Services

What is a service?

Service is an object that does only one operation, nothing more, nothing less.

Service may usually be implemented as follows:

class Service
  def call
    # ...
  end
end

It has a single public method, often named call or run, process, perform, etc, that is used to invoke its logic.

service = Service.new

service.call

Why do we need services?

Hang on a minute! According to the definition above, a service is almost the same as a regular function/method. Why do we need a new concept?

— A curious developer

Usual Ruby methods may solve similar problems as services most of the time.

Moreover, when it is possible to achieve the task only by using plain methods, it is almost always preferable.

As a result, services should NOT be considered competitors or replacements for methods, they are additions to them.

It is like a new option in the development toolbox.

You have primitives, methods, classes, etc, and now there is an ability to use a service.

For example, removing duplicates from an array can be implemented in multiple ways, you decide whether to utilize an array, hash or a set, depending on your environment limitations.

The same case is with services. Just use them when you feel they bring advantages compared to other approaches.