Class: Vernier::Middleware

Inherits:
Object
  • Object
show all
Defined in:
lib/vernier/middleware.rb

Instance Method Summary collapse

Constructor Details

#initialize(app, permit: ->(_env) { true }) ⇒ Middleware

Returns a new instance of Middleware.



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# File 'lib/vernier/middleware.rb', line 3

def initialize(app, permit: ->(_env) { true })
  @app = app
  @permit = permit
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/vernier/middleware.rb', line 8

def call(env)
  request = Rack::Request.new(env)
  return @app.call(env) unless request.GET.has_key?("vernier")

  permitted = @permit.call(request)
  return @app.call(env) unless permitted

  interval = request.GET.fetch("vernier_interval", 200).to_i
  allocation_interval = request.GET.fetch("vernier_allocation_interval", 200).to_i

  result = Vernier.trace(interval:, allocation_interval:, hooks: [:rails]) do
    @app.call(env)
  end
  body = result.to_firefox(gzip: true)
  filename = "#{request.path.gsub("/", "_")}_#{DateTime.now.strftime("%Y-%m-%d-%H-%M-%S")}.vernier.json.gz"
  headers = {
    "Content-Type" => "application/octet-stream",
    "Content-Disposition" => "attachment; filename=\"#{filename}\"",
    "Content-Length" => body.bytesize.to_s
  }

  Rack::Response.new(body, 200, headers).finish
end