Grip

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

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 93657 requests/second per instance, and still going.

Super Simple ⚡️

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

class Index < Grip::HttpConsumer
  # Only match the route / and methods defined below
  route "/", ["GET", "POST", "PUT", "PATCH", "DELETE", "OPTIONS"]

  def get(env)
    # Render the content, the default content type is JSON
    {:ok, {"body": "Hello, GET!"}}
  end

  def post(env)
    {:created, {"content" => "Hello, POST!"}}
  end

  def put(env)
    {200, "Something interesting happened"}
  end

  def patch(env)
    {201, {"is_it_real": true}}
  end

  def delete(env)
    {:OK, {"size": 404.404}}
  end

  def options(env)
    {:CREATED, {"body": "Hello, OPTIONS!"}}
  end
end

class Indexed < Grip::HttpConsumer
  route "/:id", ["GET"]

  def get(env)
    puts json?(env) # Get the JSON parameters which are sent to the server
    puts query?(env) # Get the query parameters which are sent to the server
    puts url?(env) # Get the url specified parameters like the :id which are sent to the server
    puts headers?(env) # Get the headers which are sent to the server

    # Set headers via two different methods
    headers(env, "Host", "github.com")
    headers(env, 
            {
              "X-Custom-Header" => "This is a custom value",
              "X-Custom-Header-Two" => "This is a custom value"
            }
    )
    
    {:ok, {"body": "Hello, #{url?(env)["id"]}!"}}
  end
end

class Echo < Grip::WebSocketConsumer
  route "/:id" # The routing is based on the kemal router which supports the same routing powers.

  def on_message(env, message)
    puts url?(env) # This gets the hash instance of the route url specified variables
    puts headers?(env) # 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(env, message)
    puts message
  end
end

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

# Add the handlers to the handler list
add_handlers [Index, Indexed, Echo]

# Add the default routers to the stack
Grip.config.add_router Grip::HttpRouteHandler::INSTANCE
Grip.config.add_router Grip::WebSocketRouteHandler::INSTANCE

# 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.