1. The Ruby /
MongoDB ecosystem
Harold Giménez
Mongo Boston - Sept 20, 2010

2. Harold Giménez
@hgimenez
thoughtbot, inc.

3. Why Ruby?
• Expressiveness, Elegance
• Powerful
• Simple, flexible syntax
• Open Source
• Community
• Library support: rubygems

4. ...maybe too many
libraries

6. mongo-ruby-driver
http://github.com/mongodb/mongo-ruby-driver

7. Start here
Closest to mongo’s lingo, almost-native query syntax
require 'mongo'
db = Mongo::Connection.new.db('mongo-boston')
people = db.collection('people')
people.insert({'name' => 'Harold',
'address' => {
'city' => 'Boston'
}
})
people.insert({'name' => 'Jack'})
people.find('name' => 'Harold').to_a
people.find('address.city' => 'Boston').to_a

8. Tools
mongoid Mongomatic
MongoMapper MongoODM
connection, cursor, CRUD
mongo-ruby-driver

9. mongoid
http://github.com/mongoid/mongoid

10. class Person
include Mongoid::Document
field :cool_dude, :type => Boolean, :default => false
field :name
field :age, :type => Integer
embeds_one :address
validates_presence_of :name
end
class Address
include Mongoid::Document
field :city
field :zip_code
embedded_in :person, :inverse_of => :address
end

11. class Person
include Mongoid::Document
field :cool_dude, :type => Boolean, :default => false
field :name
field :age, :type => Integer
embeds_one :address
embeds_many
references_one
validates_presence_of :name
references_many
end
referenced_in
class Address
include Mongoid::Document
field :city
field :zip_code
embedded_in :person, :inverse_of => :address
end

12. > me = Person.create!(:cool_dude => true)
Mongoid::Errors::Validations: Validation failed - Name can't be blank.
> me = Person.create(:name => 'Harold', :cool_dude => true)
=> #<Person name: "Harold", _id:
BSON::ObjectId('4c950d73fff2cb4262000007'), cool_dude: true>
> me.address = Address.new(:city => 'Boston')
=> #<Address city: "Boston", zip_code: nil, _id:
BSON::ObjectId('4c950d83fff2cb4262000008')>
> me.save
{
"_id" : ObjectId("4c950d73fff2cb4262000007"),
"address" : { "_id" : ObjectId("4c950d83fff2cb4262000008"),
"city" : "Boston",
"zip_code" : null
},
"name" : "Harold",
"cool_dude" : true
}

13. mongoid criteria
me = Person.create(:name => 'Harold', :cool_dude => true)
another_harold = Person.create(:name => 'Harold')
someone_else = Person.create(:name => 'Jack', :cool_dude => true)
Person.where(:name => 'Harold')
Person.where(:cool_dude => true)
Person.where(:name => 'Harold').where(:cool_dude => true)
class Person
def self.cool_dudes
where(:cool_dude => true)
end
def self.harolds
where(:name => 'Harold')
end
end
Person.cool_dudes.harolds
Person.harolds.not_in("address.city" =>
["Boston"]).asc("address.city")Person.cool_dudes.only(:id).where("address.
city" => "Boston")

14. more querying
Person.all_in(:name => [ "Harold", "Ha, Lord!" ])
Person.any_in(:status => ["Single", "Divorced", "Separated"])
Person.any_of({ :name => "Harold" }, { :cool_dude => true })
Person.and(:name => "Harold", :cool_dude => false)
Person.excludes("address.city" => "Boston")
Person.limit(20)
Person.not_in(:name => ["Harold", "Jack"])
Person.where(:address.exists => true)
Person.where(:age.gt => 21)
Person.where(:age.gte => 21)
Person.where(:age.lt => 30)
Person.where(:age.lte => 30)

15. Mongoid::Paranoia
class Person
include Mongoid::Document
include Mongoid::Paranoia
end
person.delete # person.deleted_at = Time.now
person.restore # phew!
person.delete!
person.restore # it's gone :(

16. cursor proxy
module Mongoid
class Cursor
include Enumerable
OPERATIONS = [
:close, :closed?, :count, :explain,
:fields, :full_collection_name, :hint, :limit,
:order, :query_options_hash, :query_opts, :selector,
:skip, :snapshot, :sort, :timeout
]
OPERATIONS.each do |name|
define_method(name) { |*args| @cursor.send(name, *args) }
end
def each
# ...
end
def next_document
# ...
end
def to_a
# ...
end
end

17. Enables caching vs. lazy loading of big datasets
Person.all.cache.each { |person| person.hug }
or
class Person
include Mongoid::Document
cache
end
Person.all.each { |person| person.hug }

