MongoMapper - Mapping Ruby to and from Mongo

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

Using Extending Prophesying

...and many more.

class Item end

class Item include MongoMapper::Document end

class Datum include MongoMapper::EmbeddedDocument end

Free Stuﬀ

Free Stuﬀ Persistence

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

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

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

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

Persistence Never gonna give you up

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

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

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

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

Types What you be baby boo?

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

But Mongo is Schema-less?

Instead of database schema Think App Schema

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

Custom Types Its shake and bake and I helped!

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

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

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

Typeless I do not know who I am

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

Validations Currently using fork of validatable

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

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

validates_presence_of validates_length_of validates_format_of validates_numericality_of validates_acceptance_of validates_confirmation_of validates_inclusion_of validates_exclusion_of

Callbacks Ripped from AS2’s cold, dead ﬁngers

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

: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

Associations I belong to you

to Docs belongs_to, one, many, many :in

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

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

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

to Embedded Docs many, one

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

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

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

Plugins Conventional way to extend

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

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

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

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

Good Example Joint: github.com/jnunemaker/joint

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

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

Descendant Appends Fancy Schmancy and Stolen

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

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

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'

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

Active Model Validations, callbacks, serialization, etc.

Blank Document Mix and match whatever you want

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

ideafoundry.info/mongodb

mongotips.com

railstips.org

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

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MongoMapper - Mapping Ruby to and from Mongo

by John Nunemaker

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