Merge remote-tracking branch 'origin/dev' into feat/pagina-om-leerpaden-te-bekijken-#41

# Conflicts:
#	backend/src/controllers/learning-objects.ts
#	frontend/src/controllers/base-controller.ts

backend/src/app.ts

@@ -5,15 +5,16 @@ import cors from './middleware/cors.js';
 import { getLogger, Logger } from './logging/initalize.js';
 import { responseTimeLogger } from './logging/responseTimeLogger.js';
 import responseTime from 'response-time';
-import { EnvVars, getNumericEnvVar } from './util/envvars.js';
+import { envVars, getNumericEnvVar } from './util/envVars.js';
 import apiRouter from './routes/router.js';
 import swaggerMiddleware from './swagger.js';
 import swaggerUi from 'swagger-ui-express';
+import { errorHandler } from './middleware/error-handling/error-handler.js';
 
 const logger: Logger = getLogger();
 
 const app: Express = express();
-const port: string | number = getNumericEnvVar(EnvVars.Port);
+const port: string | number = getNumericEnvVar(envVars.Port);
 
 app.use(express.json());
 app.use(cors);
@@ -26,7 +27,9 @@ app.use('/api', apiRouter);
 // Swagger
 app.use('/api-docs', swaggerUi.serve, swaggerMiddleware);
 
-async function startServer() {
+app.use(errorHandler);
+
+async function startServer(): Promise<void> {
     await initORM();
 
     app.listen(port, () => {

backend/src/config.ts

@@ -1,7 +1,7 @@
-import { EnvVars, getEnvVar } from './util/envvars.js';
+import { envVars, getEnvVar } from './util/envVars.js';
 
 // API
-export const DWENGO_API_BASE = getEnvVar(EnvVars.LearningContentRepoApiBaseUrl);
-export const FALLBACK_LANG = getEnvVar(EnvVars.FallbackLanguage);
+export const DWENGO_API_BASE = getEnvVar(envVars.LearningContentRepoApiBaseUrl);
+export const FALLBACK_LANG = getEnvVar(envVars.FallbackLanguage);
 
 export const FALLBACK_SEQ_NUM = 1;

backend/src/controllers/assignments.ts

@@ -2,7 +2,7 @@ import { Request, Response } from 'express';
 import { createAssignment, getAllAssignments, getAssignment, getAssignmentsSubmissions } from '../services/assignments.js';
 import { AssignmentDTO } from '../interfaces/assignment.js';
 
-// Typescript is annoy with with parameter forwarding from class.ts
+// Typescript is annoying with parameter forwarding from class.ts
 interface AssignmentParams {
     classid: string;
     id: string;
@@ -41,7 +41,7 @@ export async function createAssignmentHandler(req: Request<AssignmentParams>, re
 }
 
 export async function getAssignmentHandler(req: Request<AssignmentParams>, res: Response): Promise<void> {
-    const id = +req.params.id;
+    const id = Number(req.params.id);
     const classid = req.params.classid;
 
     if (isNaN(id)) {
@@ -61,7 +61,7 @@ export async function getAssignmentHandler(req: Request<AssignmentParams>, res:
 
 export async function getAssignmentsSubmissionsHandler(req: Request<AssignmentParams>, res: Response): Promise<void> {
     const classid = req.params.classid;
-    const assignmentNumber = +req.params.id;
+    const assignmentNumber = Number(req.params.id);
     const full = req.query.full === 'true';
 
     if (isNaN(assignmentNumber)) {

backend/src/controllers/auth.ts

@@ -1,16 +1,16 @@
-import { EnvVars, getEnvVar } from '../util/envvars.js';
+import { envVars, getEnvVar } from '../util/envVars.js';
 
-type FrontendIdpConfig = {
+interface FrontendIdpConfig {
     authority: string;
     clientId: string;
     scope: string;
     responseType: string;
-};
+}
 
-type FrontendAuthConfig = {
+interface FrontendAuthConfig {
     student: FrontendIdpConfig;
     teacher: FrontendIdpConfig;
-};
+}
 
 const SCOPE = 'openid profile email';
 const RESPONSE_TYPE = 'code';
@@ -18,14 +18,14 @@ const RESPONSE_TYPE = 'code';
 export function getFrontendAuthConfig(): FrontendAuthConfig {
     return {
         student: {
-            authority: getEnvVar(EnvVars.IdpStudentUrl),
-            clientId: getEnvVar(EnvVars.IdpStudentClientId),
+            authority: getEnvVar(envVars.IdpStudentUrl),
+            clientId: getEnvVar(envVars.IdpStudentClientId),
             scope: SCOPE,
             responseType: RESPONSE_TYPE,
         },
         teacher: {
-            authority: getEnvVar(EnvVars.IdpTeacherUrl),
-            clientId: getEnvVar(EnvVars.IdpTeacherClientId),
+            authority: getEnvVar(envVars.IdpTeacherUrl),
+            clientId: getEnvVar(envVars.IdpTeacherClientId),
             scope: SCOPE,
             responseType: RESPONSE_TYPE,
         },

backend/src/controllers/groups.ts

@@ -12,14 +12,14 @@ interface GroupParams {
 export async function getGroupHandler(req: Request<GroupParams>, res: Response): Promise<void> {
     const classId = req.params.classid;
     const full = req.query.full === 'true';
-    const assignmentId = +req.params.assignmentid;
+    const assignmentId = Number(req.params.assignmentid);
 
     if (isNaN(assignmentId)) {
         res.status(400).json({ error: 'Assignment id must be a number' });
         return;
     }
 
-    const groupId = +req.params.groupid!; // Can't be undefined
+    const groupId = Number(req.params.groupid!); // Can't be undefined
 
     if (isNaN(groupId)) {
         res.status(400).json({ error: 'Group id must be a number' });
@@ -40,7 +40,7 @@ export async function getAllGroupsHandler(req: Request, res: Response): Promise<
     const classId = req.params.classid;
     const full = req.query.full === 'true';
 
-    const assignmentId = +req.params.assignmentid;
+    const assignmentId = Number(req.params.assignmentid);
 
     if (isNaN(assignmentId)) {
         res.status(400).json({ error: 'Assignment id must be a number' });
@@ -56,7 +56,7 @@ export async function getAllGroupsHandler(req: Request, res: Response): Promise<
 
 export async function createGroupHandler(req: Request, res: Response): Promise<void> {
     const classid = req.params.classid;
-    const assignmentId = +req.params.assignmentid;
+    const assignmentId = Number(req.params.assignmentid);
 
     if (isNaN(assignmentId)) {
         res.status(400).json({ error: 'Assignment id must be a number' });
@@ -78,14 +78,14 @@ export async function getGroupSubmissionsHandler(req: Request, res: Response): P
     const classId = req.params.classid;
     const full = req.query.full === 'true';
 
-    const assignmentId = +req.params.assignmentid;
+    const assignmentId = Number(req.params.assignmentid);
 
     if (isNaN(assignmentId)) {
         res.status(400).json({ error: 'Assignment id must be a number' });
         return;
     }
 
-    const groupId = +req.params.groupid!; // Can't be undefined
+    const groupId = Number(req.params.groupid); // Can't be undefined
 
     if (isNaN(groupId)) {
         res.status(400).json({ error: 'Group id must be a number' });

backend/src/controllers/learning-objects.ts

@@ -2,18 +2,19 @@ import { Request, Response } from 'express';
 import { FALLBACK_LANG } from '../config.js';
 import { FilteredLearningObject, LearningObjectIdentifier, LearningPathIdentifier } from '../interfaces/learning-content.js';
 import learningObjectService from '../services/learning-objects/learning-object-service.js';
-import { EnvVars, getEnvVar } from '../util/envvars.js';
 import { Language } from '../entities/content/language.js';
-import {BadRequestException, NotFoundException} from '../exceptions.js';
 import attachmentService from '../services/learning-objects/attachment-service.js';
+import { BadRequestException } from '../exceptions/bad-request-exception.js';
+import { NotFoundException } from '../exceptions/not-found-exception.js';
+import { envVars, getEnvVar } from '../util/envVars.js';
 
 function getLearningObjectIdentifierFromRequest(req: Request): LearningObjectIdentifier {
     if (!req.params.hruid) {
         throw new BadRequestException('HRUID is required.');
     }
     return {
-        hruid: req.params.hruid as string,
-        language: (req.query.language || getEnvVar(EnvVars.FallbackLanguage)) as Language,
+        hruid: req.params.hruid,
+        language: (req.query.language || getEnvVar(envVars.FallbackLanguage)) as Language,
         version: parseInt(req.query.version as string),
     };
 }
@@ -23,7 +24,7 @@ function getLearningPathIdentifierFromRequest(req: Request): LearningPathIdentif
         throw new BadRequestException('HRUID is required.');
     }
     return {
-        hruid: req.params.hruid as string,
+        hruid: req.params.hruid,
         language: (req.query.language as Language) || FALLBACK_LANG,
     };
 }

backend/src/controllers/learning-paths.ts

@@ -2,13 +2,14 @@ import { Request, Response } from 'express';
 import { themes } from '../data/themes.js';
 import { FALLBACK_LANG } from '../config.js';
 import learningPathService from '../services/learning-paths/learning-path-service.js';
-import { BadRequestException, NotFoundException } from '../exceptions.js';
 import { Language } from '../entities/content/language.js';
 import {
     PersonalizationTarget,
     personalizedForGroup,
     personalizedForStudent,
 } from '../services/learning-paths/learning-path-personalization-util.js';
+import { BadRequestException } from '../exceptions/bad-request-exception.js';
+import { NotFoundException } from '../exceptions/not-found-exception.js';
 
 /**
  * Fetch learning paths based on query parameters.

backend/src/controllers/questions.ts

@@ -17,7 +17,7 @@ function getObjectId(req: Request, res: Response): LearningObjectIdentifier | nu
     return {
         hruid,
         language: (lang as Language) || FALLBACK_LANG,
-        version: +version,
+        version: Number(version),
     };
 }
 

backend/src/controllers/students.ts

@@ -46,7 +46,7 @@ export async function getStudentHandler(req: Request, res: Response): Promise<vo
     res.json(user);
 }
 
