This addon to the shale Ruby gem adds a simple yet powerful builder DSL.
It also adds support for sorbet and tapioca in shale. This gem includes a custom tapioca DSL compiler designed for shale.
Install the gem and add to the application's Gemfile by executing:
$ bundle add shale-builder
If bundler is not being used to manage dependencies, install the gem by executing:
$ gem install shale-builder
Build your shale classes like a boss.
transaction = Transaction.build do |t|
t.cvv_code = '123'
t.amount do |a|
a.value = 2.3
a.currency = 'PLN'
end
t.payment_instrument do |p|
p.number = '4242424242424242'
p.expiration_year = 2045
p.expiration_month = 12
end
endThis gem adds a module named Shale::Builder. It's meant to be included
in subclasses of Shale::Mapper to provide an easier way of building
instances.
You can use it like that:
require 'shale/builder'
class Amount < Shale::Mapper
include Shale::Builder
attribute :value, Shale::Type::Float
attribute :currency, Shale::Type::String
endNow instead of creating an instance like that:
amount = Amount.new(value: 2.3, currency: 'PLN')You can do it like that:
amount = Amount.build do |a|
a.value = 2.3
a.currency = 'PLN'
endIt's kind of pointless when you've got a flat structure. It really shines when nested objects come into play.
Let's say that you've got a structure like this:
class Amount < Shale::Mapper
include Shale::Builder
attribute :value, Shale::Type::Float
attribute :currency, Shale::Type::String
end
class PaymentInstrument < Shale::Mapper
include Shale::Builder
attribute :number, Shale::Type::String
attribute :expiration_year, ::Shale::Type::Integer
attribute :expiration_month, ::Shale::Type::Integer
end
class Transaction < Shale::Mapper
include Shale::Builder
attribute :cvv_code, Shale::Type::String
attribute :amount, Amount
attribute :payment_instrument, PaymentInstrument
endNormally you would instantiate it like that:
transaction = Transaction.new(
cvv_code: '123',
amount: Amount.new(
value: 2.3,
currency: 'PLN'
),
payment_instrument: PaymentInstrument.new(
number: '4242424242424242',
expiration_year: 2045,
expiration_month: 12
)
)It's really repetitive and it makes it hard to modify the values of certain attributes or omit them conditionally.
This gem provides a better way:
transaction = Transaction.build do |t|
t.cvv_code = '123'
t.amount do |a|
a.value = 2.3
a.currency = 'PLN'
end
t.payment_instrument do |p|
p.number = '4242424242424242'
p.expiration_year = 2045
p.expiration_month = 12
end
endThat's possible because the getters of attributes with non-primitive types have been overridden to accept blocks. When a block is given to such a getter, it instantiates an empty object of its type and yields it to the block.
Whenever you call a getter with a block for a collection attribute, the built object will be appended to the array.
Let's define a schema like this.
class Client < Shale::Mapper
include Shale::Builder
attribute :first_name, Shale::Type::String
attribute :last_name, Shale::Type::String
attribute :email, Shale::Type::String
end
class Transaction < Shale::Mapper
include Shale::Builder
attribute :clients, Client, collection: true
endYou can easily build add new clients to the collection like so:
transaction = Transaction.build do |t|
# this will be added as the first element of the collection
t.clients do |c|
c.first_name = 'Foo'
c.last_name = 'Bar'
end
# this will be added as the second element of the collection
t.clients do |c|
c.first_name = 'Grant'
c.last_name = 'Taylor'
end
end
p transaction.clients
# [
# #<Client:0x00000001066c2828 @first_name="Foo", @last_name="Bar", @email=nil>,
# #<Client:0x00000001066c24b8 @first_name="Grant", @last_name="Taylor", @email=nil>
# ]This DSL makes it extremely easy to build nested objects conditionally.
transaction = Transaction.build do |t|
t.cvv_code = '123'
t.amount do |a|
a.value = 2.3 if some_flag?
a.currency = 'PLN'
end
t.payment_instrument do |p|
p.number = '4242424242424242'
if some_condition?
p.expiration_year = 2045
p.expiration_month = 12
end
end
endShale-builder adds support for sorbet and tapioca.
