nodest

Minimalist framework on top of koa, inspired by nodal.

• Simple application spinup
• Express-style routing to controllers.
• Controllers for API and templated HTML.
• Controller support for callbacks and generators.
• JSON configuration.
• Logging.
• Multiple HTTP services.
• Multiple routers.

Status

Currently alpha, functionally complete, tests being written.

Installation

Install using npm:

$ npm install nodest

Basic Usage

The following demonstrates a simple, HelloWorld Nodest app.

const Nodest = require("nodest");
 
class Controller extends Nodest.Controller {
    index() {
        this.ctx.body = "HelloWorld";
    }
}
 
class App extends Nodest.Application {
    init() {
        this.route("/", Controller);
    }
}
 
new Nodest.Bootstrapper(App).start((app) => { app.listen(3000) });

Using ES6 class syntax, a class derived from Nodest.Application is defined. It's init() method is overriden to define a route for "/" to a class derived from Nodest.Controller. The controller override method index which will be called automatically when the route is matched on the request. The index() method uses Koa's context to set the body of the response. The Nodest.Bootstrapper is used to start the app on port 3000.

Typical Usage

Clone the following bootstrap repositories for typical usage scenarios:

Bootstrap Web App https://github.com/davideweaver/nodest-bootstrap-web

Bootstrap REST API App https://github.com/davideweaver/nodest-bootstrap-rest

Nodest and Koa

One of the goals for Nodest was to provide a very minimal layer around Koa. Nodest provides Koa access points so that you can use the Koa classes as you normally would but in a slightly more organized (in our opinion) way. Nodest accomplishes that by defining small wrapper classes around the Koa classes.

The Nodest.Application class has a .koa property that represents the Koa.Application class. The Nodest.Controller classes have a .ctx property that represents the Koa.Context class. Using these properties you can configure your app and respond to HTTP requests like you would normally do in Koa.

As seen in the basic example above, we use the .ctx property of our controller to respond to the HTTP request with "HelloWorld".

Reference Classes in Separate Files

The basic usage example above references the App and Controller classes directly. You could also import the classes from another file. Nodest also supports a shortcut for referencing those classes. You can reference the App or Controllers exported from another file using a path instead of a class reference. This lets you organize your project by breaking up classes into separate files, yet reduces the amount of code required to do so. For example, create a new file...

controller.js

const Nodest = require("nodest");
 
class Controller extends Nodest.Controller {
    index() {
        this.ctx.body = "HelloWorld";
    }
}
 
module.exports = Controller;

and reference like...

const Controller = require("./controller.js");
...
this.route("/", Controller)

or simply...

this.route("/", "./controller.js")

Controllers

Nodest.Controllers are your primary way of interacting with HTTP requests. Just create a route in you application that points to a controller. When a request comes in with a path matching your route, your controller will be created and called.

As shown in the basic usage example, you can override the index() method of your controller and interact with the Koa.Context class. Nodest also provides some built-in functionality that may make your job a little easier.

const Nodest = require("nodest");
 
class Controller extends Nodest.Controller {
    index() {
        this.ctx.body = "HelloWorld";
    }
}
 
module.exports = Controller;

Controller Types

Nodest provides two controller base classes. The main controller class that you derive your controllers from is Nodest.Controller. Use Nodest.Controller as a general way of returning HTML to the client.

There is also the Nodest.ApiController class that should be used for implementing API-style responses, typically using JSON to respond to a non-browser client. This controller will handle things slightly different if it knows the client is not a browser. For example, errors that are thrown will be formatted as a JSON message instead of HTML content.

Response Helpers

As mentioned before, you are free to use the .ctx property to respond to the HTTP request. Nodest also has some methods to respond to requests.

HTML Rendering with Templates

Nodest makes it pretty easy to render HTML using HTML templates. This example won't go into the details of how templates work (see HTML Templating), but it will show a useful example.

