Making Rails Really restful

Making Rails really RestfulImproving the world of Resources on Rails with Restfulie

Fabio Akita - akitaonrails.com - @akitaonrails

Wednesday, June 9, 2010

The greatest thing about talking to you


We’ve been through this already!



No WSDL and WS-*



No WSDL and WS-*No XML-RPC




No $$ enterprisey stuff




No $$ enterprisey stuff

♥ HTTP


♥ HTTP


♥ HTTP

Shared Nothing Architecture


♥ HTTP

Shared Nothing ArchitectureStateless


♥ HTTP


Caching


♥ HTTP


CachingProxies and Reverse Proxies


♥ HTTP


CachingProxies and Reverse Proxies


Discovering a world of

Resources on RailsDavid Heinemeir Hansson RailsConf 2006


Create Read Update Delete



GET POST PUT DELETE

!nd create update destroy

SELECT INSERT UPDATE DELETE


GET POST PUT DELETE




GET POST PUT DELETE




GET POST PUT DELETE




POST /people/createGET /people/show/1POST /people/update/1POST /people/destroy/1


POST /peopleGET /people/1PUT /people/1DELETE /people/1


MyApp::Application.routes.draw do |map| resources :peopleend


class PeopleController < ApplicationController # POST /people/1 # POST /people/1.xml def create end

# GET /people # GET /people.xml def show end

# PUT /people/1 # PUT /people/1.xml def update end

# DELETE /people/1 # DELETE /people/1.xml def destroy endend

form_for(@person) do |f| f.text_field :nameend






link_to 'Show', person






form_for(@person) do |f| f.text_field :nameend






link_to 'Destroy', person, :method => :delete


Answering to mime types



One controller for many clients



One controller for many clientsOne action returning different representations



One controller for many clientsOne action returning different representations

“Content Negotiation"


class PeopleController < ApplicationController def index @people = Person.all

respond_to do |format| format.html # index.html.erb format.js # index.js.erb format.atom # index.atom.builder format.xml { render :xml => @people } end endend


class PeopleController < ApplicationController respond_to :html, :js, :xml def index @people = Person.all respond_with(@people) endend





GET /people=> returns HTML

GET /people.xml=> returns XML

Accept: text/javascriptGET /people=> returns JS

Accept: text/xmlGET /people=> returns XML




















2008Rails 2.2


class PeopleController < ApplicationController respond_to :html, :js, :xml def show @person = Person.find(params[:id]) if stale?(:etag => @person, :last_modified => @person.created_at.utc, :public => true) respond_with @person end endend





GET /people/1



GET /people/1=> returns:

HTTP/1.1 200 OK Etag: "fd19b85b6ba49b5778de34310d141319"Last-Modified: Fri, 21 May 2010 05:31:11 GMTContent-Type: text/html; charset=utf-8Cache-Control: public...



GET /people/1=> returns:

HTTP/1.1 200 OK Etag: "fd19b85b6ba49b5778de34310d141319"Last-Modified: Fri, 21 May 2010 05:31:11 GMTContent-Type: text/html; charset=utf-8Cache-Control: public...



If-None-Match: "fd19b85b6ba49b5778de34310d141319"GET /people/1



If-None-Match: "fd19b85b6ba49b5778de34310d141319"GET /people/1



If-None-Match: "fd19b85b6ba49b5778de34310d141319"GET /people/1=> returns:

HTTP/1.1 304 Not Modified Etag: "fd19b85b6ba49b5778de34310d141319"Last-Modified: Fri, 21 May 2010 05:31:11 GMTCache-Control: public...



If-None-Match: "fd19b85b6ba49b5778de34310d141319"GET /people/1=> returns:

HTTP/1.1 304 Not Modified Etag: "fd19b85b6ba49b5778de34310d141319"Last-Modified: Fri, 21 May 2010 05:31:11 GMTCache-Control: public...


But!


CRUD is not a goal,it’s an aspiration,

a design technique


And we are not done yet!


Why not?

ConsistencySimplicity

Discoverability


Why not?


Discoverability


Why not?


Discoverability


This is NOT necessarily REST



Using HTTP



Using HTTPUsing HTTP Verbs (PUT, DELETE)



Using HTTPUsing HTTP Verbs (PUT, DELETE)

Pretty URIs


Most of what we call “REST” is not REST


REST Principles


REST Principles

Identi"cation of Resources


REST Principles

Identi"cation of ResourcesManipulate resources through representations


REST Principles


Self-descriptive messages


REST Principles


Self-descriptive messagesHATEOAS


REST Goals


REST Goals

Scalability of component interactions


REST Goals

Scalability of component interactionsGenerality of interfaces


REST Goals


Independent deployment of components


REST Goals


Independent deployment of componentsReduce latency, enforce security


REST Goals


Independent deployment of componentsReduce latency, enforce security

http://en.wikipedia.org/wiki/Representational_State_Transfer#Guiding_principles_of_a_REST_interface




Constraints are liberating(a straight jacket for your mind)



What are we doing right?



