Grip

Class oriented fork of the Kemal framework based on a JSON request/response model with a CRUDish look.

Currently Grip is headed towards a JSON request/response type interface, which makes this framework non-HTML friendly, it is still possible to render HTML but it is not advised to use Grip for that purpose.

So far at 158,762 requests/second, and still going.

Super Simple ⚡️

require "grip"
require "uuid" # Needed for the random UUID generation

class IndexHttpConsumer < Grip::HttpConsumer
  def create(req)
    res(
      HTTP::Status::OK, # The status code is a mix of a built-in and an integer.
      {
        "id": "#{UUID.random}"
      }
    )
  end

  def read(req)
    # By default the response code is 200, this format of content conversion is okay
    # since it gets converted to json by the router.
    {
      "id": "#{UUID.random}"
    }
  end

  def update(req)
    res(
      HTTP::Status::OK,
      {
        "id": "#{UUID.random}"
      }
    )
  end

  def delete(req)
    res(
      HTTP::Status::OK,
      {
        "id": "#{UUID.random}"
      }
    )
  end
end

class IndexedHttpConsumer < Grip::HttpConsumer
  def read(req)
    res(
      HTTP::Status::OK,
      "Hello, World!"
    )
  end
end

class EchoWebSocketConsumer < Grip::WebSocketConsumer
  def on_message(req, message)
    puts url # This gets the hash instance of the route url specified variables
    puts headers # This gets the http headers

    if message == "close"
      close "Received a 'close' message, closing the connection!" # This closes the connection
    end

    send message
  end

  def on_close(req, message)
    puts message
  end
end

# This gets executed before * (all) routes, the scope can be changed to a specific route
before_all "*" do |req|
  req.response.headers.merge!({"btag" => UUID.random.to_s})
end

# This gets executed after * (all) routes, the scope can be changed to a specific route
after_all "*" do |req|
  req.response.headers.merge!({"atag" => UUID.random.to_s})
end

# Add the handlers to the handler list

add_handlers(
  {
    # Http consumers
    IndexHttpConsumer => "/",
    IndexedHttpConsumer => "/:id",

    # WebSocket consumers
    EchoWebSocketConsumer => "/:id"
  }
)

# Run the server
Grip.run

The default port of the application is 3000, you can set it by either compiling it and providing a -p flag or by changing it from the source code.

Start your application!

If you want logging to show up in the stdout put this line right above the Grip.run in your source code.

logging true # Keep in mind that logging slows down the server since it is an IO bound operation

Installation

Add this to your application's shard.yml:

dependencies:
  grip:
    github: grkek/grip

Features

• Support all REST verbs
• Websocket support
• Request/Response context, easy parameter handling
• Middleware support
• Built-in JSON support

Documentation

• For the framework development just use the crystal docs feature and browse through the module.
• Check out the official documentation available here

Thanks

Thanks to Manas for their awesome work on Frank.

Thanks to Serdar for the awesome work on Kemal.

Thanks to the official gitter chat of the Crystal programming language.