niko
53 lines
2.9 KiB
C#
53 lines
2.9 KiB
C#
using System.Collections;
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namespace CampusNet.Services;
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/// <summary>
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/// Room chat crosses the game server as RPC event 36 carrying the text wrapped as
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/// "<noparse>...</noparse>". A normal client has already run it through the Campus
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/// server's chat filter, so what arrives is masked. Each chat message is held until the Campus
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/// server (POST /photon/chatguard, localhost) says whether its filter would still change it -
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/// if so the text skipped the filter (a chat prompt echoed into chat by a circuit, or a client
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/// that never asked), the message is dropped and the sender disconnected; the Campus server
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/// times them out. If the Campus server does not answer in time the message goes through:
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/// chat must never stop working because of this check. CAMPUSNET_CHAT_GUARD=0 turns it off.
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/// </summary>
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public static class ChatGuard
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{
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public static readonly bool Enabled = Environment.GetEnvironmentVariable("CAMPUSNET_CHAT_GUARD") != "0";
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private static readonly string Url = Environment.GetEnvironmentVariable("CAMPUSNET_CHATGUARD_URL") ?? "http://127.0.0.1:8080/photon/chatguard";
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private static readonly HttpClient Http = new() { Timeout = TimeSpan.FromMilliseconds(1500) };
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private const string Open = "<noparse>", Close = "</noparse>";
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/// <summary>The chat text inside an event-36 payload, or null when it is not a chat message.</summary>
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public static string? ChatText(object? o, int depth = 0)
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{
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if (o == null || depth > 4) return null;
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if (o is string s)
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return s.Length > Open.Length + Close.Length && s.StartsWith(Open, StringComparison.Ordinal) && s.EndsWith(Close, StringComparison.Ordinal)
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? s.Substring(Open.Length, s.Length - Open.Length - Close.Length) : null;
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if (o is Hashtable ht) { foreach (DictionaryEntry e in ht) { var t = ChatText(e.Value, depth + 1); if (t != null) return t; } return null; }
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if (o is IEnumerable en and not byte[]) { int n = 0; foreach (var x in en) { if (n++ > 64) break; var t = ChatText(x, depth + 1); if (t != null) return t; } }
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return null;
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}
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/// <summary>True only when the Campus server says the text skipped the filter; false on any doubt.</summary>
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public static async Task<bool> IsBypass(string? userId, string room, string text)
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{
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if (string.IsNullOrEmpty(userId) || !ulong.TryParse(userId, out _)) return false;
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try
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{
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using var body = new FormUrlEncodedContent(new[]
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{
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new KeyValuePair<string, string>("id", userId),
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new KeyValuePair<string, string>("room", room),
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new KeyValuePair<string, string>("text", text),
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});
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using var resp = await Http.PostAsync(Url, body);
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return resp.IsSuccessStatusCode && (await resp.Content.ReadAsStringAsync()).Trim() == "bypass";
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}
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catch { return false; }
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}
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}
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