Recursive Case Indifferent Ostruct

Takes a hash of snake, camel, train, or kabab case and make its attributes accessible with any other case.

The main application is for working with JSON from an API and standardizing to a Ruby-centric underscore/snake case interface.

##Usage

Gemfile

gem "recursive_case_indifferent_ostruct"

Examples

user = RecursiveCaseIndifferentOstruct.new({
  "firstName"   => "Tommy",
  "first-name"  => "Bobby",
  "LAST_NAME"   => "Johnson",
  "Birth-Place" => "Springfield",
  "father"      => {
    "age"     72
  },
  "siblings"    => [
    {relation: "brother", age: 12}
  ]
}, :lower_camel)

# access attributes like so
user.first_name # "Tommy"
user.last_name # "Johnson"
user.father.age # 72
user.siblings[0].age # 12

user.birth_place    = "New York" # sets Birth-Place
user.first_name     = "Ken" # sets {"firstName" => "Ken", "first-name" => "Ken"}
user.mothers_maiden = "Woods" # Since case is mixed in that hash, use default :lower_camel


user.to_h
# {
#   "firstName"   => "Ken",
#   "first-name"  => "Ken",
#   "LAST_NAME"   => "Johnson",
#   "Birth-Place" => "New York",
#   "father"      => {
#     "age"     72
#   },
#   "siblings"    => [
#     {relation: "brother", age: 12}
#   ],
#   "mothersMaiden" => "Woods",
# }

# .merge() is case insensitive
user = RecursiveCaseIndifferentOstruct.new(first_name: "Bob")
new_user = user.merge({"FirstName" => "Bobby"})
new_user.first_name # Bobby
user.first_name # Bob

user.merge!({"FirstName" => "Bobby"})
user.first_name # Bobby

Case Matching

Since the key matching is fuzzy, should there be two attributes with the same name but different case (first-name and firstName), the library will return first value that it finds. For an assignment it will assign all matching attributes to the new value.

Default Case

Should you assign an attribute to the hash that does not already exist the library will try to figure out which case to use based on other keys in the hash. If it cannot determine which case is being used it will fall back to RecursiveCaseIndifferentOstruct::DEFAULT_CASE=:snake which you could set to override. Another option is to pass the default case on initialization RecursiveCaseIndifferentOstruct.new(hash, :snake).

Available options:

:snake this_is_snake
:lower_camel thisIsLowerCamel
:upper_camel ThisIsUpperCamel
:kabab this-is-kabab
:train This-Is-Train

If you need to assign a value to a key that has an odd case you can use a string with the bracket syntax like so: json["PI:Value"] = 3.14. The value can still be accessed via json.pi_value.

Hash Methods

RecursiveCaseIndifferentOstruct will pass methods along to the hash if the method is not defined and there is not attribute matching that name. However, all the hash methods operate on the original hash, so #has_key?, #each, #fetch, etc, will not be case-indifferent. Feel free to implement them and submit a PR.

json = RecursiveCaseIndifferentOstruct.new({
  ID: 123,
  userName: "pax"
})

json.has_key?(:user_name) # false
json.has_key?("userName") # true
json.fetch(:id) # nil
json.keys # [:ID, :userName]

Tests