Add NORAD ID endpoint

Author: MrTalon63

bun.lock

@@ -26,6 +26,7 @@
 		"keyv": "^5.6.0",
 		"keyv-file": "^5.3.3",
 		"prom-client": "^15.1.3",
+		"tle": "^3.0.1",
 		"winston": "^3.19.0"
 	}
 }

package.json

@@ -2,6 +2,7 @@ import { Elysia } from "elysia";
 import { html } from "@elysiajs/html";
 
 import tleRoute from "./routes/tle";
+import noradRoute from "./routes/norad";
 
 import index from "./pub/index.tsx";
 import kv from "./utils/kv";
@@ -24,6 +25,7 @@ new Elysia()
 
 	// Subroutes registers
 	.use(tleRoute) // Import TLE routes
+	.use(noradRoute) // Import NORAD routes
 
 	.listen(config.port, () => {
 		log.info(`Server is running on port ${config.port}`);

src/main.ts

@@ -0,0 +1,11 @@
+import { Elysia } from "elysia";
+
+import tleGetter from "../utils/tleGetter";
+
+const noradRoute = new Elysia({ prefix: "/norad" }).get("/:id", async ({ params }) => {
+	const noradId = parseInt(params.id, 10);
+	const tleData = await tleGetter(noradId);
+	return new Response(tleData, { headers: { "Content-Type": "text/plain", "Cache-Control": "max-age=3600" } });
+});
+
+export default noradRoute;

src/routes/norad.ts

@@ -1,10 +1,12 @@
 const config = {
 	allowedGroups: process.env.ALLOWED_GROUPS ? process.env.ALLOWED_GROUPS.split(",").concat("active") : ["active"],
+	logLevel: process.env.LOG_LEVEL || "info",
 	port: process.env.PORT ? parseInt(process.env.PORT) : 3000,
 	rateLimitWindow: process.env.RATE_LIMIT_WINDOW ? parseInt(process.env.RATE_LIMIT_WINDOW) * 1000 : 60 * 1000,
 	rateLimitMaxRequests: process.env.RATE_LIMIT_MAX_REQUESTS ? parseInt(process.env.RATE_LIMIT_MAX_REQUESTS) : 60,
 	cacheDuration: process.env.CACHE_DURATION ? parseInt(process.env.CACHE_DURATION) * 1000 : 24 * 60 * 60 * 1000,
 	cacheActiveDuration: process.env.CACHE_ACTIVE_DURATION ? parseInt(process.env.CACHE_ACTIVE_DURATION) * 1000 : 2 * 60 * 60 * 1000,
+	cacheNoradDuration: process.env.CACHE_NORAD_DURATION ? parseInt(process.env.CACHE_NORAD_DURATION) * 1000 : 24 * 60 * 60 * 1000,
 };
 
 export default config;

src/utils/config.ts

@@ -1,7 +1,9 @@
 import winston from "winston";
 
+import config from "./config";
+
 const log = winston.createLogger({
-	level: process.env.LOG_LEVEL || "info",
+	level: config.logLevel,
 	format: winston.format.combine(
 		winston.format.timestamp(),
 		winston.format.colorize(),

src/utils/logger.ts

@@ -11,7 +11,7 @@ async function fetchTle(group: string) {
 		const response = await fetch(url, {
 			headers: {
 				"If-Modified-Since": lastFetch ? new Date(lastFetch).toUTCString() : "",
-				"User-Agent": `ReTLEctor/${version} (https://github.com/MrTalon63/retlector)`,
+				"User-Agent": `ReTLEctor/${version} (https://github.com/MrTalon63/ReTLEctor)`,
 			},
 		});
 		if (!response.ok) {

src/utils/tleFetcher.ts

@@ -0,0 +1,92 @@
+import tle from "tle";
+
+import kv from "./kv";
+import log from "./logger";
+import config from "./config";
+import fetchTle from "./tleFetcher";
+import { version } from "../../package.json";
+
+async function getObjectsTle(noradId: number) {
+	let tleData = (await kv.get(`tle_${noradId}`)) as string | null;
+	let timestamp = await kv.get(`tle_${noradId}_timestamp`);
+	const now = Date.now();
+	const isStale = timestamp ? now - timestamp > config.cacheNoradDuration : true;
+
+	if (!tleData || isStale) {
+		let allTles = (await kv.get("active")) as string | null;
+		if (!allTles) {
+			await fetchTle("active");
+		}
+		allTles = (await kv.get("active")) as string | null;
+
+		// If we still don't have the active TLEs then something went wrong with fetching, so we throw an error
+		if (!allTles) {
+			log.error("Failed to fetch active TLEs from Celestrak");
+			throw new Error("Failed to fetch active TLEs from Celestrak");
+		}
+		const lines = allTles.split("\n");
+		const setPromises: Promise<boolean>[] = [];
+		for (let i = 0; i < lines.length; i += 3) {
+			const idLine = lines[i + 0];
+			const tleLine1 = lines[i + 1];
+			const tleLine2 = lines[i + 2];
+
+			if (idLine && tleLine1 && tleLine2) {
+				const parsed = tle.parse(`${idLine}\n${tleLine1}\n${tleLine2}`);
+				const tleString = `${idLine}\n${tleLine1}\n${tleLine2}`;
+				if (parsed.number === noradId) {
+					tleData = tleString;
+				}
+				setPromises.push(kv.set(`tle_${parsed.number}`, tleString));
+			}
+		}
+		await Promise.all(setPromises);
+	}
+
+	// If we're here then active group doesn't contain the requested NORAD ID, try fetching the TLE directly from Celestrak, but be aware of rate limits so we don't get blocked
+	if (!tleData) {
+		log.verbose(`NORAD ID ${noradId} not found in active group. Attempting to fetch directly from Celestrak...`);
+		const url = `https://celestrak.org/NORAD/elements/gp.php?CATNR=${noradId}&FORMAT=tle`;
+		try {
+			let tries: number = (await kv.get(`celestrakTries`)) || 0;
+			const lastTry: number | undefined = await kv.get(`celestrakLastTry`);
+
+			// Reset the counters if more than an hour has passed since the last request
+			if (lastTry && Date.now() - lastTry >= 60 * 60 * 1000) {
+				tries = 0;
+				await kv.set(`celestrakTries`, 0);
+				await kv.set(`celestrakLastTry`, Date.now());
+			}
+
+			// We don't want to spam Celestrak with more than 20 requests per hour
+			if (tries >= 20) {
+				throw new Error("Rate limit exceeded for Celestrak fetches");
+			}
+
+			const response = await fetch(url, {
+				// Celestrak doesn't support If-Modified-Since or ETag headers, so we have to implement our own rate limiting and caching mechanism to avoid getting blocked
+				headers: {
+					"User-Agent": `ReTLEctor/${version} (https://github.com/MrTalon63/ReTLEctor)`,
+				},
+			});
+
+			if (!response.ok) {
+				log.error(`Failed to fetch TLE from Celestrak: ${response.status} ${response.statusText}`);
+				throw new Error(`Failed to fetch TLE from Celestrak`);
+			}
+
+			tleData = (await response.text()) as string;
+			await kv.set(`tle_${noradId}`, tleData);
+			await kv.set(`celestrakTries`, tries + 1);
+			await kv.set(`celestrakLastTry`, Date.now());
+			log.info(`Successfully fetched TLE for NORAD ID ${noradId} from Celestrak.`);
+		} catch (error) {
+			log.error(`Error fetching TLE for NORAD ID ${noradId}: ${error}`);
+			throw error;
+		}
+	}
+
+	return tleData;
+}
+
+export default getObjectsTle;