fix: api helper voor extra error checks bij fetch dwengo api + schrijffout in controllers/themes

backend/src/controllers/themes.ts

@@ -17,7 +17,7 @@ function loadTranslations(language: string): Translations {
         return yaml.load(yamlFile) as Translations;
     } catch (error) {
         console.error(
-            `Cant load for language: ${language}, fallen back on dutch`
+            `Cannot load translation for: ${language}, fallen back to Dutch`
         );
         console.error(error);
         const fallbackPath = path.join(process.cwd(), '_i18n', 'nl.yml');

backend/src/routes/learningObjects.ts

@@ -3,9 +3,12 @@ import { getAllLearningObjects } from '../controllers/learningObjects.js';
 
 const router = express.Router();
 
+// DWENGO learning objects
+
 // Arg: hruid learningPath
 // Query: language
 // Route to fetch list of learning objects based on hruid of learning path
+// example: http://localhost:3000/learningObject/un_artificiele_intelligentie
 router.get('/:hruid', getAllLearningObjects);
 
 export default router;

backend/src/routes/learningPaths.ts

@@ -8,6 +8,8 @@ import {
 
 const router = express.Router();
 
+// DWENGO learning paths
+
 // Query: hruids(list), language
 // Route to fetch learning paths based on a list of HRUIDs
 // Example: http://localhost:3000/learningPath?hruids=pn_werking&hruids=art1

backend/src/services/learningObjects.ts

@@ -1,5 +1,6 @@
 import axios from 'axios';
 import { DWENGO_API_BASE } from '../config/config.js';
+import { fetchWithLogging } from "../util/apiHelper.js";
 
 interface LearningObjectNode {
     _id: string;
@@ -18,7 +19,7 @@ function filterLearningObjectMetadata(data: any, htmlUrl: string) {
 
         title: data.title,
         htmlUrl,
-        // Html content object
+        // Url to fetch html content
         language: data.language,
         difficulty: data.difficulty,
         estimatedTime: data.estimated_time,
@@ -50,15 +51,18 @@ export async function getLearningObjectsFromPath(
 ) {
     try {
         const learningPathUrl = `${DWENGO_API_BASE}/learningPath/${hruid}/${language}`;
-        const learningPathResponse = await axios.get(learningPathUrl);
+        const learningPathData = await fetchWithLogging<{ nodes: LearningObjectNode[] }>(
-        const nodes = learningPathResponse.data.nodes;
+            learningPathUrl,
+            `Learning path for HRUID "${hruid}" in language "${language}"`
+        );
 
-        if (!nodes || nodes.length === 0) {
+        if (!learningPathData || !learningPathData.nodes || learningPathData.nodes.length === 0) {
-            throw new Error('No learning objects found in this learning path.');
+            console.error(`⚠️ WARNING: Learning path "${hruid}" exists but contains no learning objects.`);
+            return [];
         }
 
         return await Promise.all(
-            nodes.map(async (node: LearningObjectNode) => {
+            learningPathData.nodes.map(async (node: LearningObjectNode) => {
                 const metadataUrl = `${DWENGO_API_BASE}/learningObject/getMetadata?hruid=${node.learningobject_hruid}&version=${node.version}&language=${language}`;
                 const metadataResponse = await axios.get(metadataUrl);
 
@@ -72,6 +76,5 @@ export async function getLearningObjectsFromPath(
         );
     } catch (error) {
         console.error('Error fetching learning objects:', error);
-        throw new Error('Failed to fetch learning objects.');
     }
 }

backend/src/util/apiHelper.ts

@@ -0,0 +1,29 @@
+import axios from 'axios';
+
+// !!!! when logger is done -> change
+
+/**
+ * Utility function to fetch data from an API endpoint with error handling.
+ * Logs errors but does NOT throw exceptions to keep the system running.
+ *
+ * @param url The API endpoint to fetch from.
+ * @param description A short description of what is being fetched (for logging).
+ * @returns The response data if successful, or null if an error occurs.
+ */
+export async function fetchWithLogging<T>(url: string, description: string): Promise<T | null> {
+    try {
+        const response = await axios.get<T>(url);
+        return response.data;
+    } catch (error: any) {
+        if (error.response) {
+            if (error.response.status === 404) {
+                console.error(`❌ ERROR: ${description} not found (404) at "${url}".`);
+            } else {
+                console.error(`❌ ERROR: Failed to fetch ${description}. Status: ${error.response.status} - ${error.response.statusText} (URL: "${url}")`);
+            }
+        } else {
+            console.error(`❌ ERROR: Network or unexpected error when fetching ${description}:`, error.message);
+        }
+        return null;
+    }
+}