472 lines
20 KiB
C#
472 lines
20 KiB
C#
using System.Text;
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using System.Text.RegularExpressions;
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using App.Metrics;
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using Myriad.Cache;
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using Myriad.Extensions;
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using Myriad.Gateway;
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using Myriad.Rest;
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using Myriad.Rest.Exceptions;
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using Myriad.Rest.Types.Requests;
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using Myriad.Types;
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using PluralKit.Core;
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using Serilog;
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namespace PluralKit.Bot;
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public class ProxyService
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{
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private static readonly TimeSpan MessageDeletionDelay = TimeSpan.FromMilliseconds(1000);
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private readonly IDiscordCache _cache;
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private readonly IDatabase _db;
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private readonly DispatchService _dispatch;
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private readonly LastMessageCacheService _lastMessage;
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private readonly LogChannelService _logChannel;
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private readonly ILogger _logger;
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private readonly ProxyMatcher _matcher;
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private readonly IMetrics _metrics;
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private readonly ModelRepository _repo;
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private readonly DiscordApiClient _rest;
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private readonly WebhookExecutorService _webhookExecutor;
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private readonly NodaTime.IClock _clock;
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public ProxyService(LogChannelService logChannel, ILogger logger, WebhookExecutorService webhookExecutor,
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DispatchService dispatch, IDatabase db, ProxyMatcher matcher, IMetrics metrics, ModelRepository repo,
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NodaTime.IClock clock, IDiscordCache cache, DiscordApiClient rest, LastMessageCacheService lastMessage)
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{
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_logChannel = logChannel;
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_webhookExecutor = webhookExecutor;
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_dispatch = dispatch;
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_db = db;
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_matcher = matcher;
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_metrics = metrics;
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_repo = repo;
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_cache = cache;
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_lastMessage = lastMessage;
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_rest = rest;
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_clock = clock;
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_logger = logger.ForContext<ProxyService>();
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}
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public async Task<bool> HandleIncomingMessage(MessageCreateEvent message, MessageContext ctx,
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Guild guild, Channel channel, bool allowAutoproxy, PermissionSet botPermissions)
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{
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if (!ShouldProxy(channel, message, ctx))
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return false;
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var autoproxySettings = await _repo.GetAutoproxySettings(ctx.SystemId.Value, guild.Id, null);
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if (autoproxySettings.AutoproxyMode == AutoproxyMode.Latch && IsUnlatch(message))
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{
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// "unlatch"
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await _repo.UpdateAutoproxy(ctx.SystemId.Value, guild.Id, null, new()
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{
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AutoproxyMember = null
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});
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return false;
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}
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var rootChannel = await _cache.GetRootChannel(message.ChannelId);
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List<ProxyMember> members;
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// Fetch members and try to match to a specific member
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using (_metrics.Measure.Timer.Time(BotMetrics.ProxyMembersQueryTime))
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members = (await _repo.GetProxyMembers(message.Author.Id, message.GuildId!.Value)).ToList();
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if (!_matcher.TryMatch(ctx, autoproxySettings, members, out var match, message.Content, message.Attachments.Length > 0,
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allowAutoproxy)) return false;
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// this is hopefully temporary, so not putting it into a separate method
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if (message.Content != null && message.Content.Length > 2000)
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throw new PKError("PluralKit cannot proxy messages over 2000 characters in length.");
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// Permission check after proxy match so we don't get spammed when not actually proxying
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if (!CheckBotPermissionsOrError(botPermissions, rootChannel.Id))
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return false;
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// this method throws, so no need to wrap it in an if statement
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CheckProxyNameBoundsOrError(match.Member.ProxyName(ctx));
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// Check if the sender account can mention everyone/here + embed links
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// we need to "mirror" these permissions when proxying to prevent exploits
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var senderPermissions = PermissionExtensions.PermissionsFor(guild, rootChannel, message);
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var allowEveryone = senderPermissions.HasFlag(PermissionSet.MentionEveryone);
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var allowEmbeds = senderPermissions.HasFlag(PermissionSet.EmbedLinks);
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// Everything's in order, we can execute the proxy!
