Class: Otto::Security::RateLimiting

Inherits:
Object
  • Object
show all
Defined in:
lib/otto/security/rate_limiter.rb

Overview

Rate limiting implementation using Rack::Attack

Direct Known Subclasses

MCP::RateLimiter

Constant Summary collapse

RACK_ATTACK_REQUIREMENT = 
'~> 6.7'

Class Method Summary collapse

Class Method Details

.configure_logging ⇒ Object 



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# File 'lib/otto/security/rate_limiter.rb', line 72

def self.configure_logging
  # Log blocked requests if ActiveSupport is available
  return unless defined?(ActiveSupport::Notifications)

  ActiveSupport::Notifications.subscribe('rack.attack') do |_name, _start, _finish, _request_id, payload|
    log_throttled_request(payload)
  end
end

.configure_rack_attack!(config = {}) ⇒ Object 



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# File 'lib/otto/security/rate_limiter.rb', line 24

def self.configure_rack_attack!(config = {})
  ensure_available!

  # Use provided cache store or default
  Rack::Attack.cache.store = config[:cache_store] if config[:cache_store]

  # Default rules
  default_requests_per_minute = config.fetch(:requests_per_minute, 100)

  # General request throttling. Internal paths (/_mcp, /_status, ...)
  # are skipped by default. PATH_INFO, not Rack::Request#path: #path
  # prepends SCRIPT_NAME, so with Otto mounted under `map '/api'` the
  # internal /_mcp request read as /api/_mcp and was counted here while
  # the MCP throttle, comparing the same way, never saw it at all.
  Rack::Attack.throttle('requests', limit: default_requests_per_minute, period: 60) do |request|
    request.ip unless request.path_info.start_with?('/_')
  end

  # Apply custom rules if provided
  if config[:custom_rules]
    config[:custom_rules].each do |name, rule_config|
      limit = rule_config[:limit]
      period = rule_config[:period] || 60
      condition = rule_config[:condition]

      Rack::Attack.throttle(name.to_s, limit: limit, period: period) do |request|
        if condition
          request.ip if condition.call(request)
        else
          request.ip
        end
      end
    end
  end

  configure_responses
  configure_logging
end

.configure_responses ⇒ Object

Rack::Attack holds a single throttled_responder and each subscriber to 'rack.attack' fires on every throttle event. Subclasses override throttled_response and log_throttled_request instead of registering their own responder or subscriber after super, so the hosting app never gets a redundant responder assignment or doubled log lines.



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# File 'lib/otto/security/rate_limiter.rb', line 68

def self.configure_responses
  Rack::Attack.throttled_responder = ->(request) { throttled_response(request) }
end

.ensure_available! ⇒ Object 



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# File 'lib/otto/security/rate_limiter.rb', line 15

def self.ensure_available!
  Otto::OptionalDependency.require!(
    'rack-attack',
    RACK_ATTACK_REQUIREMENT,
    require_path: 'rack/attack',
    feature: 'Rate limiting'
  )
end

.general_throttled_response(request, headers, match_data) ⇒ Object

Custom response for rate limited requests



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# File 'lib/otto/security/rate_limiter.rb', line 96

def self.general_throttled_response(request, headers, match_data)
  # Content negotiation for rate limit response
  # Route's response_type takes precedence over Accept header
  route_def = request.env['otto.route_definition']
  wants_json = (route_def&.response_type == 'json') ||
               request.env['HTTP_ACCEPT'].to_s.include?('application/json')

  if wants_json
    error_response = {
      error: 'Rate limit exceeded',
      message: 'Too many requests',
      retry_after: headers['retry-after'].to_i,
      limit: match_data[:limit],
      period: match_data[:period],
    }
    [429, headers, [JSON.generate(error_response)]]
  else
    body = "Rate limit exceeded. Retry after #{headers['retry-after']} seconds."
    headers['content-type'] = 'text/plain'
    [429, headers, [body]]
  end
end

.log_throttled_request(payload) ⇒ Object

Rack::Attack is mounted by the hosting app AHEAD of Otto, so this subscriber sees the raw peer regardless of where IPPrivacyMiddleware sits in Otto's own stack. Log a masked address, never req.ip: a deployment on the default :masked profile must not write raw client IPs to its logs every time a limit trips (issue #219).



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# File 'lib/otto/security/rate_limiter.rb', line 124

def self.log_throttled_request(payload)
  req = payload[:request]
  ip  = Otto::LoggingHelpers.privacy_safe_ip(req.env, req.ip)
  Otto.logger.warn "[Otto] Rate limit #{payload[:match_type]} for #{ip}: #{payload[:matched]}"
end

.throttle_headers(match_data) ⇒ Object 



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# File 'lib/otto/security/rate_limiter.rb', line 86

def self.throttle_headers(match_data)
  now = match_data[:epoch_time]

  {
    'content-type' => 'application/json',
    'retry-after' => (match_data[:period] - (now % match_data[:period])).to_s,
  }
end

.throttled_response(request) ⇒ Object 



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# File 'lib/otto/security/rate_limiter.rb', line 81

def self.throttled_response(request)
  match_data = request.env['rack.attack.match_data']
  general_throttled_response(request, throttle_headers(match_data), match_data)
end