-export async function createStudentHandler(req: Request, res: Response) {
+export async function createStudentHandler(req: Request, res: Response): Promise<void> {
     const userData = req.body as StudentDTO;
 
     if (!userData.username || !userData.firstName || !userData.lastName) {
@@ -68,7 +68,7 @@ export async function createStudentHandler(req: Request, res: Response) {
     res.status(201).json(newUser);
 }
 
-export async function deleteStudentHandler(req: Request, res: Response) {
+export async function deleteStudentHandler(req: Request, res: Response): Promise<void> {
     const username = req.params.username;
 
     if (!username) {
@@ -93,9 +93,7 @@ export async function getStudentClassesHandler(req: Request, res: Response): Pro
 
     const classes = await getStudentClasses(username, full);
 
-    res.json({
-        classes: classes,
-    });
+    res.json({ classes: classes });
 }
 
 // TODO

backend/src/controllers/submissions.ts

@@ -10,7 +10,7 @@ interface SubmissionParams {
 
 export async function getSubmissionHandler(req: Request<SubmissionParams>, res: Response): Promise<void> {
     const lohruid = req.params.hruid;
-    const submissionNumber = +req.params.id;
+    const submissionNumber = Number(req.params.id);
 
     if (isNaN(submissionNumber)) {
         res.status(400).json({ error: 'Submission number is not a number' });
@@ -30,7 +30,7 @@ export async function getSubmissionHandler(req: Request<SubmissionParams>, res:
     res.json(submission);
 }
 
-export async function createSubmissionHandler(req: Request, res: Response) {
+export async function createSubmissionHandler(req: Request, res: Response): Promise<void> {
     const submissionDTO = req.body as SubmissionDTO;
 
     const submission = await createSubmission(submissionDTO);
@@ -43,9 +43,9 @@ export async function createSubmissionHandler(req: Request, res: Response) {
     res.json(submission);
 }
 
-export async function deleteSubmissionHandler(req: Request, res: Response) {
+export async function deleteSubmissionHandler(req: Request, res: Response): Promise<void> {
     const hruid = req.params.hruid;
-    const submissionNumber = +req.params.id;
+    const submissionNumber = Number(req.params.id);
 
     const lang = languageMap[req.query.language as string] || Language.Dutch;
     const version = (req.query.version || 1) as number;

backend/src/controllers/teachers.ts

@@ -43,7 +43,7 @@ export async function getTeacherHandler(req: Request, res: Response): Promise<vo
     res.json(user);
 }
 
-export async function createTeacherHandler(req: Request, res: Response) {
+export async function createTeacherHandler(req: Request, res: Response): Promise<void> {
     const userData = req.body as TeacherDTO;
 
     if (!userData.username || !userData.firstName || !userData.lastName) {
@@ -63,7 +63,7 @@ export async function createTeacherHandler(req: Request, res: Response) {
     res.status(201).json(newUser);
 }
 
-export async function deleteTeacherHandler(req: Request, res: Response) {
+export async function deleteTeacherHandler(req: Request, res: Response): Promise<void> {
     const username = req.params.username;
 
     if (!username) {
@@ -83,7 +83,7 @@ export async function deleteTeacherHandler(req: Request, res: Response) {
 }
 
 export async function getTeacherClassHandler(req: Request, res: Response): Promise<void> {
-    const username = req.params.username as string;
+    const username = req.params.username;
     const full = req.query.full === 'true';
 
     if (!username) {
@@ -102,7 +102,7 @@ export async function getTeacherClassHandler(req: Request, res: Response): Promi
 }
 
 export async function getTeacherStudentHandler(req: Request, res: Response): Promise<void> {
-    const username = req.params.username as string;
+    const username = req.params.username;
     const full = req.query.full === 'true';
 
     if (!username) {
@@ -121,7 +121,7 @@ export async function getTeacherStudentHandler(req: Request, res: Response): Pro
 }
 
 export async function getTeacherQuestionHandler(req: Request, res: Response): Promise<void> {
-    const username = req.params.username as string;
+    const username = req.params.username;
     const full = req.query.full === 'true';
 
     if (!username) {

backend/src/controllers/themes.ts

@@ -3,25 +3,23 @@ import { themes } from '../data/themes.js';
 import { loadTranslations } from '../util/translation-helper.js';
 
 interface Translations {
-    curricula_page: {
-        [key: string]: { title: string; description?: string };
-    };
+    curricula_page: Record<string, { title: string; description?: string }>;
 }
 
-export function getThemesHandler(req: Request, res: Response) {
-    const language = (req.query.language as string)?.toLowerCase() || 'nl';
+export function getThemesHandler(req: Request, res: Response): void {
+    const language = ((req.query.language as string) || 'nl').toLowerCase();
     const translations = loadTranslations<Translations>(language);
     const themeList = themes.map((theme) => ({
         key: theme.title,
-        title: translations.curricula_page[theme.title]?.title || theme.title,
-        description: translations.curricula_page[theme.title]?.description,
+        title: translations.curricula_page[theme.title].title || theme.title,
+        description: translations.curricula_page[theme.title].description,
         image: `https://dwengo.org/images/curricula/logo_${theme.title}.png`,
     }));
 
     res.json(themeList);
 }
 
-export function getHruidsByThemeHandler(req: Request, res: Response) {
+export function getHruidsByThemeHandler(req: Request, res: Response): void {
     const themeKey = req.params.theme;
 
     if (!themeKey) {

backend/src/data/assignments/assignment-repository.ts

@@ -3,13 +3,13 @@ import { Assignment } from '../../entities/assignments/assignment.entity.js';
 import { Class } from '../../entities/classes/class.entity.js';
 
 export class AssignmentRepository extends DwengoEntityRepository<Assignment> {
-    public findByClassAndId(within: Class, id: number): Promise<Assignment | null> {
+    public async findByClassAndId(within: Class, id: number): Promise<Assignment | null> {
         return this.findOne({ within: within, id: id });
     }
-    public findAllAssignmentsInClass(within: Class): Promise<Assignment[]> {
+    public async findAllAssignmentsInClass(within: Class): Promise<Assignment[]> {
         return this.findAll({ where: { within: within } });
     }
-    public deleteByClassAndId(within: Class, id: number): Promise<void> {
+    public async deleteByClassAndId(within: Class, id: number): Promise<void> {
         return this.deleteWhere({ within: within, id: id });
     }
 }

backend/src/data/assignments/group-repository.ts

@@ -4,7 +4,7 @@ import { Assignment } from '../../entities/assignments/assignment.entity.js';
 import { Student } from '../../entities/users/student.entity.js';
 
 export class GroupRepository extends DwengoEntityRepository<Group> {
-    public findByAssignmentAndGroupNumber(assignment: Assignment, groupNumber: number): Promise<Group | null> {
+    public async findByAssignmentAndGroupNumber(assignment: Assignment, groupNumber: number): Promise<Group | null> {
         return this.findOne(
             {
                 assignment: assignment,
@@ -13,16 +13,16 @@ export class GroupRepository extends DwengoEntityRepository<Group> {
             { populate: ['members'] }
         );
     }
-    public findAllGroupsForAssignment(assignment: Assignment): Promise<Group[]> {
+    public async findAllGroupsForAssignment(assignment: Assignment): Promise<Group[]> {
         return this.findAll({
             where: { assignment: assignment },
             populate: ['members'],
         });
     }
-    public findAllGroupsWithStudent(student: Student): Promise<Group[]> {
+    public async findAllGroupsWithStudent(student: Student): Promise<Group[]> {
         return this.find({ members: student }, { populate: ['members'] });
     }
-    public deleteByAssignmentAndGroupNumber(assignment: Assignment, groupNumber: number) {
+    public async deleteByAssignmentAndGroupNumber(assignment: Assignment, groupNumber: number): Promise<void> {
         return this.deleteWhere({
             assignment: assignment,
             groupNumber: groupNumber,

backend/src/data/assignments/submission-repository.ts

@@ -5,7 +5,10 @@ import { LearningObjectIdentifier } from '../../entities/content/learning-object
 import { Student } from '../../entities/users/student.entity.js';
 
 export class SubmissionRepository extends DwengoEntityRepository<Submission> {
-    public findSubmissionByLearningObjectAndSubmissionNumber(loId: LearningObjectIdentifier, submissionNumber: number): Promise<Submission | null> {
+    public async findSubmissionByLearningObjectAndSubmissionNumber(
+        loId: LearningObjectIdentifier,
+        submissionNumber: number
+    ): Promise<Submission | null> {
         return this.findOne({
             learningObjectHruid: loId.hruid,
             learningObjectLanguage: loId.language,
@@ -14,7 +17,7 @@ export class SubmissionRepository extends DwengoEntityRepository<Submission> {
         });
     }
 
-    public findMostRecentSubmissionForStudent(loId: LearningObjectIdentifier, submitter: Student): Promise<Submission | null> {
+    public async findMostRecentSubmissionForStudent(loId: LearningObjectIdentifier, submitter: Student): Promise<Submission | null> {
         return this.findOne(
             {
                 learningObjectHruid: loId.hruid,
@@ -26,7 +29,7 @@ export class SubmissionRepository extends DwengoEntityRepository<Submission> {
         );
     }
 
-    public findMostRecentSubmissionForGroup(loId: LearningObjectIdentifier, group: Group): Promise<Submission | null> {
+    public async findMostRecentSubmissionForGroup(loId: LearningObjectIdentifier, group: Group): Promise<Submission | null> {
         return this.findOne(
             {
                 learningObjectHruid: loId.hruid,
@@ -38,15 +41,15 @@ export class SubmissionRepository extends DwengoEntityRepository<Submission> {
         );
     }
 
-    public findAllSubmissionsForGroup(group: Group): Promise<Submission[]> {
+    public async findAllSubmissionsForGroup(group: Group): Promise<Submission[]> {
         return this.find({ onBehalfOf: group });
     }
 
-    public findAllSubmissionsForStudent(student: Student): Promise<Submission[]> {
+    public async findAllSubmissionsForStudent(student: Student): Promise<Submission[]> {
         return this.find({ submitter: student });
     }
 
