Clarity: You keep using that word...

Recently, you may have watched a talk during which the speaker said: "A lot of people will gripe about 'ActiveRecord is too big, [...] has too many methods, the surface area is too big.'"

Hi, my name is "A. Lotofpeople", and I'd like to discuss with you why I've been griping. We'll talk about what "clarity" means to Rubyists, and its relationship to the hard problem of naming things. I'll share some principles that I've found helpful, coping mechanisms I've developed to allow me to "fight the framework" without suffering too badly, and thoughts on what some first steps toward bringing clarity to a Rails codebase might look like.

Or, I might just talk about cats. You'll have to attend to find out!

Transcript

1. Clarity You keep using that word… Ernie Miller http://erniemiller.org @erniemiller
12. https://twitter.com/erniemiller/status/457138562157133824
13. Class.new (2.1.1) Model View Controller Ancestors 4 56 50 63 Public/Protected Methods 99 575 244 351 Private Methods 90 126 101 105 Public/Protected Methods 55 311 405 333 Private Methods 72 160 132 115 Class Instance
17. –DHH “A lot of people will gripe about ‘ActiveRecord is too big, [...] has too many methods, the surface area is too big.’ Who gives a sh*t? Is it more readable? Is it more clear? That’s the only thing that matters.”
18. –DHH “A lot of people will gripe about ‘ActiveRecord is too big, [...] has too many methods, the surface area is too big.’ Who gives a sh*t? Is it more readable? Is it more clear? That’s the only thing that matters.”
19. class Post < ActiveRecord::Base end
20. class Post < ActiveRecord::Base end Clear Readable
21. class Post < ActiveRecord::Base end Clear Readable
22. class Post < ActiveRecord::Base end ! post = Post.first
23. class Post < ActiveRecord::Base end ! post = Post.first Post.attribute_names # => ["id", "title", "body", "created_at", "updated_at"] post.title # => "Hello, world!"
24. class Post < ActiveRecord::Base end ! post = Post.first Post.attribute_names # => ["id", "title", "body", "created_at", "updated_at"] post.title # => "Hello, world!" Post.select(:body).first post.title # => ActiveModel::MissingAttributeError: missing attribute: title
25. class Post < ActiveRecord::Base end ! post = Post.first Post.attribute_names # => ["id", "title", "body", "created_at", "updated_at"] post.title # => "Hello, world!" Post.select(:body).first post.title # => ActiveModel::MissingAttributeError: missing attribute: title Post.select('title as trololol').first post.title # => ActiveModel::MissingAttributeError: missing attribute: title post.trololol # => "Hello, world!"
26. In order to infer attribute names you must first invent the universe.
27. def inherited(child_class) child_class.initialize_generated_modules super end ! def initialize_generated_modules @generated_attribute_methods = Module.new { extend Mutex_m } @attribute_methods_generated = false include @generated_attribute_methods end active_record/attribute_methods.rb
28. def inherited(child_class) child_class.initialize_generated_modules super end ! def initialize_generated_modules @generated_attribute_methods = Module.new { extend Mutex_m } @attribute_methods_generated = false include @generated_attribute_methods end active_record/attribute_methods.rb
29. def inherited(child_class) child_class.initialize_generated_modules super end ! def initialize_generated_modules @generated_attribute_methods = Module.new { extend Mutex_m } @attribute_methods_generated = false include @generated_attribute_methods end active_record/attribute_methods.rb
30. def method_missing(method, *args, &block) self.class.define_attribute_methods if respond_to_without_attributes?(method) if attribute_method = self.class.find_generated_attribute_method(method) attribute_method.bind(self).call(*args, &block) else send(method, *args, &block) end else super end end active_record/attribute_methods.rb
