karuppasamy / nyny

New York, New York - (very) small Sinatra clone.

New York, New York.

(very) small Sinatra clone.

# myapp.rb

require 'nyny'
class App < NYNY::App
  get '/' do
    'Hello world!'
  end
end

App.run!

Install the gem:

gem install nyny

Run the file:

ruby myapp.rb

Open the browser at http://localhost:9292

• TOP
• Motivation
• Philosophy
• Why use NYNY instead of Sinatra
• Usage
  • Running
  • Defining routes
  • Request scope
  • Filters
  • Middleware
  • Helpers
• FAQ
• Contributing

Motivation

My efforts to write NYNY started when I wanted to understand how Sinatra works, and stumbled upon the base.rb. The majority of the classes that are used by sinatra are in one single file, which makes it nearly impossible for a new person to grasp.

I wanted to understand how sinatra works, but the code was pretty challenging. So I decided I should re-implement the basic things Sinatra has. Thus, NYNY was born.

Philosophy

NYNY should have only the bare minimum to write basic web servers comfortably, everything else should be in a extension. It is also trivial to use NYNY to build large and complex apps, by writing multiple sub apps and using Rack to mount them, or by using those sub apps in the "main" app as middleware.

Why use NYNY instead of Sinatra

• It's very small (<300 LOC), which is just a little overhead on top of Rack.
• Sinatra is a drop-in replacement for NYNY. Anytime you feel that you need more, you can just change your app to inherit from Sinatra::Base, your code will still work, and you will be able to use any of the Sinatra features.
• It's ~2 times faster than Sinatra (see Performance for details)
• You want to dig into the source code and change to your needs (NYNY's source code is more welcoming)
• Each NYNY app is a Rack middleware, so it can be used inside of Sinatra, Rails, or any other Rack-based app.

Usage

A NYNY app must always be in a class which inherits from NYNY::App:

class App < NYNY::App
  get '/' do
    'Hello, World'
  end
end

Running

There are two ways to run a NYNY app directly [?]:

• by requiring it in a config.ru file, and then passing it as argument to the Rack's run function:

    # config.ru
    
    require 'app'
    run App.new
  

• by using the run! method directly on the app class:

    # app.rb
    
    # ...app class definition...
  
    App.run!
  

run! takes the port number as optional argument (the default port is 9292). Also the run! method will include 2 default middlewares to make the development easier: Rack::CommonLogger and Rack::ShowExceptions. This will show all requests in the log, and will provide useful details in the case a error occurs during a request.

Defining routes

NYNY supports the following verbs for defining a route: delete, get, head, options, patch, post, put and trace.

class App < NYNY::App
  post '/' do
    'You Posted, dude!'
  end
end

NYNY also suports basic URL patterns:

class App < NYNY::App
  get '/greet/:first_name/:last_name' do
    # the last expression in the block is _always_ considered the response body.
    "Hello #{params[:first_name]} #{params[:last_name]}!"
  end
end

you can also tell NYNY to match a regex for a path:

class App < NYNY::App
  get /html/ do
    'Your URL contains html!'
  end
end

Each block that is passed to a route definition is evaluated in the context of a request scope. See below what methods are available there.

Request scope

As was said above, when you pass a block to a route definition, that block is evaluated in the context of a RequestScope. This means that several methods/objects available inside that block:

• request - A Rack::Request object which encapsulates the request to that route. (see Rack::Request documentation for more info)
• params - a hash which contains both POST body params and GET querystring params.
• headers - allows you to read/add headers to the response (ex: headers 'Content-Type' => 'text/html')
• status - allows you to set the status of the response (ex: status 403)
• redirect_to - sets the response to redirect (ex: redirect_to 'http://google.com')
• cookies - a hash which allows you to access/modify/remove cookies (ex: cookies[:foo] = 'bar')
• session - a hash which allows you to access/modify/remove session variables (ex: session[:foo] = 'bar')
• halt - allows you to instantly return a response, interrupting current handler execution (see halt)

Filters

Unlike Sinatra, NYNY supports only "generic" before and after filters. This means that you can't declare a filter to execute depending on a URL pattern. However, you can obtain the same effect by calling next in a before block if the request.path matches a pattern.

class App < NYNY::App
  before do
    next unless /html/ =~ request.path
    headers 'Content-Type' => 'text/html'
  end

  after do
    puts response.inspect
  end

  get '/' do
    'hello'
  end
end

Before and after filters are also evaluated in a RequestScope context. A little exception are the after filters, which can access the response object (Rack::Response).

Middleware

A NYNY app is a Rack middleware, which means that it can be used inside Sinatra, Rails, or any other Rack-based app:

class MyApp < Sinatra::Base
  use MyNYNYApp
end

NYNY also supports middleware itself, and that means you can use Rack middleware (or a Sinatra app) inside a NYNY app:

class App < NYNY::App
  # this will serve all the files in the "public" folder
  use Rack::Static :url => ['public']
  use SinatraApp
end

I recommend looking at the list of Rack middlewares

Helpers

NYNY supports helpers as Sinatra does:

class App < NYNY::App
  helpers MyHelperModule
end

Using a helper implies that the helper module is included in the RequestScope, and that all the methods in that module will be available inside a route definition block.

F. A. Q.

TBD.

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request