-    public deleteSubmissionByLearningObjectAndSubmissionNumber(loId: LearningObjectIdentifier, submissionNumber: number): Promise<void> {
+    public async deleteSubmissionByLearningObjectAndSubmissionNumber(loId: LearningObjectIdentifier, submissionNumber: number): Promise<void> {
         return this.deleteWhere({
             learningObjectHruid: loId.hruid,
             learningObjectLanguage: loId.language,

backend/src/data/classes/class-join-request-repository.ts

@@ -4,13 +4,13 @@ import { ClassJoinRequest } from '../../entities/classes/class-join-request.enti
 import { Student } from '../../entities/users/student.entity.js';
 
 export class ClassJoinRequestRepository extends DwengoEntityRepository<ClassJoinRequest> {
-    public findAllRequestsBy(requester: Student): Promise<ClassJoinRequest[]> {
+    public async findAllRequestsBy(requester: Student): Promise<ClassJoinRequest[]> {
         return this.findAll({ where: { requester: requester } });
     }
-    public findAllOpenRequestsTo(clazz: Class): Promise<ClassJoinRequest[]> {
+    public async findAllOpenRequestsTo(clazz: Class): Promise<ClassJoinRequest[]> {
         return this.findAll({ where: { class: clazz } });
     }
-    public deleteBy(requester: Student, clazz: Class): Promise<void> {
+    public async deleteBy(requester: Student, clazz: Class): Promise<void> {
         return this.deleteWhere({ requester: requester, class: clazz });
     }
 }

backend/src/data/classes/class-repository.ts

@@ -4,20 +4,20 @@ import { Student } from '../../entities/users/student.entity.js';
 import { Teacher } from '../../entities/users/teacher.entity';
 
 export class ClassRepository extends DwengoEntityRepository<Class> {
-    public findById(id: string): Promise<Class | null> {
+    public async findById(id: string): Promise<Class | null> {
         return this.findOne({ classId: id }, { populate: ['students', 'teachers'] });
     }
-    public deleteById(id: string): Promise<void> {
+    public async deleteById(id: string): Promise<void> {
         return this.deleteWhere({ classId: id });
     }
-    public findByStudent(student: Student): Promise<Class[]> {
+    public async findByStudent(student: Student): Promise<Class[]> {
         return this.find(
             { students: student },
             { populate: ['students', 'teachers'] } // Voegt student en teacher objecten toe
         );
     }
 
-    public findByTeacher(teacher: Teacher): Promise<Class[]> {
+    public async findByTeacher(teacher: Teacher): Promise<Class[]> {
         return this.find({ teachers: teacher }, { populate: ['students', 'teachers'] });
     }
 }

backend/src/data/classes/teacher-invitation-repository.ts

@@ -4,16 +4,16 @@ import { TeacherInvitation } from '../../entities/classes/teacher-invitation.ent
 import { Teacher } from '../../entities/users/teacher.entity.js';
 
 export class TeacherInvitationRepository extends DwengoEntityRepository<TeacherInvitation> {
-    public findAllInvitationsForClass(clazz: Class): Promise<TeacherInvitation[]> {
+    public async findAllInvitationsForClass(clazz: Class): Promise<TeacherInvitation[]> {
         return this.findAll({ where: { class: clazz } });
     }
-    public findAllInvitationsBy(sender: Teacher): Promise<TeacherInvitation[]> {
+    public async findAllInvitationsBy(sender: Teacher): Promise<TeacherInvitation[]> {
         return this.findAll({ where: { sender: sender } });
     }
-    public findAllInvitationsFor(receiver: Teacher): Promise<TeacherInvitation[]> {
+    public async findAllInvitationsFor(receiver: Teacher): Promise<TeacherInvitation[]> {
         return this.findAll({ where: { receiver: receiver } });
     }
-    public deleteBy(clazz: Class, sender: Teacher, receiver: Teacher): Promise<void> {
+    public async deleteBy(clazz: Class, sender: Teacher, receiver: Teacher): Promise<void> {
         return this.deleteWhere({
             sender: sender,
             receiver: receiver,

backend/src/data/content/attachment-repository.ts

@@ -4,7 +4,7 @@ import { Language } from '../../entities/content/language';
 import { LearningObjectIdentifier } from '../../entities/content/learning-object-identifier';
 
 export class AttachmentRepository extends DwengoEntityRepository<Attachment> {
-    public findByLearningObjectIdAndName(learningObjectId: LearningObjectIdentifier, name: string): Promise<Attachment | null> {
+    public async findByLearningObjectIdAndName(learningObjectId: LearningObjectIdentifier, name: string): Promise<Attachment | null> {
         return this.findOne({
             learningObject: {
                 hruid: learningObjectId.hruid,
@@ -15,7 +15,11 @@ export class AttachmentRepository extends DwengoEntityRepository<Attachment> {
         });
     }
 
-    public findByMostRecentVersionOfLearningObjectAndName(hruid: string, language: Language, attachmentName: string): Promise<Attachment | null> {
+    public async findByMostRecentVersionOfLearningObjectAndName(
+        hruid: string,
+        language: Language,
+        attachmentName: string
+    ): Promise<Attachment | null> {
         return this.findOne(
             {
                 learningObject: {

backend/src/data/content/learning-object-repository.ts

@@ -5,7 +5,7 @@ import { Language } from '../../entities/content/language.js';
 import { Teacher } from '../../entities/users/teacher.entity.js';
 
 export class LearningObjectRepository extends DwengoEntityRepository<LearningObject> {
-    public findByIdentifier(identifier: LearningObjectIdentifier): Promise<LearningObject | null> {
+    public async findByIdentifier(identifier: LearningObjectIdentifier): Promise<LearningObject | null> {
         return this.findOne(
             {
                 hruid: identifier.hruid,
@@ -18,7 +18,7 @@ export class LearningObjectRepository extends DwengoEntityRepository<LearningObj
         );
     }
 
-    public findLatestByHruidAndLanguage(hruid: string, language: Language) {
+    public async findLatestByHruidAndLanguage(hruid: string, language: Language): Promise<LearningObject | null> {
         return this.findOne(
             {
                 hruid: hruid,
@@ -33,7 +33,7 @@ export class LearningObjectRepository extends DwengoEntityRepository<LearningObj
         );
     }
 
-    public findAllByTeacher(teacher: Teacher): Promise<LearningObject[]> {
+    public async findAllByTeacher(teacher: Teacher): Promise<LearningObject[]> {
         return this.find(
             { admins: teacher },
             { populate: ['admins'] } // Make sure to load admin relations

backend/src/data/content/learning-path-repository.ts

@@ -3,7 +3,7 @@ import { LearningPath } from '../../entities/content/learning-path.entity.js';
 import { Language } from '../../entities/content/language.js';
 
 export class LearningPathRepository extends DwengoEntityRepository<LearningPath> {
-    public findByHruidAndLanguage(hruid: string, language: Language): Promise<LearningPath | null> {
+    public async findByHruidAndLanguage(hruid: string, language: Language): Promise<LearningPath | null> {
         return this.findOne({ hruid: hruid, language: language }, { populate: ['nodes', 'nodes.transitions'] });
     }
 

backend/src/data/dwengo-entity-repository.ts

@@ -1,12 +1,14 @@
 import { EntityRepository, FilterQuery } from '@mikro-orm/core';
+import { EntityAlreadyExistsException } from '../exceptions/entity-already-exists-exception.js';
 
 export abstract class DwengoEntityRepository<T extends object> extends EntityRepository<T> {
-    public async save(entity: T) {
-        const em = this.getEntityManager();
-        em.persist(entity);
-        await em.flush();
+    public async save(entity: T, options?: { preventOverwrite?: boolean }): Promise<void> {
+        if (options?.preventOverwrite && (await this.findOne(entity))) {
+            throw new EntityAlreadyExistsException(`A ${this.getEntityName()} with this identifier already exists.`);
+        }
+        await this.getEntityManager().persistAndFlush(entity);
     }
-    public async deleteWhere(query: FilterQuery<T>) {
+    public async deleteWhere(query: FilterQuery<T>): Promise<void> {
         const toDelete = await this.findOne(query);
         const em = this.getEntityManager();
         if (toDelete) {

backend/src/data/questions/answer-repository.ts

@@ -4,7 +4,7 @@ import { Question } from '../../entities/questions/question.entity.js';
 import { Teacher } from '../../entities/users/teacher.entity.js';
 
 export class AnswerRepository extends DwengoEntityRepository<Answer> {
-    public createAnswer(answer: { toQuestion: Question; author: Teacher; content: string }): Promise<Answer> {
+    public async createAnswer(answer: { toQuestion: Question; author: Teacher; content: string }): Promise<Answer> {
         const answerEntity = this.create({
             toQuestion: answer.toQuestion,
             author: answer.author,
@@ -13,13 +13,13 @@ export class AnswerRepository extends DwengoEntityRepository<Answer> {
         });
         return this.insert(answerEntity);
     }
-    public findAllAnswersToQuestion(question: Question): Promise<Answer[]> {
+    public async findAllAnswersToQuestion(question: Question): Promise<Answer[]> {
         return this.findAll({
             where: { toQuestion: question },
             orderBy: { sequenceNumber: 'ASC' },
         });
     }
-    public removeAnswerByQuestionAndSequenceNumber(question: Question, sequenceNumber: number): Promise<void> {
+    public async removeAnswerByQuestionAndSequenceNumber(question: Question, sequenceNumber: number): Promise<void> {
         return this.deleteWhere({
             toQuestion: question,
             sequenceNumber: sequenceNumber,

backend/src/data/questions/question-repository.ts

@@ -5,7 +5,7 @@ import { Student } from '../../entities/users/student.entity.js';
 import { LearningObject } from '../../entities/content/learning-object.entity.js';
 
