perf: use a memory cache for Slowmode

backend/src/plugins/Slowmode/SlowmodePlugin.ts

@@ -42,7 +42,11 @@ export const SlowmodePlugin = zeppelinGuildPlugin<SlowmodePluginType>()({
     prettyName: "Slowmode",
   },
 
-  dependencies: () => [LogsPlugin],
+  // prettier-ignore
+  dependencies: () => [
+    LogsPlugin,
+  ],
+
   configSchema: ConfigSchema,
   defaultOptions,
 
@@ -61,6 +65,7 @@ export const SlowmodePlugin = zeppelinGuildPlugin<SlowmodePluginType>()({
     state.slowmodes = GuildSlowmodes.getGuildInstance(guild.id);
     state.savedMessages = GuildSavedMessages.getGuildInstance(guild.id);
     state.logs = new GuildLogs(guild.id);
+    state.channelSlowmodeCache = new Map();
   },
 
   afterLoad(pluginData) {

backend/src/plugins/Slowmode/commands/SlowmodeSetCmd.ts

@@ -144,7 +144,12 @@ export const SlowmodeSetCmd = slowmodeCmd({
         });
       }
 
+      // Set bot-maintained slowmode
       await pluginData.state.slowmodes.setChannelSlowmode(channel.id, rateLimitSeconds);
+
+      // Update cache
+      const slowmode = await pluginData.state.slowmodes.getChannelSlowmode(channel.id);
+      await pluginData.state.channelSlowmodeCache.set(channel.id, slowmode ?? null);
     }
 
     const humanizedSlowmodeTime = humanizeDuration(args.time);

backend/src/plugins/Slowmode/types.ts

@@ -3,6 +3,7 @@ import { BasePluginType, typedGuildCommand, typedGuildEventListener } from "knub
 import { GuildLogs } from "../../data/GuildLogs";
 import { GuildSavedMessages } from "../../data/GuildSavedMessages";
 import { GuildSlowmodes } from "../../data/GuildSlowmodes";
+import { SlowmodeChannel } from "../../data/entities/SlowmodeChannel";
 
 export const ConfigSchema = t.type({
   use_native_slowmode: t.boolean,
@@ -20,6 +21,7 @@ export interface SlowmodePluginType extends BasePluginType {
     logs: GuildLogs;
     clearInterval: NodeJS.Timeout;
     serverLogs: GuildLogs;
+    channelSlowmodeCache: Map<string, SlowmodeChannel | null>;
 
     onMessageCreateFn;
   };

backend/src/plugins/Slowmode/util/disableBotSlowmodeForChannel.ts

@@ -24,5 +24,8 @@ export async function disableBotSlowmodeForChannel(
     }
   }
 
+  // Clear cache
+  pluginData.state.channelSlowmodeCache.set(channel.id, null);
+
   return { failedUsers };
 }

backend/src/plugins/Slowmode/util/onMessageCreate.ts

@@ -10,6 +10,7 @@ import { LogsPlugin } from "../../Logs/LogsPlugin";
 import { BOT_SLOWMODE_PERMISSIONS } from "../requiredPermissions";
 import { SlowmodePluginType } from "../types";
 import { applyBotSlowmodeToUserId } from "./applyBotSlowmodeToUserId";
+import { SlowmodeChannel } from "../../../data/entities/SlowmodeChannel";
 
 export async function onMessageCreate(pluginData: GuildPluginData<SlowmodePluginType>, msg: SavedMessage) {
   if (msg.is_bot) return;
@@ -22,8 +23,16 @@ export async function onMessageCreate(pluginData: GuildPluginData<SlowmodePlugin
   if (thisMsgLock.interrupted) return;
 
   // Check if this channel even *has* a bot-maintained slowmode
-  const channelSlowmode = await pluginData.state.slowmodes.getChannelSlowmode(channel.id);
-  if (!channelSlowmode) return thisMsgLock.unlock();
+  let channelSlowmode: SlowmodeChannel | null;
+  if (pluginData.state.channelSlowmodeCache.has(channel.id)) {
+    channelSlowmode = pluginData.state.channelSlowmodeCache.get(channel.id) ?? null;
+  } else {
+    channelSlowmode = (await pluginData.state.slowmodes.getChannelSlowmode(channel.id)) ?? null;
+    pluginData.state.channelSlowmodeCache.set(channel.id, channelSlowmode);
+  }
+  if (!channelSlowmode) {
+    return thisMsgLock.unlock();
+  }
 
   // Make sure this user is affected by the slowmode
   const member = await resolveMember(pluginData.client, pluginData.guild, msg.user_id);
@@ -32,7 +41,9 @@ export async function onMessageCreate(pluginData: GuildPluginData<SlowmodePlugin
     userId: msg.user_id,
     member,
   });
-  if (!isAffected) return thisMsgLock.unlock();
+  if (!isAffected) {
+    return thisMsgLock.unlock();
+  }
 
   // Make sure we have the appropriate permissions to manage this slowmode
   const me = pluginData.guild.members.cache.get(pluginData.client.user!.id)!;