Tweaks to showing new version available

- Added frontend translation for english
- Moved frontend api logic to hook and backend api space
- Added swagger schema for the new api endpoint
- Moved backend logic to its own internal file
- Added user agent header to github api check
- Added cypress integration test for version check api
- Added a memory cache item from github check to avoid hitting it too
  much

backend/internal/remote-version.js

@@ -0,0 +1,84 @@
+import https from "node:https";
+import { ProxyAgent } from "proxy-agent";
+import { debug, remoteVersion as logger } from "../logger.js";
+import pjson from "../package.json" with { type: "json" };
+
+const VERSION_URL = "https://api.github.com/repos/NginxProxyManager/nginx-proxy-manager/releases/latest";
+
+const internalRemoteVersion = {
+	cache_timeout: 1000 * 60 * 15, // 15 minutes
+	last_result: null,
+	last_fetch_time: null,
+
+	/**
+	 * Fetch the latest version info, using a cached result if within the cache timeout period.
+	 * @return {Promise<{current: string, latest: string, update_available: boolean}>} Version info
+	 */
+	get: async () => {
+		if (
+			!internalRemoteVersion.last_result ||
+			!internalRemoteVersion.last_fetch_time ||
+			Date.now() - internalRemoteVersion.last_fetch_time > internalRemoteVersion.cache_timeout
+		) {
+			const raw = await internalRemoteVersion.fetchUrl(VERSION_URL);
+			const data = JSON.parse(raw);
+			internalRemoteVersion.last_result = data;
+			internalRemoteVersion.last_fetch_time = Date.now();
+		} else {
+			debug(logger, "Using cached remote version result");
+		}
+
+		const latestVersion = internalRemoteVersion.last_result.tag_name;
+		const version = pjson.version.split("-").shift().split(".");
+		const currentVersion = `v${version[0]}.${version[1]}.${version[2]}`;
+		return {
+			current: currentVersion,
+			latest: latestVersion,
+			update_available: internalRemoteVersion.compareVersions(currentVersion, latestVersion),
+		};
+	},
+
+	fetchUrl: (url) => {
+		const agent = new ProxyAgent();
+		const headers = {
+			"User-Agent": `NginxProxyManager v${pjson.version}`,
+		};
+
+		return new Promise((resolve, reject) => {
+			logger.info(`Fetching ${url}`);
+			return https
+				.get(url, { agent, headers }, (res) => {
+					res.setEncoding("utf8");
+					let raw_data = "";
+					res.on("data", (chunk) => {
+						raw_data += chunk;
+					});
+					res.on("end", () => {
+						resolve(raw_data);
+					});
+				})
+				.on("error", (err) => {
+					reject(err);
+				});
+		});
+	},
+
+	compareVersions: (current, latest) => {
+		const cleanCurrent = current.replace(/^v/, "");
+		const cleanLatest = latest.replace(/^v/, "");
+
+		const currentParts = cleanCurrent.split(".").map(Number);
+		const latestParts = cleanLatest.split(".").map(Number);
+
+		for (let i = 0; i < Math.max(currentParts.length, latestParts.length); i++) {
+			const curr = currentParts[i] || 0;
+			const lat = latestParts[i] || 0;
+
+			if (lat > curr) return true;
+			if (lat < curr) return false;
+		}
+		return false;
+	},
+};
+
+export default internalRemoteVersion;