Uniform Interface (URI Templates)



Uniform Interface (URI Templates)HTTP Verbs (some)




HTTP Status Codes (some)




HTTP Status Codes (some)Content Negotiation


What is missing?


What is missing?

More HTTP (verbs, status codes, headers)


What is missing?

More HTTP (verbs, status codes, headers)Hyperlinks


What is missing?

More HTTP (verbs, status codes, headers)Hyperlinks

Semantic (media-types)


GET POST DELETE



PUT


GET POST DELETE



POST


GET POST DELETE



PATCH


GET POST PUT PATCH DELETE

!nd create replace update destroy

SELECT INSERT UPDATE UPDATE DELETE

RFC 5789 - http://www.innoq.com/blog/st/2010/03/rfc_5789_patch_method_for_http.html


http://www.innoq.com/blog/st/2010/03/rfc_5789_patch_method_for_http.html

http://www.innoq.com/blog/st/2010/03/rfc_5789_patch_method_for_http.html

Why bother?


Why bother?

Consistency


Why bother?



Why bother?


Discoverability


Richardson Restful ModelRichardson Restful Model

Level 3 Hypermedia

Level 2 HTTP

Level 1 URI



Level 3 Hypermedia

Level 2 HTTP

Level 1 URI



Level 3 Hypermedia

Level 2 HTTP

Level 1 URI



Level 3 Hypermedia

Level 2 HTTP

Level 1 URI


The Web as it is


The Web as it is


Evaluation Workflow


Evaluation WorkflowWhen there is a new app



Then move forward to evaluate it




When there is an app being evaluated




When there is an app being evaluatedAnd the app passes the criteria





Then approve the app













And the app doesn't pass the criteria







And the app doesn't pass the criteriaThen decline the app












The Automated Web?


The Automated Web?

?


require 'rubygems'require 'mechanize'

agent = Mechanize.new { |agent| agent.user_agent_alias = "Mac Safari" }

agent.get("http://localhost:3000/apps?state=new")










agent.click agent.page.link_with(:href => /apps\/\d+/)

evaluate = agent.page.link_with(:text => /Evaluate/)agent.post evaluate.href, "" if evaluate

approve = agent.page.link_with :text => /Approve/ decline = agent.page.link_with :text => /Decline/














if approve && decline description = agent.page.search("pre").text

if description =~ /Flash/ agent.post decline.href, ""

elsif description =~ /sex/ agent.post decline.href, ""

else agent.post approve.href, ""

end

end






end

end






end

end






end

end


No Mechanization?


No Mechanization?

Hyperlinks


No Mechanization?

HyperlinksNo Semantics


No Mechanization?

HyperlinksNo Semantics

Human Heuristics


require 'rubygems'require 'active_resource'

class App < ActiveResource::Base self.site = "http://localhost:3000/"end

apps = App.find(:all, :params => { :state => "new" })





GET /apps?state=new





GET /apps?state=new





GET /apps?state=new





GET /apps?state=new


ActionController::Routing::Routes.draw do |map| map.resources :apps, :member => { :evaluate => :post, :approve => :post, :decline => :post }end

POST /apps/1/evaluatePOST /apps/1/declinePOST /apps/1/approve



app = apps.firstapp.post(:evaluate) if app.state == "new"

if apps.first.description =~ /Flash/ app.post(:decline)

elsif apps.first.description =~ /sex/ app.post(:decline)

else app.post(:approve)end






































application/xml

<?xml version="1.0" encoding="UTF-8"?><app> <id type="integer">1</id> <title>Facebook</title> <updated_at type="datetime">2010-06-02T14:16:45Z</updated_at> <state>new</state> <description>Facebook for iPhone ... on the go.</description> <price type="float">0.0</price></app>


Why not ActiveResource?



No Hyperlinks



No HyperlinksNo Semantics




Doesn’t respect HTTP (etag, last modi"ed)




Doesn’t respect HTTP (etag, last modi"ed)Ruby on Rails only Conventions


Why not other web clients?HTTParty, RestClient, Typhoeus, Curb


Why not other web clients?

Most are not really “REST”

HTTParty, RestClient, Typhoeus, Curb



Most are not really “REST”Just URI consumers




Most are not really “REST”Just URI consumers

Wrappers for low level HTTP connections



One goal is to avoid tight coupling


http://restfulie.caelumobjects.com/


http://restfulie.caelum.com.br

http://restfulie.caelum.com.br

Restfulie


Restfulie

Client and Server solution


Restfulie

Client and Server solutionXML, JSON, Atom Representations


Restfulie


Enhances Ruby on Rails


Restfulie


Enhances Ruby on RailsREST Client


Restfulie

@guilhermesilveira

@caueguerra

@georgeguimaraes

@lfcipriani


app/controllers/apps_controller.rb

class AppsController < ApplicationController restfulie respond_to :html, :xml, :atom inherit_resources ...end














