Implement message preloading

src/api/routes/channels/preload-messages.ts

@@ -0,0 +1,72 @@
+/*
+	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
+	Copyright (C) 2025 Spacebar and Spacebar Contributors
+	
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published
+	by the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+	
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+	
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+import { route } from "@spacebar/api";
+import { Config, PreloadMessagesRequestSchema, Message, PreloadMessagesResponseSchema } from "@spacebar/util";
+import { Request, Response, Router } from "express";
+const router = Router();
+
+router.post(
+	"/",
+	route({
+		// // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+		// // @ts-expect-error
+		// requestBody: "PreloadMessagesRequest", // this is broken for some reason?
+		responses: {
+			200: {
+				body: "PreloadMessagesResponse",
+			},
+			400: {
+				body: "APIErrorResponse",
+			},
+		},
+	}),
+	async (req: Request, res: Response) => {
+		const body = req.body as PreloadMessagesRequestSchema;
+		if (body.channels.length > Config.get().limits.message.maxPreloadCount)
+			return res.status(400).send({
+				code: 400,
+				message: `Cannot preload more than ${Config.get().limits.message.maxPreloadCount} channels at once.`,
+			});
+
+		const messages = (
+			await Promise.all(
+				body.channels.map(
+					async (channelId) =>
+						await Message.findOne({
+							where: { channel_id: channelId },
+							order: { timestamp: "DESC" },
+						}),
+				),
+			)
+		).filter((x) => x !== null) as Message[];
+
+		const filteredMessages = messages.map((message) => {
+			const x = message.toJSON();
+			// https://docs.discord.food/resources/message#preload-messages - reactions are not included in the response
+			// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+			// @ts-expect-error
+			x.reactions = undefined;
+			return x;
+		}) as PreloadMessagesResponseSchema;
+
+		return res.status(200).send(filteredMessages);
+	},
+);
+
+export default router;

src/util/config/types/subconfigurations/limits/MessageLimits.ts

@@ -23,4 +23,5 @@ export class MessageLimits {
 	maxAttachmentSize: number = 1024 * 1024 * 1024;
 	maxBulkDelete: number = 1000;
 	maxEmbedDownloadSize: number = 1024 * 1024 * 5;
+	maxPreloadCount: number = 100;
 }

src/util/schemas/PreloadMessagesRequestSchema.ts

@@ -0,0 +1,21 @@
+/*
+	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
+	Copyright (C) 2025 Spacebar and Spacebar Contributors
+	
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published
+	by the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+	
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+	
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+export interface PreloadMessagesRequestSchema {
+	channels: string[];
+}

src/util/schemas/index.ts

@@ -1,6 +1,6 @@
 /*
 	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
-	Copyright (C) 2024 Spacebar and Spacebar Contributors
+	Copyright (C) 2025 Spacebar and Spacebar Contributors
 
 	This program is free software: you can redistribute it and/or modify
 	it under the terms of the GNU Affero General Public License as published
@@ -58,6 +58,7 @@ export * from "./MessageCreateSchema";
 export * from "./MessageEditSchema";
 export * from "./MfaCodesSchema";
 export * from "./ModifyGuildStickerSchema";
+export * from "./PreloadMessagesRequestSchema";
 export * from "./PasswordResetSchema";
 export * from "./PurgeSchema";
 export * from "./RefreshUrlsRequestSchema";

src/util/schemas/responses/PreloadMessagesResponseSchema.ts

@@ -0,0 +1,21 @@
+/*
+	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
+	Copyright (C) 2025 Spacebar and Spacebar Contributors
+	
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published
+	by the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+	
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+	
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+import { Message } from "@spacebar/util";
+
+export type PreloadMessagesResponseSchema = Message[];

src/util/schemas/responses/index.ts

@@ -1,6 +1,6 @@
 /*
 	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
-	Copyright (C) 2023 Spacebar and Spacebar Contributors
+	Copyright (C) 2025 Spacebar and Spacebar Contributors
 
 	This program is free software: you can redistribute it and/or modify
 	it under the terms of the GNU Affero General Public License as published
@@ -49,6 +49,7 @@ export * from "./InstanceStatsResponse";
 export * from "./LocationMetadataResponse";
 export * from "./MemberJoinGuildResponse";
 export * from "./OAuthAuthorizeResponse";
+export * from "./PreloadMessagesResponseSchema";
 export * from "./RefreshUrlsResponse";
 export * from "./SettingsProtoUpdateResponse";
 export * from "./TeamListResponse";