feat(backend): Added skeleton for a database learning object/path provider.

backend/src/services/learning-objects/database-learning-object-provider.ts

@@ -0,0 +1,42 @@
+import {LearningObjectProvider} from "./learning-object-provider";
+import {
+    FilteredLearningObject,
+    LearningObjectIdentifier,
+    LearningPathIdentifier
+} from "../../interfaces/learning-content";
+
+/**
+ * Service providing access to data about learning objects from the database
+ */
+const databaseLearningObjectProvider: LearningObjectProvider = {
+    /**
+     * Fetches a single learning object by its HRUID
+     */
+    getLearningObjectById(id: LearningObjectIdentifier): Promise<FilteredLearningObject | null> {
+        return Promise.resolve(null); // TODO
+    },
+
+    /**
+     * Fetch full learning object data (metadata)
+     */
+    getLearningObjectHTML(id: LearningObjectIdentifier): Promise<string | null> {
+        return Promise.resolve(null); // TODO
+    },
+
+    /**
+     * Fetch only learning object HRUIDs
+     */
+    getLearningObjectIdsFromPath(id: LearningPathIdentifier): Promise<string[]> {
+        return Promise.resolve([]);// TODO
+    },
+
+    /**
+     * Obtain a HTML-rendering of the learning object with the given identifier (as a string).
+     */
+    getLearningObjectsFromPath(id: LearningPathIdentifier): Promise<FilteredLearningObject[]> {
+        return Promise.resolve([]); // TODO
+    }
+
+}
+
+export default databaseLearningObjectProvider;

backend/src/services/learning-objects/learning-object-service.ts

@@ -5,9 +5,15 @@ import {
 } from "../../interfaces/learning-content";
 import dwengoApiLearningObjectProvider from "./dwengo-api-learning-object-provider";
 import {LearningObjectProvider} from "./learning-object-provider";
+import {EnvVars, getEnvVar} from "../../util/envvars";
+import databaseLearningObjectProvider from "./database-learning-object-provider";
 
 function getProvider(id: LearningObjectIdentifier): LearningObjectProvider {
-    return dwengoApiLearningObjectProvider
+    if (id.hruid.startsWith(getEnvVar(EnvVars.UserContentPrefix))) {
+        return databaseLearningObjectProvider;
+    } else {
+        return dwengoApiLearningObjectProvider;
+    }
 }
 
 /**

backend/src/services/learning-paths/database-learning-path-provider.ts

@@ -0,0 +1,23 @@
+import {LearningPathProvider} from "./learning-path-provider";
+import {LearningPath, LearningPathResponse} from "../../interfaces/learning-content";
+
+/**
+ * Service providing access to data about learning paths from the database.
+ */
+const databaseLearningPathProvider: LearningPathProvider = {
+    /**
+     * Fetch the learning paths with the given hruids from the database.
+     */
+    fetchLearningPaths(hruids: string[], language: string, source: string): Promise<LearningPathResponse> {
+        throw new Error("Not yet implemented"); // TODO
+    },
+
+    /**
+     * Search learning paths in the database using the given search string.
+     */
+    searchLearningPaths(query: string, language: string): Promise<LearningPath[]> {
+        return Promise.resolve([]); // TODO
+    }
+}
+
+export default databaseLearningPathProvider;

backend/src/services/learning-paths/learning-path-service.ts

@@ -1,5 +1,13 @@
-import {LearningPath, LearningPathResponse} from "../../interfaces/learning-content";
+import {
+    LearningPath,
+    LearningPathResponse
+} from "../../interfaces/learning-content";
 import dwengoApiLearningPathProvider from "./dwengo-api-learning-path-provider";
+import databaseLearningPathProvider from "./database-learning-path-provider";
+import {EnvVars, getEnvVar} from "../../util/envvars";
+
+const userContentPrefix = getEnvVar(EnvVars.UserContentPrefix);
+const allProviders = [dwengoApiLearningPathProvider, databaseLearningPathProvider]
 
 /**
  * Service providing access to data about learning paths from the appropriate data source (database or Dwengo-api)
@@ -8,15 +16,32 @@ const learningPathService = {
     /**
      * Fetch the learning paths with the given hruids from the data source.
      */
-    fetchLearningPaths(hruids: string[], language: string, source: string): Promise<LearningPathResponse> {
+    async fetchLearningPaths(hruids: string[], language: string, source: string): Promise<LearningPathResponse> {
-        return dwengoApiLearningPathProvider.fetchLearningPaths(hruids, language, source);
+        const userContentHruids = hruids.filter(hruid => hruid.startsWith(userContentPrefix));
+        const nonUserContentHruids = hruids.filter(hruid => !hruid.startsWith(userContentPrefix));
+
+        const userContentLearningPaths =
+            await databaseLearningPathProvider.fetchLearningPaths(userContentHruids, language, source);
+        const nonUserContentLearningPaths
+            = await databaseLearningPathProvider.fetchLearningPaths(nonUserContentHruids, language, source);
+
+        return {
+            data: (userContentLearningPaths.data || []).concat(nonUserContentLearningPaths.data || []),
+            source: source,
+            success: userContentLearningPaths.success || nonUserContentLearningPaths.success
+        };
     },
 
     /**
      * Search learning paths in the data source using the given search string.
      */
-    searchLearningPaths(query: string, language: string): Promise<LearningPath[]> {
+    async searchLearningPaths(query: string, language: string): Promise<LearningPath[]> {
-        return dwengoApiLearningPathProvider.searchLearningPaths(query, language);
+        const providerResponses = await Promise.all(
+            allProviders.map(
+                provider => provider.searchLearningPaths(query, language)
+            )
+        );
+        return providerResponses.flat();
     }
 }
 

backend/src/util/envvars.ts

@@ -13,6 +13,7 @@ export const EnvVars: { [key: string]: EnvVar } = {
     DbUpdate: { key: DB_PREFIX + 'UPDATE', defaultValue: false },
     LearningContentRepoApiBaseUrl: { key: PREFIX + "LEARNING_CONTENT_REPO_API_BASE_URL", defaultValue: "https://dwengo.org/backend/api"},
     FallbackLanguage: { key: PREFIX + "FALLBACK_LANGUAGE", defaultValue: "nl" },
+    UserContentPrefix: { key: DB_PREFIX + 'USER_CONTENT_PREFIX', defaultValue: "u_" },
 } as const;
 
 /**