insensitive_hash

Hash with case-insensitive, Symbol/String-indifferent key access.

Installation

gem install insensitive_hash

Instantiation

Hash#insensitive

require 'insensitive_hash'

ih = {}.insensitive

ih = { :abc => 1, 'hello world' => true }.insensitive

ih['ABC']         # 1
ih[:Hello_World]  # true

Without monkey-patching Hash

If you don't like to have Hash#insensitive method, require 'insensitive_hash/minimal'

require 'insensitive_hash/minimal'

ih = InsensitiveHash.new
ih = InsensitiveHash.new(:default_value)
ih = InsensitiveHash.new { |ih, k| ih[k] = InsensitiveHash.new }

ih = InsensitiveHash[ 'abc' => 1, :def => 2 ]
ih = InsensitiveHash[ 'abc', 1, :def, 2 ]
ih = InsensitiveHash[ [['abc', 1], [:def, 2]] ]

ih = InsensitiveHash[ 'hello world' => true ]

Revert to normal Hash

h = ih.sensitive
h = ih.to_hash

Basic usage

ih = {:abc => 1, 'DEF' => 2}.insensitive

# Case-insensitive, Symbol/String-indifferent access.
ih['Abc']          # 1
ih[:ABC]           # 1
ih['abc']          # 1
ih[:abc]           # 1
ih.has_key?(:DeF)  # true

ih['ABC'] = 10

# keys and values
ih.keys            # ['DEF', 'ABC']
ih.values          # [2, 10]

# delete
ih.delete :Abc     # 10
ih.keys            # ['DEF']

Inherited insensitivity

When an InsensitiveHash is built from another Hash, descendant Hash values are recursively converted to be insensitive.

ih = { 'kids' => { :hello => [ { :world => '!!!' } ] } }.insensitive
ih[:kids]['Hello'].first['WORLD']  # !!!

ih = {:one => [ [ [ { :a => { :b => { :c => 'd' } } } ] ] ]}.insensitive
ih['one'].first.first.first['A']['b'][:C]  # 'd'

However, once InsensitiveHash is initialized, descendant Hashes (or Hashes in Arrays) are not automatically converted.

ih = {}.insensitive
ih[:abc] = { :def => true }

ih['ABC']['DEF']     # nil

Simply build a new InsensitiveHash out of it if you need recursive conversion.

ih2 = ih.insensitive
ih2['ABC']['DEF']    # true

Example: Processing case-insensitive YAML input

db = YAML.load(File.read 'database.yml').insensitive

# Access values however you like
db['Development']['ADAPTER']
db[:production][:adapter]

Customizing insensitivity

You can provide a #call-able object (duck-typing) as the key encoder which determines the level of insensitivity.

Default encoder

The default encoder is as follows.

InsensitiveHash::DEFAULT_ENCODER =
  proc { |key|
    case key
    when String, Symbol
      key.to_s.downcase.gsub(' ', '_')
    else
      key
    end
  }

Encoder examples

ih1 = {}.insensitive(:encoder => proc { |key| key.to_s })
ih2 = {}.insensitive(:encoder => proc { |key| key.to_s.downcase })
ih3 = {}.insensitive(:encoder => proc { |key| key.to_s.downcase.gsub(/\s+/, '_') })

Enabling key-clash detection (Safe mode)

ih = InsensitiveHash.new
ih.safe = true

# Will raise InsensitiveHash::KeyClashError
h.merge!('hello world' => 1, :hello_world => 2)

# Disables key-clash detection
h.safe = false
h.merge!('hello world' => 1, :hello_world => 2)
h['Hello World']  # 2

Contributing to insensitive_hash

Check out the latest master to make sure the feature hasn't been implemented or the bug hasn't been fixed yet
Check out the issue tracker to make sure someone already hasn't requested it and/or contributed it
Fork the project
Start a feature/bugfix branch
Commit and push until you are happy with your contribution
Make sure to add tests for it. This is important so I don't break it in a future version unintentionally.
Please try not to mess with the Rakefile, version, or history. If you want to have your own version, or is otherwise necessary, that is fine, but please isolate to its own commit so I can cherry-pick around it.