ITTT trigger responder

config.ru

require_relative 'environment'

app = Server.new do
  trigger :turn_on_lightbulb do
    # Make an API request...
    Net::HTTP.post_form(URI('http://lightbulb.local'), 'status' => 'on')
    
    # Response (any JSON-like data)
    { light_bulb: "on" }
  end
  
  # Etc.
  trigger :set_ludicrous_speed do |params|
    Net::HTTP.post_form(URI('http://tesla.local'), 'ludicrous' => params[:value])
    
    { ludicrous_mode: "is now #{params[:value]}" }
  end
end

run app

environment.rb

require 'rack/request'
require 'net/http'
require 'securerandom'
require 'json'

class Trigger
  def initialize(name, &block)
    @name, @block = name, block
  end

  def response_for(request)
    request_params = JSON.parse(request.body, symbolize_names: true)
    body = JSON.generate(data: data_for(request_params))
    
    [200, Response::JSON_HEADERS, [body]]
  end
  
  def data_for(params)
    @block.call(params).merge(
      meta: {
        id: SecureRandom.uuid,
        timestamp: Time.now.to_i
      }
    )
  end
end

class Response
  TRIGGER_SLUG_PATTERN = %r{/ifttt/v1/triggers/([^/]+?)}
  JSON_HEADERS = { 'Content-Type' => 'application/json; charset=utf-8' }
  
  def initialize(server, request)
    @server, @request = server, request
  end

  def resolve
    response_from_trigger || not_found
  end

  def request_data
    JSON.parse(@request.body, symbolize_names: true)
  end

  def trigger_slug
    @trigger_slug ||= @request.path[TRIGGER_SLUG_PATTERN]&.to_sym
  end

  def response_from_trigger
    matching_trigger&.response_for(request)
  end

  def matching_trigger
    @server.triggers.find { |trigger| trigger.name == trigger_slug }
  end

  def not_found
    [404, {}, ["Not found"]]
  end
end

class Server
  def initialize(&block)
    @triggers = []
    instance_eval(&block)
  end

  def trigger(name, &block)
    @trigger << Trigger.new(name, &block)
  end

  def call(env)
    request = Rack::Request.new(env)
    Response.new(request).resolve
  end
end