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Contents
module Rack; module Throttle
##
# This rate limiter strategy throttles the application by enforcing a
# minimum interval (by default, 1 second) between subsequent allowed HTTP
# requests.
#
# @example Allowing up to two requests per second
# use Rack::Throttle::Interval, :min => 0.5 # 500 ms interval
#
# @example Allowing a request every two seconds
# use Rack::Throttle::Interval, :min => 2.0 # 2000 ms interval
#
class Interval < Limiter
##
# @param [#call] app
# @param [Hash{Symbol => Object}] options
# @option options [Float] :min (1.0)
def initialize(app, options = {})
super
end
##
# Returns `true` if sufficient time (equal to or more than
# {#minimum_interval}) has passed since the last request and the given
# present `request`.
#
# @param [Rack::Request] request
# @return [Boolean]
def allowed?(request)
t1 = request_start_time(request)
t0 = cache_get(key = cache_key(request)) rescue nil
allowed = !t0 || (dt = t1 - t0.to_f) >= minimum_interval
begin
cache_set(key, t1)
allowed
rescue StandardError => e
allowed = true
# If an error occurred while trying to update the timestamp stored
# in the cache, we will fall back to allowing the request through.
# This prevents the Rack application blowing up merely due to a
# backend cache server (Memcached, Redis, etc.) being offline.
end
end
##
# Returns the number of seconds before the client is allowed to retry an
# HTTP request.
#
# @return [Float]
def retry_after
minimum_interval
end
##
# Returns the required minimal interval (in terms of seconds) that must
# elapse between two subsequent HTTP requests.
#
# @return [Float]
def minimum_interval
@min ||= (@options[:min] || 1.0).to_f
end
end
end; end
Version data entries
7 entries across 7 versions & 2 rubygems