BlockRegistry

Register event handlers to key lookups.

Installation

Add this line to your application's Gemfile:

gem 'block_registry'

And then execute:

$ bundle

Or install it yourself as:

$ gem install block_registry

Usage

Create a BlockRegistry instance:

registry = BlockRegistry.new

Register keys with a processing block:

registry.register('user-login') do |email|
  user = User.find_by(email: email)
  puts "User #{user.email} logged in" if user
end

registry.register('user-register') do |email, password|
  user = User.create(email: email, password: password)
  puts "User #{user.email} registered" if user.persisted?
end

Call the handler with appropriate arguments:

registry.handle('user-register', 'joe@example.com', 'MyPassword123')
registry.handle('user-login', 'joe@example.com')

BlockRegistry#register

Registers a handler to a key. Expects a key name and a block whose arity matches that used by BlockRegistry#handle. Multiple handlers can be defined for a single key.

registry.register('private-message') do |sender_id, recipient_id, message|
  Message.create!(sender_id: sender_id, recipient_id: recipient_id, message: message)
end

registry.register('private-message') do |sender_id, recipient_id, message|
  NewRelic::Agent.notify('private-message', sender_id: sender_id, recipient_id: recipient_id, message: message)
end

BlockRegistry#registered?

Returns true or false to signify whether any handlers exist for a given key.

registry.register('user-register', &block)
registry.registered?('user-register')  # => true
registry.registered?('user-login')     # => false

BlockRegistry#unregister

Unregisters one or all handlers for a key. If a block is given, the matching handler is unregistered. If no block is given, then all handlers for the key are unregistered.

block = ->(email) do
  puts "#{email} signed up"
end

registry.register('user-register', &block)
registry.register('user-register') do |email|
  puts 'another handler'
end

registry.unregister('user-register', &block)
registry.registered?('user-register')  # => true

registry.unregister('user-register')
registry.registered?('user-register')  # => false

BlockRegistry#handles?

Alias for BlockRegistry#registered?

BlockRegistry#handle

Processes a message across all handlers for the given key.

registry.register('user-register') { |email| puts "#{email} signed up" }
registry.register('user-register') { |email| puts "hi, #{email}" }

registry.handle('user-register', 'joe@example.com')
# => joe@example.com signed up
# => hi, joe@example.com

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. 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 release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

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

License

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