31. def method_missing(method, *args, &block) self.class.define_attribute_methods if respond_to_without_attributes?(method) if attribute_method = self.class.find_generated_attribute_method(method) attribute_method.bind(self).call(*args, &block) else send(method, *args, &block) end else super end end active_record/attribute_methods.rb
32. def define_attribute_methods generated_attribute_methods.synchronize do return false if @attribute_methods_generated superclass.define_attribute_methods unless self == base_class super(column_names) @attribute_methods_generated = true end true end active_record/attribute_methods.rb
33. def define_attribute_methods generated_attribute_methods.synchronize do return false if @attribute_methods_generated superclass.define_attribute_methods unless self == base_class super(column_names) @attribute_methods_generated = true end true end active_record/attribute_methods.rb
34. def define_attribute_methods generated_attribute_methods.synchronize do return false if @attribute_methods_generated superclass.define_attribute_methods unless self == base_class super(column_names) @attribute_methods_generated = true end true end active_record/attribute_methods.rb
35. def column_names @column_names ||= columns.map { |column| column.name } end ! def columns @columns ||= connection.schema_cache.columns(table_name).map do |col| col = col.dup col.primary = (col.name == primary_key) col end end active_record/model_schema.rb
36. def column_names @column_names ||= columns.map { |column| column.name } end ! def columns @columns ||= connection.schema_cache.columns(table_name).map do |col| col = col.dup col.primary = (col.name == primary_key) col end end active_record/model_schema.rb
37. def column_names @column_names ||= columns.map { |column| column.name } end ! def columns @columns ||= connection.schema_cache.columns(table_name).map do |col| col = col.dup col.primary = (col.name == primary_key) col end end active_record/model_schema.rb
38. def table_name reset_table_name unless defined?(@table_name) @table_name end ! def reset_table_name self.table_name = if abstract_class? superclass == Base ? nil : superclass.table_name elsif superclass.abstract_class? superclass.table_name || compute_table_name else compute_table_name end end active_record/model_schema.rb
39. def table_name reset_table_name unless defined?(@table_name) @table_name end ! def reset_table_name self.table_name = if abstract_class? superclass == Base ? nil : superclass.table_name elsif superclass.abstract_class? superclass.table_name || compute_table_name else compute_table_name end end active_record/model_schema.rb
40. def table_name reset_table_name unless defined?(@table_name) @table_name end ! def reset_table_name self.table_name = if abstract_class? superclass == Base ? nil : superclass.table_name elsif superclass.abstract_class? superclass.table_name || compute_table_name else compute_table_name end end active_record/model_schema.rb
41. def compute_table_name base = base_class if self == base if parent < Base && !parent.abstract_class? contained = parent.table_name contained = contained.singularize if parent.pluralize_table_names contained += '_' end "#{full_table_name_prefix}#{contained}#{undecorated_table_name(name)}#{table_name_suffix}" else base.table_name end end active_record/model_schema.rb
42. def compute_table_name base = base_class if self == base if parent < Base && !parent.abstract_class? contained = parent.table_name contained = contained.singularize if parent.pluralize_table_names contained += '_' end "#{full_table_name_prefix}#{contained}#{undecorated_table_name(name)}#{table_name_suffix}" else base.table_name end end active_record/model_schema.rb
43. def undecorated_table_name(class_name = base_class.name) table_name = class_name.to_s.demodulize.underscore pluralize_table_names ? table_name.pluralize : table_name end active_record/model_schema.rb RubyGroups::BostonRb -> BostonRb -> boston_rb -> boston_rbs
