:32:28.340 --> 00:32:35.340
So, routes.draw is defined like this. It just
evaluates

00:32:37.059 --> 00:32:44.059
the given block. In the ActionDispatch routing
mapper. So,

00:32:47.570 --> 00:32:54.519
this DSL actually calls ActionDispatch::Routing::Mapper#get
method, right. And get

00:32:54.519 --> 00:32:58.799
method is like this. It calls map_method.
map_method calls

00:32:58.799 --> 00:33:05.600
match. match calls decomposed_match, and decomposed_match
calls add_route.

00:33:05.600 --> 00:33:12.600
So, anyway. It finally goes to Mapper#add_route.
And Mapper

00:33:14.190 --> 00:33:21.190
add_route calls Mapping dot new route. And
add_route returns

00:33:24.330 --> 00:33:31.330
a, finally, it returns a Journey route. And
then,

00:33:31.879 --> 00:33:37.789
like, adds the given, sorry, the traded route
into

00:33:37.789 --> 00:33:42.649
the collection. Journey::Routes collection.

00:33:42.649 --> 00:33:49.649
So. So, this is what the Journey does. And,

00:33:51.059 --> 00:33:58.059
what's this? Yeah. It finally calls Mapper
to_route, Mapping#to_route,

00:33:58.609 --> 00:34:02.340
so to_route is defined like this.

00:34:02.340 --> 00:34:09.340
I'm just gonna skip this. It's, it just returns

00:34:11.379 --> 00:34:16.219
the given app parameter, which was the endpoint
given

00:34:16.219 --> 00:34:21.239
into the methods parameter. So it finally,
finally it,

00:34:21.239 --> 00:34:28.010
it returns endpoint. And endpoint is if, if
it

00:34:28.010 --> 00:34:32.679
responds_to call, just returns that. And if
not, call

00:34:32.679 --> 00:34:34.500
Dispatcher.

00:34:34.500 --> 00:34:41.500
So. So the, the. The hash value can, could

00:34:45.239 --> 00:34:49.750
be respond_to call, for example, like this.
Or mounted

00:34:49.750 --> 00:34:53.659
engine, for example. But usually it doesn't
respond to

00:34:53.659 --> 00:35:00.660
call, so it calls dispatcher. Dispatcher is
a Routing::RouteSet::Dispatcher.

00:35:04.940 --> 00:35:08.080
And Dispatcher is also a Rack app, so it

00:35:08.080 --> 00:35:12.190
can be called. And the call the Dispatcher
goes

00:35:12.190 --> 00:35:16.900
to, dispatch method.

00:35:16.900 --> 00:35:23.900
Dispatch, so, it finally goes at the bottom
line.

00:35:25.030 --> 00:35:28.470
It finally goes to controller dot action with
a

00:35:28.470 --> 00:35:35.470
given action name, dot call. So, so finally,
what,

00:35:36.970 --> 00:35:42.730
what the router finally calls is this. FooController
dot

00:35:42.730 --> 00:35:49.730
action method with a given action, action
name. And

00:35:50.280 --> 00:35:52.830
it returns something callable.

00:35:52.830 --> 00:35:58.790
So, this is the route DSL. get "/hello" =>

00:35:58.790 --> 00:36:05.790
"foo#bar" maps to FooController dot action('bar').

00:36:10.760 --> 00:36:15.090
This is about Journey. And I think I have

00:36:15.090 --> 00:36:17.150
no time, so I'm gonna skip this. I'm gonna

00:36:17.150 --> 00:36:22.200
skip this long Journey. Anyway, it resolves
the route.

00:36:22.200 --> 00:36:26.610
So, this is a summary. The, the main point

00:36:26.610 --> 00:36:29.800
is that 'foo#bar' becomes a Rack application
generated by

00:36:29.800 --> 00:36:33.740
FooController dot action('bar').

