Simple rails rate limiter

rate_limit.rb

require 'redis'
require 'digest'

class RateLimit
  def initialize(app)
    @app = app
  end

  def call(env)
    redis = Redis.new
    timeout_seconds = 2
    post_body = env['rack.input'].read
    env['rack.input'].rewind

    fingerprint_elements = [ env["ORIGINAL_FULLPATH"], env["REMOTE_ADDR"], env["REQUEST_METHOD"], post_body ]
    fingerprint = Digest::SHA2.hexdigest(fingerprint_elements.join(""))

    if redis.get(fingerprint)
      return [429, { 'Content-Type' => 'text/html' }, [ "Too Many Requests" ]]
    else
      redis.setex(fingerprint, timeout_seconds, 1)
      @app.call(env)
    end
  end
end