config_hash
A hash that is nice to use for configurations. It takes an existing hash in at construction time, and by default returns a Hash that:
- freezes all values recursively throughout the entire config
- can be overridden with "freeze: false"
- ensures indifferent access to keys (
'foo'and:fooare the same key) - sets up '.' accessors for all values (given
{foo: :bar}, can useconfig.foo)
This is done singularly at construction time. If you want, you can also assign
processors via the :processors initialization argument, which will modify the
value returned (both with . and []) via methods at access time.
Usage
# standard accessors
config = ConfigHash.new({foo: :bar})
config.foo # :bar
config['foo'] # :bar
config[:foo] # :bar
config.x # raises an error!
# with special prcoessors
# constantize special processor
class SomeClass; end
config = ConfigHash.new({klass_reference: '::SomeClass'}, constantize: true)
config.klass_reference # SomeClass (the class itself0, NOT '::SomeClass'
# sometimes, you want to post-process instead of pre-process. this slows down the
# config hash, but may be necessary, e:g:
config = ConfigHash.new({klass_reference: '::DefinedLaterClass'}, constantize: true, lazy_loading: true)
# config.klass_reference -- would at this point return the string, as DefinedLaterClass
# does not exist.
class DefinedLaterClass; end
config.klass_reference # now returns the class DefinedLaterClass
# custom processor
module Singleton
def self.processor(value)
value.is_a?(String) ? value + ' world' : value
end
end
config = ConfigHash.new({foo: [{bar: 'hello'}]}, processors: [Singleton.method(:processor)])
config.foo # [{bar: 'hello'}]
config.foo[0].bar # 'hello world'
# by default, missing values raise an error:
config = ConfigHash.new({foo: :bar})
config.baz # raises an error!
config[:baz] # raises an error!
# if you want to have it return nil like a typical hash, pass raise_on_missing: false
config = ConfigHash.new({foo: :bar}, raise_on_missing: false)
config.baz # nil
config[:baz] # nil