Clojure is a fantastically powerful, yet simple language. Despite this assertion, it is not uncommon for those new to the language to have a hard time grasping how to build complete applications from the basic building blocks of Clojure.
This workshop will bridge the gap from the basics of data literals all the way to building a complete, stateful web backend application. Participants will learn the following key takeaways:
- Clojure is a data-centric language that frees developers to think about their problems simply and clearly.
- The core functions of Clojure can be thought of as a powerful data DSL that is appropriate for working and thinking in any domain.
- Clojure code is often developed in a bottom-up, functional style.
- Powerful libraries exist beyond Clojure core that are also built on data-driven and functional concepts.
- Stateful applications can be developed and organized in a functional manner by pushing state to the edges of their applications and isolating stateful components.
For our project we are going to build a really fun and cool application using data about hundreds of superheroes.
Specific activities we will do are:
- Model our domain as data.
- Parse existing data files into a usable format.
- Learn about and use a very powerful family of databases (including Datascript & Datahike).
- Build a stateful backend web application around our superhero database, including a simple Swagger UI.
By the end of the session, you should be able to easily adapt this application and lessons learned to your specific domains.
This tutorial is aimed at the following audiences:
- Beginning to intermediate Clojure developers who are still trying to figure out a good workflow to build complete Clojure applications.
- Anyone interested in fact-oriented databases (Datascript, Datahike, Datomic, Crux).
- People who like superheroes.
Prior to this workshop, you must:
- Have Clojure installed on your computer.
- Have Leiningen installed on your computer.
- Install a Clojure IDE (I will be using IntelliJ IDEA + Cursive).
- Clone this project, located here.
- Load the project into your IDE with a running REPL.
All namespaces are sorted, starting with ch01/x01 through ch04/x04. You can follow along with the tutorial or move ahead if anything seems too slow. All exercises have solutions in an accompanying namespace ending with _solutions. If, at any point, you feel like you are falling behind, that's ok. The whole project is documented so you can revisit it at any time and solutions are wired in at future points so that everything works.
You may also find the Marginalia documentation useful.
Copyright © 2020 Mark Bastian
This program and the accompanying materials are made available under the terms of the Eclipse Public License 2.0 which is available at http://www.eclipse.org/legal/epl-2.0.
This Source Code may also be made available under the following Secondary Licenses when the conditions for such availability set forth in the Eclipse Public License, v. 2.0 are satisfied: GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version, with the GNU Classpath Exception which is available at https://www.gnu.org/software/classpath/license.html.