firefish/packages/backend/src/misc/emoji-meta.ts

import probeImageSize from "probe-image-size";
import { Mutex } from "redis-semaphore";

import { FILE_TYPE_BROWSERSAFE } from "backend-rs";
import Logger from "@/services/logger.js";
import { Cache } from "./cache.js";
import { redisClient } from "@/db/redis.js";
import { inspect } from "node:util";

export type Size = {
	width: number;
	height: number;
};

const cache = new Cache<boolean>("emojiMeta", 60 * 10); // once every 10 minutes for the same url
const logger = new Logger("emoji");

export async function getEmojiSize(url: string): Promise<Size> {
	let attempted = true;

	const lock = new Mutex(redisClient, "getEmojiSize");
	await lock.acquire();

	try {
		attempted = (await cache.get(url)) === true;
		if (!attempted) {
			await cache.set(url, true);
		}
	} finally {
		await lock.release();
	}

	if (attempted) {
		logger.warn(`Attempt limit exceeded: ${url}`);
		throw new Error("Too many attempts");
	}

	try {
		logger.debug(`Retrieving emoji size from ${url}`);
		const { width, height, mime } = await probeImageSize(url, {
			timeout: 5000,
		});
		if (!(mime.startsWith("image/") && FILE_TYPE_BROWSERSAFE.includes(mime))) {
			throw new Error("Unsupported image type");
		}
		return { width, height };
	} catch (e) {
		throw new Error(`Unable to retrieve metadata:\n${inspect(e)}`);
	}
}

export function getNormalSize(
	{ width, height }: Size,
	orientation?: number,
): Size {
	return (orientation || 0) >= 5
		? { width: height, height: width }
		: { width, height };
}