feat: Setup for option to run as express server

.vercelignore

@@ -1,3 +1,4 @@
 .env
 package-lock.json
-coverage
+coverage
+express

express/Dockerfile

@@ -0,0 +1,19 @@
+FROM node:18-alpine
+
+# Copy express/index.js, src, themes, vercel.json, package.json, and package-lock.json
+COPY api /app/api
+COPY express/*.js /app/express/
+COPY src /app/
+COPY themes /app/
+COPY vercel.json /app/
+COPY package.json /app/
+COPY package-lock.json /app/
+
+# Create app directory
+WORKDIR /app
+
+# Install app dependencies
+RUN npm ci --omit dev --ignore-scripts --no-audit
+
+# Run the app
+CMD [ "node", "express/index.js" ]

express/index.js

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+/**
+ * @file A simple express server variant of GRS can run GRS in a docker container.
+ * This is not intended to be used in the development; please use the `vercel dev`
+ * command instead.
+ */
+import { readFileSync } from "fs";
+import http from "http";
+import https from "https";
+import glob from "glob";
+import express from "express";
+import helmet from "helmet";
+import morgan from "morgan";
+
+import { getEnv } from "../src/common/utils.js";
+
+const ENVS = {
+  PORT: "PORT",
+  HTTPS_PORT: "HTTPS_PORT",
+  REDIRECT_HTTPS: "REDIRECT_HTTPS",
+  HTTPS_KEY: "HTTPS_KEY",
+  HTTPS_CERT: "HTTPS_CERT",
+  USE_HELMET: "USE_HELMET",
+  USE_MORGAN: "USE_MORGAN",
+  MORGAN_FORMAT: "MORGAN_FORMAT",
+}
+
+const vercelConfig = JSON.parse(readFileSync("./vercel.json", "utf8"));
+const vercelFunctions = Object.keys(vercelConfig.functions);
+
+const app = express();
+
+const files = vercelFunctions.map((gl) => glob.sync(gl)).flat();
+await loadApiRoutes(app, files);
+
+const httpPort = getEnv(ENVS.PORT, 3000);
+const httpsPort = getEnv(ENVS.HTTPS_PORT, 3443);
+
+if (
+  getEnv(ENVS.REDIRECT_HTTPS, "true") === "true"
+  && getEnv(ENVS.HTTPS_KEY)
+  && getEnv(ENVS.HTTPS_CERT)
+) {
+  app.use("*", redirectHttps);
+}
+
+if (getEnv(ENVS.USE_HELMET, "true") === "true") {
+  app.use(helmet());
+}
+
+if (getEnv(ENVS.USE_MORGAN, "true") === "true") {
+  app.use(morgan(getEnv(ENVS.MORGAN_FORMAT, "combined")));
+}
+
+const server = new Server(app)
+
+server.start(
+  { http: httpPort, https: httpsPort },
+  {
+    http: () => console.log(`HTTP server listening on port ${httpPort}`),
+    https: () => console.log(`HTTPS server listening on port ${httpsPort}`),
+  }
+);
+
+/**
+ * Loads all api routes from the given paths.
+ * @param {string[]} files Api endpoint files.
+ */
+async function loadApiRoutes(app, files) {
+  for (const file of files) {
+    const route = `/${file.replace(".js", "").replace("index", "")}`;
+    console.log(`Loading route '${route}' with handler from '${file}'`);
+    const handler = await import(`../${file}`);
+    app.get(route, handler.default);
+  }
+}
+
+/**
+ * A simple express middleware to redirect all HTTP requests to HTTPS.
+ * @param {import("express").Request} req
+ * @param {import("express").Response} res
+ * @param {import("express").NextFunction} next
+ * @returns {void}
+ */
+function redirectHttps(req, res, next) {
+  if (req.secure) {
+    next();
+  } else {
+    res.redirect(`https://${req.hostname}${req.url}`);
+  }
+}
+
+/**
+ * Simple wrapper around `http` and `https` node module.
+ * @returns {{ start: (options: { http: number, https: number }, cb: { http: () => void, https: () => void }) => void }}
+ */
+function Server (app) {
+  const tls = loadTLS();
+  if (tls) {
+    this.https = https.createServer(tls, app);
+  }
+  this.http = http.createServer(app);
+  this.start = function (port, callback) {
+    const result = {};
+    if (this.https && port.https) {
+      this.https = this.https.listen(port.https, callback.https);
+    }
+    this.http = this.http.listen(port.http, callback.http);
+    return result;
+  }
+}
+
+/**
+ * Attempts to loads the SSL/TLS certificate and key from the optional
+ * environment variables `HTTPS_CERT` and `HTTPS_KEY`.
+ * @returns {{
+ *   cert: typeof import("buffer").Buffer,
+ *   key: typeof import("buffer").Buffer
+ * }} The certificate and key.
+ */
+function loadTLS() {
+  if (!getEnv(ENVS.HTTPS_KEY) || !getEnv(ENVS.HTTPS_CERT)) return null
+  return {
+    key: readFileSync(getEnv(ENVS.HTTPS_KEY)),
+    cert: readFileSync(getEnv(ENVS.HTTPS_CERT)),
+  }
+}