fix: allow relative URLs in backend_url, add other checks for valid …

…URLs (ushahidi#682)

* fix: allow relative URLs in backend_url, add other checks for valid URLs

* Update environment.ts

* Update environment.ts

---------

Co-authored-by: Wisdom Ebong <30173059+webong@users.noreply.github.com>

apps/web-mzima-client/src/app/core/helpers/environment.ts

@@ -1,11 +1,28 @@
 export const checkBackendURL = (backendUrl: string) => {
-  if (backendUrl.indexOf('http') === -1) {
-    backendUrl = `https://${backendUrl}`;
+  const parseURL = (url: string) => {
+    try {
+      return new URL(url);
+    } catch (e) {
+      // Attempt to build based on the current document
+      if (e instanceof TypeError) {
+        return new URL(url, document.baseURI);
+      } else {
+        throw e;
+      }
+    }
+  };
+
+  const result = parseURL(backendUrl);
+
+  // Query string or hash not allowed
+  if (result.search !== '' || result.hash !== '') {
+    throw new Error('Invalid backend URL');
   }
 
-  if (backendUrl.slice(-1) !== '/') {
-    backendUrl = `${backendUrl}/`;
+  // Ensure the path ends in /
+  if (result.pathname.slice(-1) !== '/') {
+    result.pathname += '/';
   }
 
-  return backendUrl;
+  return result.href;
 };