 export class QuestionRepository extends DwengoEntityRepository<Question> {
-    public createQuestion(question: { loId: LearningObjectIdentifier; author: Student; content: string }): Promise<Question> {
+    public async createQuestion(question: { loId: LearningObjectIdentifier; author: Student; content: string }): Promise<Question> {
         const questionEntity = this.create({
             learningObjectHruid: question.loId.hruid,
             learningObjectLanguage: question.loId.language,
@@ -21,7 +21,7 @@ export class QuestionRepository extends DwengoEntityRepository<Question> {
         questionEntity.content = question.content;
         return this.insert(questionEntity);
     }
-    public findAllQuestionsAboutLearningObject(loId: LearningObjectIdentifier): Promise<Question[]> {
+    public async findAllQuestionsAboutLearningObject(loId: LearningObjectIdentifier): Promise<Question[]> {
         return this.findAll({
             where: {
                 learningObjectHruid: loId.hruid,
@@ -33,7 +33,7 @@ export class QuestionRepository extends DwengoEntityRepository<Question> {
             },
         });
     }
-    public removeQuestionByLearningObjectAndSequenceNumber(loId: LearningObjectIdentifier, sequenceNumber: number): Promise<void> {
+    public async removeQuestionByLearningObjectAndSequenceNumber(loId: LearningObjectIdentifier, sequenceNumber: number): Promise<void> {
         return this.deleteWhere({
             learningObjectHruid: loId.hruid,
             learningObjectLanguage: loId.language,

backend/src/data/repositories.ts

@@ -34,8 +34,8 @@ let entityManager: EntityManager | undefined;
 /**
  * Execute all the database operations within the function f in a single transaction.
  */
-export function transactional<T>(f: () => Promise<T>) {
-    entityManager?.transactional(f);
+export async function transactional<T>(f: () => Promise<T>): Promise<void> {
+    await entityManager?.transactional(f);
 }
 
 function repositoryGetter<T extends AnyEntity, R extends EntityRepository<T>>(entity: EntityName<T>): () => R {

backend/src/data/users/student-repository.ts

@@ -1,14 +1,11 @@
 import { Student } from '../../entities/users/student.entity.js';
 import { DwengoEntityRepository } from '../dwengo-entity-repository.js';
-// Import { UserRepository } from './user-repository.js';
-
-// Export class StudentRepository extends UserRepository<Student> {}
 
 export class StudentRepository extends DwengoEntityRepository<Student> {
-    public findByUsername(username: string): Promise<Student | null> {
+    public async findByUsername(username: string): Promise<Student | null> {
         return this.findOne({ username: username });
     }
-    public deleteByUsername(username: string): Promise<void> {
+    public async deleteByUsername(username: string): Promise<void> {
         return this.deleteWhere({ username: username });
     }
 }

backend/src/data/users/teacher-repository.ts

@@ -2,10 +2,10 @@ import { Teacher } from '../../entities/users/teacher.entity.js';
 import { DwengoEntityRepository } from '../dwengo-entity-repository.js';
 
 export class TeacherRepository extends DwengoEntityRepository<Teacher> {
-    public findByUsername(username: string): Promise<Teacher | null> {
+    public async findByUsername(username: string): Promise<Teacher | null> {
         return this.findOne({ username: username });
     }
-    public deleteByUsername(username: string): Promise<void> {
+    public async deleteByUsername(username: string): Promise<void> {
         return this.deleteWhere({ username: username });
     }
 }

backend/src/data/users/user-repository.ts

@@ -2,10 +2,10 @@ import { DwengoEntityRepository } from '../dwengo-entity-repository.js';
 import { User } from '../../entities/users/user.entity.js';
 
 export class UserRepository<T extends User> extends DwengoEntityRepository<T> {
-    public findByUsername(username: string): Promise<T | null> {
+    public async findByUsername(username: string): Promise<T | null> {
         return this.findOne({ username } as Partial<T>);
     }
-    public deleteByUsername(username: string): Promise<void> {
+    public async deleteByUsername(username: string): Promise<void> {
         return this.deleteWhere({ username } as Partial<T>);
     }
 }

backend/src/entities/assignments/submission.entity.ts

@@ -16,7 +16,7 @@ export class Submission {
     learningObjectLanguage!: Language;
 
     @PrimaryKey({ type: 'numeric' })
-    learningObjectVersion: number = 1;
+    learningObjectVersion = 1;
 
     @PrimaryKey({ type: 'integer', autoincrement: true })
     submissionNumber?: number;

backend/src/entities/content/educational-goal.entity.ts

@@ -0,0 +1,10 @@
+import { Embeddable, Property } from '@mikro-orm/core';
+
+@Embeddable()
+export class EducationalGoal {
+    @Property({ type: 'string' })
+    source!: string;
+
+    @Property({ type: 'string' })
+    id!: string;
+}

backend/src/entities/content/learning-object-identifier.ts

@@ -5,5 +5,7 @@ export class LearningObjectIdentifier {
         public hruid: string,
         public language: Language,
         public version: number
-    ) {}
+    ) {
+        // Do nothing
+    }
 }

backend/src/entities/content/learning-object.entity.ts

@@ -1,28 +1,12 @@
-import { Embeddable, Embedded, Entity, Enum, ManyToMany, OneToMany, PrimaryKey, Property } from '@mikro-orm/core';
+import { Embedded, Entity, Enum, ManyToMany, OneToMany, PrimaryKey, Property } from '@mikro-orm/core';
 import { Language } from './language.js';
 import { Attachment } from './attachment.entity.js';
 import { Teacher } from '../users/teacher.entity.js';
 import { DwengoContentType } from '../../services/learning-objects/processing/content-type.js';
 import { v4 } from 'uuid';
 import { LearningObjectRepository } from '../../data/content/learning-object-repository.js';
-
-@Embeddable()
-export class EducationalGoal {
-    @Property({ type: 'string' })
-    source!: string;
-
-    @Property({ type: 'string' })
-    id!: string;
-}
-
-@Embeddable()
-export class ReturnValue {
-    @Property({ type: 'string' })
-    callbackUrl!: string;
-
-    @Property({ type: 'json' })
-    callbackSchema!: string;
-}
+import { EducationalGoal } from './educational-goal.entity.js';
+import { ReturnValue } from './return-value.entity.js';
 
 @Entity({ repository: () => LearningObjectRepository })
 export class LearningObject {
@@ -36,7 +20,7 @@ export class LearningObject {
     language!: Language;
 
     @PrimaryKey({ type: 'number' })
-    version: number = 1;
+    version = 1;
 
     @Property({ type: 'uuid', unique: true })
     uuid = v4();
@@ -62,7 +46,7 @@ export class LearningObject {
     targetAges?: number[] = [];
 
     @Property({ type: 'bool' })
-    teacherExclusive: boolean = false;
+    teacherExclusive = false;
 
     @Property({ type: 'array' })
     skosConcepts: string[] = [];
@@ -74,10 +58,10 @@ export class LearningObject {
     educationalGoals: EducationalGoal[] = [];
 
     @Property({ type: 'string' })
-    copyright: string = '';
+    copyright = '';
 
     @Property({ type: 'string' })
-    license: string = '';
+    license = '';
 
     @Property({ type: 'smallint', nullable: true })
     difficulty?: number;
@@ -91,7 +75,7 @@ export class LearningObject {
     returnValue!: ReturnValue;
 
     @Property({ type: 'bool' })
-    available: boolean = true;
+    available = true;
 
     @Property({ type: 'string', nullable: true })
     contentLocation?: string;

backend/src/entities/content/return-value.entity.ts

@@ -0,0 +1,10 @@
+import { Embeddable, Property } from '@mikro-orm/core';
+
+@Embeddable()
+export class ReturnValue {
+    @Property({ type: 'string' })
+    callbackUrl!: string;
+
+    @Property({ type: 'json' })
+    callbackSchema!: string;
+}

backend/src/entities/questions/question.entity.ts

@@ -15,7 +15,7 @@ export class Question {
     learningObjectLanguage!: Language;
 
     @PrimaryKey({ type: 'number' })
-    learningObjectVersion: number = 1;
+    learningObjectVersion = 1;
 
     @PrimaryKey({ type: 'integer', autoincrement: true })
     sequenceNumber?: number;

backend/src/entities/users/student.entity.ts

@@ -13,12 +13,4 @@ export class Student extends User {
 
     @ManyToMany(() => Group)
     groups!: Collection<Group>;
-
-    constructor(
-        public username: string,
-        public firstName: string,
-        public lastName: string
-    ) {
-        super();
-    }
 }

backend/src/entities/users/teacher.entity.ts

@@ -7,12 +7,4 @@ import { TeacherRepository } from '../../data/users/teacher-repository.js';
 export class Teacher extends User {
     @ManyToMany(() => Class)
     classes!: Collection<Class>;
-
-    constructor(
-        public username: string,
-        public firstName: string,
-        public lastName: string
-    ) {
-        super();
-    }
 }

backend/src/entities/users/user.entity.ts

@@ -6,8 +6,8 @@ export abstract class User {
     username!: string;
 
     @Property()
-    firstName: string = '';
+    firstName = '';
 
     @Property()
-    lastName: string = '';
+    lastName = '';
 }

backend/src/exceptions.ts

@@ -1,42 +0,0 @@
-/**
- * Exception for HTTP 400 Bad Request
- */
-export class BadRequestException extends Error {
-    public status = 400;
-
-    constructor(error: string) {
-        super(error);
-    }
-}
-
-/**
- * Exception for HTTP 401 Unauthorized
- */
-export class UnauthorizedException extends Error {
-    status = 401;
-    constructor(message: string = 'Unauthorized') {
-        super(message);
-    }
-}
-
-/**
- * Exception for HTTP 403 Forbidden
- */
-export class ForbiddenException extends Error {
-    status = 403;
-
-    constructor(message: string = 'Forbidden') {
-        super(message);
-    }
-}
-
-/**
- * Exception for HTTP 404 Not Found
- */
-export class NotFoundException extends Error {
-    public status = 404;
-
-    constructor(error: string) {
-        super(error);
-    }
-}

backend/src/exceptions/bad-request-exception.ts

@@ -0,0 +1,10 @@
+import { ExceptionWithHttpState } from './exception-with-http-state.js';
+
+/**
+ * Exception for HTTP 400 Bad Request
+ */
+export class BadRequestException extends ExceptionWithHttpState {
+    constructor(error: string) {
+        super(400, error);
+    }
+}

backend/src/exceptions/conflict-exception.ts

@@ -0,0 +1,12 @@
+import { ExceptionWithHttpState } from './exception-with-http-state.js';
+
+/**
+ * Exception for HTTP 409 Conflict
+ */
+export class ConflictException extends ExceptionWithHttpState {
+    public status = 409;
+
+    constructor(error: string) {
+        super(409, error);
+    }
+}

