Ruby
Livin’ La Vida Hanami
Summarized using AI
Livin’ La Vida Hanami
by Tim RileyThe video titled 'Livin’ La Vida Hanami' presented by Tim Riley at RubyConf 2023 focuses on the Hanami web framework for Ruby, particularly its 2.0 version and the upcoming 2.1 release. In this session, Tim introduces Hanami as an application framework designed to enhance the development experience by facilitating maintainability and testability.
Key points discussed include:
- Introduction to Hanami: A Ruby framework originally launched in 2014 that has evolved into a robust solution for creating maintainable applications.
- Hanami 2.0 Release: The framework has integrated Dry-RB functionalities, offering a combination of power and simplicity tailored for Ruby developers.
- Hands-on Development: Tim guides the audience through building a sample application named 'Bookshop', illustrating key components such as actions, repositories, and views.
- App Structure: Emphasis is placed on how all application code is organized and how dependencies are managed using Hanami's design patterns, including a central container concept.
- Testing and Modularization: The session highlights the testing capabilities of Hanami, including low-level and integrated tests, and introduces the concept of 'slices' for app modularization, allowing better organization as applications scale.
- Multiple Application Types: Tim reveals that Hanami is no longer just limited to web apps, demonstrating its flexibility by discussing potential use cases for CLI tools, serverless functions, and other types of applications.
In conclusion, Tim underscores Hanami's commitment to maintainability, testability, and developer joy, noting that Hanami 2 and beyond are expected to pave new pathways for Ruby application development, making it relevant across various domains. Overall, attendees are encouraged to explore and adopt Hanami for their future Ruby projects, promising a fulfilling development experience.
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Um, okay. Hi and welcome! My name is Arela, and I'm from the program committee.
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It’s my honor to present our next speaker. Tim Riley is a core team member of Hanami, Dry-RB, and ROM-RB.
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He’s a principal engineer at Buildkite. Tim has been writing Ruby for over 20 years and still loves it.
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He works to bring the joy of Ruby to writing real maintainable applications of all shapes and sizes.
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So please join me in giving a warm welcome to Tim!
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Riley.
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I like that logo a bit.
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We’re into applications, fast tests, and method calls. I've got a premonition this session is going to stun us, so let's go!
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Thank you! Yes, we’re doing this. I'm Tim.
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It is really exciting to be here at RubyConf and it is the last session in the schedule, so I hope we can have some fun together this afternoon.
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This is, in fact, my first time at RubyConf and my first time in San Diego.
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So, I did a bit of research in anticipation of speaking here, and as you can imagine, I looked into the musical background of the city.
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There's a lot of it, but being a child of the '90s, one thing stood out to me very quickly.
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I learned that this crew here, Blink-182, is a San Diego band, born and bred. Super cool!
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You might remember this setting; that's the clip of their breakthrough hit 'All the Small Things'.
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From back in 1999, which came out a mere few months after another song that we're going to become familiar with today.
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Through which we'll be making our own extremely niche contribution to San Diego music history.
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Because yes, today we are going to explore a Ruby framework under the guidance of the iconic Ricky Martin.
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In fact, speaking of San Diego, I learned that Ricky Martin himself was here on this day in 1999 as part of his "Livin' La Vida Loca" tour.
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So we are going to bring it back with a loving RubyConf reinterpretation of his hit song.
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At this point, I will share a bit more about me.
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I'm Tim, say hi to me on Mastodon, it's a fun place to chat. I work at Buildkite, we make fast, flexible, and secure CI/CD systems and more.
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And we do all of that with Ruby, which is super cool! If you're a Buildkite user or fan, or what have you, I have some stickers, so come find me afterwards.
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In the Ruby open-source world, I work on a few other things, like Hanami, Dry-RB, and ROM-RB, and we'll touch on all of these as we go.
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But we will focus mostly on Hanami.
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So what is Hanami? Well, it's an app framework for Ruby and now is the perfect time to share it, because as of last year, we are now in the 2.0 era of Hanami.
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And I’m really excited for what it might bring to us all. Not only for unlocking different possibilities for our Ruby apps...
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But also for what it might bring to each of us as Ruby developers.
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Now, this project has been around since 2014. Back when we released it, we described it as a fast and lightweight web framework.
