Tracks

Tracks is a basic Controllers / Views framework written in Ruby and modeled after Ruby on Rails. ControllerBase implements the base controller class, and Router provides routing capabilities.

ControllerBase

Key Features

ControllerBase provides the following methods for descendent classes:

Method	Description
render(template_name)	Renders the file views/controller_name/template_name.html.erb into the application's main application.html.erb file.
render_content(content, content_type)	Renders content with the specified type
redirect_to(url)	Redirects to the specified URL
session	Maintains state across HTTP requests in a hash-like object
flash and flash.now	Similar to session but state is cleared after each request.
{before,after}_action	Specifies functions to run before/after the controller action. Use :only => [] and :except => options to limit them to specific actions.
protect_from_forgery	Protects against Cross-Site Request Forgery attacks. When enabled, a valid authenticity token must accompany all data submitted to the server.

You render the CSRF token into a hidden form field as follows:

<input type="hidden" name="authenticity_token"
  value="<%= form_authenticity_token %>">

Example Usage

In the example application controllers/gifs_controller.rb implements the application controller.

Its show and search actions do not explicitly render results, but instead rely on ControllerBase to automatically render the default namesake template when an action neither renders nor redirects.

require_relative '../lib/controller_base'

class GifsController < ControllerBase
  protect_from_forgery

  def show
    @gifs = request("trending", limit: 5, rating: "G")
  end

  def search
    @gifs = request("search", q: params[:keyword], limit: 10, rating: "G",
      lang: "en")
  end

  ...

end

Router

The Router maps urls to actions in custom controllers. For example,

require_relative 'lib/router'

router = Router.new
router.draw do
  get Regexp.new("^/$"), GifsController, :show
  post Regexp.new("^/search$"), GifsController, :search
end

The first argument is the HTTP action. Next is a regular expression to match against the request path. Lastly you specify the class name of the target controller and the action to invoke.

Tracks automatically extracts parameters from the URL query string and makes them available through the controller's params method. For convenience, params accepts both strings and symbols to identity parameters

If the route path regular expression contains named groups, Tracks also extracts the matching portions of the URL and makes them available in params.

Middleware

Tracks includes these Rack middlewares to serve static assets and to handle errors:

Name	Description
Static	Serves static assets from the /assets folder. When possible, it infers the MIME type from the file extension and otherwise serves plain text.
ShowExceptions	Renders detailed errors messages when the controller raises an exception. The message includes the file name, line number and a snippet of the surrounding code.

Putting it All Together

See demo_server.rb for an example entry file.

Running the Example app

The demo application displays trending GIFs of the day and allows you to search for GIFs by keyword. To run it you need up-to-date versions of Ruby and Bundler.

1. git clone https://github.com/dextersealy/ruby-on-tracks
2. bundle install
3. ruby demo_server.rb
4. Visit http://localhost:3000

License

Tracks Copyright (c) Dexter Sealy

Tracks is free software; you can distribute it and/or modify it subject to the terms of the MIT license.