Fix config change on WebUI causing hot reload in dev mode

As a side effect, hot-reloading the config is now a feature of SNS, so it's not exclusive to dev mode.

src/controllers/custom/getConfigDataController.ts

@@ -1,8 +1,8 @@
 import { RequestHandler } from "express";
-import configFile from "@/config.json";
+import { config } from "@/src/services/configService";
 
 const getConfigDataController: RequestHandler = (_req, res) => {
-    res.json(configFile);
+    res.json(config);
 };
 
 export { getConfigDataController };

src/controllers/custom/updateConfigDataController.ts

@@ -1,16 +1,9 @@
 import { RequestHandler } from "express";
-import path from "path";
-import fs from "fs";
-const rootDir = path.join(__dirname, "../../..");
+import { updateConfig } from "@/src/services/configService";
 
-const updateConfigDataController: RequestHandler = req => {
-    const updateSettingsData = req.body;
-
-    fs.writeFile(path.join(rootDir, "config.json"), updateSettingsData, function (err: any) {
-        if (err) {
-            return console.log(err);
-        }
-    });
+const updateConfigDataController: RequestHandler = async (req, res) => {
+    await updateConfig(req.body.toString());
+    res.end();
 };
 
 export { updateConfigDataController };

src/services/configService.ts

@@ -1,4 +1,22 @@
-import rawConfig from "@/config.json";
+import path from "path";
+import fs from "fs";
+import fsPromises from "fs/promises";
+import { logger } from "@/src/utils/logger";
+
+const rootDir = path.join(__dirname, "../..");
+const repoDir = path.basename(rootDir) == "build" ? path.join(rootDir, "..") : rootDir;
+const configPath = path.join(repoDir, "config.json");
+export const config: IConfig = JSON.parse(fs.readFileSync(configPath, "utf-8"));
+
+let amnesia = false;
+fs.watchFile(configPath, () => {
+    if (amnesia) {
+        amnesia = false;
+    } else {
+        logger.info("Detected a change to config.json, reloading its contents.");
+        Object.assign(config, JSON.parse(fs.readFileSync(configPath, "utf-8")));
+    }
+});
 
 interface IConfig {
     mongodbUrl: string;
@@ -26,4 +44,7 @@ interface ILoggerConfig {
     level: string; // "fatal" | "error" | "warn" | "info" | "http" | "debug" | "trace";
 }
 
-export const config: IConfig = rawConfig;
+export const updateConfig = async (data: string) => {
+    amnesia = true;
+    return await fsPromises.writeFile(configPath, data);
+};