@edwardhotchkiss Subdomain port for Koa.js https://github.com/edwardhotchkiss/subdomain

subdomain-koa.js

function subdomain(options) {

    // options?
    options = options || {};

    if (!options.base) {
        throw new Error('options.base required!');
    } else {
        options.removeWWW = options.removeWWW || false;
        options.debug = options.debug || false;
        options.ignoreWWW = options.ignoreWWW || false;
        options.prefix = options.prefix || 'subdomain';
    };

    // return middleware
    return function*(next) {

        // get host & protocol
        var host = this.request.headers.host,
            protocol = this.request.socket.encrypted ? 'https' : 'http';

        // remove 'www' prefix from URL? (tacky, right?)
        if (options.removeWWW === true) {
            if (/^www/.test(host)) {
                return this.response.redirect(protocol + '://' + host.replace(/^www\./, '') + this.request.url);
            };
        };

        // subdomain specific middleware
        if (host === options.base || host === 'localhost:8000' || (options.ignoreWWW && /^www\./.test(host))) {
            // not a subdomain or ignoring www subdomain
            yield next;
        } else {
            // test for subdomain
            var matches = host.match(new RegExp('(.*)\.' + options.base));
            // subdomain
            if (matches && matches.length === 2) {
                this.request.url = '/' + options.prefix + '/' + matches[1] + this.request.url;
                yield next;
            } else {
                yield next;
            }
        };
    };

};
module.exports = subdomain;