gistfile1.txt

import connect from 'connect';

class ErrEmpty extends Error {
    constructor() {
        super()
        this.message = 'Empty string';
    }
}

class StringService {
    uppercase(s) {
        if (typeof s !== 'string' || !s.length) {
            throw new ErrEmpty();
        }
        return s.toUpperCase();
    }

    count(s) {
        return s.length;
    }
}

const toSvcArgs = (data) => { s: data.s };
const fromSvcResults = (err, val="") => { v: val, err };

const makeUppercaseEndpoint = svc => function(ctx, req) {
    var params = toSvcArgs(req);
    var svcRes, err = null;
    try {
        svcRes = svc.uppercase(params.s);
    catch (err_) {
        err = err_;
    }
    return fromSvcResults(err, svcRes);
};

const makeCountEndpoint = svc => function(ctx, req) {
    var params = toSvcArgs(req);
    var v = svc.count(params.s);
    return fromSvcResults(null, v);
};

class Controller {
    constructor(ctx, e, dec, enc, ...options) {
        this.ctx = ctx;
        this.endpoint = e;
        this.decode = dec,
        this.encode = enc;
        // @todo: process options
    }

    handle(req_, res_) {
        //var ctx = new Context(this.ctx);
        var req = this.decode(req_);
        // @todo Error handeling
        var results = this.endpoint(ctx, req);
        return this.encode(res_, results);
    }
}

// app.js

const decodeReq = req => req.body;
const encodeRes = (res, data) => res.end(JSON.stringify(data));

const app = connect(function(req, res) {
    var ctx = new Map();
    const svc = new StringService();

    const uppercaseCtrl = new Controller(
        ctx,
        makeUppercaseEndpoint(svc),
        decodeReq,
        encodeRes
    );

    const countCtrl = new Controller(
        ctx,
        makeCountEndpoint(srv),
        decodeReq,
        encodeRes
    );

    switch (req.url) {

    case '/uppercase': 
        uppercaseCtrl.handle(req, res);
        break;

    case '/count':
        countCtrl.handle(req, res);
        break;
    
    }
});

app.listen(3001, () => console.log('Server is here!'));

See https://github.com/narqo/node-mcro