MongoMapper - Mapping Ruby To and From Mongo

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Ordered List John Nunemaker Mongo Chicago October 20, 2010 MongoMapper Mapping Ruby To and From Mongo

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Using Extending Prophesying

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Using Extending Prophesying

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class Item end

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class Item include MongoMapper::Document end

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class Datum include MongoMapper::EmbeddedDocument end

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Free Stuﬀ

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Free Stuﬀ Persistence

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

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

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

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

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Persistence Never gonna give you up

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

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

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

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

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Types What you be baby boo?

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

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But Mongo is Schema-less?

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Think App Schema Instead of database schema

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

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Custom Types Its shake and bake and I helped!

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

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

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

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Typeless I do not know who I am

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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

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Validations Currently using fork of validatable

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

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

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validates_presence_of validates_length_of validates_format_of validates_numericality_of validates_acceptance_of validates_confirmation_of validates_inclusion_of validates_exclusion_of

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Callbacks Ripped from AS2’s cold, dead ﬁngers

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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

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: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

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Scopes Plucky Power!

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class User include MongoMapper::Document scope :johns, where(:name => 'John') end User.johns.all User.johns.first

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class User include MongoMapper::Document scope :by_ages, lambda { |low, high| where(:age.gte => low, :age.lte => high) } end User.by_ages(13, 19).count User.by_ages(13, 19).all

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class User include MongoMapper::Document scope :teen, where(:age.gte => 13, :age.lte => 19) def self.by_tag(tag) where(:tags => tag) end end User.teen.by_tag('bieber').count User.by_tag('bieber').teen.all

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Associations I belong to you

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to Docs belongs_to, one, many, many :in

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

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

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

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to Embedded Docs many, one

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

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

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

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Using Extending Prophesying

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Plugins Conventional way to extend

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

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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

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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

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

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Good Example Joint: github.com/jnunemaker/joint

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

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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

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Descendant Appends Fancy Schmancy and Stolen

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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

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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

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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'

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

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Using Extending Prophesying

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Active Model rails3 branch

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Documentation http://mongomapper.com

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“ Brian Ford @brixen Documentation: n. paradoxically repeating yourself so you do not need to repeat yourself.

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Ordered List Thank you! [email protected] John Nunemaker Mongo Chicago October 20, 2010 @jnunemaker