Their main role is to wrap data and expose logic on top of it.
Think of HTTP params, Entities, Presenters. It makes no sense for them to be "callable objects", as they don't perform an operation.
They are most of the time the input/output of an operation. Params are input coming from Rack env, Entities the returning value from/to the db.
They are most of the time the input/output of an operation. Params are input coming from Rack env, Entities the returning value from/to the db.
Why would we wrap data into an object instead of using Ruby primitives? Because we want to expose logic that is meaningful to our domain, where Ruby primitives are general purpose tools.
E.g. Params: you don't want to use Hash for that.
Read @tenderlove tenderlovemaking.com/2014/06/02/yag…
E.g. Params: you don't want to use Hash for that.
Read @tenderlove tenderlovemaking.com/2014/06/02/yag…
Data objects are a great solution to overcome Primitive Obsession code smell.
blog.dnsimple.com/2016/10/overco…
blog.dnsimple.com/2016/11/purpos…
blog.dnsimple.com/2016/10/overco…
blog.dnsimple.com/2016/11/purpos…
What you should be very careful is how those objects (mainly HTTP Params and Entities) are serialized.
Serialization is an important topic to make sure your system can be compatible outside of its boundaries: eg. send them to Sidekiq or Kafka which only understand primitive data
Serialization is an important topic to make sure your system can be compatible outside of its boundaries: eg. send them to Sidekiq or Kafka which only understand primitive data
Luckily #Ruby offers powerful protocols to make your data objects to play well outside of the boundaries.
blog.dnsimple.com/2016/12/ruby-c…
blog.dnsimple.com/2017/01/ruby-c…
blog.dnsimple.com/2016/12/ruby-c…
blog.dnsimple.com/2017/01/ruby-c…
