host-identification-lambda.js

'use strict';
exports.handler = (event, context, callback) => {
    
    console.log(JSON.stringify(event.Records[0].cf));
    
    var request = event.Records[0].cf.request
     
    var host = request.headers.host[0].value;

    var uri = request.uri;
    
    request.uri = '/' + host + uri;
    
    console.log('new uri', request.uri)
    
    // Return to CloudFront
    return callback(null, request);

};