Rails Gems realize RESTful modeling patterns@tkawaRubyKaigi 2013, June 1

@tkawa

Ruby programmer (2000-)*RESTafarian (2005-) inspired by @yohei

Rails programmer (2006-)*Sendagaya.rb (2012-)

Toru KAWAMURA

* with some blank of career

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Concept: Looking forward to the weekly meetup makes our everyday working fun

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Rails Gems realize RESTful modeling patterns@tkawa

Rails Gems realize RESTful resource modeling patterns@tkawa

Point of Departure

Rails is RESTful

Since RubyKaigi 2006June 11, 2006

# config/routes.rbFoobar::Application.routes.draw do resources :usersend

resources :users

GET /users users#indexPOST /users users#createGET /users/new users#newGET /users/:id/edit users#editGET /users/:id users#showPUT /users/:id users#updateDELETE /users/:id users#destroy

$ rake routes

GET POST PUT DELETE

/users index create - -

/users/:id show - update destroy

in addition, “new” and “edit” as supplementary resources

resources :users

That’s it.That makes for really simple design.

REST’s advantage is...

SimpleConsistentTo reap the benefits of HTTP (“HTTP way”)

Generally:

Easy to designEasy to understand

On Rails “resources” particularly:

“resources” makes iteasy to design

For developer him/herself“resources” decides on a resource form

All you have to do is to decide on a resource name, such as “users”

/user/1 /users/1 /users/user/1 /users/user-1

“resources” makes iteasy to understand

For developer him/herself, co-developer, and external developer (e.g. using API)Suggest that there are corresponding controller, model, view, etc, such as UsersController, User model

“resources” makes iteasy to design & understand

Rails has demonstrated thatthis simplicity goes well“Constraints are liberating”

You might think it does not go well in these cases:

AuthenticationSearchState changesExecution of procedural operationOperation to a list / SortWizard / Confirmation page

AuthenticationSearchState changesExecution of procedural operationOperation to a list / SortWizard / Confirmation page

How do I write routes.rb?

How about Controller? Model?

We need another technique.But...

resources :users

GET POST PUT DELETE

/users index create - -

/users/:id show - update destroy

in addition, “new” and “edit” as supplementary resources

GET POST PUT DELETE

/users index create - -

/users/:id show - update destroy

This is a pattern

“resources” makes iteasy to design & understand

A pattern makes iteasy to design & understand

“resources” is the fundamental pattern

If there is a smaller and more concrete pattern, we can design well accordingly

We want more (concrete) patterns!

コストがかかるかもしれない問題解決を実際に行う前の先行調査として大変役に立つ

パターンには名前がついていることが重要である。なぜなら、名前がついていることで問題や解決策を記述したり、会話の中で取り上げたりすることができるようになるからである

ja.wikipedia.org/wiki/デザインパターン_(ソフトウェア)

A pattern is not a wild card, but a card with many benefits

Using a pattern is similar to Rails way, and...

We have “RubyGems”

Suppose a gem provides the implementation of a specific pattern

Then routes.rb will be the description of the patterns to be used

Discover the pattern from RubyGems

AuthenticationSearchState changesExecution of procedural operationOperation to a list / SortWizard / Confirmation page

Authentication

“Sign in” / “Sign out”Those are represented as what?

devise.plataformatec.com.br

Deviseby Plataformatec

GET /users/sign_in devise/sessions#newPOST /users/sign_in devise/sessions#createDELETE /users/sign_out devise/sessions#destroy…

# config/routes.rbdevise_for :users

“Sessions” is a resource(that doesn’t involve a model)

GET /users/sign_in devise/sessions#newPOST /users/sign_in devise/sessions#createDELETE /users/sign_out devise/sessions#destroy…

# config/routes.rbdevise_for :users

Session is singular

Only one “authentication session” for each user

Session Resource patternProposal

GET /sessionPUT(POST) /session →sign inDELETE /session →sign out

rest-pattern.hatenablog.com/entry/session-resource

Singular resource in Rails

resources :usersresource :user

resource :session

POST /session sessions#createGET /session/new sessions#newGET /session/edit sessions#editGET /session sessions#showPUT /session sessions#updateDELETE /session sessions#destroy

$ rake routes

GET POST PUT DELETE

/session show create update destroy

in addition, “new” and “edit” as supplementary resources

GET POST PUT DELETE

/session show create update destroyThis is also a pattern

Authlogic

github.com/binarylogic/authlogic

by Ben Johnson of Binary Logic

# app/models/session.rbclass Session < Authlogic::Session::Baseend

# app/models/session.rbclass Session < Authlogic::Session::Baseend

If they have no model, let them create it.(not an ActiveRecord)

# app/controllers/sessions_controler.rbclass SessionsController < ApplicationController # POST /session def create @session = Session.new(session_params) if @session.save flash[:notice] = "Login successful!" redirect_back_or_default account_url else render :action => :new end endend

resource :session

Rails way!!

I wish Devise were like that...I’m planning to do this...

AuthenticationSearchState changesExecution of procedural operationOperation to a list / SortWizard / Confirmation page

Search

Search for users with the name that contains “tkawa”Search for users that were created before 2012

Ransack

github.com/ernie/ransack

by Ernie Miller

GET /users?q[name_cont]=tkawaGET /users?q[created_at_lt]=2013-01-01

Search from collection= Filtering

Filtered Collection patternProposal

/users?role=admin/users?since_id=123/users?page=2

rest-pattern.hatenablog.com/entry/filtered-collection

Kaminari

github.com/amatsuda/kaminari

by Akira Matsuda

GET /users?page=2&per=10

I wish I could use query parameters like models (w/ validation)...

class PostsController < ApplicationController private def filter_params # using strong parameters @_filter_params ||= begin params.default( # you can set default value per: '10' ).permit( :date, :q, :page, :per ).validate( # you can validate like a model date: { format: /\A\d{4}-\d{2}-\d{2}\Z/ }, q: { length: { maximum: 20 } } ) end end helper_method :filter_paramsend

github.com/tkawa/collection_filter

Query parameters like models

AuthenticationSearchState changesExecution of procedural operationOperation to a list / SortWizard / Confirmation page

Wizard

Enter data in multiple steps with page transitions

Wickedby Richard Schneeman

github.com/schneems/wicked

GET /user_steps/personalPUT /user_steps/personalGET /user_steps/socialPUT /user_steps/socialGET /user_steps/finish

Partial Resource patternProposal

/users/1/personal/users/1/name,email/users/1?fields=name,email

rest-pattern.hatenablog.com/entry/partial-resource

Provides only some attributes (fields)to GET/PUT

Transaction Resource patternProposal

POST /transactionsPUT /transactions/123PUT /transactions/123/committed

rest-pattern.hatenablog.com/entry/transaction-resource

Rest of patterns are...Proposal

Filtered SubresourceMulti-member ResourcePrivate Resource / Private NamespaceImplicit Collection

rest-pattern.hatenablog.com

Conclusion

RESTful patterns including “resources” are significant

Focusing on these patterns encourages good resource design

RubyGems are also useful for this purpose

If you are at a loss on resource modeling...

Focus on gems’ pattern

You will come up with the right resource by referring to the design of a good gem

“resources” is fundamental

Diverging from the “resources” is the last resort

If you are creating a gem...

You should consider designing around resources, if possibleLet's stick to the fundamentals of “resources”And your gem will realize a pattern!

Thank you for your attention.

Let me know if you discover more patterns!

rest-pattern.hatenablog.com