00:36:33.740 --> 00:36:39.870
So, the final chapter. Controllers and actions.
This, what's

00:36:39.870 --> 00:36:42.770
gonna happen when the server got a request?
It,

00:36:42.770 --> 00:36:49.770
it, it just calls this. So what is this?

00:36:50.500 --> 00:36:57.500
Firstly, the action method is defined like
this. It's,

00:37:00.730 --> 00:37:06.140
it calls the new dot dispatch inside the block.

00:37:06.140 --> 00:37:09.260
New, new means Controller dot new.

00:37:09.260 --> 00:37:16.260
So, dispatch, dispatch method creates set,
call set_response! and

00:37:16.430 --> 00:37:20.310
then calls super. So, what this dispatch method
does

00:37:20.310 --> 00:37:27.310
is creates Rails response object. And then
dispatch method,

00:37:29.720 --> 00:37:34.320
then creates request object. Whoops.

00:37:34.320 --> 00:37:39.990
All right. It sets the request object into
the

00:37:39.990 --> 00:37:46.990
instance. And then calls process method. Dispatch
finally calls

00:37:47.730 --> 00:37:53.940
ActionController::Metal#process. So, this
is what's written inside the process

00:37:53.940 --> 00:37:58.590
method. process method calls process_action,
and process_action calls send_action,

00:37:58.590 --> 00:38:05.590
and send_action is aliased to send. Ruby's
send method,

00:38:07.140 --> 00:38:09.130
right.

00:38:09.130 --> 00:38:16.130
So, FooController dot action('bar') creates
the Rails Request and

00:38:17.140 --> 00:38:21.780
Response objects into the controller instance.
Then, it just

00:38:21.780 --> 00:38:25.370
calls, calls the method name bar via Ruby
send

00:38:25.370 --> 00:38:28.810
method, OK.

00:38:28.810 --> 00:38:34.240
So, it can be like, FooController dot new,
with

00:38:34.240 --> 00:38:38.400
something, dot bar. It's a very simple Ruby
method

00:38:38.400 --> 00:38:43.080
call, finally. So, this is what's happening
inside the

00:38:43.080 --> 00:38:50.080
HTTP request. When the Rails server accepts
the HTTP

00:38:51.980 --> 00:38:57.360
request, it, it kind of, the Journey kind
of,

00:38:57.360 --> 00:39:02.060
somehow, resolves the results, and finally
calls this simple

00:39:02.060 --> 00:39:06.430
Ruby method. OK?

00:39:06.430 --> 00:39:10.530
And I guess it's, yeah. I guess it's time.

00:39:10.530 --> 00:39:17.530
I have thirty, thirty seconds left. So.

00:39:18.840 --> 00:39:24.270
Obviously there's more and more and more topics
about

00:39:24.270 --> 00:39:29.220
Rails internals, but unfortunately I had,
I just had

00:39:29.220 --> 00:39:32.090
forty minutes. Forty minutes was not enough
to talk

00:39:32.090 --> 00:39:37.740
about, like, ActiveRecord internals or helpers
or ActionPack, ActionController

00:39:37.740 --> 00:39:40.940
- these things.

00:39:40.940 --> 00:39:44.920
So, this is the end of my talk. But

00:39:44.920 --> 00:39:49.930
I'm kind of planning to write a book titled

00:39:49.930 --> 00:39:56.930
Ruby on Rails Hacking Guide. So, so hopefully.
I'm

00:39:57.580 --> 00:39:59.810
planning to write it in Japanese first and
then

00:39:59.810 --> 00:40:03.760
translate it into English later. So, hopefully
can find

00:40:03.760 --> 00:40:07.330
it, like, next year, maybe.

00:40:07.330 --> 00:40:12.900
And, yeah. I'll write everything in that book.
So

00:40:12.900 --> 00:40:19.900
please wait until the book is coming. Thank
you

00:40:19.900 --> 00:40:21.140
very much.