Web Applications With Rails (not Ruby)

Web Applications with Ruby David Padilla @dabit

Image from: ezilon.com

Manzanillo, Mexico

June 4 - 6 2014

Web applications with Ruby (not Rails)

I invented MVC on ASP Classic

Not really

<% set conn=Server.CreateObject("ADODB.Connection") conn.Open "northwind" %> <html> <head> <title>Super App</title>
<link href="style.css" /> </head> <body> <h1>Page 1</h1> <% ' Some code here that connects to the DB and ' displays stuff %> </body> </html> page1.asp

<% set conn=Server.CreateObject("ADODB.Connection") conn.Open "northwind" %> <html> <head> <title>Super App</title>
<link href="style.css" /> </head> <body> <h1>Another Page</h1> <% ' Some code here that connects to the DB and ' displays stuff %> </body> </html> AnotherPage.asp

Index.asp  <html> <head> <title>Super App</title> <link href="style.css" />
</head> <body> <% page = Request.QueryString("page") Select Case page Case "page1" %> <% Case "AnotherPage" %> <% End Select %> </body> </html>

http://therantygirl.ﬁles.wordpress.com/2012/07/happy-cat.jpg

Mid Programmer Life Crisis

Programming Web applications with Rails is BORING

Building websites with Rails is not programming

Most of us don’t know what’s going on outside of
Rails

We used to have all these problems

We used to actually write SQL

Bring programming back

I invented rhp

<% $greeting = "Hello World" %> <% require "includes/stylesheets.rb" %>
<html> <head> <title>RHP Rocks!</title> <%= Stylesheets.render() %> </head> <body> <h1><%= $greeting %></h1> <p>RHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML. If you are new to RHP and want to get some idea of how it works, try the introductory tutorial. After that, check out the online manual.</p> </body> </html> cgi/index.erb

<% $greeting = "Hello World" %> <% require "includes/stylesheets.rb" %>
<html> <head> <title>RHP Rocks!</title> <%= Stylesheets.render() %> </head> <body> <h1><%= $greeting %></h1> <p>RHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML. If you are new to RHP and want to get some idea of how it works, try the introductory tutorial. After that, check out the online manual.</p> </body> </html>

I invented rhp (not really)

Rack is cool as Bowties

Web applications with Ruby (not Rails)

Web Server Web Application A hash with request headers that
we call ENV

we call ENV respond_to(:call)

we call ENV

[http_code, headers, body] Integer Hash Responds to :each

Web Server Web Application [http_code, headers, body]

run -> (env) { puts env [200, {}, []] }
conﬁg.ru

conﬁg.ru run -> (env) { [200, headers, [body]] } body
= "<html><body><h1>Hello World</h1></body><html>" headers = { "Content-Length" => body.length.to_s }

Router

/posts PostController #index

conﬁg.ru run -> (env) { [200, headers, [body]] } body
= "<html><body><h1>Hello World</h1></body><html>" headers = { "Content-Length" => body.length.to_s }

conﬁg.ru $: << '.' require 'app' run App.new

app.rb class App def call(env) body = "<html><body><h1>Hello World</h1></body><html>" headers
= { "Content-Length" => body.length.to_s } [200, headers, [body]] end end

controllers/root_controller.rb class RootController def show body = "<html><body><h1>Hello World</h1></body><html>" headers

app.rb class App def call(env) body = "<html><body><h1>Hello World</h1></body><html>" headers
= { "Content-Length" => body.length.to_s } [200, headers, [body]] end end RootController.new.show end end

app.rb class App def call(env) RootController.new.show end end

app.rb class App def call(env) path = env["REQUEST_PATH"] case path
when %r{^/$} RootController.new.show else [404, { "Content-Length" => "9"}, ["Not found"]] end end end

conﬁg.ru $: << '.' require 'app' require 'controllers/root_controller' run App.new
require 'haml'

views/root/show.html.haml %html %body %h1 Hello World

controllers/root_controller.rb class RootController # ... end def render(view_path) template =
File.open(view_path, 'r').read Haml::Engine.new(template).render end

