CORS plugin for the Insaner HTTP server

This plugin allows you to handle CORS in Insaner.

Installation:

npm install --save @insaner/cors

Usage:

import { HttpServer } from 'insaner';
import { Cors } from '@insaner/cors';

const server = new HttpServer();
const cors = new Cors({
  route: /^/, // which URLs should be handled; defaults to all URLs
  origin: true,
  headers: true,
  methods: true,
  credentials: true, // allow credentials; defaults to false
  maxAge: 100, // how long should browsers cache preflight results
});

cors.install(server);

// shorthand:
Cors.install(server, { ...options });

The origin, headers, and methods options can be specified in a couple of ways:

• Not specifying an option (or setting it to undefined) means that the corresponding Access-Control-Allow-* response header will never be sent.
• true will make the handler echo the corresponding request value back to the client, e.g. a request with Origin: https://example.com will receive a response with Access-Control-Allow-Origin: https://example.com.
• A string or an array of strings will make the handler always respond with the specified value; an array will be concatenated as appropriate. The origin option behaves slightly differently: the value is always converted to an array and the handler will respond back with the request origin if the origin is found in the array.
• A regular expression will make the handler echo the values specified in the corresponding request headers filtered to only contain items matching the regular expression. For example, with methods: /^(get|post)$/, a pre-flight request with Access-Control-Request-Method: POST will result in a Access-Control-Allow-Methods: POST response header.