18. ActiveModel under
the hood
ActiveModel::Conversion
ActiveModel::Naming
ActiveModel::Serialization
ActiveModel::MassAssignmentSecurity
ActiveModel::Translation
ActiveModel::Validation
ActiveModel::Callbacks

19. MongoMapper
http://github.com/jnunemaker/mongomapper

20. class Person
include MongoMapper::Document
key :cool_dude, Boolean, :default => false
key :name, String, :required => true
key :age, Integer
one :address
end
class Address
include MongoMapper::EmbeddedDocument
key :city, String
key :zip_code, String
end

21. class Person
include MongoMapper::Document
key :cool_dude, Boolean, :default => false
key :name, String, :required => true
key :age, Integer
one :address many
end belongs_to
class Address
include MongoMapper::EmbeddedDocument
key :city, String
key :zip_code, String
end

22. class Person
include MongoMapper::Document
key :cool_dude, Boolean, :default => false
key :name, String, :required => true
key :age, Integer
one :address
end
class Address
include MongoMapper::EmbeddedDocument
key :city, String
key :zip_code, String
end

23. class Person
include MongoMapper::Document
key :cool_dude, Boolean, :default => false
key :name, String, :required => true
key :age, Integer
one :address
Alternative
end
validation syntax
class Address
include MongoMapper::EmbeddedDocument
key :city, String
key :zip_code, String
end

24. > me = Person.create!(:cool_dude => true)
MongoMapper::DocumentNotValid: Validation failed: Name can't be empty
> me = Person.create(:name => 'Harold', :cool_dude => true)
=> #<Person name: "Harold", _id:
BSON::ObjectId('4c9508fbfff2cb4096000007'), cool_dude: true>
> me.address = Address.new(:city => 'Boston')
=> #<Address city: "Boston", zip_code: nil, _id:
BSON::ObjectId('4c950911fff2cb4096000008')>
> me.save
{
"_id" : ObjectId("4c9508fbfff2cb4096000007"),
"address" : { "_id" : ObjectId("4c950911fff2cb4096000008"),
"city" : "Boston",
"zip_code" : null
},
"name" : "Harold",
"cool_dude" : true
}

25. Plugin architecture
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 associations, dirty, document
dynamic_querying, embedded_document, equality
indexes, logger modifiers, pagination
persistence, protected, querying
safe, SCI, scopes, serialization, validations,
and more (pretty much everything in MM)

26. Querying (plucky)
Person.where(:address.exists => true).all
Person.where(:age.gt => 21).limit(10).all
Person.where(:age.gte => 21).all
Person.where(:age.lt => 30).all
Person.where(:age.lte => 30).all
( Similar to mongoid’s
querying and scoping )
Except for no support for
#not_in, #exists, #any_of
and others found in mongoid

27. Notable difference:
mongoid MongoMapper
#<Mongoid::Criteria:
Person.where(:name => 'Harold') 0x101754bd8 @klass=Person, #<Plucky::Query name:
@options={}, @documents=[], "Harold">
@selector={:name=>"Harold"}>
#<Mongoid::Criteria:
0x101754bd8 @klass=Person,
Person.where(:name => 'Harold').all @options={}, @documents=[],
[#<Person name: "Harold"]
@selector={:name=>"Harold"}>
Person.where(:name => 'Harold').all.to_a [#<Person name: "Harold"] [#<Person name: "Harold"]
or #each, #map, etc

28. cache_key
class Person
include MongoMapper::Document
end
Person.new.cache_key
# => "Person/new"
Person.create.cache_key
# => "Person/4c9508fbfff2cb4096000007"

29. Custom data types
class MongoSet
def self.to_mongo(value)
value.to_a
end
def self.from_mongo(value)
Set.new(value || [])
end
end
class Person
include MongoMapper::Document
key :aliases, MongoSet
end

30. Typecasting
class Person
include MongoMapper::Document
key :friend_ids, Array, :typecast => 'ObjectId'
end
Person.new(:friend_ids => %w(4c950520fff2cb3fb9000004
4c950558fff2cb3fb9000005
4c950911fff2cb4096000008) )

31. Both MongoMapper
and Mongoid provide:
#cache_key Cursor wrapper/cache
plugins embraces ActiveModel
custom data types thorough query syntax abstraction
typecasting Persistance
Querying
Associations
Embedded Docs
Serialization
Dynamic Finders
Pagination
Scopes
Rails 3

32. Rails 2, you are...
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.th us an
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go e!
MongoMapper m
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Mongoid

