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https://github.com/spider-gazelle/rethinkdb-orm

RethinkDB ORM for Crystal lang
https://github.com/spider-gazelle/rethinkdb-orm

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RethinkDB ORM for Crystal lang

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# RethinkDB ORM for Crystal Lang

[![CI](https://github.com/spider-gazelle/rethinkdb-orm/actions/workflows/ci.yml/badge.svg)](https://github.com/spider-gazelle/rethinkdb-orm/actions/workflows/ci.yml)
[![Documentation](https://img.shields.io/badge/Documentation-available-brightgreen.svg)](https://spider-gazelle.github.io/rethinkdb-orm)

Extending [ActiveModel](https://github.com/spider-gazelle/active-model) for attribute definitions, callbacks and validations

- [RethinkDB ORM for Crystal Lang](#rethinkdb-orm-for-crystal-lang)
- [Callbacks](#callbacks)
- [Associations](#associations)
- [`belongs_to`](#belongsto)
- [`has_many`](#hasmany)
- [`has_one`](#hasone)
- [Dependency](#dependency)
- [Indexes](#indexes)
- [Changefeeds](#changefeeds)
- [Validations](#validations)
- [`ensure_unique`](#ensureunique)
- [Timestamps](#timestamps)

## Configuration

```crystal
# Below is the list of settings exposed by RethinkORM and their defaults
RethinkORM::Settings.configure do |settings|
settings.host = ENV["RETHINKDB_HOST"]? || "localhost"
settings.port = (ENV["RETHINKDB_PORT"]? || 28015).to_i
settings.db = ENV["RETHINKDB_DB"]? || ENV["RETHINKDB_DATABASE"]? || "test"
settings.user = ENV["RETHINKDB_USER"]? || "admin"
settings.password = ENV["RETHINKDB_PASSWORD"]? || ""
settings.lock_expire = (ENV["RETHINKDB_LOCK_EXPIRE"]? || 30).to_i.seconds
settings.lock_timeout = (ENV["RETHINKDB_LOCK_TIMEOUT"]? || 5).to_i.seconds
settings.retry_interval = (ENV["RETHINKDB_TIMEOUT"]? || 2).to_i.seconds

# Driver level reconnection attempts
settings.retry_attempts = ENV["RETHINKDB_RETRIES"]?.try(&.to_i) || 10

# ORM level query retries
settings.query_retries = ENV["RETHINKDB_QUERY_RETRIES"]?.try &.to_i || 10
end
```

## Callbacks

Register callbacks for `save`, `update`, `create` and `destroy` by setting the corresponding before/after callback handler.

```crystal
class ModelWithCallbacks < RethinkORM::Base
attribute address : String
attribute age : Int32 = 10

before_create :set_address
after_update :set_age
before_destroy do
self.name = "joe"
end

def set_address
self.address = "23"
end

def set_age
self.age = 30
end
end
```

## Associations

Set associations with `belongs_to`, `has_many` and `has_one`.

Access children in parent by accessing the method correpsonding to the pluralised child. Children collection method name is generated by dumb pluralisation (appending an s). Optionally set children collection name in `has_many` by setting `collection_name` param.

The `has_many` association requires the `belongs_to` association on the child. By default, `belongs_to` creates a secondary index on the foreign key.

```crystal
class Parent < RethinkORM::Base
attribute name : String
has_many Child, collection_name: "children"
end

class Child < RethinkORM::Base
attribute age : Int32
belongs_to Parent
has_many Pet
end

class Pet < RethinkORM::Base
attribute name : String
belongs_to Child
end

parent = Parent.new(name: "Phil")
parent.children.empty? # => true

child = Child.new(age: 99)
child.pets.empty? # => true
```

### `belongs_to`

Parameter | | Default
-------------- | ------------------------------------------------------------- | -------
`parent_class` | The parent class who this class is dependent on |
`dependent` | Sets destroy behaviour. One of `:none`, `:destroy`, `:delete` | `:none`
`create_index` | Create a secondary index on the foreign key | `true`

### `has_many`

Parameter | | Default
----------------- | ----------------------------------------------------------------------------- | -------
`child_class` | The parent class who this class is dependent on |
`dependent` | Sets destroy behaviour. One of `:none`, `:destroy`, `:delete` | `:none`
`collection_name` | Define collection name, otherwise collection named through dumb pluralisation | `nil`

### `has_one`

Parameter | | Default
----------------- | ----------------------------------------------------------------------------- | -------
`child_class` | The parent class who this class is dependent on |
`dependent` | Sets destroy behaviour. One of `:none`, `:destroy`, `:delete` | `:none`
`collection_name` | Define collection name, otherwise collection named through dumb pluralisation | `nil`

### Dependency

`dependent` param in the association definition macros defines the fate of the association on model destruction.

Default is `:none`, `:destroy` and `:delete` ensure destruction of association dependents.

## Indexes

Set secondary indexes with `secondary_index`

Parameter | |
----------- | --------------------------------------------- |
`attribute` | defines the field on which to create an index |

## Changefeeds

Access the changefeed of a document or table through the `changes` query.

Defaults to watch for events on a table if no id provided.

Parameter | | Default
--------- | ----------------------------------- | -------
`id` | id of document to watch for changes | nil

Returns an iterator that emits `NamedTuple(value: T, event: Event)`

- `Changefeed::Event::Deleted` events yield the deleted model
- `Changefeed::Event::Created` events yield the created model
- `Changefeed::Event::Updated` events yield the updated model

```crystal
class Game < RethinkORM::Base
attribute type : String
attribute score : Int32, default: 0
end

ballgame = Game.create!(type: "footy")

# Observe changes on a single document
spawn do
Game.changes(ballgame.id).each do |change|
game = change.value
puts "looks like the score is #{game.score}" unless game.nil?
end
end

# Observe changes on a table
spawn do
Game.changes.each do |change|
game = change.value
puts "#{game.type}: #{game.score}" unless game.nil?
puts "game event: #{change.event}"
end
end
```

## Validations

Builds on [active-model's validation](https://github.com/spider-gazelle/active-model#validations)

### `ensure_unique`

Fails to validate if field with duplicate value present in db.
If scope is set, the callback/block signature must be a tuple with types matching that of the scope.
The field(s) are set with the result of the transform block upon successful validation

Parameter | | Default
----------------------- | ------------------------------------------------------- | -------
`field` | Model attribute on which to guarantee uniqueness |
`scope` | Attributes passed to the transform, defaults to :field | nil
`create_index` | Whether or not to generate a secondary index | true
`callback : T -> T` | Optional function to transform field value | nil
`block : T -> T` | Optional block to transform field value before querying | nil

## Timestamps

Adds creates `created_at` and `updated_at` attributes.
- `updated_at` is set through the `before_update` callback, and initially set in the `before_save` callback.
- `created_at` is set through the `before_create` callback.

The generated timestamp is UTC.

```crystal
class Timo < RethinkORM::Base
# Simply include the module
include RethinkORM::Timestamps

attribute name : String
end
```