backend/src/exceptions/entity-already-exists-exception.ts

@@ -0,0 +1,7 @@
+import { ConflictException } from './conflict-exception.js';
+
+export class EntityAlreadyExistsException extends ConflictException {
+    constructor(message: string) {
+        super(message);
+    }
+}

backend/src/exceptions/exception-with-http-state.ts

@@ -0,0 +1,11 @@
+/**
+ * Exceptions which are associated with a HTTP error code.
+ */
+export abstract class ExceptionWithHttpState extends Error {
+    constructor(
+        public status: number,
+        public error: string
+    ) {
+        super(error);
+    }
+}

backend/src/exceptions/forbidden-exception.ts

@@ -0,0 +1,12 @@
+import { ExceptionWithHttpState } from './exception-with-http-state.js';
+
+/**
+ * Exception for HTTP 403 Forbidden
+ */
+export class ForbiddenException extends ExceptionWithHttpState {
+    status = 403;
+
+    constructor(message = 'Forbidden') {
+        super(403, message);
+    }
+}

backend/src/exceptions/not-found-exception.ts

@@ -0,0 +1,12 @@
+import { ExceptionWithHttpState } from './exception-with-http-state.js';
+
+/**
+ * Exception for HTTP 404 Not Found
+ */
+export class NotFoundException extends ExceptionWithHttpState {
+    public status = 404;
+
+    constructor(error: string) {
+        super(404, error);
+    }
+}

backend/src/exceptions/unauthorized-exception.ts

@@ -0,0 +1,10 @@
+import { ExceptionWithHttpState } from './exception-with-http-state.js';
+
+/**
+ * Exception for HTTP 401 Unauthorized
+ */
+export class UnauthorizedException extends ExceptionWithHttpState {
+    constructor(message = 'Unauthorized') {
+        super(401, message);
+    }
+}

backend/src/interfaces/assignment.ts

@@ -3,6 +3,7 @@ import { Assignment } from '../entities/assignments/assignment.entity.js';
 import { Class } from '../entities/classes/class.entity.js';
 import { languageMap } from '../entities/content/language.js';
 import { GroupDTO } from './group.js';
+import { getLogger } from '../logging/initalize.js';
 
 export interface AssignmentDTO {
     id: number;
@@ -46,5 +47,7 @@ export function mapToAssignment(assignmentData: AssignmentDTO, cls: Class): Assi
     assignment.learningPathLanguage = languageMap[assignmentData.language] || FALLBACK_LANG;
     assignment.within = cls;
 
+    getLogger().debug(assignment);
+
     return assignment;
 }

backend/src/interfaces/learning-content.ts

@@ -58,7 +58,7 @@ export interface EducationalGoal {
 
 export interface ReturnValue {
     callback_url: string;
-    callback_schema: Record<string, any>;
+    callback_schema: Record<string, unknown>;
 }
 
 export interface LearningObjectMetadata {

backend/src/interfaces/student.ts

@@ -1,4 +1,5 @@
 import { Student } from '../entities/users/student.entity.js';
+import { getStudentRepository } from '../data/repositories.js';
 
 export interface StudentDTO {
     id: string;
@@ -23,7 +24,9 @@ export function mapToStudentDTO(student: Student): StudentDTO {
 }
 
 export function mapToStudent(studentData: StudentDTO): Student {
-    const student = new Student(studentData.username, studentData.firstName, studentData.lastName);
-
-    return student;
+    return getStudentRepository().create({
+        username: studentData.username,
+        firstName: studentData.firstName,
+        lastName: studentData.lastName,
+    });
 }

backend/src/interfaces/teacher.ts

@@ -1,4 +1,5 @@
 import { Teacher } from '../entities/users/teacher.entity.js';
+import { getTeacherRepository } from '../data/repositories.js';
 
 export interface TeacherDTO {
     id: string;
@@ -22,8 +23,10 @@ export function mapToTeacherDTO(teacher: Teacher): TeacherDTO {
     };
 }
 
-export function mapToTeacher(TeacherData: TeacherDTO): Teacher {
-    const teacher = new Teacher(TeacherData.username, TeacherData.firstName, TeacherData.lastName);
-
-    return teacher;
+export function mapToTeacher(teacherData: TeacherDTO): Teacher {
+    return getTeacherRepository().create({
+        username: teacherData.username,
+        firstName: teacherData.firstName,
+        lastName: teacherData.lastName,
+    });
 }

backend/src/logging/initalize.ts

@@ -1,7 +1,7 @@
 import { createLogger, format, Logger as WinstonLogger, transports } from 'winston';
 import LokiTransport from 'winston-loki';
 import { LokiLabels } from 'loki-logger-ts';
-import { EnvVars, getEnvVar } from '../util/envvars.js';
+import { envVars, getEnvVar } from '../util/envVars.js';
 
 export class Logger extends WinstonLogger {
     constructor() {
@@ -9,7 +9,7 @@ export class Logger extends WinstonLogger {
     }
 }
 
-const Labels: LokiLabels = {
+const lokiLabels: LokiLabels = {
     source: 'Dwengo-Backend',
     service: 'API',
     host: 'localhost',
@@ -22,28 +22,28 @@ function initializeLogger(): Logger {
         return logger;
     }
 
-    const logLevel = getEnvVar(EnvVars.LogLevel);
+    const logLevel = getEnvVar(envVars.LogLevel);
 
     const consoleTransport = new transports.Console({
-        level: getEnvVar(EnvVars.LogLevel),
+        level: getEnvVar(envVars.LogLevel),
         format: format.combine(format.cli(), format.colorize()),
     });
 
-    if (getEnvVar(EnvVars.RunMode) === 'dev') {
+    if (getEnvVar(envVars.RunMode) === 'dev') {
         return createLogger({
             transports: [consoleTransport],
         });
     }
 
-    const lokiHost = getEnvVar(EnvVars.LokiHost);
+    const lokiHost = getEnvVar(envVars.LokiHost);
 
     const lokiTransport: LokiTransport = new LokiTransport({
         host: lokiHost,
-        labels: Labels,
+        labels: lokiLabels,
         level: logLevel,
         json: true,
         format: format.combine(format.timestamp(), format.json()),
-        onConnectionError: (err) => {
+        onConnectionError: (err): void => {
             // eslint-disable-next-line no-console
             console.error(`Connection error: ${err}`);
         },

backend/src/logging/mikroOrmLogger.ts

@@ -5,35 +5,54 @@ import { LokiLabels } from 'loki-logger-ts';
 export class MikroOrmLogger extends DefaultLogger {
     private logger: Logger = getLogger();
 
-    log(namespace: LoggerNamespace, message: string, context?: LogContext) {
+    static createMessage(namespace: LoggerNamespace, messageArg: string, context?: LogContext): unknown {
+        const labels: LokiLabels = {
+            service: 'ORM',
+        };
+
+        let message: string;
+        if (context?.label) {
+            message = `[${namespace}] (${context.label}) ${messageArg}`;
+        } else {
+            message = `[${namespace}] ${messageArg}`;
+        }
+
+        return {
+            message: message,
+            labels: labels,
+            context: context,
+        };
+    }
+
+    log(namespace: LoggerNamespace, message: string, context?: LogContext): void {
         if (!this.isEnabled(namespace, context)) {
             return;
         }
 
         switch (namespace) {
             case 'query':
-                this.logger.debug(this.createMessage(namespace, message, context));
+                this.logger.debug(MikroOrmLogger.createMessage(namespace, message, context));
                 break;
             case 'query-params':
                 // TODO Which log level should this be?
-                this.logger.info(this.createMessage(namespace, message, context));
+                this.logger.info(MikroOrmLogger.createMessage(namespace, message, context));
                 break;
             case 'schema':
-                this.logger.info(this.createMessage(namespace, message, context));
+                this.logger.info(MikroOrmLogger.createMessage(namespace, message, context));
                 break;
             case 'discovery':
-                this.logger.debug(this.createMessage(namespace, message, context));
+                this.logger.debug(MikroOrmLogger.createMessage(namespace, message, context));
                 break;
             case 'info':
-                this.logger.info(this.createMessage(namespace, message, context));
+                this.logger.info(MikroOrmLogger.createMessage(namespace, message, context));
                 break;
             case 'deprecated':
-                this.logger.warn(this.createMessage(namespace, message, context));
+                this.logger.warn(MikroOrmLogger.createMessage(namespace, message, context));
                 break;
             default:
                 switch (context?.level) {
                     case 'info':
-                        this.logger.info(this.createMessage(namespace, message, context));
+                        this.logger.info(MikroOrmLogger.createMessage(namespace, message, context));
                         break;
                     case 'warning':
                         this.logger.warn(message);
@@ -47,23 +66,4 @@ export class MikroOrmLogger extends DefaultLogger {
                 }
         }
     }
-
-    private createMessage(namespace: LoggerNamespace, messageArg: string, context?: LogContext) {
-        const labels: LokiLabels = {
-            service: 'ORM',
-        };
-
-        let message: string;
-        if (context?.label) {
-            message = `[${namespace}] (${context?.label}) ${messageArg}`;
-        } else {
-            message = `[${namespace}] ${messageArg}`;
-        }
-
-        return {
-            message: message,
-            labels: labels,
-            context: context,
-        };
-    }
 }

backend/src/logging/responseTimeLogger.ts

@@ -1,7 +1,7 @@
 import { getLogger, Logger } from './initalize.js';
 import { Request, Response } from 'express';
 
