Lambda edge logic to determine what dash manifest

multi-codec-lambda-edge-logic.js

'use strict';

const https = require('https');

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

    console.log('Request: ', request);
    console.log('Requested URI: ', uri);

    console.log('Requested origin HEADERS: ', headers);

    if (headers['x-supported-codecs-list'] && headers['x-supported-codecs-list'].length > 0 && headers['x-supported-codecs-list'][0].value.includes("hevc")) {
        var masterUri = request.uri;
        const cache_host =  'https://s3via.cloudfront.net';
        const cacheUrl =  cache_host + masterUri.replace('master.mpd', 'master-hevc.mpd');
        https.get(cacheUrl, (res) => {
            if (res.statusCode === 200) {
                request.uri = masterUri.replace('master.mpd', 'master-hevc.mpd');
                console.log(`Request uri set to "${request.uri}"`);
                callback(null, request);
            } else {
                callback(null, request);
            }
        }).on("error", (err) => {
            console.log("Error: " + err.message);
            callback(null, request);
        });
    } else {
        var masterUri = request.uri;
        const cache_host =  'https://s3via.cloudfront.net';
        const cacheUrl =  cache_host + masterUri.replace('master.mpd', 'master-avc-hevc.mpd');
        https.get(cacheUrl, (res) => {
            if (res.statusCode === 200) {
                request.uri = masterUri.replace('master.mpd', 'master-avc-hevc.mpd');
                console.log(`Request uri set to "${request.uri}"`);
                callback(null, request);
            } else {
                callback(null, request);
            }
        }).on("error", (err) => {
            console.log("Error: " + err.message);
            callback(null, request);
        });
    }
};