Jim Weirich gave us many things. Among his last was Wyriki, a small Rails app described in his own words as an "Experimental Rails application to explore decoupling app logic from Rails." Many of us paid our final respects to Jim on his last commit to this project. Now it's time to learn from it. In this talk we'll explore how Jim applied the principles of Object Oriented Design to achieve his goals of decoupling; look at how he used decoupling to speed up testing; how decoupling improved and simplified his tests; and look at his design style. Jim's legacy leaves a lot to learn from, let's do it.

1. Enable Labs @mark_menard
A Tour of Wyriki
Mark Menard
Ruby Nation!
June 7, 2014
@mark_menard !
Enable Labs

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Jim Weirich

3. Enable Labs @mark_menardhttp://www.flickr.com/photos/langalex

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TDD

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Yea…
whatever…

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What is Wyriki?

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The Wyriki Domain
Page
Wiki
*
1
Create Wiki
Create Page
Update
Page
Create User
Loged
In User
Anony
mous
User

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Business Logic
ActiveRecord
ActionPack
Controllers
MySQL MongoDB PostgreSQL
Redis
Sidekiq
Resque
What was Jim trying to accomplish?

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Testing

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Why?!
!
When?

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Typical Rails

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Create Page
Loged
In User
Action
Controller ::
Base
ActiveRecord
:: Base
Pages
Controller
Application
Controller
Page
Wiki

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Create Page
Loged
In User
Action
Controller ::
Base
ActiveRecord
:: Base
Pages
Controller
Application
Controller
Page
Wiki

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Create Page
Loged
In User
Action
Controller ::
Base
ActiveRecord
:: Base
Pages
Controller
Application
Controller
Page
Wiki

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# app/controllers/pages_controller.rb
def create
@wiki = Wiki.find(params[:wiki_id])
@page = @wiki.pages.new(page_params)
if @page.save
redirect_to [@wiki, @page], notice: "#{@page.name} created"
else
render :new
end
end

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Wyriki Style

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Runners
class Runner
attr_reader :context
!
def initialize(context)
@callbacks = NamedCallbacks.new
@context = context
yield(@callbacks) if block_given?
end
!
def repo
context.repo
end
!
def success(*args)
callback(:success, *args)
end
!
def failure(*args)
callback(:failure, *args)
end
!
def callback(name, *args)
@callbacks.call(name, *args)
args
end
end
class Model < SimpleDelegator
include BlockActiveRecord
! def data
datum = self
while datum.biz?
datum = datum.__getobj__
end
datum
end
! def ==(other)
if other.respond_to?(:data)
data == other.data
else
data == other
end
end
! def biz?
true
end
! def class
data.class
end
! def self.wrap(model)
model ? new(model) : nil
end
! def self.wraps(models)
models.map { |model| wrap(model) }
end
!end
Business
Models
Repositories
module UserMethods
def all_users
Biz::User.wraps(User.all_users)
end
! def new_user(attrs={})
Biz::User.wrap(User.new(attrs))
end
! def find_user(user_id)
Biz::User.wrap(User.find(user_id))
end
! def save_user(user)
user.data.save
end
! def update_user(user, attrs)
user.data.update_attributes(attrs)
end
! def destroy_user(user_id)
User.destroy(user_id)
end
end

18. Enable Labs @mark_menard
Action
Controller ::
Base
ActiveRecord
:: Base
Page
Controller
Application
Controller
Page
Wiki
Create Page
Runner
<<protocol>>
Repo
Repo
<<protocol>>
context
<<protocol>>
Biz Page
<<protocol>>
Biz Wiki
Biz::Wiki
Biz::Page
<<protocol>>
Wiki Data
<<protocol>>
Page Data
<<wraps>>
<<wraps>>

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Action
Controller ::
Base
ActiveRecord
:: Base
Page
Controller
Application
Controller
Some Model
Runner
Repo
Biz Model
<< wraps >>
<< gets and saves
stuff >>

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Action
Controller ::
Base
ActiveRecord
:: Base
Page
Controller
Application
Controller
Some Model
Runner
Repo
Biz Model
<< wraps >>
<< gets and saves
stuff >>

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Runners

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Action
Controller ::
Base
ActiveRecord
:: Base
Page
Controller
Application
Controller
Page
Wiki
Create Page
Runner
<<protocol>>
context
Rails
Not Rails
Create Page
Loged
In User

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This is the !
Domain

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This is the !
Domain
This is Rails

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This is our Context.

