Normalize backend protocol for web vitals reporting

Author: shayancoin

frontend/src/app/reportWebVitals.ts

@@ -3,12 +3,27 @@ import type { Metric } from 'next/app';
 const DEFAULT_ENDPOINT = '/observability/web-vitals';
 const APP_LABEL = process.env.NEXT_PUBLIC_WEB_VITALS_APP ?? 'frontend';
 
+function normalizeProtocol(protocol: string | undefined): string | undefined {
+  if (protocol === undefined) {
+    return undefined;
+  }
+
+  const trimmedProtocol = protocol.trim();
+
+  if (!trimmedProtocol) {
+    return undefined;
+  }
+
+  return trimmedProtocol.endsWith(':') ? trimmedProtocol : `${trimmedProtocol}:`;
+}
+
 function buildEndpoint(): string {
   if (typeof window === 'undefined') {
     return DEFAULT_ENDPOINT;
   }
 
-  const protocol = process.env.NEXT_PUBLIC_BACKEND_PROTOCOL ?? window.location.protocol ?? 'http:';
+  const normalizedProtocol = normalizeProtocol(process.env.NEXT_PUBLIC_BACKEND_PROTOCOL);
+  const protocol = normalizedProtocol ?? window.location.protocol ?? 'http:';
   const host = process.env.NEXT_PUBLIC_BACKEND_HOST ?? window.location.hostname;
   const port = process.env.NEXT_PUBLIC_BACKEND_PORT ?? '';
   const endpoint = process.env.NEXT_PUBLIC_WEB_VITALS_ENDPOINT ?? DEFAULT_ENDPOINT;