next-swagger-doc

Welcome to next-swagger-doc 👋

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Version Downloads/week Prerequisite Documentation License: MIT Twitter: jellydn

Generate Swagger JSON API from NextJS Api Routes

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Demo

Prerequisites

  • Nextjs >= 9
  • Node >= 18

Motivation

This package reads your JSDoc-annotated source code on NextJS API route and generates an OpenAPI (Swagger) specification.

nextjs + swagger-jsdoc = next-swagger-doc

Install

yarn add next-swagger-doc

Usage #1: next-swagger-doc with Next.js 13

To incorporate next-swagger-doc with your Next.js 13 project, follow these steps. This setup will generate Swagger documentation for your API based on your code and provide a built-in Swagger UI for viewing the documentation.

1. Create Swagger Spec

Next, create a new file lib/swagger.ts. This file uses the next-swagger-doc library to create a Swagger specification based on the API routes in your Next.js project.

import { createSwaggerSpec } from 'next-swagger-doc';

export const getApiDocs = async () => {
const spec = createSwaggerSpec({
apiFolder: 'app/api', // define api folder under app folder
definition: {
openapi: '3.0.0',
info: {
title: 'Next Swagger API Example',
version: '1.0',
},
components: {
securitySchemes: {
BearerAuth: {
type: 'http',
scheme: 'bearer',
bearerFormat: 'JWT',
},
},
},
security: [],
},
});
return spec;
};

2. Create Swagger UI Component

Generate a new file named app/api-doc/react-swagger.tsx. In this file, create and export a React component that utilizes the swagger-ui-react library to render the Swagger UI according to the provided specification.

For demonstration purposes, here is an example using swagger-ui-react

Feel free to employ any alternative swagger UI library, such as stoplightio/elements. I have added an example using this library in the example folder.

'use client';

import SwaggerUI from 'swagger-ui-react';
import 'swagger-ui-react/swagger-ui.css';

type Props = {
spec: Record<string, any>,
};

function ReactSwagger({ spec }: Props) {
return <SwaggerUI spec={spec} />;
}

export default ReactSwagger;

3. Create API Documentation Page

Create a new file app/api-doc/page.tsx. This page imports the Swagger spec and the Swagger UI component to display the Swagger documentation.

import { getApiDocs } from '@/lib/swagger';
import ReactSwagger from './react-swagger';

export default async function IndexPage() {
const spec = await getApiDocs();
return (
<section className="container">
<ReactSwagger spec={spec} />
</section>
);
}

4. Add Swagger Comment to API Route

Lastly, add a Swagger comment to your API route in app/api/hello/route.ts. This comment includes metadata about the API endpoint which will be read by next-swagger-doc and included in the Swagger spec.

/**
* @swagger
* /api/hello:
* get:
* description: Returns the hello world
* responses:
* 200:
* description: Hello World!
*/
export async function GET(_request: Request) {
// Do whatever you want
return new Response('Hello World!', {
status: 200,
});
}

Now, navigate to localhost:3000/api-doc (or wherever you host your Next.js application), and you should see the swagger UI.

https://gyazo.com/6bfa919c4969b000615df6bb9cabcd02.gif

Usage #2: Create an single API document

yarn add next-swagger-doc swagger-ui-react
  • Create an live swagger page, e.g: pages/api-doc.tsx
import { GetStaticProps, InferGetStaticPropsType } from 'next';
import { createSwaggerSpec } from 'next-swagger-doc';
import dynamic from 'next/dynamic';
import 'swagger-ui-react/swagger-ui.css';

const SwaggerUI = dynamic<{
spec: any;
}>(import('swagger-ui-react'), { ssr: false });

function ApiDoc({ spec }: InferGetStaticPropsType<typeof getStaticProps>) {
return <SwaggerUI spec={spec} />;
}

export const getStaticProps: GetStaticProps = async () => {
const spec: Record<string, any> = createSwaggerSpec({
apiFolder: 'pages/api' // or 'src/pages/api',
definition: {
openapi: '3.0.0',
info: {
title: 'Next Swagger API Example',
version: '1.0',
},
},
});

return {
props: {
spec,
},
};
};

export default ApiDoc;

https://gyazo.com/af250bab0d07f931c596ebc8c955ae2e.gif

Usage #3: Use NextJS API route to create Swagger JSON spec

  • Step 1: Create an api route on nextjs, e.g: pages/api/doc.ts
import { withSwagger } from 'next-swagger-doc';

const swaggerHandler = withSwagger({
definition: {
openapi: '3.0.0',
info: {
title: 'NextJS Swagger',
version: '0.1.0',
},
},
apiFolder: 'pages/api',
});
export default swaggerHandler();
  • Step 2: Add JSdoc to any NextJS API routes, for example: pages/api/hello.ts
import { NextApiRequest, NextApiResponse } from 'next';

/**
* @swagger
* /api/hello:
* get:
* description: Returns the hello world
* responses:
* 200:
* description: hello world
*/
const handler = (_req: NextApiRequest, res: NextApiResponse) => {
res.status(200).json({
result: 'hello world',
});
};

export default handler;
  • Step 3: Access the Swagger API doc

https://gyazo.com/0bcf45f0e15778a5cb851b40526324f3.gif

Usage #4: Generate Swagger file from CLI

  • Step 1: create a JSON config file as next-swagger-doc.json
{
"apiFolder": "pages/api",
"schemaFolders": ["models"],
"definition": {
"openapi": "3.0.0",
"info": {
"title": "Next Swagger API Example",
"version": "1.0"
}
}
}
  • Step 2: run cli for generating swagger file
yarn next-swagger-doc-cli next-swagger-doc.json

Run example app

gh repo clone jellydn/next-swagger-doc
cd example
yarn install
yarn dev

Then open http://localhost:3000/api-doc or http://localhost:3000/ on your browser ./example-screenshot.png

Linter

In order to set an eslint rule that checks that all the APIs actually have a swagger JsDoc description we can use the following settings:

Install the JsDoc eslint plugin:

yarn add -D eslint-plugin-jsdoc

Create the custom rule in your eslint configuration file:

{
//...your configuration
"overrides": [
//...your overrides
{
// Force the setting of a swagger description on each api endpoint
"files": ["pages/api/**/*.ts"],
"plugins": ["jsdoc"],
"rules": {
"jsdoc/no-missing-syntax": [
"error",
{
"contexts": [
{
"comment": "JsdocBlock:has(JsdocTag[tag=swagger])",
"context": "any",
"message": "@swagger documentation is required on each API. Check this out for syntax info: https://github.com/jellydn/next-swagger-doc"
}
]
}
]
}
]
}

Author

👤 Huynh Duc Dung

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Contributors ✨

Thanks goes to these wonderful people (emoji key):

Dung Duc Huynh (Kaka)
Dung Duc Huynh (Kaka)

💻 📖
tmirkovic
tmirkovic

📖
Matthew Holloway
Matthew Holloway

💻
leventemihaly
leventemihaly

📖
PAHRIZAL MA'RUP
PAHRIZAL MA'RUP

💻
Aris
Aris

📖
Valerio Ageno
Valerio Ageno

📖
cachho
cachho

💻

This project follows the all-contributors specification. Contributions of any kind welcome!

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