You can leverage an additional doc keyword argument in attribute definitions.
It will be used to generate a comment in the RBI file.
require 'shale/builder'
class Amount < Shale::Mapper
include Shale::Builder
attribute :value, Shale::Type::Float
attribute :currency, Shale::Type::String, doc: <<~DOC
This is some custom documentation that can be used by sorbet.
It will be used by the tapioca DSL compiler
to generate the RBI documentation for this attribute.
DOC
endIf you use sorbet and run bundle exec tapioca dsl you'll get the following RBI file.
# typed: true
# DO NOT EDIT MANUALLY
# This is an autogenerated file for dynamic methods in `Amount`.
# Please instead update this file by running `bin/tapioca dsl Amount`.
class Amount
include ShaleAttributeMethods
module ShaleAttributeMethods
sig { returns(T.nilable(Float)) }
def value; end
sig { params(value: T.nilable(Float)).returns(T.nilable(Float)) }
def value=(value); end
# This is some custom documentation that can be used by sorbet.
# It will be used by the tapioca DSL compiler
# to generate the RBI documentation for this attribute.
sig { returns(T.nilable(String)) }
def currency; end
# This is some custom documentation that can be used by sorbet.
# It will be used by the tapioca DSL compiler
# to generate the RBI documentation for this attribute.
sig { params(value: T.nilable(String)).returns(T.nilable(String)) }
def currency=(value); end
end
endIf you define custom primitive types in Shale by inheriting from Shale::Type::Value
you can describe the return type of the getter of the field that uses this primitive type by defining the return_type method that returns a sorbet type.
def self.return_type = T.nilable(String)You can also describe the accepted argument type in the setter by defining the setter_type method that returns a sorbet type.
def self.setter_type = T.any(String, Float, Integer)Here is a full example.
# typed: true
require 'shale/builder'
# Cast from XML string to BigDecimal.
# And from BigDecimal to XML string.
class BigDecimalShaleType < Shale::Type::Value
class << self
extend T::Sig
# the return type of the field that uses this class as its type
def return_type = T.nilable(BigDecimal)
# the type of the argument given to a setter of the field
# that uses this class as its type
def setter_type = T.any(BigDecimal, String, NilClass)
# Decode from XML.
sig { params(value: T.any(BigDecimal, String, NilClass)).returns(T.nilable(BigDecimal)) }
def cast(value)
return if value.nil?
BigDecimal(value)
end
# Encode to XML.
#
# @param value: Value to convert to XML
sig { params(value: T.nilable(BigDecimal)).returns(T.nilable(String)) }
def as_xml_value(value)
return if value.nil?
value.to_s('F')
end
end
end
class Amount < Shale::Mapper
include Shale::Builder
# `value` uses BigDecimalShaleType as its type
attribute :value, BigDecimalShaleType
endAfter running bundle exec tapioca dsl you'll get the following RBI file.
# typed: true
# DO NOT EDIT MANUALLY
# This is an autogenerated file for dynamic methods in `Amount`.
# Please instead update this file by running `bin/tapioca dsl Amount`.
class Amount
include ShaleAttributeMethods
module ShaleAttributeMethods
sig { returns(T.nilable(::BigDecimal)) }
def value; end
sig { params(value: T.nilable(T.any(::BigDecimal, ::String))).returns(T.nilable(T.any(::BigDecimal, ::String))) }
def value=(value); end
end
endAfter checking out the repo, run bin/setup to install dependencies. Then, run rake test 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 the created tag, and push the .gem file to rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/Verseth/ruby-shale-builder.
The gem is available as open source under the terms of the MIT License.