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await ExecuteProxy(message, ctx, autoproxySettings, match, allowEveryone, allowEmbeds);
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return true;
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}
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public bool ShouldProxy(Channel channel, Message msg, MessageContext ctx)
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{
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// Make sure author has a system
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if (ctx.SystemId == null)
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throw new ProxyChecksFailedException(Errors.NoSystemError.Message);
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// Make sure channel is a guild text channel and this is a normal message
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if (!DiscordUtils.IsValidGuildChannel(channel))
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throw new ProxyChecksFailedException("This channel is not a text channel.");
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if (msg.Type != Message.MessageType.Default && msg.Type != Message.MessageType.Reply)
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throw new ProxyChecksFailedException("This message is not a normal message.");
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// Make sure author is a normal user
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if (msg.Author.System == true || msg.Author.Bot || msg.WebhookId != null)
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throw new ProxyChecksFailedException("This message was not sent by a normal user.");
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// Make sure proxying is enabled here
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if (ctx.InBlacklist)
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throw new ProxyChecksFailedException(
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"Proxying was disabled in this channel by a server administrator (via the proxy blacklist).");
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// Make sure the system has proxying enabled in the server
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if (!ctx.ProxyEnabled)
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throw new ProxyChecksFailedException(
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"Your system has proxying disabled in this server. Type `pk;proxy on` to enable it.");
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// Make sure we have either an attachment or message content
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var isMessageBlank = msg.Content == null || msg.Content.Trim().Length == 0;
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if (isMessageBlank && msg.Attachments.Length == 0)
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throw new ProxyChecksFailedException("Message cannot be blank.");
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if (msg.Activity != null)
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throw new ProxyChecksFailedException("Message contains an invite to an activity, which cannot be re-sent by PluralKit.");
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if (msg.StickerItems != null) // && msg.StickerItems.Any(s => s.Type == Sticker.StickerType.GUILD && s.GuildId != msg.GuildId))
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throw new ProxyChecksFailedException("Message contains stickers, which cannot be re-sent by PluralKit.");
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// All good!
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return true;
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}
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private async Task ExecuteProxy(Message trigger, MessageContext ctx, AutoproxySettings autoproxySettings,
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ProxyMatch match, bool allowEveryone, bool allowEmbeds)
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{
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// Create reply embed
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var embeds = new List<Embed>();
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if (trigger.Type == Message.MessageType.Reply && trigger.MessageReference?.ChannelId == trigger.ChannelId)
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{
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var repliedTo = trigger.ReferencedMessage.Value;
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if (repliedTo != null)
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{
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var (nickname, avatar) = await FetchReferencedMessageAuthorInfo(trigger, repliedTo);
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var embed = CreateReplyEmbed(match, trigger, repliedTo, nickname, avatar);
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if (embed != null)
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embeds.Add(embed);
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}
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// TODO: have a clean error for when message can't be fetched instead of just being silent
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}
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// Send the webhook
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var content = match.ProxyContent;
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if (!allowEmbeds) content = content.BreakLinkEmbeds();
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var messageChannel = await _cache.GetChannel(trigger.ChannelId);
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var rootChannel = await _cache.GetRootChannel(trigger.ChannelId);
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var threadId = messageChannel.IsThread() ? messageChannel.Id : (ulong?)null;
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var guild = await _cache.GetGuild(trigger.GuildId.Value);
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var proxyMessage = await _webhookExecutor.ExecuteWebhook(new ProxyRequest
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{
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GuildId = trigger.GuildId!.Value,
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ChannelId = rootChannel.Id,
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ThreadId = threadId,
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Name = await FixSameName(messageChannel.Id, ctx, match.Member),
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AvatarUrl = AvatarUtils.TryRewriteCdnUrl(match.Member.ProxyAvatar(ctx)),
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Content = content,
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Attachments = trigger.Attachments,
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FileSizeLimit = guild.FileSizeLimit(),