33. MongoODM
http://github.com/carlosparamio/mongo_odm
Mongomatic
MongoMapper
http://github.com/benmyles/mongomatic

34. A fresh look
Query chaining
Lazy loading
Validations
Callbacks
Rails integration
Worth keeping an eye on!

35. Mongoid MongoMapper
Side by side!
Mongomatic MongoODM

36. Number of Files
300
250
200
project
mongoid
files
MongoMapper
mongomatic
150
MongoODM
100
50
May−09 Aug−09 Nov−09 Feb−10 May−10 Aug−10
day

37. Number of Lines
30000
number_of_lines
project
mongoid
20000
MongoMapper
mongomatic
MongoODM
10000
0
May−09 Aug−09 Nov−09 Feb−10 May−10 Aug−10
day

38. Number of Collaborators
80
60
project
collaborators
mongoid
MongoMapper
mongomatic
40
MongoODM
20
0
May−09 Aug−09 Nov−09 Feb−10 May−10 Aug−10
day

39. Number of Commits
1500
project
1000
mongoid
commits
MongoMapper
mongomatic
MongoODM
500
0
May−09 Aug−09 Nov−09 Feb−10 May−10 Aug−10
day

40. mongoid release cycle
25
20
prior_days
15
10
5
0
2.0.0.beta.102.0.0.beta1v0.0.1 v0.10.5v0.11.4v0.12.0 v0.2.5v0.3.2v0.4.2v0.4.8v0.5.2v0.5.7 v0.6.2v0.6.7 v0.7.2v0.7.7 v0.8.2v0.8.7 v0.9.11 v0.9.6v1.0.1v1.0.6v1.1.4 v1.2.13 v1.2.5v1.9.0
2.0.0.beta.11 2.0.0.beta11v0.10.2v0.11.1v0.11.7 v0.2.2v0.2.7v0.3.4v0.4.4v0.5.1v0.5.4v0.5.9v0.6.3v0.6.8 v0.7.3v0.7.8 v0.8.3v0.8.8 v0.9.12 v0.9.7v1.0.2v1.1.0v1.2.0 v1.2.14 v1.2.6v1.9.1
2.0.0.beta.12 2.0.0.beta2 v0.10.3v0.11.2v0.11.8 v0.2.3v0.3.0v0.4.0v0.4.5 v0.5.11 v0.5.8 v0.6.4v0.6.9 v0.7.4v0.7.9 v0.8.4v0.8.9 v0.9.2 v0.9.8v1.0.3v1.1.1v1.2.1 v1.2.15 v1.2.7v2.0.0
2.0.0.beta.13 2.0.0.beta7 v0.10.4v0.11.3v0.11.9 v0.2.4v0.3.1v0.4.1v0.4.7 v0.5.3 v0.6.0 v0.6.5v0.7.0 v0.7.5v0.8.0 v0.8.5v0.9.0 v0.9.3 v0.9.9v1.0.4v1.1.2 v1.2.11 v1.2.3v1.2.8
2.0.0.beta.14 2.0.0.beta8 v0.10.6v0.11.5 v0.2.0 v0.2.6v0.3.3v0.4.3v0.5.0 v0.5.5 v0.6.1 v0.6.6v0.7.1 v0.7.6v0.8.1 v0.8.6v0.9.1 v0.9.4 v1.0.0v1.0.5v1.1.3 v1.2.12 v1.2.4v1.2.9
2.0.0.beta.16 2.0.0.beta9 v0.11.0v0.11.6 v0.2.1
2.0.0.beta.17
2.0.0.beta.7
2.0.0.beta.8 v0.10.0
2.0.0.beta.9 v0.10.1
2.0.0.beta10 v0.5.10 v0.5.6 v0.6.10 v0.7.10 v0.8.10 v0.9.10 v0.9.5 v1.2.10 v1.2.2 v2.0.0.beta1
v2.0.0.beta3
v2.0.0.beta4
tag

41. MongoMapper release cycle
50
40
30
prior_days
20
10
0
v0.1.0 v0.1.2 v0.3.0 v0.3.2 v0.3.4 v0.4.0 v0.4.2 v0.5.1 v0.5.3 v0.5.5 v0.5.7 v0.6.0 v0.6.10 v0.6.3 v0.6.5 v0.6.7 v0.6.9 v0.7.1 v0.7.3 v0.7.5 v0.8.0 v0.8.2 v0.8.4
v0.1.1 v0.2.0 v0.3.1 v0.3.3 v0.3.5 v0.4.1 v0.5.0 v0.5.2 v0.5.4 v0.5.6 v0.5.8 v0.6.1 v0.6.2 v0.6.4 v0.6.6 v0.6.8 v0.7.0 v0.7.2 v0.7.4 v0.7.6 v0.8.1 v0.8.3
tag

42. the end