Using MiniProfiler in production on Heroku

application_controller.rb

# app/controllers/application_controller.rb
class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception
  before_filter :miniprofiler

  # just authorize all requests
  private
  def miniprofiler
    Rack::MiniProfiler.authorize_request
  end
end

Gemfile

# it's best to depend on trunk of MiniProfiler, e.g. due to the issue I had with
# graphs not showing up over HTTPS which is fixed in
# https://github.com/SamSaffron/MiniProfiler/commit/831b917e70d57bc3c03858c46b3c5828f73e3f35
gem 'rack-mini-profiler',         git: 'git://github.com/SamSaffron/MiniProfiler.git'

mini_profiler.rb

# config/initializers/mini_profiler.rb

# Heroku + Unicorn will not work with either:
# FileStore (no persistent disk access allowed)
# MemoryStore (data kept in one process, but Unicorn forks multiple processes)
# Easiest to use is therefore MemcacheStore. RedisStore requires more setup. 
if Rails.env.production?
  Rack::MiniProfiler.config.storage = Rack::MiniProfiler::MemcacheStore
  
  # optional: set a user_provider which defaults to always the same user 
  # by default MiniProfiler separates requests by IP address
  # Rack::MiniProfiler.config.user_provider = Proc.new { |env| "tom" }
end