mrmaxie / openapigen

OpenAPI 2/3 transformer & codegen

OApiCodeGen

This package provides an easy and efficient way to generate code for various programming languages from OpenAPI specifications (both OpenAPI 2 and OpenAPI 3 are supported).

Features

• Language-agnostic code generation for various programming languages, including TypeScript, JavaScript, Python, and more
• Generate client libraries for RESTful APIs
• Type-safe code generation
• Supports both OpenAPI 2 (Swagger) and OpenAPI 3

Installation

npm install --save-dev oapicodegen

Usage

First, import the package in one of your files:

import { Api } from 'oapicodegen';

First of all create context object for future needs:

/* Example data loading:
const openapiJson = await fs.readFile('openapi3.json', 'utf8');
const openapi = JSON.parse(openapiJson);
*/

const api = await Api.load(openapi);

You can get different result depending on the next steps.

Useful examples

Search for all operations with get method

const operations = api
    .paths
    .flatMap((path) => path.operations)
    .filter((operation) => operation.method === 'get');

Find elements by segments of path

const operations = api
    .getPathBySegments(['pets', 'findByStatus'])
    .operations; // operations of /pets/findByStatus path

Find all child elements of a given element

const operations = api
    .getStaticSegmentsAtNextLevel(['pets', 'findByStatus'])
    .operations; // operations of /pets/findByStatus/* paths

Find response by status code

const response = api
    .getPathBySegments(['pets', 'findByStatus'])
    .operations[0]
    .getResponseByStatus(200); // response with status code 200

It's useful to use prettier to format the generated code

import { format } from 'prettier';

const code = format('const a = 1;', { parser: 'typescript' });

Creating zod types from schema

const schema = api
    .getPathBySegments(['pets', 'findByStatus'])
    .operations[0]
    .responses[0]
    .content['application/json']
    .schema;

`const PetResponse = z[${schema?.type}]();`

Project goal

The mission of this project is simple - to help convert an existing OpenAPI 2 or 3 schema in variable form to text.

What this project does NOT do:

• Downloading files
• Importing files
• Exporting files
• Operating on dependencies other than local
• Authentication
• Using with the CLI