1. MongoMapper
Mapping Ruby To and From Mongo
MongoSF San Francisco, CA John Nunemaker
April 30, 2010 Ordered List

2. Using
Extending
Prophesying

3. Using
Extending
Prophesying

4. ...and many more.

5. class Item
end

6. class Item
include MongoMapper::Document
end

7. class Datum
include MongoMapper::EmbeddedDocument
end

8. Free Stuff

9. Free Stuff
Persistence

10. Free Stuff
Persistence
Validations [presence, length, inclusion, ...]

11. Free Stuff
Persistence
Validations [presence, length, inclusion, ...]
Callbacks [before/after validate, create, save, ...]

12. Free Stuff
Persistence
Validations [presence, length, inclusion, ...]
Callbacks [before/after validate, create, save, ...]
Associations [many, belongs_to, one, ...]

13. Free Stuff
Persistence
Validations [presence, length, inclusion, ...]
Callbacks [before/after validate, create, save, ...]
Associations [many, belongs_to, one, ...]
Serialization [to_json]

14. Persistence
Never gonna give you up

15. item = Item.create({
:title => 'MongoSF',
:location => 'San Fran',
:when => Time.now
})

16. puts item.to_mongo
{
"_id" => ObjectID('4bd8cc5cbcd1b313b3000001'),
"title" => "MongoSF",
"location" => "San Fran",
"when" => Wed Apr 28 17:01:32 -0700 2010
}

17. item = Item.new
item[:title] = 'MongoSF'
item[:location] = 'San Fran'
item[:when] = Time.now
item.save

18. puts item.to_mongo
{
"_id" => ObjectID('4bd8cc5cbcd1b313b3000001'),
"title" => "MongoSF",
"location" => "San Fran",
"when" => Wed Apr 28 17:01:32 -0700 2010
}

19. Types
What you be baby boo?

20. class Item
include MongoMapper::Document
key :title, String
key :path, String
end

21. But Mongo is Schema-less?

22. Instead of database schema
Think App Schema

23. Built-in Types
Array, Binary, Boolean, Date, Float, Hash,
Integer, Nil, ObjectId, Set, String, Time

24. Custom Types
Its shake and bake and I helped!

25. class Set
def self.to_mongo(value)
value.to_a
end
def self.from_mongo(value)
Set.new(value || [])
end
end

26. class DowncasedString
def self.to_mongo(value)
value.nil? ? nil : value.to_s.downcase
end
def self.from_mongo(value)
value.nil? ? nil : value.to_s.downcase
end
end

27. class User
include MongoMapper::Document
key :email, DowncasedString
end

28. Typeless
I do not know who I am

29. class Foo
include MongoMapper::Document
key :bar
end
foo = Foo.new
foo.bar = 'Some text'
# foo.bar => "Some text"
foo.bar = 24
# foo.bar => 24

30. Validations
Currently using fork of validatable

31. class Item
include MongoMapper::Document
key :title, String
validates_presence_of :title
end

32. class Item
include MongoMapper::Document
key :title, String, :required => true
end

33. validates_presence_of
validates_length_of
validates_format_of
validates_numericality_of
validates_acceptance_of
validates_confirmation_of
validates_inclusion_of
validates_exclusion_of

34. Callbacks
Ripped from AS2’s cold, dead fingers

35. class Item
include MongoMapper::Document
key :title, String
key :path, String
key :parent_id, ObjectId
belongs_to :parent
before_validation :set_path
private
def set_path
self.path = parent.path + title.parameterize
end
end

36. :before_save, :after_save,
:before_create, :after_create,
:before_update, :after_update,
:before_validation, :after_validation,
:before_validation_on_create, :after_validation_on_create,
:before_validation_on_update, :after_validation_on_update,
:before_destroy, :after_destroy,
:validate_on_create, :validate_on_update,
:validate

37. Associations
I belong to you

38. to Docs
belongs_to, one, many, many :in

39. class Account
include MongoMapper::Document
many :sites
end
class Site
include MongoMapper::Document
key :account_id, ObjectId
belongs_to :account
end

