Class: Philiprehberger::Debounce::RateLimiter

Inherits:
Object
  • Object
show all
Defined in:
lib/philiprehberger/debounce/rate_limiter.rb

Overview

Sliding window rate limiter.

Instance Method Summary collapse

Constructor Details

#initialize(limit:, window:) ⇒ RateLimiter

Returns a new instance of RateLimiter.

Raises:

  • (ArgumentError) 


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# File 'lib/philiprehberger/debounce/rate_limiter.rb', line 7

def initialize(limit:, window:)
  raise ArgumentError, 'Limit must be a positive integer' unless limit.is_a?(Integer) && limit.positive?
  raise ArgumentError, 'Window must be a positive number' unless window.is_a?(Numeric) && window.positive?

  @limit = limit
  @window = window
  @requests = Hash.new { |h, k| h[k] = [] }
  @mutex = Mutex.new
end

Instance Method Details

#call(key = :default) ⇒ Object 



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# File 'lib/philiprehberger/debounce/rate_limiter.rb', line 17

def call(key = :default)
  now = Process.clock_gettime(Process::CLOCK_MONOTONIC)

  @mutex.synchronize do
    cleanup!(key, now)
    remaining = @limit - @requests[key].length

    if remaining.positive?
      @requests[key] << now
      { allowed: true, remaining: remaining - 1, retry_after: 0 }
    else
      oldest = @requests[key].first
      retry_after = oldest + @window - now
      { allowed: false, remaining: 0, retry_after: [retry_after, 0].max }
    end
  end
end

#reset(key = :default) ⇒ Object 



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# File 'lib/philiprehberger/debounce/rate_limiter.rb', line 35

def reset(key = :default)
  @mutex.synchronize { @requests.delete(key) }
  self
end