swagger2-koa/src/router.ts

Koa 2 middleware for loading, parsing and validating requests via swagger2

// router.ts

/*
 * Koa2 router implementation for validating against a Swagger document
 */

/*
 The MIT License

 Copyright (c) 2014-2025 Carl Ansley

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 */

import Koa from 'koa';
import body from '@koa/bodyparser';
import koaCors from '@koa/cors';
import KoaRouter from '@koa/router';
import * as swagger from 'swagger2';

import validate from './validate.ts';

import debug from './debug.ts';

export interface Request {
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  query: any;
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  body?: any;
  method: string;
  url: string;
  ip: string;
  ips: string[];
  subdomains: string[];
  origin: string;
  host: string;
  length: number;
  originalUrl: string;
  href: string;
  querystring: string;
  search: string;
  hostname: string;
  type: string;
  charset?: string;
  fresh: boolean;
  stale: boolean;
  idempotent: boolean;
  get: (field: string) => string;
  // eslint-disable-next-line @typescript-eslint/consistent-indexed-object-style
  header: { [name: string]: string };
  // eslint-disable-next-line @typescript-eslint/consistent-indexed-object-style
  headers: { [name: string]: string };
}

export interface Response {
  get: (field: string) => string;
  set: (field: string, value: string) => void;
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  body?: any;
  status?: number;
  message?: string;
  redirect: (url: string, alt?: string) => void;
  // eslint-disable-next-line @typescript-eslint/consistent-indexed-object-style
  header: { [name: string]: string };
}

export interface Context extends Request, Response {
  // eslint-disable-next-line @typescript-eslint/consistent-indexed-object-style
  params: { [name: string]: string };
  request: Request;
  response: Response;
}

// eslint-disable-next-line @typescript-eslint/no-explicit-any
export type Middleware = (context: Context, next: () => void) => any;

export interface Router {
  get: (path: string, ...middleware: Middleware[]) => Router;
  head: (path: string, ...middleware: Middleware[]) => Router;
  put: (path: string, ...middleware: Middleware[]) => Router;
  post: (path: string, ...middleware: Middleware[]) => Router;
  del: (path: string, ...middleware: Middleware[]) => Router;
  patch: (path: string, ...middleware: Middleware[]) => Router;
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  app: () => any;
}

interface HttpRouter extends Router {
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  routes: () => (context: Koa.Context, next: () => void) => any;
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  allowedMethods: () => (context: Koa.Context, next: () => void) => any;
}

export default function (swaggerDocument: unknown): Router {
  const router = new KoaRouter() as unknown as HttpRouter;
  const app = new Koa();

  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  let document: any;

  if (typeof swaggerDocument === 'string') {
    // eslint-disable-next-line n/no-sync
    document = swagger.loadDocumentSync(swaggerDocument);
  } else {
    document = swaggerDocument;
  }

  if (!swagger.validateDocument(document)) {
    throw new Error(`Document does not conform to the Swagger 2.0 schema`);
  }

  app.use(debug('swagger2-koa:router'));
  app.use(koaCors());
  app.use(body());
  // eslint-disable-next-line @typescript-eslint/no-unsafe-argument
  app.use(validate(document));
  app.use(router.routes());
  app.use(router.allowedMethods());

  const full = (path: string) =>
    // eslint-disable-next-line unicorn/no-negated-condition,@typescript-eslint/no-unsafe-member-access,@typescript-eslint/restrict-plus-operands
    document.basePath !== undefined ? document.basePath + path : path;

  return {
    get: (path, ...middleware) => router.get(full(path), ...middleware),
    head: (path, ...middleware) => router.head(full(path), ...middleware),
    put: (path, ...middleware) => router.put(full(path), ...middleware),
    post: (path, ...middleware) => router.post(full(path), ...middleware),
    del: (path, ...middleware) => router.del(full(path), ...middleware),
    patch: (path, ...middleware) => router.patch(full(path), ...middleware),
    app: () => app,
  };
}