Registry & Resolver
Register options
call
This boolean option determines whether or not the registered item should be invoked when resolved, i.e.
container = Dry::Container.new
container.register(:key_1, call: false) { "Integer: #{rand(1000)}" }
container.register(:key_2, call: true) { "Integer: #{rand(1000)}" }
container.resolve(:key_1) # => <Proc:0x007f98c90454c0@dry_c.rb:23>
container.resolve(:key_1) # => <Proc:0x007f98c90454c0@dry_c.rb:23>
container.resolve(:key_2) # => "Integer: 157"
container.resolve(:key_2) # => "Integer: 713"
memoize
This boolean option determines whether or not the registered item should be memoized on the first invocation, i.e.
container = Dry::Container.new
container.register(:key_1, memoize: true) { "Integer: #{rand(1000)}" }
container.register(:key_2, memoize: false) { "Integer: #{rand(1000)}" }
container.resolve(:key_1) # => "Integer: 734"
container.resolve(:key_1) # => "Integer: 734"
container.resolve(:key_2) # => "Integer: 855"
container.resolve(:key_2) # => "Integer: 282"
Customization
You can configure how items are registered and resolved from the container. Currently, registry can be as simple as a proc but custom resolver should subclass the default one or have the same public interface.
class CustomResolver < Dry::Container::Resolver
RENAMED_KEYS = { 'old' => 'new' }
def call(container, key)
container.fetch(key.to_s) {
fallback_key = RENAMED_KEYS.fetch(key.to_s) {
raise Error, "Missing #{ key }"
}
container.fetch(fallback_key) {
raise Error, "Missing #{ key } and #{ fallback_key }"
}
}.call
end
end
class Container
extend Dry::Container::Mixin
config.registry = ->(container, key, item, options) { container[key] = item }
config.resolver = CustomResolver
end
class ContainerObject
include Dry::Container::Mixin
config.registry = ->(container, key, item, options) { container[key] = item }
config.resolver = CustomResolver
end
This allows you to customise the behaviour of Dry::Container, for example, the default registry (Dry::Container::Registry) will raise a Dry::Container::Error exception if you try to register under a key that is already used, you may want to just overwrite the existing value in that scenario, configuration allows you to do so.