-export function responseTimeLogger(req: Request, res: Response, time: number) {
+export function responseTimeLogger(req: Request, res: Response, time: number): void {
     const logger: Logger = getLogger();
 
     const method = req.method;

backend/src/middleware/auth/auth.ts

@@ -1,12 +1,13 @@
-import { EnvVars, getEnvVar } from '../../util/envvars.js';
+import { envVars, getEnvVar } from '../../util/envVars.js';
 import { expressjwt } from 'express-jwt';
+import * as jwt from 'jsonwebtoken';
 import { JwtPayload } from 'jsonwebtoken';
 import jwksClient from 'jwks-rsa';
 import * as express from 'express';
-import * as jwt from 'jsonwebtoken';
 import { AuthenticatedRequest } from './authenticated-request.js';
 import { AuthenticationInfo } from './authentication-info.js';
-import { ForbiddenException, UnauthorizedException } from '../../exceptions.js';
+import { UnauthorizedException } from '../../exceptions/unauthorized-exception.js';
+import { ForbiddenException } from '../../exceptions/forbidden-exception.js';
 
 const JWKS_CACHE = true;
 const JWKS_RATE_LIMIT = true;
@@ -32,12 +33,12 @@ function createJwksClient(uri: string): jwksClient.JwksClient {
 
 const idpConfigs = {
     student: {
-        issuer: getEnvVar(EnvVars.IdpStudentUrl),
-        jwksClient: createJwksClient(getEnvVar(EnvVars.IdpStudentJwksEndpoint)),
+        issuer: getEnvVar(envVars.IdpStudentUrl),
+        jwksClient: createJwksClient(getEnvVar(envVars.IdpStudentJwksEndpoint)),
     },
     teacher: {
-        issuer: getEnvVar(EnvVars.IdpTeacherUrl),
-        jwksClient: createJwksClient(getEnvVar(EnvVars.IdpTeacherJwksEndpoint)),
+        issuer: getEnvVar(envVars.IdpTeacherUrl),
+        jwksClient: createJwksClient(getEnvVar(envVars.IdpTeacherJwksEndpoint)),
     },
 };
 
@@ -63,7 +64,7 @@ const verifyJwtToken = expressjwt({
         }
         return signingKey.getPublicKey();
     },
-    audience: getEnvVar(EnvVars.IdpAudience),
+    audience: getEnvVar(envVars.IdpAudience),
     algorithms: [JWT_ALGORITHM],
     credentialsRequired: false,
     requestProperty: REQUEST_PROPERTY_FOR_JWT_PAYLOAD,
@@ -74,7 +75,7 @@ const verifyJwtToken = expressjwt({
  */
 function getAuthenticationInfo(req: AuthenticatedRequest): AuthenticationInfo | undefined {
     if (!req.jwtPayload) {
-        return;
+        return undefined;
     }
     const issuer = req.jwtPayload.iss;
     let accountType: 'student' | 'teacher';
@@ -84,8 +85,9 @@ function getAuthenticationInfo(req: AuthenticatedRequest): AuthenticationInfo |
     } else if (issuer === idpConfigs.teacher.issuer) {
         accountType = 'teacher';
     } else {
-        return;
+        return undefined;
     }
+
     return {
         accountType: accountType,
         username: req.jwtPayload[JWT_PROPERTY_NAMES.username]!,
@@ -100,10 +102,10 @@ function getAuthenticationInfo(req: AuthenticatedRequest): AuthenticationInfo |
  * Add the AuthenticationInfo object with the information about the current authentication to the request in order
  * to avoid that the routers have to deal with the JWT token.
  */
-const addAuthenticationInfo = (req: AuthenticatedRequest, res: express.Response, next: express.NextFunction) => {
+function addAuthenticationInfo(req: AuthenticatedRequest, _res: express.Response, next: express.NextFunction): void {
     req.auth = getAuthenticationInfo(req);
     next();
-};
+}
 
 export const authenticateUser = [verifyJwtToken, addAuthenticationInfo];
 
@@ -113,9 +115,8 @@ export const authenticateUser = [verifyJwtToken, addAuthenticationInfo];
  * @param accessCondition Predicate over the current AuthenticationInfo. Access is only granted when this evaluates
  *                        to true.
  */
-export const authorize =
-    (accessCondition: (auth: AuthenticationInfo) => boolean) =>
-    (req: AuthenticatedRequest, res: express.Response, next: express.NextFunction): void => {
+export function authorize(accessCondition: (auth: AuthenticationInfo) => boolean) {
+    return (req: AuthenticatedRequest, _res: express.Response, next: express.NextFunction): void => {
         if (!req.auth) {
             throw new UnauthorizedException();
         } else if (!accessCondition(req.auth)) {
@@ -124,6 +125,7 @@ export const authorize =
             next();
         }
     };
+}
 
 /**
  * Middleware which rejects all unauthenticated users, but accepts all authenticated users.

backend/src/middleware/auth/authentication-info.d.ts

@@ -1,11 +1,11 @@
 /**
  * Object with information about the user who is currently logged in.
  */
-export type AuthenticationInfo = {
+export interface AuthenticationInfo {
     accountType: 'student' | 'teacher';
     username: string;
     name?: string;
     firstName?: string;
     lastName?: string;
     email?: string;
-};
+}

backend/src/middleware/cors.ts

@@ -1,7 +1,7 @@
 import cors from 'cors';
-import { EnvVars, getEnvVar } from '../util/envvars.js';
+import { envVars, getEnvVar } from '../util/envVars.js';
 
 export default cors({
-    origin: getEnvVar(EnvVars.CorsAllowedOrigins).split(','),
-    allowedHeaders: getEnvVar(EnvVars.CorsAllowedHeaders).split(','),
+    origin: getEnvVar(envVars.CorsAllowedOrigins).split(','),
+    allowedHeaders: getEnvVar(envVars.CorsAllowedHeaders).split(','),
 });

backend/src/middleware/error-handling/error-handler.ts

@@ -0,0 +1,15 @@
+import { NextFunction, Request, Response } from 'express';
+import { getLogger, Logger } from '../../logging/initalize.js';
+import { ExceptionWithHttpState } from '../../exceptions/exception-with-http-state.js';
+
+const logger: Logger = getLogger();
+
+export function errorHandler(err: unknown, _req: Request, res: Response, _: NextFunction): void {
+    if (err instanceof ExceptionWithHttpState) {
+        logger.warn(`An error occurred while handling a request: ${err} (-> HTTP ${err.status})`);
+        res.status(err.status).json(err);
+    } else {
+        logger.error(`Unexpected error occurred while handing a request: ${JSON.stringify(err)}`);
+        res.status(500).json(err);
+    }
+}

backend/src/mikro-orm.config.ts

@@ -1,6 +1,6 @@
 import { LoggerOptions, Options } from '@mikro-orm/core';
 import { PostgreSqlDriver } from '@mikro-orm/postgresql';
-import { EnvVars, getEnvVar, getNumericEnvVar } from './util/envvars.js';
+import { envVars, getEnvVar, getNumericEnvVar } from './util/envVars.js';
 import { SqliteDriver } from '@mikro-orm/sqlite';
 import { MikroOrmLogger } from './logging/mikroOrmLogger.js';
 
@@ -42,33 +42,35 @@ const entities = [
     Question,
 ];
 
-function config(testingMode: boolean = false): Options {
+function config(testingMode = false): Options {
     if (testingMode) {
         return {
             driver: SqliteDriver,
-            dbName: getEnvVar(EnvVars.DbName),
+            dbName: getEnvVar(envVars.DbName),
             subscribers: [new SqliteAutoincrementSubscriber()],
             entities: entities,
+            persistOnCreate: false, // Do not implicitly save entities when they are created via `create`.
             // EntitiesTs: entitiesTs,
 
             // Workaround: vitest: `TypeError: Unknown file extension ".ts"` (ERR_UNKNOWN_FILE_EXTENSION)
             // (see https://mikro-orm.io/docs/guide/project-setup#testing-the-endpoint)
-            dynamicImportProvider: (id) => import(id),
+            dynamicImportProvider: async (id) => import(id),
         };
     }
 
     return {
         driver: PostgreSqlDriver,
-        host: getEnvVar(EnvVars.DbHost),
-        port: getNumericEnvVar(EnvVars.DbPort),
-        dbName: getEnvVar(EnvVars.DbName),
-        user: getEnvVar(EnvVars.DbUsername),
-        password: getEnvVar(EnvVars.DbPassword),
+        host: getEnvVar(envVars.DbHost),
+        port: getNumericEnvVar(envVars.DbPort),
+        dbName: getEnvVar(envVars.DbName),
+        user: getEnvVar(envVars.DbUsername),
+        password: getEnvVar(envVars.DbPassword),
         entities: entities,
+        persistOnCreate: false, // Do not implicitly save entities when they are created via `create`.
         // EntitiesTs: entitiesTs,
 
         // Logging
-        debug: getEnvVar(EnvVars.LogLevel) === 'debug',
+        debug: getEnvVar(envVars.LogLevel) === 'debug',
         loggerFactory: (options: LoggerOptions) => new MikroOrmLogger(options),
     };
 }

backend/src/orm.ts

@@ -1,10 +1,10 @@
 import { EntityManager, MikroORM } from '@mikro-orm/core';
 import config from './mikro-orm.config.js';
-import { EnvVars, getEnvVar } from './util/envvars.js';
+import { envVars, getEnvVar } from './util/envVars.js';
 import { getLogger, Logger } from './logging/initalize.js';
 
 let orm: MikroORM | undefined;
-export async function initORM(testingMode: boolean = false) {
+export async function initORM(testingMode = false): Promise<void> {
     const logger: Logger = getLogger();
 
     logger.info('Initializing ORM');
@@ -12,7 +12,7 @@ export async function initORM(testingMode: boolean = false) {
 
     orm = await MikroORM.init(config(testingMode));
     // Update the database scheme if necessary and enabled.
-    if (getEnvVar(EnvVars.DbUpdate)) {
+    if (getEnvVar(envVars.DbUpdate)) {
         await orm.schema.updateSchema();
     } else {
         const diff = await orm.schema.getUpdateSchemaSQL();

backend/src/routes/assignments.ts

@@ -19,7 +19,7 @@ router.get('/:id', getAssignmentHandler);
 
 router.get('/:id/submissions', getAssignmentsSubmissionsHandler);
 
-router.get('/:id/questions', (req, res) => {
+router.get('/:id/questions', (_req, res) => {
     res.json({
         questions: ['0'],
     });

backend/src/routes/auth.ts

@@ -4,21 +4,21 @@ import { authenticatedOnly, studentsOnly, teachersOnly } from '../middleware/aut
 const router = express.Router();
 
 // Returns auth configuration for frontend
-router.get('/config', (req, res) => {
+router.get('/config', (_req, res) => {
     res.json(getFrontendAuthConfig());
 });
 
