# File actionpack/lib/action_dispatch/http/content_security_policy.rb, line 30
def initialize(app)
  @app = app
end

# File actionpack/lib/action_dispatch/http/content_security_policy.rb, line 34
def call(env)
  status, headers, _ = response = @app.call(env)

  # Returning CSP headers with a 304 Not Modified is harmful, since nonces in the
  # new CSP headers might not match nonces in the cached HTML.
  return response if status == 304

  return response if policy_present?(headers)

  request = ActionDispatch::Request.new env

  if policy = request.content_security_policy
    nonce = request.content_security_policy_nonce
    nonce_directives = request.content_security_policy_nonce_directives
    context = request.controller_instance || request
    headers[header_name(request)] = policy.build(context, nonce, nonce_directives)
  end

  response
end