GdatastoreMapper

GdatastoreMapper is a mapper framework for Google Cloud Datastore in Ruby / Ruby on Rails. Once you install GdatastoreMapper you can use Google Cloud Datastore like ActiveRecord.

Table of Contents

• Demo
• Requirements
• Installation
• Configuration
• Model Setting
• Persistence Methods
• Scoping Methods
• Timestamp
• Associations
  • One to Many
  • Method Chaining
• Callbacks
• Validations
• Contact
• Development

Demo

Here is demo. The demo works with Google Cloud Datastore.

Source code is here.

Requirements

GdatastoreMapper requires Rails version >= 5

Installation

Execute rails new with --skip-active-record

$ rails new your_project --skip-active-record

Add this line to your application's Gemfile:

gem 'gdatastore_mapper'

And then execute:

$ bundle

Or install it yourself as:

$ gem install gdatastore_mapper

Configuration

GdatastoreMapper configuration can be done through a database.yml. The simplest configuration is as follows, which sets the emulator_host to "localhost:8444" and dataset_id.

# config/database.yml
production:
  dataset_id: your-google-cloud-platform-project-id

staging:
  dataset_id: your-google-cloud-platform-project-id

development:
  dataset_id: your-google-cloud-platform-project-id
  emulator_host: localhost:8444

test:
  dataset_id: your-google-cloud-platform-project-id
  emulator_host: localhost:8444

Model Setting

Only 2 things you need to do.

1. To include GdatastoreMapper
2. To set attr_accessor as column

That's it! No need to db:migrate.

class Book
  include GdatastoreMapper::Base

  attr_accessor :title, :author
end

Persistence Methods

new record

book = Book.new
book.title = 'Harry Potter'
book.save

book = Book.new(title: 'Harry Potter')
book.save

Book.create(title: 'Harry Potter')

update

book.update(title: 'Harry Potter 2')

delete

book.delete

Book.delete_all

Scoping Methods

Book.where(title: 'Harry Potter')
=> [#<Book:0x00 @created_at=2017-04-08 21:22:31 +0200, @title="Harry Potter",
    @id=70, @updated_at=2017-04-08 21:22:31 +0200>]

Book.find(12)
=> #<Book:0x00 @created_at=2017-04-07 10:03:54 +0200, @title="Harry Potter",
    @id=12, @updated_at=2017-04-07 22:57:57 +0200>

Book.find_by(title: 'Harry Potter')
=> #<Book:0x00 @title="Harry Potter" ....

Book.order(title: :asc)
=> [#<Book:0x00 @title="Harry Potter" .... ]

Book.first
=> #<Book:0x00 @title="Harry Potter" ....

Book.last
=> #<Book:0x00 @title="Harry Potter" ....

Book.count
=> 100

Book.all
=> [#<Book:0x00 @title="Harry Potter" .... ]

Timestamp

All records have created_at and updated_at. They will be updated automatically.

Associations

One to Many

Associations can be set the same as Active Record.

example of one to many relationship

class Book
  include GdatastoreMapper::Base

  attr_accessor :title

  belongs_to :author
end

class Author
  include GdatastoreMapper::Base

  attr_accessor :name

  has_many :books
end

books.create

rowling = Author.create(name: 'J. K. Rowling')
harry_poter = rolling.books.create(title: 'Harry Poter')
harry_poter2 = rolling.books.create(title: 'Harry Poter 2')

books

rowling.books
=> [#<Book:0x00 @title="Harry Potter" .... ]

books.count

rowling.books.count
=> 2

harry_poter.author
=> [#<Author:0x00 @name="J. K. Rowling" .... ]

Method Chaining

rowling.books.order(created_at: :desc).limit(3)
=> [#<Book:0x00 @title="Harry Potter" .... ]

rowling.books.where(series: 'Harry Potter').order(published_at: :asc).limit(3)
=> [#<Book:0x00 @title="Harry Potter" .... ]

Callbacks

class Book
  include GdatastoreMapper::Base

  before_save :something_before_save

  private
  def something_before_save
    something that you want
  end

end

Validations

class Author
  include GdatastoreMapper::Base

  attr_accessor :email

  validates :email, presence: true, format: { with: /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i }
  validates :email, length: { in: 3..20 }
  validates_uniqueness_of :email
end

Contact

Please shoot me an e-mail if you find any issues, ideas and comments. shinya.kitamura.14@gmail.com Thanks!

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/shinyaK14/gdatastore_mapper. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.