-router.get('/testAuthenticatedOnly', authenticatedOnly, (req, res) => {
+router.get('/testAuthenticatedOnly', authenticatedOnly, (_req, res) => {
     /* #swagger.security = [{ "student": [ ] }, { "teacher": [ ] }] */
     res.json({ message: 'If you see this, you should be authenticated!' });
 });
 
-router.get('/testStudentsOnly', studentsOnly, (req, res) => {
+router.get('/testStudentsOnly', studentsOnly, (_req, res) => {
     /* #swagger.security = [{ "student": [ ] }] */
     res.json({ message: 'If you see this, you should be a student!' });
 });
 
-router.get('/testTeachersOnly', teachersOnly, (req, res) => {
+router.get('/testTeachersOnly', teachersOnly, (_req, res) => {
     /* #swagger.security = [{ "teacher": [ ] }] */
     res.json({ message: 'If you see this, you should be a teacher!' });
 });

backend/src/routes/groups.ts

@@ -14,7 +14,7 @@ router.get('/:groupid', getGroupHandler);
 router.get('/:groupid', getGroupSubmissionsHandler);
 
 // The list of questions a group has made
-router.get('/:id/questions', (req, res) => {
+router.get('/:id/questions', (_req, res) => {
     res.json({
         questions: ['0'],
     });

backend/src/routes/students.ts

@@ -9,6 +9,7 @@ import {
     getStudentHandler,
     getStudentSubmissionsHandler,
 } from '../controllers/students.js';
+
 const router = express.Router();
 
 // Root endpoint used to search objects
@@ -36,7 +37,7 @@ router.get('/:id/assignments', getStudentAssignmentsHandler);
 router.get('/:id/groups', getStudentGroupsHandler);
 
 // A list of questions a user has created
-router.get('/:id/questions', (req, res) => {
+router.get('/:id/questions', (_req, res) => {
     res.json({
         questions: ['0'],
     });

backend/src/routes/submissions.ts

@@ -3,7 +3,7 @@ import { createSubmissionHandler, deleteSubmissionHandler, getSubmissionHandler
 const router = express.Router({ mergeParams: true });
 
 // Root endpoint used to search objects
-router.get('/', (req, res) => {
+router.get('/', (_req, res) => {
     res.json({
         submissions: ['0', '1'],
     });

backend/src/routes/teachers.ts

@@ -28,7 +28,7 @@ router.get('/:username/students', getTeacherStudentHandler);
 router.get('/:username/questions', getTeacherQuestionHandler);
 
 // Invitations to other classes a teacher received
-router.get('/:id/invitations', (req, res) => {
+router.get('/:id/invitations', (_req, res) => {
     res.json({
         invitations: ['0'],
     });

backend/src/services/assignments.ts

@@ -1,6 +1,7 @@
 import { getAssignmentRepository, getClassRepository, getGroupRepository, getSubmissionRepository } from '../data/repositories.js';
 import { AssignmentDTO, mapToAssignment, mapToAssignmentDTO, mapToAssignmentDTOId } from '../interfaces/assignment.js';
 import { mapToSubmissionDTO, mapToSubmissionDTOId, SubmissionDTO, SubmissionDTOId } from '../interfaces/submission.js';
+import { getLogger } from '../logging/initalize.js';
 
 export async function getAllAssignments(classid: string, full: boolean): Promise<AssignmentDTO[]> {
     const classRepository = getClassRepository();
@@ -37,7 +38,7 @@ export async function createAssignment(classid: string, assignmentData: Assignme
 
         return mapToAssignmentDTO(newAssignment);
     } catch (e) {
-        console.error(e);
+        getLogger().error(e);
         return null;
     }
 }
@@ -83,7 +84,7 @@ export async function getAssignmentsSubmissions(
     const groups = await groupRepository.findAllGroupsForAssignment(assignment);
 
     const submissionRepository = getSubmissionRepository();
-    const submissions = (await Promise.all(groups.map((group) => submissionRepository.findAllSubmissionsForGroup(group)))).flat();
+    const submissions = (await Promise.all(groups.map(async (group) => submissionRepository.findAllSubmissionsForGroup(group)))).flat();
 
     if (full) {
         return submissions.map(mapToSubmissionDTO);

backend/src/services/classes.ts

@@ -23,11 +23,15 @@ export async function getAllClasses(full: boolean): Promise<ClassDTO[] | string[
 export async function createClass(classData: ClassDTO): Promise<ClassDTO | null> {
     const teacherRepository = getTeacherRepository();
     const teacherUsernames = classData.teachers || [];
-    const teachers = (await Promise.all(teacherUsernames.map((id) => teacherRepository.findByUsername(id)))).filter((teacher) => teacher !== null);
+    const teachers = (await Promise.all(teacherUsernames.map(async (id) => teacherRepository.findByUsername(id)))).filter(
+        (teacher) => teacher !== null
+    );
 
     const studentRepository = getStudentRepository();
     const studentUsernames = classData.students || [];
-    const students = (await Promise.all(studentUsernames.map((id) => studentRepository.findByUsername(id)))).filter((student) => student !== null);
+    const students = (await Promise.all(studentUsernames.map(async (id) => studentRepository.findByUsername(id)))).filter(
+        (student) => student !== null
+    );
 
     const classRepository = getClassRepository();
 

backend/src/services/groups.ts

@@ -8,6 +8,7 @@ import {
 import { Group } from '../entities/assignments/group.entity.js';
 import { GroupDTO, mapToGroupDTO, mapToGroupDTOId } from '../interfaces/group.js';
 import { mapToSubmissionDTO, mapToSubmissionDTOId, SubmissionDTO, SubmissionDTOId } from '../interfaces/submission.js';
+import { getLogger } from '../logging/initalize.js';
 
 export async function getGroup(classId: string, assignmentNumber: number, groupNumber: number, full: boolean): Promise<GroupDTO | null> {
     const classRepository = getClassRepository();
@@ -42,9 +43,11 @@ export async function createGroup(groupData: GroupDTO, classid: string, assignme
     const studentRepository = getStudentRepository();
 
     const memberUsernames = (groupData.members as string[]) || []; // TODO check if groupdata.members is a list
-    const members = (await Promise.all([...memberUsernames].map((id) => studentRepository.findByUsername(id)))).filter((student) => student !== null);
+    const members = (await Promise.all([...memberUsernames].map(async (id) => studentRepository.findByUsername(id)))).filter(
+        (student) => student !== null
+    );
 
-    console.log(members);
+    getLogger().debug(members);
 
     const classRepository = getClassRepository();
     const cls = await classRepository.findById(classid);
@@ -70,7 +73,7 @@ export async function createGroup(groupData: GroupDTO, classid: string, assignme
 
         return newGroup;
     } catch (e) {
-        console.log(e);
+        getLogger().error(e);
         return null;
     }
 }
@@ -94,8 +97,7 @@ export async function getAllGroups(classId: string, assignmentNumber: number, fu
     const groups = await groupRepository.findAllGroupsForAssignment(assignment);
 
     if (full) {
-        console.log('full');
-        console.log(groups);
+        getLogger().debug({ full: full, groups: groups });
         return groups.map(mapToGroupDTO);
     }
 

backend/src/services/learning-objects.ts

@@ -1,6 +1,7 @@
 import { DWENGO_API_BASE } from '../config.js';
 import { fetchWithLogging } from '../util/api-helper.js';
 import { FilteredLearningObject, LearningObjectMetadata, LearningObjectNode, LearningPathResponse } from '../interfaces/learning-content.js';
+import { getLogger } from '../logging/initalize.js';
 
 function filterData(data: LearningObjectMetadata, htmlUrl: string): FilteredLearningObject {
     return {
@@ -37,7 +38,7 @@ export async function getLearningObjectById(hruid: string, language: string): Pr
     );
 
     if (!metadata) {
-        console.error(`⚠️ WARNING: Learning object "${hruid}" not found.`);
+        getLogger().error(`⚠️ WARNING: Learning object "${hruid}" not found.`);
         return null;
     }
 
@@ -48,7 +49,7 @@ export async function getLearningObjectById(hruid: string, language: string): Pr
 /**
  * Generic function to fetch learning paths
  */
-function fetchLearningPaths(arg0: string[], language: string, arg2: string): LearningPathResponse | PromiseLike<LearningPathResponse> {
+function fetchLearningPaths(_arg0: string[], _language: string, _arg2: string): LearningPathResponse | PromiseLike<LearningPathResponse> {
     throw new Error('Function not implemented.');
 }
 
@@ -60,7 +61,7 @@ async function fetchLearningObjects(hruid: string, full: boolean, language: stri
         const learningPathResponse: LearningPathResponse = await fetchLearningPaths([hruid], language, `Learning path for HRUID "${hruid}"`);
 
         if (!learningPathResponse.success || !learningPathResponse.data?.length) {
-            console.error(`⚠️ WARNING: Learning path "${hruid}" exists but contains no learning objects.`);
+            getLogger().error(`⚠️ WARNING: Learning path "${hruid}" exists but contains no learning objects.`);
             return [];
         }
 
@@ -74,7 +75,7 @@ async function fetchLearningObjects(hruid: string, full: boolean, language: stri
             objects.filter((obj): obj is FilteredLearningObject => obj !== null)
         );
     } catch (error) {
-        console.error('❌ Error fetching learning objects:', error);
+        getLogger().error('❌ Error fetching learning objects:', error);
         return [];
     }
 }

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

@@ -3,7 +3,7 @@ import { Attachment } from '../../entities/content/attachment.entity.js';
 import { LearningObjectIdentifier } from '../../interfaces/learning-content.js';
 
 const attachmentService = {
-    getAttachment(learningObjectId: LearningObjectIdentifier, attachmentName: string): Promise<Attachment | null> {
+    async getAttachment(learningObjectId: LearningObjectIdentifier, attachmentName: string): Promise<Attachment | null> {
         const attachmentRepo = getAttachmentRepository();
 
         if (learningObjectId.version) {

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

@@ -1,7 +1,6 @@
 import { LearningObjectProvider } from './learning-object-provider.js';
 import { FilteredLearningObject, LearningObjectIdentifier, LearningPathIdentifier } from '../../interfaces/learning-content.js';
 import { getLearningObjectRepository, getLearningPathRepository } from '../../data/repositories.js';
-import { Language } from '../../entities/content/language.js';
 import { LearningObject } from '../../entities/content/learning-object.entity.js';
 import { getUrlStringForLearningObject } from '../../util/links.js';
 import processingService from './processing/processing-service.js';
@@ -41,10 +40,10 @@ function convertLearningObject(learningObject: LearningObject | null): FilteredL
     };
 }
 
