Overview

I had the opportunity to enable OpenAPI in Drupal, so this is a memo. Note that the JSON:API module has already been enabled.

Installing Modules

Install the following two modules.

OpenAPI

This module allows you to make your Drupal information architecture (as exposed by your web service of choice) discoverable using the OpenAPI standard.

Drupal.org

OpenAPI for JSON:API

Integrates with the base OpenAPI module to generate the definitions for JSON:API. Version notes Versions 2.x and 3.x implement version 2 of the Open API specification.

Drupal.org

As a result, JSON can be obtained from the following URL.

/openapi/jsonapi

Accessing the following displays "No UI ...". Next, let's add a UI.

/admin/config/services/openapi

Adding a UI

Install the following two modules.

OpenAPI UI

The OpenAPI UI module implements an API around displaying OpenAPI specs inside a Drupal site. This library implements a plugin base which can be used to initialize a API explorer UI within your site.

Drupal.org

ReDoc for OpenAPI UI

ReDoc is a javascript library which allows a user to explore the api documentation for a web services API.

Drupal.org

As a result, an "Explore" button is displayed.

Clicking the button navigates to the following screen.

/admin/config/services/openapi/redoc/jsonapi

A Swagger UI-like screen is displayed.

Note that Redoc is described as follows.

Redoc is an open-source tool for generating documentation from OpenAPI (fka Swagger) definitions.

GitHub - Redocly/redoc: 📘 OpenAPI/Swagger-generated API Reference Documentation

📘 OpenAPI/Swagger-generated API Reference Documentation - Redocly/redoc

GitHub

References

I also tried installing the following "Swagger UI for OpenAPI UI," but it resulted in an error in my environment.

Swagger UI for OpenAPI UI

Swagger UI is a javascript library which allows a user to explore the api documentation for a web services API.

Drupal.org

Summary

We hope this serves as a useful reference when using OpenAPI with Drupal.