avoiding deep hash queries in ruby - ruby

Question

How can I tidy up code that sets and requests deep hash values in ruby?
For example, say I have a hash like this:
hash = {
user_settings: {
notifications: {
overdue_tasks: { enabled: true, duration: 30 },
created_overdue_tasks: { enabled: true, duration: 30 }
}
}
}
How can I avoid writing brittle access code like this:
hash[:user_settings][:notifications][:overdue_tasks][:duration] = 5
Also, is there a recursive symbolize_keys that will symbolize all keys and not just the top level?

Answer 1

I don't know such way to reduce to code to fetch the desired key/value, but I have a suggestion to make your hash plain by naming.
How about
hash = {
user_settings: {
overdue_task_notification_enabled: true,
overdue_task_notification_duration: 30,
created_overdue_tasks_enabled: true,
created_overdue_tasks_duration: 30
}
}
Then fetch it like
hash[:user_settings][:created_overdue_tasks_duration]
I think this arrangement looks easier to understand for peers and users.

Answer 2

Taking the help from the blog :- Ruby Nested Hash - Deep Fetch - Returning a (Default) Value for a Key That Does Not Exist in a Nested Hash :
class Hash
def deep_fetch(key, default = nil)
default = yield if block_given?
(deep_find(key) or default) or raise KeyError.new("key not found: #{key}")
end
def deep_find(key)
key?(key) ? self[key] : self.values.inject(nil) {|memo, v| memo ||= v.deep_find(key) if v.respond_to?(:deep_find) }
end
end
hash = {
user_settings: {
notifications: {
overdue_tasks: { enabled: true, duration: 30 },
created_overdue_tasks: { enabled: true, duration: 30 }
}
}
}
p hash.deep_fetch(:duration)
# >> 30