EPS Web Framework

An oppinionated reactive server side web framework for node.js based off of RxJS.

Install

Clone the repo to a destination of your choice:

git clone git@github.com:WarpcoreLabs/eps.git

Install the dependencies:

npm install

Fire the bass cannon:

npm start

Pick up your loot at http://localhost:3000

The basics

EPS is part framework part lego kit. It gives you lots of powerful components to snap together and you can choose to create or replace whatever components you see fit.

A basic setup starts with a master process spawning, monitoring and reviving worker processes. The worker processes spin up HTTP servers and compose a set of request handling components together known as root middleware. At the end of the root middleware composition there is a responseConsumer subscribed too it that takes responses and sends them to the client.

This basic setup typically lives in your src/main.js file and will look something like the following:

var cluster             = require("cluster");
var os                  = require("os");
var RxHttpServer        = require("rx-http-server");
var requestLogger       = require("./middleware/root/request-logger");
var less                = require("./middleware/root/less");
var staticFiles         = require("./middleware/root/static-files");
var services            = require("./middleware/root/services");
var cookieReader        = require("./middleware/root/cookie/reader");
var cookieWriter        = require("./middleware/root/cookie/writer");
var flashSessionReader  = require("./middleware/root/flash-session/reader");
var flashSessionWriter  = require("./middleware/root/flash-session/writer");
var signedSessionReader = require("./middleware/root/signed-session/reader");
var signedSessionWriter = require("./middleware/root/signed-session/writer");
var router              = require("./middleware/root/router");

var cpus       = os.cpus().length;
var server     = new RxHttpServer();
var lessPath   = path.join(__dirname, "public/css/main.less");
var publicPath = path.join(__dirname, "public");

if (cluster.isMaster) {
    for (var i = 0; i < cpus; i++) {
        cluster.fork();
    }
    cluster.on("exit", function(worker, code, signal) {
        logger.error(new WorkerDiedAction(worker));
        cluster.fork();
    });
} else {
    server
        .requests
        .flatMap(services)
        .flatMap(requestLogger)
        .flatMap(less("/public/css/main.css", lessPath))
        .flatMap(staticFiles("/public", publicPath))
        .flatMap(cookieReader)
        .flatMap(flashSessionReader)
        .flatMap(signedSessionReader("Why is a raven like a writing desk?"))
        .flatMap(router)
        .flatMap(signedSessionWriter("Why is a raven like a writing desk?"))
        .flatMap(flashSessionWriter)
        .flatMap(cookieWriter)
        .subscribe(responseConsumer);
    server.listen(3000);
}

Likewise, each controller is a composition of components. The actual controller action is preceded by an optional and custom preAction pipeline and followed by another optional and custom postAction pipeline.

A simple example that makes sure a user is unauthenticated and grabs the template service in the preAction pipeline and does etag cache checking in the postAction pipeline would look something like this:

var Rx              = require("rx");
var handler         = require("rx-request-handler");
var OkResponse      = require("responses/response/ok");
var response        = require("../util/response");
var unauthenticated = require("../middleware/controller/pre/unauthenticated");
var requireService  = require("../middleware/controller/pre/require-service");
var etagHit         = require("../middleware/controller/post/etag-hit");
var etagResponse    = require("../middleware/controller/post/etag-response");

module.exports = handler({

    preAction: function(observable) {
        return observable
            .flatMap(unauthenticated)
            .flatMap(requireService("templates"));
    },

    action: function(data) {
        return response(OkResponse, data, function() {
            return data.services.templates("index.jade");
        });
    },

    postAction: function(observables) {
        return observables
            .flatMap(etagHit)
            .flatMap(etagResponse);
    }

});