Reduce image size by pruning stuff and things

Ref https://github.com/orgs/fosrl/discussions/2069

server/nextServer.ts

@@ -1,5 +1,7 @@
 import next from "next";
 import express from "express";
+import fs from "fs";
+import path from "path";
 import { parse } from "url";
 import logger from "@server/logger";
 import config from "@server/lib/config";
@@ -8,9 +10,28 @@ import { stripDuplicateSesions } from "./middlewares/stripDuplicateSessions";
 const nextPort = config.getRawConfig().server.next_port;
 
 export async function createNextServer() {
+    const dev = process.env.ENVIRONMENT !== "prod";
+
+    // The image only ships the files Next traced for its standalone output,
+    // which leaves out what is needed to load next.config at runtime. Hand
+    // Next the config resolved at build time instead, the same way the
+    // generated .next/standalone/server.js does.
+    const requiredServerFilesPath = path.join(
+        process.cwd(),
+        ".next",
+        "required-server-files.json"
+    );
+    if (!dev && fs.existsSync(requiredServerFilesPath)) {
+        const { config: nextConfig } = JSON.parse(
+            fs.readFileSync(requiredServerFilesPath, "utf8")
+        );
+        process.env.__NEXT_PRIVATE_STANDALONE_CONFIG =
+            JSON.stringify(nextConfig);
+    }
+
     //   const app = next({ dev });
     const app = next({
-        dev: process.env.ENVIRONMENT !== "prod",
+        dev,
         turbopack: false
     });
     const handle = app.getRequestHandler();