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Embeds = embeds.ToArray(),
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Stickers = trigger.StickerItems,
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AllowEveryone = allowEveryone
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});
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await HandleProxyExecutedActions(ctx, autoproxySettings, trigger, proxyMessage, match);
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}
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public async Task ExecuteReproxy(Message trigger, PKMessage msg, List<ProxyMember> members, ProxyMember member)
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{
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var originalMsg = await _rest.GetMessageOrNull(msg.Channel, msg.Mid);
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if (originalMsg == null)
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throw new PKError("Could not reproxy message.");
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// Get a MessageContext for the original message
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MessageContext ctx =
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await _repo.GetMessageContext(msg.Sender, msg.Guild!.Value, msg.Channel);
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// Make sure proxying is enabled here
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if (ctx.InBlacklist)
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throw new ProxyChecksFailedException(
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"Proxying was disabled in this channel by a server administrator (via the proxy blacklist).");
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var autoproxySettings = await _repo.GetAutoproxySettings(ctx.SystemId.Value, msg.Guild!.Value, null);
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var prevMatched = _matcher.TryMatch(ctx, autoproxySettings, members, out var prevMatch, originalMsg.Content,
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originalMsg.Attachments.Length > 0, false);
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var match = new ProxyMatch
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{
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Member = member,
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Content = prevMatched ? prevMatch.Content : originalMsg.Content,
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ProxyTags = member.ProxyTags.First(),
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};
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var messageChannel = await _rest.GetChannelOrNull(msg.Channel!);
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var rootChannel = await _rest.GetChannelOrNull(messageChannel.IsThread() ? messageChannel.ParentId!.Value : messageChannel.Id);
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var threadId = messageChannel.IsThread() ? messageChannel.Id : (ulong?)null;
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var guild = await _rest.GetGuildOrNull(msg.Guild!.Value);
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// Grab user permissions
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var senderPermissions = PermissionExtensions.PermissionsFor(guild, rootChannel, trigger.Author.Id, null);
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var allowEveryone = senderPermissions.HasFlag(PermissionSet.MentionEveryone);
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// Make sure user has permissions to send messages
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if (!senderPermissions.HasFlag(PermissionSet.SendMessages))
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throw new PKError("You don't have permission to send messages in the channel that message is in.");
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// Send the reproxied webhook
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var proxyMessage = await _webhookExecutor.ExecuteWebhook(new ProxyRequest
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{
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GuildId = guild.Id,
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ChannelId = rootChannel.Id,
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ThreadId = threadId,
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Name = match.Member.ProxyName(ctx),
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AvatarUrl = AvatarUtils.TryRewriteCdnUrl(match.Member.ProxyAvatar(ctx)),
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Content = match.ProxyContent!,
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Attachments = originalMsg.Attachments!,
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FileSizeLimit = guild.FileSizeLimit(),
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Embeds = originalMsg.Embeds!.ToArray(),
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Stickers = originalMsg.StickerItems!,
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AllowEveryone = allowEveryone
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});
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await HandleProxyExecutedActions(ctx, autoproxySettings, trigger, proxyMessage, match, deletePrevious: false);
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await _rest.DeleteMessage(originalMsg.ChannelId!, originalMsg.Id!);
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}
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private async Task<(string?, string?)> FetchReferencedMessageAuthorInfo(Message trigger, Message referenced)
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{
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if (referenced.WebhookId != null)
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return (null, null);
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try
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{
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var member = await _rest.GetGuildMember(trigger.GuildId!.Value, referenced.Author.Id);
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return (member?.Nick, member?.Avatar);
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}
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catch (ForbiddenException)
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{
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_logger.Warning(
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"Failed to fetch member {UserId} in guild {GuildId} when getting reply nickname, falling back to username",
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referenced.Author.Id, trigger.GuildId!.Value);
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return (null, null);
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}
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}
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private Embed CreateReplyEmbed(ProxyMatch match, Message trigger, Message repliedTo, string? nickname,
