MongoMapper - Mapping Ruby To and From Mongo

Presentation at MongoChicago 2010 on mapping MongoDB to and from Ruby using MongoMapper.

Transcript

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

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2. Using
   Extending
   Prophesying
   

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3. Using
   Extending
   Prophesying
   

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5. class Item
   end
   

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6. class Item
   include MongoMapper::Document
   end
   

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7. class Datum
   include MongoMapper::EmbeddedDocument
   end
   

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8. Free Stuff
   

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9. Free Stuff
   Persistence
   

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

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

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

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13. 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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14. Persistence
    Never gonna give you up
    

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

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

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18. 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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19. Types
    What you be baby boo?
    

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

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21. But Mongo is Schema-less?
    

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22. Think App Schema
    Instead of database schema
    

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

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

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25. 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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26. 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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27. class User
    include MongoMapper::Document
    key :email, DowncasedString
    end
    

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28. Typeless
    I do not know who I am
    

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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
    

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30. Validations
    Currently using fork of validatable
    

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

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

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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
    

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

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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
    

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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
    

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37. Scopes
    Plucky Power!
    

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

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39. 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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40. 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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41. Associations
    I belong to you
    

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

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

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45. [
    {
    '_id' => ObjectID('...'),
    'title' => 'OL',
    'domain' => 'orderedlist.com'
    'account_id' => ObjectID('...'),
    },
    {
    '_id' => ObjectID('...'),
    'title' => 'RT',
    'domain' => 'railstips.org'
    'account_id' => ObjectID('...'),
    }
    ]
    

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46. to Embedded Docs
    many, one
    

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

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

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49. {
    '_id' => ObjectID('...'),
    'title' => 'MongoSF',
    'data' => [
    {
    '_id' => ObjectID('...'),
    'key' => 'description'
    'value' => 'Awesome.',
    }
    ]
    }
    

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50. Using
    Extending
    Prophesying
    

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51. Plugins
    Conventional way to extend
    

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52. 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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55. 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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56. 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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57. class Foo
    include MongoMapper::Document
    plugin ActsAsListFu
    end
    Foo.reorder(...)
    Foo.new.move_to_top
    

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

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

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60. 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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61. Descendant Appends
    Fancy Schmancy and Stolen
    

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62. 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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63. 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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64. 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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65. module IdentityMapAddition
    def self.included(model)
    model.plugin MongoMapper::Plugins::IdentityMap
    end
    end
    MongoMapper::Document.append_inclusions(IdentityMapAddition)
    

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66. Using
    Extending
    Prophesying
    

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67. Active Model
    rails3 branch
    

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68. Documentation
    http://mongomapper.com
    

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69. “
    Brian Ford @brixen
    Documentation: n.
    paradoxically repeating
    yourself so you do not
    need to repeat yourself.
    

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72. Ordered List
    Thank you!
    john@orderedlist.com
    John Nunemaker
    Mongo Chicago
    October 20, 2010
    @jnunemaker
    

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