@reedchan/koa-http-proxy/app/steps/copyProxyResHeadersToUserRes.js

http proxy middleware for koa

"use strict";

function copyProxyResHeadersToUserRes(container) {
  return new Promise(function (resolve) {
    var ctx = container.user.ctx;
    var rsp = container.proxy.res;
    var strippedHeaders = container.options.strippedHeaders || [];
    var userResHeadersDecorator =
      container.options.userResHeadersDecorator ||
      function (headers) {
        return headers;
      };

    if (ctx.headerSent || ctx.status === 504) {
      return resolve(container);
    }
    ctx.status = rsp.statusCode;
    Promise.resolve(userResHeadersDecorator(rsp.headers)).then(
      function (decoratedHeaders) {
        Object.keys(decoratedHeaders)
          .filter(function (item) {
            return strippedHeaders.indexOf(item) < 0;
          })
          .filter(function (item) {
            return item !== "transfer-encoding";
          })
          .forEach(function (item) {
            ctx.set(item, decoratedHeaders[item]);
          });
        resolve(container);
      },
    );
  });
}

module.exports = copyProxyResHeadersToUserRes;