44. def undecorated_table_name(class_name = base_class.name) table_name = class_name.to_s.demodulize.underscore pluralize_table_names ? table_name.pluralize : table_name end active_record/model_schema.rb RubyGroups::BostonRb -> BostonRb -> boston_rb -> boston_rbs Animals::Moose -> Moose -> moose -> mooses
45. module ActiveSupport Inflector.inflections(:en) do |inflect| inflect.plural(/$/, 's') inflect.plural(/s$/i, 's') inflect.plural(/^(ax|test)is$/i, '\1es') inflect.plural(/(octop|vir)us$/i, '\1i') inflect.plural(/(octop|vir)i$/i, '\1i') inflect.plural(/(alias|status)$/i, '\1es') inflect.plural(/(bu)s$/i, '\1ses') inflect.plural(/(buffal|tomat)o$/i, '\1oes') inflect.plural(/([ti])um$/i, '\1a') inflect.plural(/([ti])a$/i, '\1a') inflect.plural(/sis$/i, 'ses') inflect.plural(/(?:([^f])fe|([lr])f)$/i, '\1\2ves') inflect.plural(/(hive)$/i, '\1s') inflect.plural(/([^aeiouy]|qu)y$/i, '\1ies') inflect.plural(/(x|ch|ss|sh)$/i, '\1es') inflect.plural(/(matr|vert|ind)(?:ix|ex)$/i, '\1ices') inflect.plural(/^(m|l)ouse$/i, '\1ice') inflect.plural(/^(m|l)ice$/i, '\1ice') inflect.plural(/^(ox)$/i, '\1en') inflect.plural(/^(oxen)$/i, '\1') inflect.plural(/(quiz)$/i, '\1zes') ! inflect.singular(/s$/i, '') inflect.singular(/(ss)$/i, '\1') inflect.singular(/(n)ews$/i, '\1ews') inflect.singular(/([ti])a$/i, '\1um') inflect.singular(/((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)(sis|ses)$/i, '\1sis') inflect.singular(/(^analy)(sis|ses)$/i, '\1sis') inflect.singular(/([^f])ves$/i, '\1fe') inflect.singular(/(hive)s$/i, '\1') inflect.singular(/(tive)s$/i, '\1') inflect.singular(/([lr])ves$/i, '\1f') inflect.singular(/([^aeiouy]|qu)ies$/i, '\1y') inflect.singular(/(s)eries$/i, '\1eries') inflect.singular(/(m)ovies$/i, '\1ovie') inflect.singular(/(x|ch|ss|sh)es$/i, '\1') inflect.singular(/^(m|l)ice$/i, '\1ouse') inflect.singular(/(bus)(es)?$/i, '\1') inflect.singular(/(o)es$/i, '\1') active_support/inflections.rb
46. inflect.singular(/(ss)$/i, '\1') inflect.singular(/(n)ews$/i, '\1ews') inflect.singular(/([ti])a$/i, '\1um') inflect.singular(/((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)(sis|ses)$/i, '\1sis') inflect.singular(/(^analy)(sis|ses)$/i, '\1sis') inflect.singular(/([^f])ves$/i, '\1fe') inflect.singular(/(hive)s$/i, '\1') inflect.singular(/(tive)s$/i, '\1') inflect.singular(/([lr])ves$/i, '\1f') inflect.singular(/([^aeiouy]|qu)ies$/i, '\1y') inflect.singular(/(s)eries$/i, '\1eries') inflect.singular(/(m)ovies$/i, '\1ovie') inflect.singular(/(x|ch|ss|sh)es$/i, '\1') inflect.singular(/^(m|l)ice$/i, '\1ouse') inflect.singular(/(bus)(es)?$/i, '\1') inflect.singular(/(o)es$/i, '\1') inflect.singular(/(shoe)s$/i, '\1') inflect.singular(/(cris|test)(is|es)$/i, '\1is') inflect.singular(/^(a)x[ie]s$/i, '\1xis') inflect.singular(/(octop|vir)(us|i)$/i, '\1us') inflect.singular(/(alias|status)(es)?$/i, '\1') inflect.singular(/^(ox)en/i, '\1') inflect.singular(/(vert|ind)ices$/i, '\1ex') inflect.singular(/(matr)ices$/i, '\1ix') inflect.singular(/(quiz)zes$/i, '\1') inflect.singular(/(database)s$/i, '\1') ! inflect.irregular('person', 'people') inflect.irregular('man', 'men') inflect.irregular('child', 'children') inflect.irregular('sex', 'sexes') inflect.irregular('move', 'moves') inflect.irregular('zombie', 'zombies') ! inflect.uncountable(%w(equipment information rice money species series fish sheep jeans police)) end end active_support/inflections.rb
47. ActiveSupport::Inflector.inflections(:en) do |inflect| inflect.uncountable 'moose' end config/initializers/inflections.rb
48. class Moose < ActiveRecord::Base self.table_name = 'moose' end app/models/moose.rb
50. class Post < ImaginaryRecord::Record self.table_name 'posts' ! attribute :id, Attr::Integer attribute :title, Attr::String attribute :body, Attr::String attribute :created_at, Attr::Timestamp attribute :updated_at, Attr::Timestamp end in/your/imagination.rb