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Bringing a strong focus on testability and maintainability.
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Then a year later, the Dry-RB project began, and that's where I was personally involved at the time.
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Through this project, we were releasing a range of Ruby gems focused on solving common tasks in Ruby.
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But each one was motivated by helping us all write more maintainable applications.
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By 2018, both of our teams realized we were largely traveling in the same direction, trying to reach the same goals.
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So we teamed up, and a few years later, Hanami 2.0 came out around this time last year.
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It brings all the power and flexibility of Dry-RB along with a friendly and streamlined out-of-the-box experience.
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In just a couple of weeks, version 2.1 will be coming out. We worked really hard to get it ready around this time for RubyConf.
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We have a release candidate that you can already try out, so I'm really excited to share what we’re bringing to you in 2.1.
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As we go through our journey today, getting to this point was a true team effort.
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I might be the one sharing it right here, but I’d like to give a shout-out to all these legends, including my friends Luca and Peter.
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They are my teammates on the core team. I also have a few extra people to thank courtesy of the wonderful Community Day that kicked off this conference.
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So I'd like to say thanks to Dan and Roman, who are already writing their first PRs for Hanami, which is fantastic.
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Ariel helped me debug a tricky issue with our front-end asset preparation.
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So thanks to RubyConf and these three people for pitching in.
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So that's the team.
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But as for today, we're all on Team Ricky!
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This means that from here, we'll be progressing through his song.
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As we go from verse all the way through to chorus, we will learn and progress our understanding of Hanami.
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We'll see what it's like to get started with the framework and then learn more about its features.
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Lastly, we'll step back and see what this means for all of us living that life with Hanami.
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So let's get started building! This is how we'll get started with the framework.
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Like any gem, the first thing we can do is install it using the command: gem install Hanami.
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From there, we can create a new app with the command: hanami new, and let's call our app 'Bookshop'.
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That's enough for us to hop into our terminal, run the Hanami Dev servers, and from there, we can open our web browser.
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We'll see this lovely welcome screen, which gives us everything we need to know to learn more about Hanami.
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We developed this just for version 2.1, so you'll see this in the release candidate.
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It'll be the first thing people experience when they try the 2.1.0 version in a few weeks' time.
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Luckily, however, we don't need to click these links because we're all here together.
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So let's continue our tour directly. We can start by looking at the app class, and this is nice and simple.
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We won't need to spend too long here, but there's one thing to point out, even at this stage: in Hanami, all our app code lives together.
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In a single namespace matching our app's name. So here we have module Bookshop.
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This is the module where all of our code will live.
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Now, from the app, we can take our tour across to the routes, and what we see here is a blank slate.
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We need to get started, so the first thing we'll do to make our app real is to create an action.
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Hanami gives us a generator we can use, so for our Bookshop app, let's go ahead and make a products index action.
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Something that can return a list of products. If we come back to our routes, we'll see that the generator has made one for us.
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This looks pretty straightforward: a GET request to /products will take us through to that products index action.
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Here's the action the generator made for us.
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This is a basic starter action. The thing to know about actions in Hanami is that they handle all our app's HTTP logic.
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We have exactly one action class per endpoint, and it's the handle method that’s the most important part of each action.
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That's where we tell it how to behave. We can see that we're given separate request and response objects.
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We can use these for inspecting the request params or setting the response body.
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Now, speaking of those params, Hanami gives us flexible param validation schemas.
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This can help ensure those incoming params meet our expectations both in terms of their structure and types.
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Since this is an index action, let's go ahead and add a couple of optional params: one for a page number and another for a per-page value.
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In both these cases, if they're provided, we want to make sure these are integers and are greater than zero.
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Now with this done, that's enough for us to go ahead and return an error response if any of those params are not valid.
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Hanami actions give us a number of different features that are helpful for managing that HTTP behavior.
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What about our business logic? This is our index action. Where will we do the job of fetching the products to give back to the user?
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Well, to do this, let's get to know one of Hanami's most important features, and that is: in Hanami, our app is also a container.
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A container here works as a central organizing object responsible for loading and providing access to all the components in our app.
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Now, what is a component here? Well, it's just our Ruby objects. Our action is already a component.
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We can access it by using a key that matches its name, just like this.
