54 lines
1.8 KiB
C#
54 lines
1.8 KiB
C#
using System;
|
|
using System.Collections.Generic;
|
|
|
|
namespace Kerobot.Modules.AutoScriptResponder
|
|
{
|
|
/// <summary>
|
|
/// Helper class for managing rate limit data.
|
|
/// </summary>
|
|
class RateLimit<T>
|
|
{
|
|
public const ushort DefaultTimeout = 20; // Skeeter's a cool guy and you can't convince me otherwise.
|
|
|
|
public ushort Timeout { get; }
|
|
private readonly object _lock = new object();
|
|
private Dictionary<T, DateTime> _table = new Dictionary<T, DateTime>();
|
|
|
|
public RateLimit() : this(DefaultTimeout) { }
|
|
public RateLimit(ushort timeout) => Timeout = timeout;
|
|
|
|
/// <summary>
|
|
/// 'Permit?' - Checks if the given value is permitted through the rate limit.
|
|
/// Executing this method may create a rate limit entry for the given value.
|
|
/// </summary>
|
|
/// <param name="id"></param>
|
|
/// <returns>True if the given value is permitted by the rate limiter.</returns>
|
|
public bool Permit(T value)
|
|
{
|
|
if (Timeout == 0) return true;
|
|
|
|
lock (_lock)
|
|
{
|
|
Clean();
|
|
if (_table.ContainsKey(value)) return false;
|
|
_table.Add(value, DateTime.Now);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Clean up expired entries.
|
|
/// </summary>
|
|
private void Clean()
|
|
{
|
|
var now = DateTime.Now;
|
|
var newTable = new Dictionary<T, DateTime>();
|
|
foreach (var item in _table)
|
|
{
|
|
// Copy items that have not yet timed out to the new dictionary. Discard the rest.
|
|
if (item.Value.AddSeconds(Timeout) > now) newTable.Add(item.Key, item.Value);
|
|
}
|
|
lock (_lock) _table = newTable;
|
|
}
|
|
}
|
|
}
|