prerender lambda@edge

origin-response.js

'use strict';
const https = require('https');
const BASE_URL_RENDERER = 'YOUR_PRERENDER_SERVER?url=';

exports.handler = (event, context, callback) => {
    const request = event.Records[0].cf.request;
    const response = event.Records[0].cf.response;
    const headers = response.headers;


    const SHOULD_PRERENDER = request.headers['x-should-prerender'][0].value === 'true';
    const PRERENDER_URL = request.headers['x-prerender-uri'][0].value;

    if (SHOULD_PRERENDER && PRERENDER_URL) {
        const URL = BASE_URL_RENDERER + PRERENDER_URL;

        downloadContent(URL, (body) => {
            callback(null, {
                status: '200',
                statusDescription: 'OK',
                headers: response.headers,
                body
            });

        });
    } else {
        callback(null, response);
    }
};


const downloadContent = function (url, callback) {
    https
        .get(url, function (res) {
            var body = '';

            res.on('data', function (chunk) {
                body += chunk.toString();
            });

            res.on('end', function () {
                callback(body, null);
            });
        })
        .on('error', function (e) {
            callback(null, e);
        });
};