DSL for rulesets

[boardfish]

When writing up this feature request for Rails, I realized what the ruleset DSL could look like:

# config/ruleset/stripe/js.rb
# Ruleset for Stripe's JS library.
ruleset do
  connect_src 'https://api.stripe.com'
  frame_src 'https://js.stripe.com', 'https://hooks.stripe.com'
  script_src 'https://js.stripe.com'
  other_src 'https://example.com'
  # A common problem is that some rules are environment-specific.
  group :development do
    other_src 'https://example2.com'
  end
end

Remaining questions I have around this are:

• What if an entire ruleset should only load in development?
• What about lambda conditions for groups?

In order to implement this, we'll need to support the same declaration being fired multiple times as compounding on the same rule, so:

  other_src 'https://example.com'
  # A common problem is that some rules are environment-specific.
  group :development do
    other_src 'https://example2.com'
  end

would result in:

other-src: https://example.com, https://example2.com