61 lines
1.8 KiB
C#
61 lines
1.8 KiB
C#
using System;
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using System.Collections.Generic;
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namespace Noikoio.RegexBot.Feature.AutoRespond
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{
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/// <summary>
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/// Stores rate limit settings and caches.
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/// </summary>
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class RateLimitCache
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{
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public const ushort DefaultTimeout = 20; // this is Skeeter's fault
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private readonly ushort _timeout;
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private Dictionary<ulong, DateTime> _cache;
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public ushort Timeout => _timeout;
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/// <summary>
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/// Sets up a new instance of <see cref="RateLimitCache"/>.
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/// </summary>
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public RateLimitCache(ushort timeout)
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{
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_timeout = timeout;
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_cache = new Dictionary<ulong, DateTime>();
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}
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/// <summary>
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/// Checks if a "usage" is allowed for the given value.
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/// Items added to cache will be removed after the number of seconds specified in <see cref="Timeout"/>.
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/// </summary>
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/// <param name="id">The ID to add to the cache.</param>
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/// <returns>True on success. False if the given ID already exists.</returns>
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public bool AllowUsage(ulong id)
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{
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if (_timeout == 0) return true;
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lock (this)
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{
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Clean();
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if (_cache.ContainsKey(id)) return false;
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_cache.Add(id, DateTime.Now);
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}
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return true;
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}
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private void Clean()
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{
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var now = DateTime.Now;
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var clean = new Dictionary<ulong, DateTime>();
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foreach (var kp in _cache)
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{
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if (kp.Value.AddSeconds(Timeout) > now)
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{
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// Copy items that have not yet timed out to the new dictionary
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clean.Add(kp.Key, kp.Value);
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}
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}
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_cache = clean;
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}
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}
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}
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