refactor: allow route prefix

apps/server/src/externals.ts

@@ -2,6 +2,9 @@
  * This file contains a list of constants that may need to be resolved at runtime
  */
 
+import { readFileSync, writeFileSync } from 'node:fs';
+import { resolve } from 'node:path';
+
 // =================================================
 // resolve running environment
 const env = process.env.NODE_ENV || 'production';
@@ -10,3 +13,25 @@ export const isTest = Boolean(process.env.IS_TEST);
 export const environment = isTest ? 'test' : env;
 export const isDocker = env === 'docker';
 export const isProduction = isDocker || (env === 'production' && !isTest);
+
+/**
+ * Updates the router prefix in the index.html file
+ * This is only needed in the cloud environment where the client is not at the root segment
+ * ie: https://cloud.getontime.com/client-hash/timer
+ */
+export function updateRouterPrefix(prefix: string | undefined = process.env.ROUTER_PREFIX) {
+  if (!prefix) {
+    return;
+  }
+
+  const indexFile = resolve('.', 'client', 'index.html');
+  try {
+    const data = readFileSync(indexFile, { encoding: 'utf-8', flag: 'r' }).replace(
+      /<base href="[^"]*">/g,
+      `<base href="${prefix}>"`,
+    );
+    writeFileSync(indexFile, data, { encoding: 'utf-8', flag: 'w' });
+  } catch (_error) {
+    /** unhandled */
+  }
+}