pmcelhaney / counterfact / 6053254142

import koaProxy from "koa-proxy";

const HTTP_STATUS_CODE_OK = 200;

function addCors(ctx, headers) {

  // Always append CORS headers, reflecting back the headers requested if any

  ctx.set("Access-Control-Allow-Origin", headers?.origin || "*");

  ctx.set("Access-Control-Allow-Methods", "GET,HEAD,PUT,POST,DELETE,PATCH");

  ctx.set(

    "Access-Control-Allow-Headers",

    headers?.["access-control-request-headers"],

  );

  ctx.set(

    "Access-Control-Expose-Headers",

    headers?.["access-control-request-headers"],

  );

  ctx.set("Access-Control-Allow-Credentials", "true");

}

export function koaMiddleware(dispatcher, options = {}, proxy = koaProxy) {

  return async function middleware(ctx, next) {

    const { body, headers, method, path, query } = ctx.request;

    if (options.proxyEnabled && options.proxyUrl) {

      return proxy({ host: options.proxyUrl })(ctx, next);

    }

    addCors(ctx, headers);

    // If the method is OPTIONS then always return OK

    } else {

      const response = await dispatcher.request({

        body,

        headers,

        method,

        path,

        query,

        req: ctx.req,

      });

      /* eslint-disable require-atomic-updates */

      ctx.body = response.body;

      ctx.status = response.status ?? HTTP_STATUS_CODE_OK;

      /* eslint-enable require-atomic-updates */

    }

    return undefined;

  };

}