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What we get back is an instance of our action ready for us to work with.
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In fact, any class we put into app will become available as a component.
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So in this case, let's go and make a component for a product repository.
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This repository will return a list of products for our action and could look something like this.
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Since we put this in the app/repos directory, we give it a matching namespace inside Bookshop.
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We then can add a method to find and return the latest products from our database.
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This uses the full query API from the ROM-RB collection of gems.
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These are standalone Ruby gems that have been in use for many years, tested and refined in real production environments.
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Our plan for Hanami is to make these available to you in an easy-to-use way.
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So now our repo's done. We have two components: our action and our repository.
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But how do we get them to know about each other? What we really want is to use this repository inside our action.
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To do this, we can use Hanami's deps mixin. We can include this mixin inside any class in a Hanami app.
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Then we can pass it a list of components we want to make available as dependencies.
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'Deps' here is our shorthand for dependencies, and those components become available as instance methods.
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This means we can use the latest products from our product repository and return a JSON response from this action.
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Now with this done, we can go back to our terminal and this time make a request.
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We see here are our products returned to us as JSON, so that's a simple API.
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We’re already making progress, but what if we wanted to build a more full-stack kind of application?
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Something that can return our products as HTML? Well, for this, we can introduce a view.
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Just like actions, every view has its own class in Hanami. This one here is for our products index.
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Like everywhere else in a Hanami app, we can include dependencies inside our view.
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Here we’ll bring in that product repo, so we can get access to our products where we need them.
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Now, from here, the main job of views is to prepare exposures. These are the values we want to pass over to our template.
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Let's pass over those latest products, and then in our template, we can prepare the HTML however we need.
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To get the response that we want to give our users. Since our views are classes in Hanami apps, they are components as well.
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So we can bring it in as a dependency to the action we created earlier.
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In our handle method, we can render the view onto the response.
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This will now return our products as HTML. Rendering a view from an action is such a common task.
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Hanami will take care of finding that matching view for us, so we don’t even need the boilerplate.
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After this, we can run our server again and see our products come back as HTML.
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Well done, everybody, we've just made our first working feature with Hanami!
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Now, you'll see because we’re onto the next verse, we’re into new sensations, new code broken up by slices.
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By the way, no ChatGPT was used or harmed in the preparation of this presentation.
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So now we've given Hanami a go, and we're in a great position to learn more of its features.
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There's no better place to start than with the testing experience.
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How might we test this view that we just created? Well, views like every part of Hanami are designed to be directly testable.
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We can call new directly on our view like this, even passing a test double for that product repo dependency.
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This will let us control its behavior for the purposes of this test.
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Now from here, that's enough for us to go ahead and call our view and assert that its output meets our expectations.
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What we see here is a very low-level isolated unit test.
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For things like views or actions, we won’t typically want to go this far.
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A more appropriate path would be to make an integrated end-to-end test, like a request spec or a Capybara-driven feature spec.
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These are available in every new Hanami app.
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The thing to take away is that because all the objects in a Hanami app are designed to be directly tested, it means we as the app authors get.
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To make the best testing choice for each situation.
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Now we've interacted with our code through tests.
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We can also do this through the console. In Hanami, you can load the console via the Hanami console command.
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And when you're in, you can use this app shortcut to refer to our app.
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From there, we can access our components that come back as instances ready for us to use and interact with.
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This console always starts quickly, no matter the size of our app, because we provide a lightweight boot mode across all aspects of Hanami development.
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We use this for the console to running our tests, which is great for a responsive TDD flow.
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Even when starting the dev servers, no matter how big our apps grow, all our development interactions will remain snappy.
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Now, another thing that Hanami does when it boots our app is load our settings.
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These are the values we give our apps to help them run correctly in each environment.
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Things like keys, secrets, and flags. We can define our settings.
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Say we want to extend our app now to send emails when new products are created.
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To do this, we want to use some kind of third-party email API.
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Here we can add a setting for its API key and specify we want this to be a string.
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Hanami will then load these settings from matching environment variables by their names.
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When we're working locally, we can pull these in from files as well.
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Now, once that's done, we can access our loaded settings as another component in our app called settings.
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It comes with methods defined for every one of the settings that we prepared.