40. account = Account.create(:title => 'OL', :sites => [
Site.new(:title => 'OL', :domain => 'orderedlist.com'),
Site.new(:title => 'RT', :domain => 'railstips.org'),
])

41. [
{
'_id' => ObjectID('...'),
'title' => 'OL',
'domain' => 'orderedlist.com'
'account_id' => ObjectID('...'),
},
{
'_id' => ObjectID('...'),
'title' => 'RT',
'domain' => 'railstips.org'
'account_id' => ObjectID('...'),
}
]

42. to Embedded Docs
many, one

43. class Item
include MongoMapper::Document
many :data
end
class Datum
include MongoMapper::EmbeddedDocument
key :key, String
key :value
end

44. Item.create(:title => 'MongoSF', :data => [
Datum.new(:key => 'description', :value => 'Awesome.')
])

45. {
'_id' => ObjectID('...'),
'title' => 'MongoSF',
'data' => [
{
'_id' => ObjectID('...'),
'key' => 'description'
'value' => 'Awesome.',
}
]
}

46. Using
Extending
Prophesying

47. Plugins
Conventional way to extend

48. MongoMapper is
Powered by Plugins
associations, callbacks, clone, descendants,
dirty, equality, identity_map, inspect, keys,
logger, modifiers, pagination, persistence,
protected, rails, serialization, timestamps,
userstamps, validations

51. module MongoMapper
module Plugins
def plugins
@plugins ||= []
end
def plugin(mod)
extend mod::ClassMethods if mod.const_defined?(:ClassMethods)
include mod::InstanceMethods if mod.const_defined?(:InstanceMethods)
mod.configure(self) if mod.respond_to?(:configure)
plugins << mod
end
end
end

52. module ActsAsListFu
module ClassMethods
def reorder(ids)
# reorder ids...
end
end
module InstanceMethods
def move_to_top
# move to top
end
end
def self.configure(model)
model.key :position, Integer, :default => 1
end
end

53. class Foo
include MongoMapper::Document
plugin ActsAsListFu
end
Foo.reorder(...)
Foo.new.move_to_top

54. Good Example
Joint: github.com/jnunemaker/joint

55. class Asset
include MongoMapper::Document
plugin Joint
attachment :image
attachment :file
end

56. asset = Asset.create({
:image => File.open('john.jpg', 'r'),
:file => File.open('foo.txt', 'r'),
})
asset.image.id
asset.image.name
asset.image.type
asset.image.size
asset.image.read

57. Descendant Appends
Fancy Schmancy and Stolen

58. module FancySchmancy
def some_method
puts 'some method'
end
end
MongoMapper::Document.append_extensions(FancySchmancy)
class Foo
include MongoMapper::Document
end
Foo.some_method # puts 'some method'
Foo.new.some_method # NoMethodError

59. module FancySchmancy
def some_method
puts 'some method'
end
end
MongoMapper::Document.append_inclusions(FancySchmancy)
class Foo
include MongoMapper::Document
end
Foo.new.some_method # puts 'some method'
Foo.some_method # NoMethodError

60. module FancySchmancy
def some_method
puts 'some method'
end
end
class Foo
include MongoMapper::Document
end
MongoMapper::Document.append_extensions(FancySchmancy)
class Bar
include MongoMapper::Document
end
Foo.some_method # puts 'some method'
Bar.some_method # puts 'some method'

61. module IdentityMapAddition
def self.included(model)
model.plugin MongoMapper::Plugins::IdentityMap
end
end
MongoMapper::Document.append_inclusions(IdentityMapAddition)

62. Using
Extending
Prophesying

63. Active Model
Validations, callbacks, serialization, etc.

64. Blank Document
Mix and match whatever you want

65. Mongo::Query
Fancy query magic for the ruby driver
github.com/jnunemaker/mongo-query

66. ideafoundry.info/mongodb

67. mongotips.com

68. railstips.org

69. Thank you!
john@orderedlist.com
@jnunemaker
MongoSF San Francisco, CA John Nunemaker
April 30, 2010 Ordered List