Host Wildcard Subdomain in One S3 Bucket https://blackbing.medium.com/host-wildcard-subdomain-in-one-s3-bucket-with-lambda-edge-979c7cb282dc

Host-Wildcard-Subdomain-in-One-S3-Bucket-viewer-request.js

exports.handler = (event, context, callback) => {
    const request = event.Records[0].cf.request;
    const headers = request.headers;
    
    const host = headers.host[0].value;
    const hash = /([0-9a-z-]+)\.m\.verybuy\.io/.exec(host)
    
    if (hash && hash[1]) {
        headers['X-Domain-Hash'] = [{
            key: "X-Domain-Hash",
            value: hash[1],
        }];
    }
    
    callback(null, request);
};