The .render() method sends back HTML to the client, similar to this.ctx.body = "HelloWorld";. This example uses the .template() method to load and generate HTML from *.html files. Shown here is a hierarchy of templates, referenced in the template as .child().

class ExampleController extends Nodest.Controller {
  index() {
    this.render(
      this.template("layout.html", "index.html")
        .generate({
          title: "My Page",
          body: "This is my first post"
        })
    );
  }
}

layout.html

<!DOCTYPE html>
<html>
  <head>
    <title>{{=data.title}}</title>
  </head>
  <body>
    <div class="container">
      {{=this.child()}}
    </div>
  </body>
</html>

index.html

<div>
  <h1>{{=data.title}}</h1>
  <p>{{=data.body}}</p>
</div>

JSON Responses

If your controller is handling an API-style request you'll want to send back JSON. Use the respond() method for doing that and it will serialize correctly with the appropriate Content-Type. Notice we are using the Nodest.ApiControllerclass.

class ExampleController extends Nodest.ApiController {
  get() {
    this.respond({
      id: 102,
      name: "Joe Smith",
      email: "[e-mail]"	
    });
  }
}

Mapped Controller Methods

Nodest will attempt to map the current HTTP Method to methods of your controller class. For example, when a request is received with the GET method, the index() method will be called on your controller. If a DELETE method is received the del() method will be called.

NOTE In addition to Method mapping, the route will be inspected for the :id token. If the :id token exists in your route and resolved in the current request, the method called on your controller will be different.

HTTP METHOD	:id Resolved	Controller Method
GET	No	Controller.index()
GET	Yes	Controller.get()
POST	No	Controller.post()
POST	Yes	Controller.post()
PUT	No	Controller.put()
PUT	Yes	Controller.update()
DELETE	No	Controller.del()
DELETE	Yes	Controller.del()

If the :id token is resolved then the value for that id can be found in the this.vars.params.id property of the controller. Here is a complete REST-style example using mapped methods.

Be sure to register your API controller using the :id argument so Nodest knows how to parse it. The ? trailing the route means the :id argument is optional. This is important, otherwise calls to this controller will not be found unless the id is passed.

// register controller
this.route("/contacts/:id?", "./contacts.controller.js");

Now the controller. Notice the * before each method. This example uses ES6 generators to allow us to yield on our async Contacts API.

const Contacts = require("./lib/contacts.es6");
 
class ContactsController extends Nodest.ApiController {
    
  * index() {
    this.respond(yield Contacts.all());
  }
    
  * get() {
    this.respond(yield Contacts.find(this.vars.params.id));
  }
    
  * post() {
    var contact = Contacts.fromBody(this.ctx);
    this.respondWithStatus(yield Contacts.add(contact), 201);
  }
    
  * update() {
    var contact = Contacts.fromBody(this.ctx);
    this.respondWithStatus(yield Contacts.update(this.vars.params.id, contact), 200);
  }
    
  * del() {
    yield Contacts.del(this.vars.params.id));
    this.respondWithNoContent();
  }
}

Async Controller Methods

As you can see in the previous example, we use ES6 Generators to handle responses using our async Contacts API. By adding the * in front of our built-in methods, Nodest knows how to call them. Nodest also supports traditional callback-style APIs. Just provide a next argument in the built-in methods like this example.

const Contacts = require("./lib/contacts");
 
class ContactsController extends Nodest.ApiController {
  index(next) {
    this.respond(Contacts.all(next));
  }
}

Routes

Routing in Nodest is handled by the routes module. It's pretty similar to routes in Express.

this.route("/articles/:title?", ArticleController);
this.route("/admin/*?", auth);
this.route("/:controller/:action/:id.:format?", GenericController);

Besides routing the request to the correct controller, these routes will create two collections under the Controller.vars property. One collection will be .vars.params which will contain each token and it's corresponding value. The other collection will be .vars.splats which is an array of values matching the wildcard portion of the route.

Using the routes defined above, /posts/show/1.json would result in...

{
  params: {
    controller: 'posts',
    action: 'show',
    id: '1',
    format: 'json'
  },
  splats: []
}

And /admin/reports would result in...

{
  params: {},
  splats: [ "reports" ]
}

See https://www.npmjs.com/package/routes for more information on routing.

Middleware

Nodest takes the same approach for middleware as it does for the controllers. You can use our light-weight wrappers for setting up your middleware, or you can do it directly with Koa.

Write Your Own Middleware

To write your own custom logic as middleware you simply have to write a class derived from the Nodest.Middleware class. Your class can handle the HTTP request as it comes in and/or handle the HTTP response on it's way out. Below is an example of a class doing both.

class TimerMiddleware extends Nodest.Middleware {
  in() {
    this.start = new Date().getTime();	
  }
  out() {
    var ms = new Date().getTime() - this.start;
    this.ctx.set('X-Response-Time', ms + 'ms');
  }	
}

This will start a timer when the request is received and record the duration in a custom header on the way out. You can implement one or both of the base methods.

