I searched the docs for how to implement relationships among entities (eg, one-to-many, many-to-many, etc), but didn't find any examples.
So I tried a reasonable guess. Here's my attempt at implementing a Person who can be tagged with Tags:
require 'moocho_query'
require 'hanami/model'
require 'hanami/model/adapters/file_system_adapter'
class Person
include Hanami::Entity
attributes :name, :age, :tags
end
class Tag
include Hanami::Entity
attributes :name
end
class PersonRepository
include Hanami::Repository
end
class TagRepository
include Hanami::Repository
end
Hanami::Model.configure do
adapter type: :file_system, uri: './file_db'
mapping do
collection :people do
entity Person
repository PersonRepository
attribute :id, Integer
attribute :name, String
attribute :age, Integer
attribute :tags, type: Array[Tag]
end
collection :tags do
entity Tag
repository TagRepository
attribute :id, Integer
attribute :name, String
end
end
end.load!
me = Person.new(name: 'Jonah', age: 99)
t1 = Tag.new(name: 'programmer')
t2 = Tag.new(name: 'nice')
me.tags = [t1, t2]
PersonRepository.create(me)
This fails on the load! call, with the following error:
/Users/x/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/hanami-utils-0.7.0/lib/hanami/utils/class.rb:90:in `load_from_pattern!': uninitialized constant (Hanami::Model::Mapping::Coercers::{:type=>[Tag]}|
{:type=>[Tag]}) (NameError)
from /Users/jg/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/hanami-model-0.6.0/lib/hanami/model/mapping/attribute.rb:80:in `coercer'
from /Users/jg/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/hanami-model-0.6.0/lib/hanami/model/mapping/attribute.rb:53:in `load_coercer'
What is the correct way to implement relationships in Hanami?
I know it's an old question, but I'll leave this answer in case somebody stumbles here:
Hanami added many-to-many support on version 1.1
http://hanamirb.org/guides/1.1/associations/has-many-through/
% bundle exec hanami generate model user
create lib/bookshelf/entities/user.rb
create lib/bookshelf/repositories/user_repository.rb
create db/migrations/20171024083639_create_users.rb
create spec/bookshelf/entities/user_spec.rb
create spec/bookshelf/repositories/user_repository_spec.rb
% bundle exec hanami generate model story
create lib/bookshelf/entities/story.rb
create lib/bookshelf/repositories/story_repository.rb
create db/migrations/20171024085712_create_stories.rb
create spec/bookshelf/entities/story_spec.rb
create spec/bookshelf/repositories/story_repository_spec.rb
% bundle exec hanami generate model comment
create lib/bookshelf/entities/comment.rb
create lib/bookshelf/repositories/comment_repository.rb
create db/migrations/20171024085858_create_comments.rb
create spec/bookshelf/entities/comment_spec.rb
create spec/bookshelf/repositories/comment_repository_spec.rb
# db/migrations/20171024083639_create_users.rb
Hanami::Model.migration do
change do
create_table :users do
primary_key :id
column :name, String, null: false
column :created_at, DateTime, null: false
column :updated_at, DateTime, null: false
end
end
end
# db/migrations/20171024085712_create_stories.rb
Hanami::Model.migration do
change do
create_table :stories do
primary_key :id
foreign_key :user_id, :users, null: false, on_delete: :cascade
column :text, String, null: false
column :created_at, DateTime, null: false
column :updated_at, DateTime, null: false
end
end
end
# db/migrations/20171024085858_create_comments.rb
Hanami::Model.migration do
change do
create_table :comments do
primary_key :id
foreign_key :user_id, :users, null: false, on_delete: :cascade
foreign_key :story_id, :stories, null: false, on_delete: :cascade
column :text, String, null: false
column :created_at, DateTime, null: false
column :updated_at, DateTime, null: false
end
end
end
# lib/bookshelf/repositories/user_repository.rb
class UserRepository < Hanami::Repository
associations do
has_many :stories
has_many :comments
end
end
# lib/bookshelf/repositories/story_repository.rb
class StoryRepository < Hanami::Repository
associations do
belongs_to :user
has_many :comments
has_many :users, through: :comments
end
def find_with_comments(id)
aggregate(:user, comments: :user).where(id: id).map_to(Story).one
end
def find_with_commenters(id)
aggregate(:users).where(id: id).map_to(Story).one
end
end
# lib/bookshelf/repositories/comment_repository.rb
class CommentRepository < Hanami::Repository
associations do
belongs_to :story
belongs_to :user
end
end
user_repo = UserRepository.new
author = user_repo.create(name: "Luca")
# => #<User:0x00007ffe71bc3b18 @attributes={:id=>1, :name=>"Luca", :created_at=>2017-10-24 09:06:57 UTC, :updated_at=>2017-10-24 09:06:57 UTC}>
commenter = user_repo.create(name: "Maria G")
# => #<User:0x00007ffe71bb3010 @attributes={:id=>2, :name=>"Maria G", :created_at=>2017-10-24 09:07:16 UTC, :updated_at=>2017-10-24 09:07:16 UTC}>
story_repo = StoryRepository.new
story_repo.create(user_id: author.id, text: "Hello, folks")
# => #<Story:0x00007ffe71b4ace0 @attributes={:id=>1, :user_id=>1, :text=>"Hello folks", :created_at=>2017-10-24 09:09:59 UTC, :updated_at=>2017-10-24 09:09:59 UTC}>
story = story_repo.find_with_comments(story.id)
# => #<Story:0x00007fd45e327e60 @attributes={:id=>2, :user_id=>1, :text=>"Hello folks", :created_at=>2017-10-24 09:09:59 UTC, :updated_at=>2017-10-24 09:09:59 UTC, :user=>#<User:0x00007fd45e326bc8 @attributes={:id=>1, :name=>"Luca", :created_at=>2017-10-24 09:06:57 UTC, :updated_at=>2017-10-24 09:06:57 UTC}>, :comments=>[#<Comment:0x00007fd45e325930 @attributes={:id=>1, :user_id=>2, :story_id=>2, :text=>"Hi and welcome!", :created_at=>2017-10-24 09:12:30 UTC, :updated_at=>2017-10-24 09:12:30 UTC, :user=>#<User:0x00007fd45e324490 @attributes={:id=>2, :name=>"Maria G", :created_at=>2017-10-24 09:07:16 UTC, :updated_at=>2017-10-24 09:07:16 UTC}>}>]}>
story.comments
# => [#<Comment:0x00007fe289f2d618 @attributes={:id=>1, :user_id=>2, :story_id=>2, :text=>"Hi and welcome!", :created_at=>2017-10-24 09:12:30 UTC, :updated_at=>2017-10-24 09:12:30 UTC, :commenter=>#<User:0x00007fe289f2c420 @attributes={:id=>2, :name=>"Maria G", :created_at=>2017-10-24 09:07:16 UTC, :updated_at=>2017-10-24 09:07:16 UTC}>}>]