Class: Discordrb::Commands::Bucket

Inherits:
Object
  • Object
show all
Defined in:
lib/discordrb/commands/rate_limiter.rb

Overview

This class represents a bucket for rate limiting - it keeps track of how many requests have been made and when exactly the user should be rate limited.

Instance Method Summary collapse

Constructor Details

#initialize(limit, time_span, delay) ⇒ Bucket

Makes a new bucket

Parameters:

  • limit (Integer, nil) —

    How many requests the user may perform in the given time_span, or nil if there should be no limit.

  • time_span (Integer, nil) —

    The time span after which the request count is reset, in seconds, or nil if the bucket should never be reset. (If this is nil, limit should be nil too)

  • delay (Integer, nil) —

    The delay for which the user has to wait after performing a request, in seconds, or nil if the user shouldn't have to wait.

Raises:

  • (ArgumentError) 


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# File 'lib/discordrb/commands/rate_limiter.rb', line 11

def initialize(limit, time_span, delay)
  raise ArgumentError, '`limit` and `time_span` have to either both be set or both be nil!' if !limit != !time_span

  @limit = limit
  @time_span = time_span
  @delay = delay

  @bucket = {}
end

Instance Method Details

#clean(rate_limit_time = nil) ⇒ Object

Cleans the bucket, removing all elements that aren't necessary anymore

Parameters:

  • rate_limit_time (Time) (defaults to: nil) —

    The time to base the cleaning on, only useful for testing.



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# File 'lib/discordrb/commands/rate_limiter.rb', line 23

def clean(rate_limit_time = nil)
  rate_limit_time ||= Time.now

  @bucket.delete_if do |_, limit_hash|
    # Time limit has not run out
    return false if @time_span && rate_limit_time < (limit_hash[:set_time] + @time_span)

    # Delay has not run out
    return false if @delay && rate_limit_time < (limit_hash[:last_time] + @delay)

    true
  end
end

#rate_limited?(thing, rate_limit_time = nil, increment: 1) ⇒ Integer, false

Performs a rate limiting request

Parameters:

  • thing (#resolve_id, Integer, Symbol) —

    The particular thing that should be rate-limited (usually a user/channel, but you can also choose arbitrary integers or symbols)

  • rate_limit_time (Time) (defaults to: nil) —

    The time to base the rate limiting on, only useful for testing.

  • increment (Integer) (defaults to: 1) —

    How much to increment the rate-limit counter. Default is 1.

Returns:

  • (Integer, false) —

    the waiting time until the next request, in seconds, or false if the request succeeded



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# File 'lib/discordrb/commands/rate_limiter.rb', line 42

def rate_limited?(thing, rate_limit_time = nil, increment: 1)
  key = resolve_key thing
  limit_hash = @bucket[key]

  # First case: limit_hash doesn't exist yet
  unless limit_hash
    @bucket[key] = {
      last_time: Time.now,
      set_time: Time.now,
      count: increment
    }

    return false
  end

  # Define the time at which we're being rate limited once so it doesn't get inaccurate
  rate_limit_time ||= Time.now

  if @limit && (limit_hash[:count] + increment) > @limit
    # Second case: Count is over the limit and the time has not run out yet
    return (limit_hash[:set_time] + @time_span) - rate_limit_time if @time_span && rate_limit_time < (limit_hash[:set_time] + @time_span)

    # Third case: Count is over the limit but the time has run out
    # Don't return anything here because there may still be delay-based limiting
    limit_hash[:set_time] = rate_limit_time
    limit_hash[:count] = 0
  end

  if @delay && rate_limit_time < (limit_hash[:last_time] + @delay)
    # Fourth case: we're being delayed
    (limit_hash[:last_time] + @delay) - rate_limit_time
  else
    # Fifth case: no rate limiting at all! Increment the count, set the last_time, and return false
    limit_hash[:last_time] = rate_limit_time
    limit_hash[:count] += increment
    false
  end
end