Register your middleware class in the init() routine of you application with Application.use().

class App extends Nodest.Application {  
  init() {
    this.use("./timer.middleware.js");
  }
}

Use Koa Middleware

Nodest makes it pretty simple to load pre-built Koa middleware from npm. Derive your middleware class as you did previously. This time implement the use() method instead of in() and out(). Have that method return an array of your require'd modules.

const KoaBodyParser = require("koa-body-parser");
const KoaCors = require("kcors");
 
class TimerMiddleware extends Nodest.Middleware {
  use() {
    return [ KoaBodyParser(), KoaCors() ];
  }
}

Register this the same way you registered your custom middleware class.

NOTE You can also use the .koa property of your application class to register Koa middleware.

this.koa.use(KoaStaticFolder("./static"));

Example: Serve Static Content with Koa Middleware

It's pretty common to want to serve static files like images or stylesheets from your app. That's can be done pretty easily using koa-static-folder middleware. Use npm to install the module first. Then create your middleware class...

static.middleware.js

const Nodest = require("nodest");
const KoaStaticFolder = require("koa-static-folder");
 
class StaticMiddleware extends Nodest.Middleware {
  use() {
    return [ KoaStaticFolder("./static") ];
  }
}
 
module.exports = StaticMiddleware;

app.js

const Nodest = require("nodest");
 
class App extends Nodest.Application {  
  init() {
    this.use("./static.middleware.js");
  }
}

That will allow your HTML files to reference static content under the /static folder of your root. For example...

<a href="/"><img src="/static/images/logo.png" /></a>

Error Handling

TDB

HTML Templates

TBD

Configuration

Nodest supports configuration using the config module. Just create a config directory at the root of your application and create a file in there. This file contains JSON that can be easily referenced from within your app.

config/default.json

{
  "server": {
    "port": 3000,
    "static": "./static",
    "verbose": true
  }
}

From within your app you have access to that configuration using the Nodest namespace.

const Nodest = require("nodest");
...
app.listen(Nodest.config.server.port);

You can also override your config for your production environment.

config/production.json

{
  "server": {
    "port": 80,
    "verbose": false
  }
}

Use the NODE_ENV environment variable to control which configuration gets loaded.

$ export NODE_ENV=production
$ node index.js

Now when you access those variables from within your app, "port" and "verbose" have a new value while remains "static" unchanged.

Logging

Nodest provides a simple logging mechanism. The App and Controller base classes each contain a .log property that you can use.

app.log("simple logging");

This will produce the following line on the console.

3 Feb 08:00:04 - [app] [info] simple logging

You'll notice the message is logged with the time, scope (app) and channel (info). You have finer control of your log messages. The call above logs your message to the info channel. You can specify the channel you want to log to by calling a different function.

app.log.info("this is information");
app.log.debug("for debug messages"); // controlled by Nodest.settings.verbose
app.log.warn("you're getting too close");
app.log.error("something bad happened");

You're also able to control the scope your messages will use by scoping the log function. There are a couple ways you'll want to use scoping. The long way is to do it inline.

Nodest.Log.scoped("mycode").warn("this is a warning");

As a shortcut, define your scoped log as a variable.

var log = Nodest.Log.scoped("mycode");
log("this is info");
log.warn("this is a warning");

This will produce...

3 Feb 08:00:04 - [mycode] [info] this is info
3 Feb 08:00:04 - [mycode] [warn] this is a warning

Settings

You can change the default behavior of certain Nodest features by applying different settings. This is typically done before bootstrapping your application. Here is the current list of settings.

{
  verbose: false, // show debug logging
  errors: {
    expose: false // show detailed errors
  },
  service: {
    templates: {
      cache: true // cache HTML templates
    }
  }
}

To override the defaults, prior to bootstrapping the app...

Nodest.applySettings({
  verbose: true
});
...
new Nodest.Bootstrapper(App).start((app) => { app.listen(3000) });

Contributing

Please submit all issues and pull requests to the davideweaver/nodest repository!

Tests

Run tests using npm test. (not available yet)

Support

If you have any problem or suggestion please open an issue here.