hodur-visualizer-schema

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#+TITLE: Hodur Visualizer Schema #+AUTHOR: Tiago Luchini #+EMAIL: [email protected] #+OPTIONS: toc:t

[[https://img.shields.io/clojars/v/hodur/engine.svg]] [[https://img.shields.io/clojars/v/hodur/visualizer-schema.svg]] [[https://img.shields.io/badge/License-MIT-blue.svg]] [[https://img.shields.io/badge/project%20status-experimental-brightgreen.svg]]

[[./docs/logo-tag-line.png]]

Hodur is a descriptive domain modeling approach and related collection of libraries for Clojure.

By using Hodur you can define your domain model as data, parse and validate it, and then either consume your model via an API making your apps respond to the defined model or use one of the many plugins to help you achieve mechanical, repetitive results faster and in a purely functional manner.

#+BEGIN_QUOTE This Hodur plugin provides the ability to visualize your Hodur model on a dynamically, hot-reloaded web page. #+END_QUOTE

• Motivation

  For a deeper insight into the motivations behind Hodur, check the [[https://github.com/luchiniatwork/hodur-engine/blob/master/docs/MOTIVATION.org][motivation doc]].

• Getting Started

  Hodur has a highly modular architecture. [[https://github.com/luchiniatwork/hodur-engine][Hodur Engine]] is always required as it provides the meta-database functions and APIs consumed by plugins.

  Therefore, refer the [[https://github.com/luchiniatwork/hodur-engine#getting-started][Hodur Engine's Getting Started]] first and then return here for Lacinia-specific setup.

  After having set up ~hodur-engine~ as described above, we also need to add ~hodur/visualizer-schema~, a plugin that creates and shows Hodur models on a web browser to the ~deps.edn~ file:

#+BEGIN_SRC clojure {:deps {hodur/engine {:mvn/version "0.1.2"} hodur/visualizer-schema {:mvn/version "0.1.1"}}} #+END_SRC

While you are at your ~deps.edn~ file also make sure you have both ~"src"~ and ~"resources"~ to your ~:paths~:

#+BEGIN_SRC clojure {:paths ["src" "resources"]} #+END_SRC

Visualizer utilizes a JavaScript library called [[https://gojs.net/][GoJS]] for the rendering and interactive bits. This library is unfortunately under a proprietary license so it can't be embedded in an Open Source project directly. You have to download a personal evaluation copy and to your project:

#+BEGIN_SRC bash $ mkdir -p resources/public/scripts $ curl https://gojs.net/latest/release/go.js -o resources/public/scripts/go.js #+END_SRC

It is also recommended that you list ~resources/public/scripts/go.js~ out of your SCM (i.e. GitHub) to avoid legal issues.

#+BEGIN_QUOTE If you have suggestions of more Open Source-friendly libraries with equivalent features please DM me at [[https://twitter.com/tiagoluchini][@tiagoluchini]] #+END_QUOTE

Create a ~cljs~ main file that will bootstrap your visualizer app. For instance, if you want to call it ~hello.core~, add the file ~core.cljs~ to ~src/hello~:

#+BEGIN_SRC clojure (ns hello.core (:require [hodur-engine.core :as engine] [hodur-visualizer-schema.core :as visualizer]))

(def meta-db (engine/init-schema '[Person [^String first-name ^String last-name ^Gender gender]

              ^:enum
              Gender
              [MALE FEMALE IRRELEVANT]]))

(-> meta-db visualizer/schema visualizer/apply-diagram!) #+END_SRC

We are creating a simple Hodur model with an Entity called ~Person~ and an enum called ~Gender~ and putting it in a meta database on ~meta-db~.

Before explaining the last function calls on this document, let's fire up a [[https://figwheel.org/][figwheel]] environment with the following helper main (where ~hello.core~ is the name of the main ~cljs~ namespace you created above:

#+BEGIN_SRC bash $ clojure -m hodur-visualizer-schema.main hello.core #+END_SRC

Figwheel will bootstrap a browser-connected repl and launch a browser pointing to ~localhost:9500~ after while. You should see something like this:

[[./docs/diagram.png]]

Feel free to interact with the diagram. You can drag entities around, collapse them and there's a handy tooltip when you hover over entities and fields.

Hot-reload is also enabled, if you change your model on ~hello.core~ you should see the changes reflected on your browser immediately.

As for the last two functions of the ~hello.core~ we are using the meta-database on ~meta-db~ to get a visualizer-parsed version of the schema (through the function ~visualizer/schema~) and, at last, we call visualizer's side-effect function ~visualizer/apply-diagram!~ that updates the diagram on your browser.

• Model Definition

  All Hodur plugins follow the [[https://github.com/luchiniatwork/hodur-engine#model-definition][Model Definition]] as described on Hodur [[https://github.com/luchiniatwork/hodur-engine#model-definition][Engine's documentation]].

• Bugs

  If you find a bug, submit a [[https://github.com/luchiniatwork/hodur-visualizer-schema/issues][GitHub issue]].

• Help!

  This project is looking for team members who can help this project succeed! If you are interested in becoming a team member please open an issue.

• License

  Copyright © 2018 Tiago Luchini

  Distributed under the MIT License (see [[./LICENSE][LICENSE]]).