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Remember how we declared the string type for this setting? This allows Hanami to give us early feedback if we ever boot our app into an environment where the settings don't meet our expectations.
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Which is really good for safety, because it means that we never get into an unexpected state as we work within our app.
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The other benefit of having this settings object available as a component is that we can bring it into any class in our app thanks to the deps mixin.
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So we can confidently access our settings wherever we need them.
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No direct accesses to end sprinkled throughout our app!
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Aside from our settings, so far we've only seen those components loaded from the classes we create in our app directory.
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What if we wanted a component that needed some kind of special handling as part of its setup?
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This is where providers help and we need to make one now for our email service.
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We've already gone and created the setting for its API key. Now we need to go and use it.
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Providers have their own folder in config, and here we're registering a provider for our email service.
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Inside each provider, we have a couple of lifecycle steps that we can work with.
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In this case, the first thing we'll do is require the gem that will let us interact with this third-party email service.
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Then we’ll grab our API key from the settings we just prepared, pass it in to configure an instance of this email client.
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Then we can register this instance directly in our app using a key called email_service.
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With this done, we can now use email_service as a dependency inside any class in our app.
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We can be confident that it’s the properly set up object that we've just managed here.
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By this point, we've covered nearly everything we need to know about Hanami apps.
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But there's one more important thing for us to discover, and that's slices.
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Slices help us organize our app into separate domains or technical concerns.
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They're a great way for introducing modularity and clearer internal boundaries to our apps as they grow.
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If at this point you're thinking of Packwerk packs or Phoenix umbrella apps, then you're on the right track.
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In a new Hanami app, you don’t see slices up front.
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That's because we want the apps to be as approachable and simple as possible in that earlier state.
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But they are built in and will appear as soon as we start putting code into the slices directory.
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Hanami gives us a friendly generator we can use.
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So for today, let's go and make an admin slice, which will prepare an admin slice directory for us.
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Into this directory, we can create a products create action.
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Just like our app, every slice maps to a single Ruby namespace.
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So here we have an admin namespace, and Hanami gives an admin slice object that we can interact with.
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This works exactly like our app, offering access to our components with the only restriction being that it only loads components from inside the slice directory.
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Also, like the app, slices come with their own deps mixin, but it only loads components from inside the slice.
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Now we’ve seen that both our app and slices act as containers for arranging and organizing our components.
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Thanks to our deps mixin, we can clearly recognize the dependencies and the relationships between those components.
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This starts to help us visualize our app as a big directed graph.
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From here, we can take things one step further because slices can import components from other slices.
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This means we can now envision an equally clear graph of all of our app’s high-level concerns.
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This is a powerful approach; we have the tools built into the framework to help us organize our code at every level.
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For easier understanding and maintainability. Slices also help us with operational flexibility.
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Because we can choose which slices we want to load for each deployment of our app.
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One thing we want to do with Hanami is extend this power to apps of all kinds, not just web apps.
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Let's take a look at the Gemfile of a new Hanami app.
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What we're seeing here is a web app because it includes the router, view, and controller gems.
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But these are not fixed dependencies of the framework; this is why they’re here in the Gemfile.
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Say we wanted to build something different than a web app; all we need to do is remove these extra lines.
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With the one core Hanami gem that remains, we have all the quality-of-life features we've just learned.
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We have app containers, components, deps, settings, providers, the console, even slices.
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And we can put all these features to use for any kind of app.
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This means we get to keep everything we need and nothing we don't.
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Hanami 2 is no longer just a web framework; it's an everything framework.
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Say we want to build a CLI tool, a serverless function, a stream consumer, or a chatbot.
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For each of these, we still want all the conveniences that a full framework might give us.
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Now we can do it with Hanami. I'm not sure if Ruby has ever had something quite like this.
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I’m really excited to see where people might take it.
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Now we’ve seen every part of Hanami.
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Everything you see on the screen is either released or imminently releasing in the next few weeks.
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This means you have enough to build an API or even now a full-stack web app that goes all the way through to HTML views.
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Along with fully integrated and fast-to-compile frontend assets.
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Now we’re a small team who’ve been building this.
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We have been looking to maintain our quality and momentum by releasing things progressively.
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This means the database layer is coming next year, but by virtue of us using ROM, which is an already released Ruby gem...
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