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# app/controllers/page_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page], notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end

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# app/controllers/page_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page], notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end

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# app/controllers/page_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page], notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end

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# app/runners/page_runners.rb
class Create < Runner
def run(wiki_id, page_params)
wiki = Wiki.find(params[:wiki_id])
page = wiki.pages.new(page_params)
if page.save
success(page)
else
failure(wiki, page)
end
end
end

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# app/runners/page_runners.rb
class Create < Runner
def run(wiki_id, page_params)
wiki = Wiki.find(params[:wiki_id])
page = wiki.pages.new(page_params)
if page.save
success(page)
else
failure(wiki, page)
end
end
end
# app/controllers/page_controller.rb
def create
Create.new(self, params[:wiki_id], page_params).run do |on|
on.success { |page|
redirect_to [page.wiki, page], notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end

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# app/runners/page_runners.rb
class Create < Runner
def run(wiki_id, page_params)
wiki = Wiki.find(params[:wiki_id])
page = wiki.pages.new(page_params)
if page.save
success(page)
else
failure(wiki, page)
end
end
end
# app/controllers/page_controller.rb
def create
Create.new(self, params[:wiki_id], page_params).run do |on|
on.success { |page|
redirect_to [page.wiki, page], notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end

34. Enable Labs @mark_menard
Action
Controller ::
Base
ActiveRecord
:: Base
Page
Controller
Application
Controller
Page
Wiki
Create Page
Runner
<<protocol>>
context
Rails
Not Rails
Create Page
Loged
In User

35. Enable Labs @mark_menard
Enough Architecture! !
What about the Ruby!!
!
How did Jim actually !
do the callbacks and the
runners?

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Runner
Named
Callbacks
<<protocol>>
context
<<protocol>>
Repo

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# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end
Runner
Named
Callbacks
<<protocol>>
context
<<protocol>>
Repo

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# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end
Runner
Named
Callbacks
<<protocol>>
context
<<protocol>>
Repo

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# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end
Runner
Named
Callbacks
<<protocol>>
context
<<protocol>>
Repo

40. Enable Labs @mark_menard
# app/runners/runner.rb
class Runner
attr_reader :context
!
def initialize(context)
@callbacks = NamedCallbacks.new
@context = context
yield(@callbacks) if block_given?
end
!
def repo
context.repo
end
!
def success(*args)
callback(:success, *args)
end
!
def failure(*args)
callback(:failure, *args)
end
!
def callback(name, *args)
@callbacks.call(name, *args)
args
end
end
# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end
Runner
Named
Callbacks
<<protocol>>
context
<<protocol>>
Repo

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# app/runners/runner.rb
class Runner
attr_reader :context
!
def initialize(context)
@callbacks = NamedCallbacks.new
@context = context
yield(@callbacks) if block_given?
end
!
def repo
context.repo
end
!
def success(*args)
callback(:success, *args)
end
!
def failure(*args)
callback(:failure, *args)
end
!
def callback(name, *args)
@callbacks.call(name, *args)
args
end
end
# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end
Runner
Named
Callbacks
<<protocol>>
context
<<protocol>>
Repo

42. Enable Labs @mark_menard
# app/runners/runner.rb
class Runner
attr_reader :context
!
def initialize(context)
@callbacks = NamedCallbacks.new
@context = context
yield(@callbacks) if block_given?
end
!
# …
end
# app/runners/named_callbacks.rb
class NamedCallbacks
def initialize
@callbacks = {}
end
!
def method_missing(sym, *args, &block)
@callbacks[sym] = block
end
!
# …
end
# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end

43. Enable Labs @mark_menard
# app/runners/runner.rb
class Runner
attr_reader :context
!
def initialize(context)
@callbacks = NamedCallbacks.new
@context = context
yield(@callbacks) if block_given?
end
!
# …
end
# app/runners/named_callbacks.rb
class NamedCallbacks
def initialize
@callbacks = {}
end
!
def method_missing(sym, *args, &block)
@callbacks[sym] = block
end
!
# …
end
# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end

44. Enable Labs @mark_menard
# app/runners/named_callbacks.rb
class NamedCallbacks
def initialize
@callbacks = {}
end
!
def method_missing(sym, *args, &block)
@callbacks[sym] = block
end
!
# …
end
# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end

45. Enable Labs @mark_menard
# app/runners/named_callbacks.rb
class NamedCallbacks
def initialize
@callbacks = {}
end
!
def method_missing(sym, *args, &block)
@callbacks[sym] = block
end
!
# …
end
# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end

46. Enable Labs @mark_menard
# app/runners/named_callbacks.rb
class NamedCallbacks
def initialize
@callbacks = {}
end
!
def method_missing(sym, *args, &block)
@callbacks[sym] = block
end
!
# …
end
# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end