51. class MagicRecord < ImaginaryRecord::Record def method_missing(method, *args, &block) self.class.define_attribute_methods # ... end ! def self.define_attribute_methods # ... klass.table_name(compute_table_name) columns_from_table(table_name).each do |column| klass.attribute column.name, column.type end # ... end end in/your/imagination.rb
52. class Post < MagicRecord end
53. ActiveRecord
54. ActiveRecord Attribute typecasting Serialization Macro reflection Transactions Nested attributes Associations Secure passwords Timestamps Lifecycle callbacks Dirty tracking Validations Mass assignment sanitation
55. ActiveRecord Attribute typecasting Serialization Macro reflection Transactions Nested attributes Associations Secure passwords Timestamps Lifecycle callbacks Dirty tracking Validations Mass assignment sanitation Querying Persisting
56. MyModel #<Module:0x007fc42ad68878> ActiveRecord::Base ActiveRecord::Store ActiveRecord::Serialization ActiveModel::Serializers::Xml ActiveModel::Serializers::JSON ActiveModel::Serialization ActiveRecord::Reflection ActiveRecord::Transactions ActiveRecord::Aggregations ActiveRecord::NestedAttributes ActiveRecord::AutosaveAssociation ActiveModel::SecurePassword ActiveRecord::Associations ActiveRecord::Timestamp ActiveModel::Validations::Callbacks ActiveRecord::Callbacks ActiveRecord::AttributeMethods::Serialization ActiveRecord::AttributeMethods::Dirty
57. ActiveModel::Validations ActiveRecord::Integration ActiveModel::Conversion ActiveRecord::AttributeAssignment ActiveModel::ForbiddenAttributesProtection ActiveRecord::Sanitization ActiveRecord::Scoping::Named ActiveRecord::Scoping::Default ActiveRecord::Scoping ActiveRecord::Inheritance ActiveRecord::ModelSchema ActiveRecord::ReadonlyAttributes ActiveRecord::NoTouching ActiveRecord::Persistence ActiveRecord::Core Object ActiveSupport::Dependencies::Loadable JSON::Ext::Generator::GeneratorMethods::Object Kernel BasicObject
58. ActiveModel::Validations ActiveRecord::Integration ActiveModel::Conversion ActiveRecord::AttributeAssignment ActiveModel::ForbiddenAttributesProtection ActiveRecord::Sanitization ActiveRecord::Scoping::Named ActiveRecord::Scoping::Default ActiveRecord::Scoping ActiveRecord::Inheritance ActiveRecord::ModelSchema ActiveRecord::ReadonlyAttributes ActiveRecord::NoTouching ActiveRecord::Persistence ActiveRecord::Core Object ActiveSupport::Dependencies::Loadable JSON::Ext::Generator::GeneratorMethods::Object Kernel BasicObject “Clarity”
59. ActiveRecord A passable implementation of the Repository Pattern
60. “A Repository mediates between the domain and data mapping layers, acting like an in-memory domain object collection. Client objects construct query specifications declaratively and submit them to Repository for satisfaction.” http://martinfowler.com/eaaCatalog/repository.html
61. Post. where(:title => 'First post!’). includes(:comments) Query Specification
62. def to_a load @records end ! def load exec_queries unless loaded? ! self end ! private ! def exec_queries @records = eager_loading? ? find_with_associations : @klass.find_by_sql(arel, bind_values) ! preload = preload_values preload += includes_values unless eager_loading? preloader = ActiveRecord::Associations::Preloader.new preload.each do |associations| preloader.preload @records, associations end ! @records.each { |record| record.readonly! } if readonly_value ! @loaded = true @records end lib/active_record/relation.rb
63. def to_a load @records end ! def load exec_queries unless loaded? ! self end ! private ! def exec_queries @records = eager_loading? ? find_with_associations : @klass.find_by_sql(arel, bind_values) ! preload = preload_values preload += includes_values unless eager_loading? preloader = ActiveRecord::Associations::Preloader.new preload.each do |associations| preloader.preload @records, associations end ! @records.each { |record| record.readonly! } if readonly_value ! @loaded = true @records end lib/active_record/relation.rb
64. Single Responsibility Principle Simple, for sufficiently large values of “responsibility.”
65. –DHH “Give up the need for hard- science experiments, float freely with the world.”