Tokamak


Tokamak


app/views/apps/index.tokamak

collection(@apps) do |collection| collection.values do |values| values.id apps_url values.title "Apps List" values.updated_at Time.now.utc end collection.members do |member, app| partial "member", :locals => { :member => member, :app => app } endend


app/views/apps/index.tokamak

collection(@apps) do |collection| collection.values do |values| values.id apps_url values.title "Apps List" values.updated_at Time.now.utc end collection.members do |member, app| partial "member", :locals => { :member => member, :app => app } endend


app/views/apps/_member.tokamak

member.values do |value| value.id app.id value.title app.name value.updated_at app.updated_at.utc value.state app.state value.description app.description value.price app.priceendmember.link "show", app_url(app) if app.state == "new" member.link "evaluate", evaluate_app_url(app)elsif app.state == "evaluating" member.link "approve", approve_app_url(app) member.link "decline", decline_app_url(app)end

















curl -H “Accept: application/atom+xml” http://localhost:3000/apps/1

<entry xmlns="http://www.w3.org/2005/Atom"> <id>1</id> <title>Facebook</title> <updated_at>2010-06-02T14:16:45Z</updated_at> <state>new</state> <description>Facebook for iPhone ... on the go. </description> <price>0.0</price> <link href="http://localhost:3000/apps/1" rel="show" type="application/atom+xml"/> <link href="http://localhost:3000/apps/1/evaluate" rel="evaluate" type="application/atom+xml"/></entry>


http://localhost:3000/apps/1












<?xml version="1.0"?><app> <id>1</id> <title>Facebook</title> <updated_at>2010-06-02T14:16:45Z</updated_at> <state>new</state> <description>Facebook for iPhone ... on the go. </description> <price>0.0</price> <link href="http://localhost:3000/apps/1" rel="show" type="application/xml"/> <link href="http://localhost:3000/apps/1/evaluate" rel="evaluate" type="application/xml"/></app>

curl -H “Accept: application/xml” http://localhost:3000/apps/1














Mechanizable Web


Mechanizable Web

Hyperlinks


Mechanizable Web

HyperlinksLink Relations


Mechanizable Web


Media Types


Mechanizable Web


Media TypesDomain Application Protocol (DAP)


Mechanizable Web



HATEOAS


Mechanizable Web



HATEOASHypermedia As The Engine of Application State


Protocols

Contract


Protocols

Contract

HTTP idioms

Entry-point URIs

Media Types

Protocol


Formats Link Relations

Processing Models

Media Type

Schema

Protocols

Contract

HTTP idioms

Entry-point URIs

Media Types

Protocol


Improving Restfulie


Improving Restfulie

Single interface for representations


Improving Restfulie

Single interface for representationsSmart defaults for serialization


Improving Restfulie


XML serialization compatible with Rails


Improving Restfulie


XML serialization compatible with RailsRails 3 compatibility



One more thing


Mikyung







And the app doesn't pass the criteriaThen decline the app


evaluation_process.rb

require 'restfulie'

class EvaluationProcess < Restfulie::Client::Mikyung::RestProcessModel at "http://localhost:3000/apps/list_new" current_dir File.dirname(__FILE__) follow true

def initialize(*black_list) @black_list = black_list end

def completed?(resource) resource.entries.size == 0 end

def self.run goal = EvaluationProcess.new("Flash", "sex") result = Restfulie::Mikyung.new.achieve(goal).run puts result.response.body endend



require 'restfulie'







require 'restfulie'







require 'restfulie'






steps/evaluation_process.rb

def is_valid?(app) result = true @black_list.each do |word| if app.description =~ /#{word}/ result = false end end resultend

Then "move forward to evaluate it" do |resource| @app = @app.links.evaluate.follow.post!("") resourceend

When "the app passes the criteria" do |resource| is_valid?(@app)end


steps/evaluation_process.rb

def is_valid?(app) result = true @black_list.each do |word| if app.description =~ /#{word}/ result = false end end resultend

Then "move forward to evaluate it" do |resource| @app = @app.links.evaluate.follow.post!("") resourceend

When "the app passes the criteria" do |resource| is_valid?(@app)end


scenarios/evaluation_process.scenario

When there is a new appThen move forward to evaluate it

When there is an app being evaluatedAnd the app passes the criteriaThen approve the app

When there is an app being evaluatedAnd the app doesnt pass the criteriaThen decline the app


scenarios/evaluation_process.scenario

When there is a new appThen move forward to evaluate it

When there is an app being evaluatedAnd the app passes the criteriaThen approve the app

When there is an app being evaluatedAnd the app doesnt pass the criteriaThen decline the app

This is Ruby Code!


EvaluationProcess.run

http://bit.ly/railsconf2010-restfulie


http://github.com/akitaonrails/RailsConf-2010---Restfulie


Adaptable Client


Adaptable Client

Goal Oriented


Adaptable Client

Goal OrientedPattern Matching


Adaptable Client

Goal OrientedPattern Matching

Can adapt to some changes



Level 3 Hypermedia

Level 2 HTTP

Level 1 URI


Caelum Restful ModelCaelum Restful Model

Level 5 Code on Demand

Level 4 Adaptable Clients

Level 3 Hypermedia

Level 2 HTTP

Level 1 URI


We’re not done yet!



Thank you!@AkitaOnRails

http://bit.ly/railsconf2010-restfulie




Technology

Making Rails Really restful