47. Enable Labs @mark_menard
# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end
Weirich Block Style

48. Enable Labs @mark_menard
# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end
# app/controllers/pages_controller.rb
def create
run(Create, params[:wiki_id], page_params) do |on|
on.success { |page|
redirect_to [page.wiki, page],
notice: "#{page.name} created"
}
on.failure { |wiki, page|
render :new
}
end
end
Weirich Block Style

49. Enable Labs @mark_menard
Some Lessons

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Repositories

51. Enable Labs @mark_menard
Domain Rails

52. Enable Labs @mark_menard

53. Enable Labs @mark_menard

54. Enable Labs @mark_menard
Action
Controller ::
Base
ActiveRecord
:: Base
Page
Controller
Application
Controller
Page
Wiki
Create Page
Runner
<<protocol>>
Repo
Repo
<<protocol>>
context

55. Enable Labs @mark_menard
Action
Controller ::
Base
ActiveRecord
:: Base
Page
Controller
Application
Controller
Page
Wiki
Create Page
Runner
<<protocol>>
Repo
Repo
<<protocol>>
context
Domain

56. Enable Labs @mark_menard
Action
Controller ::
Base
ActiveRecord
:: Base
Page
Controller
Application
Controller
Page
Wiki
Create Page
Runner
<<protocol>>
Repo
Repo
<<protocol>>
context
Domain

57. Enable Labs @mark_menard
Action
Controller ::
Base
ActiveRecord
:: Base
Page
Controller
Application
Controller
Page
Wiki
Create Page
Runner
<<protocol>>
Repo
Repo
<<protocol>>
context
Domain

58. Enable Labs @mark_menard
# app/services/wiki_repository.rb
class WikiRepository
include Repo::UserMethods
include Repo::WikiMethods
include Repo::PageMethods
include Repo::PermissionMethods
end

59. Enable Labs @mark_menard
# app/services/repo/page_methods.rb
module PageMethods
def find_wiki_page(wiki_id, page_id)
wiki = Wiki.find(wiki_id)
page = wiki.pages.find(page_id)
!
# …
end
!
# …
!
def save_page(page)
page.data.save
end
!
# …
end

60. Enable Labs @mark_menard
Domain

61. Enable Labs @mark_menard
Biz Objects

62. Enable Labs @mark_menard
Action
Controller ::
Base
ActiveRecord
:: Base
Page
Controller
Application
Controller
Page
Wiki
Create Page
Runner
<<protocol>>
Repo
Repo
<<protocol>>
context
Domain

63. Enable Labs @mark_menard
Biz Model
ActiveRecord
:: Base
Simple
Delegator

64. Enable Labs @mark_menard
# app/models/biz/model.rb
module Biz
class Model < SimpleDelegator
include BlockActiveRecord
!
def data
datum = self
while datum.biz?
datum = datum.__getobj__
end
datum
end
!
def ==(other)
if other.respond_to?(:data)
data == other.data
else
data == other
end
end
def biz?
true
end
!
def class
data.class
end
!
def self.wrap(model)
model ? new(model) : nil
end
!
def self.wraps(models)
models.map { |model| wrap(model) }
end
!
end
end

65. Enable Labs @mark_menard
# app/models/biz/model.rb
module Biz
class Model < SimpleDelegator
include BlockActiveRecord
!
def data
datum = self
while datum.biz?
datum = datum.__getobj__
end
datum
end
!
def ==(other)
if other.respond_to?(:data)
data == other.data
else
data == other
end
end
def biz?
true
end
!
def class
data.class
end
!
def self.wrap(model)
model ? new(model) : nil
end
!
def self.wraps(models)
models.map { |model| wrap(model) }
end
!
end
end

66. Enable Labs @mark_menard
# app/models/biz/model.rb
module Biz
class Model < SimpleDelegator
include BlockActiveRecord
!
def data
datum = self
while datum.biz?
datum = datum.__getobj__
end
datum
end
!
def ==(other)
if other.respond_to?(:data)
data == other.data
else
data == other
end
end
def biz?
true
end
!
def class
data.class
end
!
def self.wrap(model)
model ? new(model) : nil
end
!
def self.wraps(models)
models.map { |model| wrap(model) }
end
!
end
end

