Crystal router 2.0

app.cr

require "./router.cr"

server = HTTP::Server.new(Router.new)
server.bind_tcp "127.0.0.1", 8080
server.listen

router.cr

require "http/server"

class Router
  include HTTP::Handler

  macro route(a, b, c = " ", d = "text/plain")
  if method == {{a}} &&
     path == "/{{b}}"
    context.response.content_type = {{d}}
    {{b}}
    context.response.print {{c}}
    context.response.close
end
end

  def initialize
  end

  def app
    puts "Never fear, app is here"
  end

  def call(context)
    method = context.request.method
    path = context.request.path

    route "GET", app, "Hello World!"

    context.response.respond_with_status(500)
  end
end

1. I'm starting up the server
2. All routes are managed by one macro.
3. The macro executes the code of the same method as the path and then stops executing further code.
4. If the route is not specified, the server returns error code 500.