ServiceCall

Adds a little niceness to callable service objects.

Add this line to your application's Gemfile:

gem 'service_call'

And then execute:

$ bundle

Or install it yourself as:

$ gem install service_call

Define a class that includes ServiceCall and implements the call method:

class MyService
  include ServiceCall

  def call(message)
    puts "MyService is #{message}"
  end
end

Then you can instantiate your class and invoke call using any of these methods:

MyService.new.call("useful")
MyService.call("useful")
MyService.new.("useful")
MyService.("useful")

If you define any attr_reader methods, ServiceCall will automatically pass any named parameters to your initializer.

class ServiceWithAttributes
  attr_reader :name

  def initialize(name:)
    @name = name
  end

  def call
    puts name
  end
end

ServiceWithAttributes.(name: "George") # => "George"

Additionally, you can define collaborators with default values using attribute.

class ServiceWithDefaults
  include ServiceCall

  attribute :other_service, default: OtherService

  def call
    puts "other_service is a #{other_service.class}"
    # If OtherService is a ServiceCall, you can invoke it like:
    other_service.()
  end
end

ServiceWithDefaults.() # => "other_service is a OtherService"
ServiceWithDefaults.new(other_service: MockService).() # => "other_service is a MockService"

Defining dependent services this way makes it easy to mock them with lambdas during testing, override them at run time, and "just use them" without complicated initialization or factory methods.

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.

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