66. –DHH “Give up the need for hard- science experiments, float freely with the world.”
67. THE WORLD IS COMPLEX
68. YOU ARE SMART
69. YOU ARE NOT THAT SMART
71. PROGRAMMING IS WRITTEN COMMUNICATION
72. WE ARE STORYTELLERS
76. FEWER DO NOT EQUAL GREATER CLARITY LINES
77. FEWER DO NOT EQUAL GREATER CLARITY FILES
78. FEWER DO NOT EQUAL GREATER CLARITY OBJECTS
79. MORE OF THE RIGHT KIND OF OBJECTS BRINGS GREATER CLARITY
80. OBJECT! ORIENTED! PROGRAMMING
81. THE GEORGE R. R. MARTIN GUIDE TO SOFTWARE DEVELOPMENT
82. THE GEORGE R. R. MARTIN GUIDE TO SOFTWARE DEVELOPMENT Create lots of characters. 1.
83. THE GEORGE R. R. MARTIN GUIDE TO SOFTWARE DEVELOPMENT Give them personality and purpose. 2.
84. THE GEORGE R. R. MARTIN GUIDE TO SOFTWARE DEVELOPMENT Don’t be afraid to kill them. 3.
88. IF YOU LIKED IT THEN YOU SHOULDA PUT AN! INITIALIZER ON IT. — Rubyoncé
90. You
91. You
92. IDD
93. IGNORANCE-DRIVEN DEVELOPMENT Blissful.
94. START WITH RUBY Ignore persistence, for now.
95. IDENTIFY THE SCARY THINGS What are you afraid you can’t write?
96. ATTACK THE SCARY THINGS (With TDD. Turns out it isn’t dead, after all.)
97. describe Monster do let(:teeth) { nil } let(:claws) { nil } subject { Monster.new(teeth, claws) } ! describe 'with no teeth or claws' do it 'cannot bite' do proc { subject.bite('Ernie') }.must_raise NoMethodError end ! it 'cannot scratch' do proc { subject.bite('Ernie') }.must_raise NoMethodError end end end class Monster def initialize(teeth = nil, claws = nil) @teeth, @claws = teeth, claws end ! def bite(target) @teeth.bite(target) end ! def scratch(target) @claws.scratch(target) end end
98. SLAY THE SCARY THINGS
99. ADMIT PERSISTENCE
100. class Monster < ActiveRecord::Base belongs_to :teeth belongs_to :claws validates :teeth, :claws, :presence => true end
101. USE MODULES
103. class Monster < ActiveRecord::Base include ::Monster::Biting include ::Monster::Scratching ! belongs_to :teeth belongs_to :claws validates :teeth, :claws, :presence => true end
104. class Monster < ActiveRecord::Base module Biting def bite(target) target.punctured!(teeth.damage_roll) end end end app/behaviors/monster/biting.rb
105. describe 'Monster::Biting' do let(:biter) { Class.new { attr_reader :teeth include ::Monster::Biting def initialize(teeth) @teeth = teeth end } } ! it ‘inflicts puncture damage' do # ... end end spec/behaviors/monster/biting_spec.rb
106. CONCERNED?
107. Monster Biting Scratching Fighting
108. Monster Biting Scratching Fighting
109. Monster Biting Scratching Fighting
110. Monster Biting Scratching Encounter class Encounter def initialize(*combatants) @combatants = combatants end ! # ... end
111. module Foo def self.included(base) base.class_eval do def self.method_injected_by_foo ... end end end end ! module Bar def self.included(base) base.method_injected_by_foo end end ! class Host include Foo # We need to include this dependency for Bar include Bar # Bar is the module that Host really needs end
112. require 'active_support/concern' ! module Foo extend ActiveSupport::Concern included do def self.method_injected_by_foo ... end end end ! module Bar extend ActiveSupport::Concern include Foo ! included do self.method_injected_by_foo end end ! class Host include Bar # works, Bar takes care now of its dependencies end