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string? avatar)
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{
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// repliedTo doesn't have a GuildId field :/
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var jumpLink = $"https://discord.com/channels/{trigger.GuildId}/{repliedTo.ChannelId}/{repliedTo.Id}";
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var content = new StringBuilder();
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var hasContent = !string.IsNullOrWhiteSpace(repliedTo.Content);
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if (hasContent)
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{
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var msg = repliedTo.Content;
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if (msg.Length > 100)
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{
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msg = repliedTo.Content.Substring(0, 100);
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var endsWithOpenMention = Regex.IsMatch(msg, @"<[at]?[@#:][!&]?(\w+:)?(\d+)?(:[tTdDfFR])?$");
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if (endsWithOpenMention)
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{
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var mentionTail = repliedTo.Content.Substring(100).Split(">")[0];
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if (repliedTo.Content.Contains(msg + mentionTail + ">"))
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msg += mentionTail + ">";
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}
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var endsWithUrl = Regex.IsMatch(msg,
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@"(http|https)(:\/\/)?(www\.)?([-a-zA-Z0-9@:%._\+~#=]{1,256})?\.?([a-zA-Z0-9()]{1,6})?\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)$");
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if (endsWithUrl)
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{
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var urlTail = repliedTo.Content.Substring(100).Split(" ")[0];
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msg += urlTail + " ";
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}
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var spoilersInOriginalString = Regex.Matches(repliedTo.Content, @"\|\|").Count;
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var spoilersInTruncatedString = Regex.Matches(msg, @"\|\|").Count;
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if (spoilersInTruncatedString % 2 == 1 && spoilersInOriginalString % 2 == 0)
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msg += "||";
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if (msg != repliedTo.Content)
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msg += "…";
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}
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content.Append($"**[Reply to:]({jumpLink})** ");
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content.Append(msg);
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if (repliedTo.Attachments.Length > 0 || repliedTo.Embeds.Length > 0)
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content.Append($" {Emojis.Paperclip}");
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}
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else
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{
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content.Append($"*[(click to see attachment)]({jumpLink})*");
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}
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var username = nickname ?? repliedTo.Author.Username;
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var avatarUrl = avatar != null
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? $"https://cdn.discordapp.com/guilds/{trigger.GuildId}/users/{repliedTo.Author.Id}/avatars/{avatar}.png"
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: $"https://cdn.discordapp.com/avatars/{repliedTo.Author.Id}/{repliedTo.Author.Avatar}.png";
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return new Embed
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{
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// unicodes: [three-per-em space] [left arrow emoji] [force emoji presentation]
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Author = new Embed.EmbedAuthor($"{username}\u2004\u21a9\ufe0f", IconUrl: avatarUrl),
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Description = content.ToString(),
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Color = match.Member.Color?.ToDiscordColor()
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};
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}
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private async Task<string> FixSameName(ulong channelId, MessageContext ctx, ProxyMember member)
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{
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var proxyName = member.ProxyName(ctx);
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var lastMessage = _lastMessage.GetLastMessage(channelId)?.Previous;
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if (lastMessage == null)
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// cache is out of date or channel is empty.
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return proxyName;
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var pkMessage = await _db.Execute(conn => _repo.GetMessage(conn, lastMessage.Id));
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if (lastMessage.AuthorUsername == proxyName)
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{
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// last message wasn't proxied by us, but somehow has the same name
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// it's probably from a different webhook (Tupperbox?) but let's fix it anyway!
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if (pkMessage == null)
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return FixSameNameInner(proxyName);
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// last message was proxied by a different member
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if (pkMessage.Member?.Id != member.Id)
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return FixSameNameInner(proxyName);
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}
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// if we fixed the name last message and it's the same member proxying, we want to fix it again
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if (lastMessage.AuthorUsername == FixSameNameInner(proxyName) && pkMessage?.Member?.Id == member.Id)
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return FixSameNameInner(proxyName);
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// No issues found, current proxy name is fine.
