Motivation / Background

Prior to this commit, :by and :with options only supported callables. This commit aims to bring rate limiting closer in parity to callbacks declarations like before_action and after_action by supporting instance method names as well.

Without this change, multi-line customized callables can make declarations difficult to read. Similarly, shared customization would require a local variable to be re-used. For example:

rate_limiting_bucket = -> { ... }
rate_limit to: 3, within: 1.minutes, by: rate_limiting_bucket
rate_limit to: 10, within: 5.minutes, by: rate_limiting_bucket
rate_limit to: 30, within: 10.minutes,
  by: -> {
    # ...
    # multiple lines
    # ...
  }, 
  with: -> {
    # ...
    # multiple lines
    # ...
  }

Detail

After this change, method names can be used and shared:

rate_limit to: 3, within: 1.minutes, by: :rate_limiting_bucket
rate_limit to: 10, within: 5.minutes, by: :rate_limiting_bucket
rate_limit to: 30, within: 10.minutes, by: :rate_limiting_bucket, with: :rate_limit_exceeded
private
  def rate_limiting_bucket
    # ...
    # multiple lines
    # ...
  end
  def rate_limit_exceeded
    # ...
    # multiple lines
    # ...
  end

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Unrelated changes should be opened in separate PRs.
• Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• Tests are added or updated if you fix a bug or add a feature.
• CHANGELOG files are updated for the changed libraries if there is a behavior change or additional feature. Minor bug fixes and documentation changes should not be included.