67. Enable Labs @mark_menard
# app/models/biz/model.rb
module Biz
class Model < SimpleDelegator
include BlockActiveRecord
!
def data
datum = self
while datum.biz?
datum = datum.__getobj__
end
datum
end
!
def ==(other)
if other.respond_to?(:data)
data == other.data
else
data == other
end
end
def biz?
true
end
!
def class
data.class
end
!
def self.wrap(model)
model ? new(model) : nil
end
!
def self.wraps(models)
models.map { |model| wrap(model) }
end
!
end
end

68. Enable Labs @mark_menard
# app/models/biz/model.rb
module Biz
class Model < SimpleDelegator
include BlockActiveRecord
!
def data
datum = self
while datum.biz?
datum = datum.__getobj__
end
datum
end
!
def ==(other)
if other.respond_to?(:data)
data == other.data
else
data == other
end
end
def biz?
true
end
!
def class
data.class
end
!
def self.wrap(model)
model ? new(model) : nil
end
!
def self.wraps(models)
models.map { |model| wrap(model) }
end
!
end
end

69. Enable Labs @mark_menard
# app/models/biz/model.rb
module Biz
class Model < SimpleDelegator
include BlockActiveRecord
!
def data
datum = self
while datum.biz?
datum = datum.__getobj__
end
datum
end
!
def ==(other)
if other.respond_to?(:data)
data == other.data
else
data == other
end
end
def biz?
true
end
!
def class
data.class
end
!
def self.wrap(model)
model ? new(model) : nil
end
!
def self.wraps(models)
models.map { |model| wrap(model) }
end
!
end
end

70. Enable Labs @mark_menard
# app/services/repo/page_methods.rb
module PageMethods
def find_wiki_page(wiki_id, page_id)
wiki = Wiki.find(wiki_id)
page = wiki.pages.find(page_id)
Biz::Page.wrap(page)
end
!
# …
!
def save_page(page)
page.data.save
end
!
# …
end

71. Enable Labs @mark_menard
# app/services/repo/page_methods.rb
module PageMethods
def find_wiki_page(wiki_id, page_id)
wiki = Wiki.find(wiki_id)
page = wiki.pages.find(page_id)
Biz::Page.wrap(page)
end
!
# …
!
def save_page(page)
page.data.save
end
!
# …
end

72. Enable Labs @mark_menard
module Biz
class Page < Model
def wiki
Biz::Wiki.wrap(super)
end
!
def html_content(context)
Kramdown::Document.new(referenced_content(context)).to_html
end
!
def referenced_content(context)
content.gsub(/(([A-Z][a-z0-9]+){2,})/) { |page_name|
if wiki.page?(context.repo, page_name)
"[#{page_name}](#{context.named_page_path(wiki.name,page_name)})"
elsif context.current_user.can_write?(wiki)
"#{page_name}[?](#{context.new_named_page_path(wiki.name, page_name)})"
else
page_name
end
}
end
end
end

73. Enable Labs @mark_menard
module Biz
class Page < Model
def wiki
Biz::Wiki.wrap(super)
end
!
def html_content(context)
Kramdown::Document.new(referenced_content(context)).to_html
end
!
def referenced_content(context)
content.gsub(/(([A-Z][a-z0-9]+){2,})/) { |page_name|
if wiki.page?(context.repo, page_name)
"[#{page_name}](#{context.named_page_path(wiki.name,page_name)})"
elsif context.current_user.can_write?(wiki)
"#{page_name}[?](#{context.new_named_page_path(wiki.name, page_name)})"
else
page_name
end
}
end
end
end

74. Enable Labs @mark_menard
Action
Controller ::
Base
ActiveRecord
:: Base
Page
Controller
Application
Controller
Some Model
Runner
Repo
Biz Model
<< wraps >>

75. Enable Labs @mark_menard
Action
Controller ::
Base
ActiveRecord
:: Base
Page
Controller
Application
Controller
Some Model
Runner
Repo
Biz Model
<< wraps >>

76. Enable Labs @mark_menard
More Lessons

77. Enable Labs @mark_menard
Why?

78. Enable Labs @mark_menard
Isolated Business Logic

79. Enable Labs @mark_menard
Incremental Approach

80. Enable Labs @mark_menard
Fast Tests

81. Enable Labs @mark_menard
$ time rspec spec/runners spec/models/biz (git)-[master]
......................................................................................................
!
Finished in 0.17573 seconds
102 examples, 0 failures
rspec spec/runners spec/models/biz 0.61s user 0.07s system 99% cpu 0.683 total

82. Enable Labs @mark_menard
Should we decouple?

83. Enable Labs @mark_menard
http://www.flickr.com/photos/dwortlehock/
Thanks for Everything Jim!

84. Enable Labs @mark_menard
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