controllers/root_controller.rb class RootController def show headers = { "Content-Length" =>
body.length.to_s } [200, headers, [body]] end def render # ... end end body = render('views/root/show.html.haml') body = "<html><body><h1>Hello World</h1></body><html>"

views/root/show.html.haml %html %body %h1 Hello World

views/layout/application.html.haml %html %body = yield

controllers/root_controller.rb class RootController def render(view_path) template = File.open(view_path, 'r').read Haml::Engine.new(template).render
end def render_with_layout(view_path) layout = File.open('views/layout/application.html.haml', 'r').re Haml::Engine.new(layout).render do render(view_path) end end end end

def render_with_layout(view_path) layout = File.open #... Haml::Engine.new(layout).render do render(view_path) end
end

controllers/root_controller.rb class RootController def show headers = { "Content-Length" =>
body.length.to_s } [200, headers, [body]] end def render # ... end end body = render('views/root/show.html.haml') body = render_with_layout('views/root/show.html.haml')

controllers/root_controller.rb class RootController def show body = render_with_layout('views/root/show.html.haml') headers =
{ "Content-Length" => body.length.to_s } [200, headers, [body]] end def render(view_path) template = File.open(view_path, 'r').read Haml::Engine.new(template).render end def render_with_layout(view_path) layout = File.open('views/layout/application.html.haml', 'r').re Haml::Engine.new(layout).render do render(view_path) end end end class RootController < Controller def show body = render_with_layout('views/root/show.html.haml') headers = { "Content-Length" => body.length.to_s } [200, headers, [body]] end end

conﬁg.ru $: << '.' require 'app' require 'controllers/root_controller' run App.new
require 'haml' require 'controller'

controller.rb class Controller def render(view_path) template = load_template_file(view_path) Haml::Engine.new(template).render end
def render_with_layout(view_path) layout_template = load_template_file(layout) Haml::Engine.new(layout_template).render do render_template(view_path) end end end

views/root/show.html.haml %h1 Hello World %h1 Hello #{@name}

controller.rb class Controller end attr_accessor :env def initialize(env) self.env =
env end def params Rack::Utils.parse_nested_query(env["QUERY_STRING"]) end

app.rb class App def call(env) path = env["REQUEST_PATH"] case path
when %r{^/$} RootController.new(env).show else [404, { "Content-Length" => "9"}, ["Not found"]] end end end

@available_on_the_view = true binding = self HAML::Engine.new(template).render(binding)

controller.rb class Controller def render(view_path) template = load_template_file(view_path) Haml::Engine.new(template).render end
def render_with_layout(view_path) layout_template = load_template_file('... ') Haml::Engine.new(layout_template).render do render(view_path) end end end class Controller def render(view_path, context = self) template = load_template_file(view_path) Haml::Engine.new(template).render(context) end def render_with_layout(view_path, context = self) layout_template = load_template_file('... ') Haml::Engine.new(layout_template).render(context) do render(view_path, context) end end end `

controllers/root_controller.rb class RootController < Controller def show body = render_with_layout('views/root/show.html.haml')
headers = { "Content-Length" => body.length.to_s } [200, headers, [body]] end end @name = params["name"] || "World"

Models

ActiveRecord::Base

require 'active_record' class User < ActiveRecord::Base #... end model/user.rb

Sequel

model/user.rb require 'sequel' DB = Sequel.sqlite class User def self.all
DB[:users].to_a end end

pg mysql

model/user.rb require 'pg' DB = PG.connect( dbname: 'test', host: 'localhost')
class User def self.all result = DB.exec "SELECT * FROM users" fields = result.fields result.collect do |row| hash = {} row.each_with_index do |value, i| hash[fields[i]] = value end end end end

Once last piece of advice

Don’t actually do this

Logging Caching Database Pooling Cookies Sessions

Read code

Try to understand how things work

You should start writing your own framework!

<3 Rails Core Team

github.com/dabit/wawr

Disclaimer: I do NOT actually think that writing web applications
with Rails is boring

@dabit [email protected] Thank You!

Web Applications With Rails (not Ruby)

Web Applications With Rails (not Ruby)

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