Hanami, Why?: Bits & Bobs — system-level patterns you should know

The useful part

Bits & Bobs | Aaron Allen Writing Welcome back to my "Hanami, Why?" series. It is my intent to keep these issues focused on singular subjects whenever possible. However, in today's issue we are going to cover several topics that are too small to warrant their own issue but still important to have for context.

How it works

• We have lots to cover, but this context will be important for a further understanding of how Hanami works.
• However, in frameworks like Rails everything is autoloaded for you, so there often are not any calls to require in the code base.
• Providers have all sorts of useful applications and are one of the many joys of working with a Hanami application.
• Types are actually a very useful abstraction and can be used to validate and normalize user inputs.
• Let us look at an example of a provider and how you might use one.

What to take from it

Because it is namespaced, every component it registers lives under the redis key, so the client component we will get to in a moment can be called anywhere in your application via include Deps["redis.client"]. As I mentioned, Hanami has a lot of important abstractions, and today we are going to be covering what I consider "system level" abstractions. Dependency Injection Most of the time Ruby is pretty great at telling you what a particular file depends on via require.

Example or evidence

• You could forgo the namespace altogether, in which case you would call the dependency via include Deps["client"].
• If you go that route, I would definitely name it redis_client instead of just client, but I hope you get the gist.
• Remember, all of the prepare blocks are invoked before any start block is invoked.
• So, if you have several providers, each of them will be prepared before any of them are started.

Details worth keeping

If you missed it, be sure to read Hanami, Why?: We are registering a namespaced provider named redis. We are requiring the redis gem in our prepare block.

Related coverage

• Wrongeverytime: Hello folks, and welcome back to Wrong Every Time.
• Hanakai: Originally appeared on Hanakai.