114. +
116. RUBY VIRTUAL ^
120. Norm
121. SQL
122. SQL No
123. RM O
124. RM No
125. An experiment in building the minimal useful API to a PostgreSQL database. What is it?
126. Even remotely ready for production. What is it not?
127. Principles Prefer composition and well-defined interfaces over modules and types No Object#is_a? and not much ===
128. Principles Keep code size smaller by only writing the code we really need ActiveRecord + ActiveModel + ActiveSupport = 28152 LOC Norm = 2540 LOC
129. Principles Minimize dependencies Currently, pg and connection_pool
130. Principles Write the simplest thing that could possibly work, build from there
131. Principles Leverage Ruby’s stock functionality instead of re-inventing the wheel “super” is my favorite word ever
132. What do I really need in a database library?
133. Attribute Typecasting and Update Tracking
134. Norm::Attributes class PersonAttributes < Norm::Attributes attribute :id, Norm::Attr::Integer attribute :name, Norm::Attr::String attribute :age, Norm::Attr::Integer attribute :created_at, Norm::Attr::Timestamp attribute :updated_at, Norm::Attr::Integer ! identity :id end ! attrs = PersonAttributes.new :name => 'Ernie', :age => 36 # => #<PersonAttributes # id: <DEFAULT>, name: "Ernie", age: 36, # created_at: <DEFAULT>, updated_at: <DEFAULT> # > attrs.identity? # => false attrs[:id] = 1 attrs.identity? # => true attrs.updated # => {:id => 1}
135. Norm::Attributes class PersonAttributes < Norm::Attributes attribute :id, Norm::Attr::Integer attribute :name, Norm::Attr::String attribute :age, Norm::Attr::Integer attribute :created_at, Norm::Attr::Timestamp attribute :updated_at, Norm::Attr::Integer ! identity :id end ! attrs = PersonAttributes.new :name => 'Ernie', :age => 36 # => #<PersonAttributes # id: <DEFAULT>, name: "Ernie", age: 36, # created_at: <DEFAULT>, updated_at: <DEFAULT> # > attrs.identity? # => false attrs[:id] = 1 attrs.identity? # => true attrs.updated # => {:id => 1} .load(value)
136. static VALUE pgconn_exec_params( int argc, VALUE *argv, VALUE self ) { // ... ! for ( i = 0; i < nParams; i++ ) { param = rb_ary_entry(params, i); if (TYPE(param) == T_HASH) { param_type = rb_hash_aref(param, sym_type); param_value_tmp = rb_hash_aref(param, sym_value); if(param_value_tmp == Qnil) param_value = param_value_tmp; else param_value = rb_obj_as_string(param_value_tmp); param_format = rb_hash_aref(param, sym_format); } ! // ... } } ext/pg_connection.c
137. static VALUE pgconn_exec_params( int argc, VALUE *argv, VALUE self ) { // ... ! for ( i = 0; i < nParams; i++ ) { param = rb_ary_entry(params, i); if (TYPE(param) == T_HASH) { param_type = rb_hash_aref(param, sym_type); param_value_tmp = rb_hash_aref(param, sym_value); if(param_value_tmp == Qnil) param_value = param_value_tmp; else param_value = rb_obj_as_string(param_value_tmp); param_format = rb_hash_aref(param, sym_format); } ! // ... } } ext/pg_connection.c
138. static VALUE pgconn_exec_params( int argc, VALUE *argv, VALUE self ) { // ... ! for ( i = 0; i < nParams; i++ ) { param = rb_ary_entry(params, i); if (TYPE(param) == T_HASH) { param_type = rb_hash_aref(param, sym_type); param_value_tmp = rb_hash_aref(param, sym_value); if(param_value_tmp == Qnil) param_value = param_value_tmp; else param_value = rb_obj_as_string(param_value_tmp); param_format = rb_hash_aref(param, sym_format); } ! // ... } } ext/pg_connection.c
139. static VALUE pgconn_exec_params( int argc, VALUE *argv, VALUE self ) { // ... ! for ( i = 0; i < nParams; i++ ) { param = rb_ary_entry(params, i); if (TYPE(param) == T_HASH) { param_type = rb_hash_aref(param, sym_type); param_value_tmp = rb_hash_aref(param, sym_value); if(param_value_tmp == Qnil) param_value = param_value_tmp; else param_value = rb_obj_as_string(param_value_tmp); param_format = rb_hash_aref(param, sym_format); } ! // ... } } ext/pg_connection.c param_value_tmp.to_s;
140. Representation of a Database Row
