Modifying the CloudFront Cache Key

control-cache-key.js

const crypto = require('crypto');

function hashText(input) {
    return crypto.createHash('md5').update(input).digest('hex');
}

function handler(event) {
    var request = event.request;
    var headers = request.headers;

    delete headers['username-cache-key'];

    if (headers['authorization']) {
        var authorizations = headers['authorization'].split(' ');
        if (authorizations.length === 2 && authorizations[0].toLowerCase() === 'basic') {
            var credentials = atob(authorizations[1]).split(':');
            
            headers['username-cache-key'] = { value: hashText(credentials[0]) };
        }
    }
    
    return request;
}