http-cors

CORS middleware for standard Request and Response.

Middleware

For a definition of Universal HTTP middleware, see the http-middleware project.

Usage

Middleware is exported by default.

In this example, the access-control-allow-origin header will add in the case of a CORS request.

import cors from "https://deno.land/x/http_cors@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std/testing/asserts.ts";

const middleware = cors();
const response = await middleware(
  new Request("http://api.test", { headers: { origin: "http://cors.test" } }),
  (request) => new Response("ok"),
);
assertEquals(response.headers.get("access-control-allow-origin"), "*");

It also returns a Request for CORS Preflight in the case of a CORS Preflight request.

import cors from "https://deno.land/x/http_cors@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std/testing/asserts.ts";

const preflightRequest = new Request("http://api.test", {
  method: "OPTIONS",
  headers: {
    origin: "http://cors.test",
    "access-control-request-method": "POST",
    "access-control-request-headers": "content-type",
  },
});
const middleware = cors();
const response = await middleware(
  preflightRequest,
  (request) => new Response("ok"),
);

assertEquals(response.status, 204);
assertEquals(await response.text(), "");
assertEquals(response.headers.get("access-control-allow-origin"), "*");

License

Released under the MIT license