Introduction to a proof of concept library 'Aqua' that uses CouchDB and other document oriented back ends to transparently persist Ruby objects.

1. Aqua A cool, clear drink of Ruby object persistence Kane Baccigalupi RubyConf 09

2. Aqua A cool, clear drink of Ruby object persistence Kane Baccigalupi RubyConf ‘09

3. Aqua A cool, clear drink of Ruby object persistence Got unemployment? Relax with CouchDB Kane Baccigalupi RubyConf ‘09

4. Aqua A cool, clear drink of Ruby object persistence ORMs are great, but normalization is expensive. # DataMapper class Mammal include DataMapper::Resource property :my_id, Serial has n, :legs end # ActiveRecord class Bird < ActiveRecord::Base # properties defined by migration has_many, :legs end Kane Baccigalupi RubyConf ‘09

5. Aqua A cool, clear drink of Ruby object persistence CouchDB + Ruby ~= CouchRest # CouchRest class Reptile < CouchRest::ExtendedDocument use_database MY_DB unique_id :my_id property :legs # a collection! end Kane Baccigalupi RubyConf ‘09

6. Aqua A cool, clear drink of Ruby object persistence CouchRest is different from ORMs because: It allows collections Models are hashes Instance variables are discarded Kane Baccigalupi RubyConf ‘09

7. Aqua A cool, clear drink of Ruby object persistence What defines Ruby object state? Instance variables @my_variable Fundamental data Hash key-values, Array values, etc. Kane Baccigalupi RubyConf ‘09

8. Aqua A cool, clear drink of Ruby object persistence Database abstractions focus on databases # DataMapper class Mammal include DataMapper::Resource property :my_id, Serial has n, :legs end # ActiveRecord class Bird < ActiveRecord::Base # properties defined by schema has_many, :legs end # CouchRest class Reptile < CouchRest::ExtendedDocument use_database MY_DB unique_id :my_id property :legs # a collection! end Kane Baccigalupi RubyConf ‘09

9. Aqua A cool, clear drink of Ruby object persistence Aqua’s goal: Focus on objects object.commit! Kane Baccigalupi RubyConf ‘09

10. Aqua A cool, clear drink of Ruby object persistence Because Ruby is awesome class Event < Range attr_accessor :name end rubyconf = Event.new(Date.parse('11/19/2009'), Date.parse('11/21/2009')) rubyconf.name = 'RubyConf 09' rubyconf.include?(Date.parse('11/20/2009')) # true Kane Baccigalupi RubyConf ‘09

11. Aqua A cool, clear drink of Ruby object persistence How does Aqua work? Kane Baccigalupi RubyConf ‘09

12. Aqua A cool, clear drink of Ruby object persistence Just add Aqua class User aquatic # ... end Kane Baccigalupi RubyConf ‘09

13. Aqua A cool, clear drink of Ruby object persistence Just add Aqua class User aquatic # ... end user = User.new # ... More stuff happens to the user # saving an object user.commit! # commit without the ! also works but raises no errors. Kane Baccigalupi RubyConf ‘09

14. Aqua A cool, clear drink of Ruby object persistence Behind the scene user.commit! Kane Baccigalupi RubyConf ‘09

15. Aqua A cool, clear drink of Ruby object persistence Behind the scene serialization user.commit! { "class"=>"User", "ivars"=>{ "@username"=>"kane", "@email"=>"baccigalupi@gmail.com", "@password"=>"secret" } } Kane Baccigalupi RubyConf ‘09

16. Aqua A cool, clear drink of Ruby object persistence Behind the scene serialization user.commit! { "class"=>"User", "ivars"=>{ "@username"=>"kane", "@email"=>"baccigalupi@gmail.com", "@password"=>"secret" } } data post Kane Baccigalupi RubyConf ‘09

17. Aqua A cool, clear drink of Ruby object persistence Objects ~= Documents, && Documents ~= Hashes # YAML for a Ruby User object --- &id001 !ruby/object:User email: baccigalupi@gmail.com password: secret username: kane # Aqua Serialization for same object { "class"=>"User", "ivars"=>{ "@username"=>"kane", "@email"=>"baccigalupi@gmail.com", "@password"=>"secret" } } Kane Baccigalupi RubyConf ‘09