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return proxyName;
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}
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private string FixSameNameInner(string name)
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=> $"{name}\u17b5";
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public static bool IsUnlatch(Message message)
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=> message.Content.StartsWith(@"\\") || message.Content.StartsWith("\\\u200b\\");
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private async Task HandleProxyExecutedActions(MessageContext ctx, AutoproxySettings autoproxySettings,
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Message triggerMessage, Message proxyMessage, ProxyMatch match,
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bool deletePrevious = true)
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{
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var sentMessage = new PKMessage
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{
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Channel = triggerMessage.ChannelId,
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Guild = triggerMessage.GuildId,
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Member = match.Member.Id,
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Mid = proxyMessage.Id,
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OriginalMid = triggerMessage.Id,
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Sender = triggerMessage.Author.Id
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};
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Task SaveMessageInDatabase()
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=> _repo.AddMessage(sentMessage);
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Task LogMessageToChannel() =>
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_logChannel.LogMessage(ctx, sentMessage, triggerMessage, proxyMessage).AsTask();
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Task SaveLatchAutoproxy() => autoproxySettings.AutoproxyMode == AutoproxyMode.Latch
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? _repo.UpdateAutoproxy(ctx.SystemId.Value, triggerMessage.GuildId, null, new()
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{
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AutoproxyMember = match.Member.Id,
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LastLatchTimestamp = _clock.GetCurrentInstant(),
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})
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: Task.CompletedTask;
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Task DispatchWebhook() => _dispatch.Dispatch(ctx.SystemId.Value, sentMessage);
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async Task DeleteProxyTriggerMessage()
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{
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if (!deletePrevious)
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return;
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// Wait a second or so before deleting the original message
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await Task.Delay(MessageDeletionDelay);
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try
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{
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await _rest.DeleteMessage(triggerMessage.ChannelId, triggerMessage.Id);
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}
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catch (NotFoundException)
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{
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_logger.Debug(
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"Trigger message {TriggerMessageId} was already deleted when we attempted to; deleting proxy message {ProxyMessageId} also",
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triggerMessage.Id, proxyMessage.Id);
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await HandleTriggerAlreadyDeleted(proxyMessage);
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// Swallow the exception, we don't need it
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}
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}
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// Run post-proxy actions (simultaneously; order doesn't matter)
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await Task.WhenAll(
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DeleteProxyTriggerMessage(),
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SaveMessageInDatabase(),
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LogMessageToChannel(),
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SaveLatchAutoproxy(),
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DispatchWebhook()
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);
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}
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private async Task HandleTriggerAlreadyDeleted(Message proxyMessage)
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{
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// If a trigger message is deleted before we get to delete it, we can assume a mod bot or similar got to it
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// In this case we should also delete the now-proxied message.
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// This is going to hit the message delete event handler also, so that'll do the cleanup for us
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try
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{
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await _rest.DeleteMessage(proxyMessage.ChannelId, proxyMessage.Id);
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}
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catch (NotFoundException) { }
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catch (UnauthorizedException) { }
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}
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private bool CheckBotPermissionsOrError(PermissionSet permissions, ulong responseChannel)
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{
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// If we can't send messages at all, just bail immediately.
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// 2020-04-22: Manage Messages does *not* override a lack of Send Messages.
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if (!permissions.HasFlag(PermissionSet.SendMessages))
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return false;
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if (!permissions.HasFlag(PermissionSet.ManageWebhooks))
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throw new PKError("PluralKit does not have the *Manage Webhooks* permission in this channel, and thus cannot proxy messages."
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+ " Please contact a server administrator to remedy this.");
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if (!permissions.HasFlag(PermissionSet.ManageMessages))
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throw new PKError("PluralKit does not have the *Manage Messages* permission in this channel, and thus cannot delete the original trigger message."
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+ " Please contact a server administrator to remedy this.");
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return true;
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}
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private void CheckProxyNameBoundsOrError(string proxyName)
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{
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if (proxyName.Length > Limits.MaxProxyNameLength) throw Errors.ProxyNameTooLong(proxyName);
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}
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public class ProxyChecksFailedException: Exception
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{
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public ProxyChecksFailedException(string message) : base(message) { }
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}
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} |