Object Identifier

Object Identifier allows quick, easy, and uniform identification of an object by inspecting its class name and outputting any desirable attributes/methods. It is great for logging, sending descriptive notification messages, etc.

Why? Because object identification output should be uniform and easy to build, and its output should be easy to read! Consistency improves readability.

For example:

some_object.identify(:id, :name)

Which is the same as:

"#{some_object.class.name}[id:#{some_object.id}, name:\"#{some_object.name}\"]"

Add this line to your application's Gemfile:

gem "object_identifier"

And then execute:

$ bundle

Or install it yourself as:

$ gem install object_identifier

Tested MRI Ruby Versions:

• 3.2
• 3.3
• 3.4

For Ruby 2.7 support, install object_identifier gem version 0.7.0.

gem "object_identifier", "0.7.0"

For Ruby 3.1 support, install object_identifier gem version 0.9.0.

gem "object_identifier", "0.9.0"

Object Identifier has no other dependencies.

Global/default values for Object Identifier can be configured via the ObjectIdentifier::Configuration object.

# config/initializers/object_identifier.rb

# Default values are shown. Customize to your liking.
ObjectIdentifier.configure do |config|
  config.formatter_class = ObjectIdentifier::StringFormatter
  config.default_attributes = %i[id]
end

identify outputs the id of the receiving object by default, if it exists and no other attributes/methods are specified.

Movie = Data.define(:id, :name, :rating)

my_movie = Movie[1, "Identifier Gadget", "7/10"]

my_movie.identify          # => "Movie[1]"

identify doesn't output labels if only identifying a single attribute/method. It includes labels when two or more attributes/methods are being identified.

my_movie.identify(:id)     # => "Movie[1]"
my_movie.identify(:name)   # => 'Movie["Identifier Gadget"]'
my_movie.identify(:rating) # => 'Movie["7/10"]'

my_movie.identify(:id, :name, :rating)
# => 'Movie[id:1, name: "Identifier Gadget", rating:"7/10"]'

Private methods can be identified just the same as public methods.

Movie =
  Data.define(:id, :name, :rating) do
    private def my_private_method = "Shh"
  end

my_movie = Movie[1, "Private Identifier", "7/10"]

my_movie.identify(:my_private_method) # => 'Movie["Shh"]'

If the object doesn't respond to a specified attribute/method it is simply ignored:

my_movie.identify(:id, :rating, :unknown)   # => 'Movie[id:1, rating:"7/10"]'

my_movie.identify(class: "MyBlockbuster")  # => "MyBlockbuster[1]"
my_movie.identify(class: nil)              # => "[1]"

nil.identify(:id, :name)                   # => "[no objects]"
nil.identify(:id, :name, class: "Nope")    # => "[no objects]"

Collections of objects are each identified in turn.

User = Data.define(:id, :name)
my_user = User[2, "Bob"]

[my_movie, my_user].identify(:id, :name)
# => 'Movie[id:1, name:"Identifier Gadget"], User[id:2, name:"Bob"]'

The number of results that will be identified from a collection can be truncated by specifying the limit option.

[my_movie, my_user].identify(:id, :name, limit: 1)
# => 'Movie[id:1, name:"Identifier Gadget"], ... (1 more)'

[].identify  # => "[no objects]"
{}.identify  # => "[no objects]"

Object Identifier works great with the Object Inspector gem.

Performance of Formatters can be tested by playing the Formatters Benchmarking Scripts in the IRB console for this gem.

Custom Formatters may be similarly gauged for comparison by putting them into constant array CUSTOM_FORMATTER_CLASSES before loading the script in the IRB console for this gem.

CUSTOM_FORMATTER_CLASSES = [MyCustomFormatter]

load "script/benchmarking/formatters.rb"
# Reporting for: Ruby v3.4.2

# == Averaged ============================================================
# ...
#
# ObjectIdentifier::StringFormatter
#     38.646k (± 1.3%) i/s   (25.88 μs/i) -    196.758k in   5.092094s
# MyCustomFormatter
#     ...

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. Or, run rake to run the tests plus linters as well as yard (to confirm proper YARD documentation practices). You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install.

To test this gem:

rake

rubocop

reek

npx prettier . --check
npx prettier . --write

To release a new version of this gem to RubyGems:

1. Update the version number in version.rb
2. Update CHANGELOG.md
3. Run bundle to update Gemfile.lock with the latest version info
4. Commit the changes. e.g. Bump to vX.Y.Z
5. Run rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

YARD documentation can be generated and viewed live:

1. Install YARD: gem install yard
2. Run the YARD server: yard server --reload
3. Open the live documentation site: open http://localhost:8808

While the YARD server is running, documentation in the live site will be auto-updated on source code save (and site reload).

Bug reports and pull requests are welcome on GitHub at https://github.com/pdobb/object_identifier.

The gem is available as open source under the terms of the MIT License.