141. class Person < Norm::Record attribute :id, Attr::Integer attribute :name, Attr::String attribute :age, Attr::Integer attribute :created_at, Attr::Timestamp attribute :updated_at, Attr::Integer end ! person = Person.new(:name => 'Ernie', :age => 36) # => #<Person #<Person::Attributes # id: <DEFAULT>, name: "Ernie", age: 36, # created_at: <DEFAULT>, updated_at: <DEFAULT> # >> person.stored? # => false person.age += 1 # => 37 person.updated_attributes # => {:age => 37} Norm::Record
142. A Query Executor
143. module Norm class Connection # ... def exec_statement(stmt, result_format = 0, &block) handling_errors do sql = finalize_placeholders(stmt.sql) @db.exec_params(sql, stmt.params, result_format) do |result| yield result, self if block_given? end end end # ... end end Norm::Connection
144. A Representation of a Query Any object that responds to #sql and #params
145. Norm::SQL::* Default query objects to make you feel at home. query = Norm::SQL.insert(:people, [:name, :age]). values('Ernie', 36). returning('*') # => #<Norm::SQL::Insert:...> puts query.sql # => INSERT INTO "people" ("name", "age") # VALUES ($?, $?) # RETURNING * query.params # => ["Ernie", 36]
146. Someplace for Queries to Live
147. Norm::Repository class PersonRepository < Norm::PostgreSQLRepository ! def select_statement Norm::SQL.select.from('people') end ! def insert_statement Norm::SQL.insert(:people, attribute_names).returning('*') end ! def update_statement Norm::SQL.update('people').returning('*') end ! def delete_statement Norm::SQL.delete('people').returning('*') end ! end
148. Norm::Repository repo = PersonRepository.new(Person) person = Person.new(:name => 'Ernie', :age => 36) repo.insert(person) repo.fetch(person.id) #all #fetch(*primary_key(s)) #insert(record) #update(record) #store(record) #delete(record) #mass_insert(records) #mass_update(records, attrs) #mass_delete(records) Concepts:! records in/out connection checkout reader/writer connections atomicity result processing strategy
149. A Place for My Business Logic
150. Norm::RecordDelegator class AuthenticatingUser include Norm::RecordDelegator(User, railsify: true) ! attr_reader :password attr_accessor :password_confirmation, :original_password validates :password, :confirmation => true validates :password, :length => { :minimum => 6 }, :if => :setting_password? validate :original_password_valid?, :if => :updating_password? ! def self.authenticate(username, password) if user = UserRepository.new(self).with_username(username) user if BCrypt::Password.new(user.password_digest) == password end end ! def password=(unencrypted_password) @password = unencrypted_password.to_s if @password.present? self.password_digest = BCrypt::Password.create(unencrypted_password) end end ! # ... end
151. Norm::RecordDelegator class AuthenticatingUser include Norm::RecordDelegator(User, railsify: true) ! attr_reader :password attr_accessor :password_confirmation, :original_password validates :password, :confirmation => true validates :password, :length => { :minimum => 6 }, :if => :setting_password? validate :original_password_valid?, :if => :updating_password? ! def self.authenticate(username, password) if user = UserRepository.new(self).with_username(username) user if BCrypt::Password.new(user.password_digest) == password end end ! def password=(unencrypted_password) @password = unencrypted_password.to_s if @password.present? self.password_digest = BCrypt::Password.create(unencrypted_password) end end ! # ... end
152. class UsersController < ApplicationController before_filter :require_authentication!, :except => [:new, :create] ! def new @user = AuthenticatingUser.new end ! def create @user = AuthenticatingUser.new.set(user_params_for_create) if repository.insert(@user) session[:user_id] = @user.id redirect_to my_plan_path end end ! def edit @user = repository.fetch(session[:user_id]) end ! def update @user = repository.fetch(session[:user_id]) @user.set(user_params_for_update) if repository.update(@user) redirect_to my_profile_path end end ! # ... ! def repository @repository ||= UserRepository.new( AuthenticatingUser, processor: ValidatingProcessor.new(AuthenticatingUser) ) end end
153. What else? I’m open to your thoughts!
154. THANKS!
155. ❤️ THANKS!