Scheemer uses Dry::Schema to enable us to write consistent looking structural parameter validation and data accessing on our services.
Scheemer::DSL ties together the parameters key translation and structural validation.
klass = Class.new do
extend Scheemer::DSL
schema do
required(:root).hash do
required(:someValue).filled(:string)
end
end
on_missing path: "book.author.name", fallback_to: { "Stephen King" }
end
record = klass.new({ root: { someValue: "testing" } })
record.some_value # => "testing"
record.book.dig(:author, :name) # => "Stephen King"When using the DSL, it's possible to inject extra parameters into your custom validations through the constructor. This can be helpful in cases where validations require access to outside data (e.g. database records, user session).
klass = Class.new do
extend Scheemer::DSL
schema do
required(:root).hash do
required(:someValue).filled(:string)
end
end
def validate!(data)
p data[:records] # => [ ... ]
p data[:some_extra_value] # => "may be for validation"
end
end
record = klass.new(
{ root: { someValue: "testing" } },
{ records: [1, 2], some_extra_value: "may be for validation" }
)Scheemer::Params handles the parameters key translation.
klass = Class.new do
extend Scheemer::Params::DSL
def initialize(...)
super
...
end
end
record = klass.new({ someValue: "testing" })
record.some_value # => "testing"Scheemer::Schema::DSL handles the structural validation.
klass = Class.new do
extend Scheemer::Schema::DSL
schema do
required(:name).filled(:string)
end
attr_reader :contents
def initialize(params)
@contents = self.class.validate_schema!(params)
end
end
klass.new({ name: 1 }) # => Error:'{:name=>['must be a string"]}"$ docker-compose run scheemer /bin/sh
$ docker-compose run scheemer rspec
$ docker-compose build scheemerInstall the gem and add to the application's Gemfile by executing:
$ bundle add aion-dk/scheemerIf bundler is not being used to manage dependencies, install the gem by executing:
$ gem install aion-dk/scheemerThe gem is available as open source under the terms of the MIT License.