@contentacms/contentajs/lib/routes/proxyHandler.js

A nodejs server that proxies to Contenta CMS and holds custom code.

"use strict";

const _ = require('lodash');

const logger = require('pino')();

const proxy = require('express-http-proxy');

const url = require('url');

const cacheControl = require('../middlewares/cacheControl');

const errorHandler = require('../middlewares/errorHandler');
/**
 * Middleware to send the requests to Contenta CMS.
 *
 * This uses 'express-http-proxy' which terminates the request after proxying.
 */


module.exports = (req, res, next) => {
  const options = {
    // We have a list of the JSON API resources available in Contenta CMS. This
    // list is a list of regular expressions that can match any path a resource,
    // taking variables into account. Filter the requests that are for
    // non-existing resources.
    filter(pRq, uRq) {
      // Extract the path part, without query string, of the current request.
      const parsed = url.parse(uRq.req.url);
      const pathIsWhitelisted = // Only filter paths if there are any whitelisted paths.
      uRq.req.jsonApiPaths.length && // Return false if it doesn't apply any regular expression path.
      !!uRq.req.jsonApiPaths.find(p => new RegExp(p).test(parsed.pathname || '')); // Make sure that the JSON API entry point is also whitelisted.

      return parsed.pathname === '/' || pathIsWhitelisted;
    },

    proxyReqPathResolver(rq) {
      const thePath = _.get(url.parse(rq.url), 'path', '');

      return `${req.jsonApiPrefix}${thePath}`;
    },

    proxyReqBodyDecorator(bodyContent, srcReq) {
      if (['GET', 'HEAD', 'OPTIONS', 'TRACE'].indexOf(srcReq.method) !== -1) {
        return '';
      }

      if (typeof srcReq.headers['content-type'] === 'undefined') {
        logger.warn('The request body was ignored because the Content-Type header is not present.');
        return '';
      }

      return bodyContent;
    },

    proxyErrorHandler: (err, eRes, eNext) => errorHandler(err, req, eRes, eNext),

    userResHeaderDecorator(headers, userReq) {
      // Make sure to overwrite the cache control headers set by the CMS.
      const fakeRes = {
        set(k, v) {
          headers[k] = v;
        }

      };
      cacheControl(userReq, fakeRes, () => {});
      return headers;
    }

  };
  return proxy(req.cmsHost, options)(req, res, next);
};