18. Aqua A cool, clear drink of Ruby object persistence Sometimes state should not hang around. There is a method for that. class User aquatic attr_accessor :username, :email, :password hide_attributes :password end Kane Baccigalupi RubyConf ‘09

19. Aqua A cool, clear drink of Ruby object persistence Going deeper with embedded objects … class Address # not an aquatic object, just plain ruby attr_accessor :name, :street, :city, :state, :zip end address = Address.new # . . . user = User.new user.addresses = [ address ] Kane Baccigalupi RubyConf ‘09

20. Aqua A cool, clear drink of Ruby object persistence Ordinary objects get serialized inside aquatic objects { "class"=>"User", "ivars"=>{ "@addresses"=>{ "class"=>"Array", "init"=>[{ "class"=>"Address", "ivars"=>{ "@city"=>"San Francisco", "@name"=>"work", "@street"=>"P0 Box 58", "@state"=>"94102" } }] }, "@username"=>"kane", "@email"=>"baccigalupi@gmail.com" } } Kane Baccigalupi RubyConf ‘09

21. Aqua A cool, clear drink of Ruby object persistence Embedded aquatic objects are saved by reference. { "class"=>"User", "ivars"=>{ # ... "@friends"=>{ "class"=>"Array", "init"=>[{ "class"=>"Aqua::Stub", "init"=>{"class"=>"User", "id"=>"32"} }] } } } class User aquatic # ... def friends @friends ||= [] end end user.friends << alex # where alex is another user object Kane Baccigalupi RubyConf ‘09

23. Triggered by #method_missing

24. Stubs/caches methods{ "class"=>"User", "ivars"=>{ # ... "@friends"=>{ "class"=>"Array", "init"=>[{ "class"=>"Aqua::Stub", "init"=>{"class"=>"User", "id"=>"32"} }] } } } Kane Baccigalupi RubyConf ‘09

25. Aqua A cool, clear drink of Ruby object persistence Stubbing methods in Aqua::Stub { "class"=>"User", "ivars"=>{ # ... "@friends"=>{ "class"=>"Array", "init"=>[{ "class"=>"Aqua::Stub", "init"=>{ "class"=>"User", "id"=>"32”, "methods"=>{"username"=>"alex"}, } }] } } } class User aquatic :embed => { :stub => :username } # ... end Kane Baccigalupi RubyConf ‘09

26. Aqua A cool, clear drink of Ruby object persistence Stubbed behavior user.reload friend = user.friends.first friend.class # Aqua::Stub friend.username# ‘alex’ # username was cached friend.email # this triggers the database call # for the friend object Kane Baccigalupi RubyConf ‘09

27. Aqua A cool, clear drink of Ruby object persistence Got Files? { "class"=>"User", "ivars"=>{ # ... "@avatar"=>{ "class"=>"Aqua::FileStub” "init"=>{ "methods"=>{ "content_type"=>"image/png", "content_length"=>{ "class"=>"Fixnum", "init"=>"26551” } } "id"=>"image_attach.png" }, } } } class User aquatic # ... attr_accessor :avatar end user.avatar = my_pic Kane Baccigalupi RubyConf ‘09

28. Aqua A cool, clear drink of Ruby object persistence Getting Objects: The basics User.load( some_id ) user.reload Kane Baccigalupi RubyConf ‘09

29. Aqua A cool, clear drink of Ruby object persistence Indexed Searches class User aquatic # ... index_on :username end " // javascript map function function(doc) { if( doc['class'] == 'User' && doc['ivars'] && doc['ivars']['@username'] ){ emit( doc['ivars']['@username'], 1 ); } } " User.query(:username, ’kane') # returns an array of all users named kane Kane Baccigalupi RubyConf ‘09

31. Criteria pattern ???

32. Custom dsl ???

33. Much coding loveKane Baccigalupi RubyConf ‘09

35. Attribute constraints for class, size, etc.

36. Collections & relationships

37. ActiveRecord conversion ???Kane Baccigalupi RubyConf ‘09

39. Singleton methods

40. Classes (are objects too)Kane Baccigalupi RubyConf ‘09

42. Stores objects, not serializations

43. commits objects as neededKane Baccigalupi RubyConf ‘09

44. Aqua A cool, clear drink of Ruby object persistence More Info Rdocs: ruby-aqua.org Get the gem: sudo gem install aqua Explore the code: github.com/baccigalupi/aqua Kane Baccigalupi RubyConf ‘09