-function findLearningObjectEntityById(id: LearningObjectIdentifier): Promise<LearningObject | null> {
+async function findLearningObjectEntityById(id: LearningObjectIdentifier): Promise<LearningObject | null> {
     const learningObjectRepo = getLearningObjectRepository();
 
-    return learningObjectRepo.findLatestByHruidAndLanguage(id.hruid, id.language as Language);
+    return learningObjectRepo.findLatestByHruidAndLanguage(id.hruid, id.language);
 }
 
 /**
@@ -65,11 +64,11 @@ const databaseLearningObjectProvider: LearningObjectProvider = {
     async getLearningObjectHTML(id: LearningObjectIdentifier): Promise<string | null> {
         const learningObjectRepo = getLearningObjectRepository();
 
-        const learningObject = await learningObjectRepo.findLatestByHruidAndLanguage(id.hruid, id.language as Language);
+        const learningObject = await learningObjectRepo.findLatestByHruidAndLanguage(id.hruid, id.language);
         if (!learningObject) {
             return null;
         }
-        return await processingService.render(learningObject, (id) => findLearningObjectEntityById(id));
+        return await processingService.render(learningObject, async (id) => findLearningObjectEntityById(id));
     },
 
     /**
@@ -96,7 +95,7 @@ const databaseLearningObjectProvider: LearningObjectProvider = {
             throw new NotFoundError('The learning path with the given ID could not be found.');
         }
         const learningObjects = await Promise.all(
-            learningPath.nodes.map((it) => {
+            learningPath.nodes.map(async (it) => {
                 const learningObject = learningObjectService.getLearningObjectById({
                     hruid: it.learningObjectHruid,
                     language: it.language,

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

@@ -1,11 +1,11 @@
 import { FilteredLearningObject, LearningObjectIdentifier, LearningPathIdentifier } from '../../interfaces/learning-content.js';
 import dwengoApiLearningObjectProvider from './dwengo-api-learning-object-provider.js';
 import { LearningObjectProvider } from './learning-object-provider.js';
-import { EnvVars, getEnvVar } from '../../util/envvars.js';
+import { envVars, getEnvVar } from '../../util/envVars.js';
 import databaseLearningObjectProvider from './database-learning-object-provider.js';
 
 function getProvider(id: LearningObjectIdentifier): LearningObjectProvider {
-    if (id.hruid.startsWith(getEnvVar(EnvVars.UserContentPrefix))) {
+    if (id.hruid.startsWith(getEnvVar(envVars.UserContentPrefix))) {
         return databaseLearningObjectProvider;
     }
     return dwengoApiLearningObjectProvider;
@@ -18,28 +18,28 @@ const learningObjectService = {
     /**
      * Fetches a single learning object by its HRUID
      */
-    getLearningObjectById(id: LearningObjectIdentifier): Promise<FilteredLearningObject | null> {
+    async getLearningObjectById(id: LearningObjectIdentifier): Promise<FilteredLearningObject | null> {
         return getProvider(id).getLearningObjectById(id);
     },
 
     /**
      * Fetch full learning object data (metadata)
      */
-    getLearningObjectsFromPath(id: LearningPathIdentifier): Promise<FilteredLearningObject[]> {
+    async getLearningObjectsFromPath(id: LearningPathIdentifier): Promise<FilteredLearningObject[]> {
         return getProvider(id).getLearningObjectsFromPath(id);
     },
 
     /**
      * Fetch only learning object HRUIDs
      */
-    getLearningObjectIdsFromPath(id: LearningPathIdentifier): Promise<string[]> {
+    async getLearningObjectIdsFromPath(id: LearningPathIdentifier): Promise<string[]> {
         return getProvider(id).getLearningObjectIdsFromPath(id);
     },
 
     /**
      * Obtain a HTML-rendering of the learning object with the given identifier (as a string).
      */
-    getLearningObjectHTML(id: LearningObjectIdentifier): Promise<string | null> {
+    async getLearningObjectHTML(id: LearningObjectIdentifier): Promise<string | null> {
         return getProvider(id).getLearningObjectHTML(id);
     },
 };

backend/src/services/learning-objects/processing/audio/audio-processor.ts

@@ -14,7 +14,7 @@ class AudioProcessor extends StringProcessor {
         super(DwengoContentType.AUDIO_MPEG);
     }
 
-    protected renderFn(audioUrl: string): string {
+    override renderFn(audioUrl: string): string {
         return DOMPurify.sanitize(`<audio controls>
             <source src="${audioUrl}" type=${type}>
             Your browser does not support the audio element.

backend/src/services/learning-objects/processing/extern/extern-processor.ts

@@ -15,7 +15,7 @@ class ExternProcessor extends StringProcessor {
         super(DwengoContentType.EXTERN);
     }
 
-    override renderFn(externURL: string) {
+    override renderFn(externURL: string): string {
         if (!isValidHttpUrl(externURL)) {
             throw new ProcessingError('The url is not valid: ' + externURL);
         }

backend/src/services/learning-objects/processing/gift/gift-processor.ts

@@ -32,7 +32,7 @@ class GiftProcessor extends StringProcessor {
         super(DwengoContentType.GIFT);
     }
 
-    override renderFn(giftString: string) {
+    override renderFn(giftString: string): string {
         const quizQuestions: GIFTQuestion[] = parse(giftString);
 
         let html = "<div class='learning-object-gift'>\n";

backend/src/services/learning-objects/processing/gift/question-renderers/category-question-renderer.ts

@@ -3,7 +3,7 @@ import { Category } from 'gift-pegjs';
 import { ProcessingError } from '../../processing-error.js';
 
 export class CategoryQuestionRenderer extends GIFTQuestionRenderer<Category> {
-    render(question: Category, questionNumber: number): string {
+    override render(_question: Category, _questionNumber: number): string {
         throw new ProcessingError("The question type 'Category' is not supported yet!");
     }
 }

backend/src/services/learning-objects/processing/gift/question-renderers/description-question-renderer.ts

@@ -3,7 +3,7 @@ import { Description } from 'gift-pegjs';
 import { ProcessingError } from '../../processing-error.js';
 
 export class DescriptionQuestionRenderer extends GIFTQuestionRenderer<Description> {
-    render(question: Description, questionNumber: number): string {
+    override render(_question: Description, _questionNumber: number): string {
         throw new ProcessingError("The question type 'Description' is not supported yet!");
     }
 }

backend/src/services/learning-objects/processing/gift/question-renderers/essay-question-renderer.ts

@@ -2,7 +2,7 @@ import { GIFTQuestionRenderer } from './gift-question-renderer.js';
 import { Essay } from 'gift-pegjs';
 
 export class EssayQuestionRenderer extends GIFTQuestionRenderer<Essay> {
-    render(question: Essay, questionNumber: number): string {
+    override render(question: Essay, questionNumber: number): string {
         let renderedHtml = '';
         if (question.title) {
             renderedHtml += `<h2 class='gift-title' id='gift-q${questionNumber}-title'>${question.title}</h2>\n`;

backend/src/services/learning-objects/processing/gift/question-renderers/matching-question-renderer.ts

@@ -3,7 +3,7 @@ import { Matching } from 'gift-pegjs';
 import { ProcessingError } from '../../processing-error.js';
 
 export class MatchingQuestionRenderer extends GIFTQuestionRenderer<Matching> {
-    render(question: Matching, questionNumber: number): string {
+    override render(_question: Matching, _questionNumber: number): string {
         throw new ProcessingError("The question type 'Matching' is not supported yet!");
     }
 }

backend/src/services/learning-objects/processing/gift/question-renderers/multiple-choice-question-renderer.ts

@@ -2,7 +2,7 @@ import { GIFTQuestionRenderer } from './gift-question-renderer.js';
 import { MultipleChoice } from 'gift-pegjs';
 
 export class MultipleChoiceQuestionRenderer extends GIFTQuestionRenderer<MultipleChoice> {
-    render(question: MultipleChoice, questionNumber: number): string {
+    override render(question: MultipleChoice, questionNumber: number): string {
         let renderedHtml = '';
         if (question.title) {
             renderedHtml += `<h2 class='gift-title' id='gift-q${questionNumber}-title'>${question.title}</h2>\n`;

backend/src/services/learning-objects/processing/gift/question-renderers/numerical-question-renderer.ts

@@ -3,7 +3,7 @@ import { Numerical } from 'gift-pegjs';
 import { ProcessingError } from '../../processing-error.js';
 
 export class NumericalQuestionRenderer extends GIFTQuestionRenderer<Numerical> {
-    render(question: Numerical, questionNumber: number): string {
+    override render(_question: Numerical, _questionNumber: number): string {
         throw new ProcessingError("The question type 'Numerical' is not supported yet!");
     }
 }

backend/src/services/learning-objects/processing/gift/question-renderers/short-question-renderer.ts

@@ -3,7 +3,7 @@ import { ShortAnswer } from 'gift-pegjs';
 import { ProcessingError } from '../../processing-error.js';
 
 export class ShortQuestionRenderer extends GIFTQuestionRenderer<ShortAnswer> {
-    render(question: ShortAnswer, questionNumber: number): string {
+    override render(_question: ShortAnswer, _questionNumber: number): string {
         throw new ProcessingError("The question type 'ShortAnswer' is not supported yet!");
     }
 }

backend/src/services/learning-objects/processing/gift/question-renderers/true-false-question-renderer.ts

@@ -3,7 +3,7 @@ import { TrueFalse } from 'gift-pegjs';
 import { ProcessingError } from '../../processing-error.js';
 
 export class TrueFalseQuestionRenderer extends GIFTQuestionRenderer<TrueFalse> {
-    render(question: TrueFalse, questionNumber: number): string {
+    override render(_question: TrueFalse, _questionNumber: number): string {
         throw new ProcessingError("The question type 'TrueFalse' is not supported yet!");
     }
 }

backend/src/services/learning-objects/processing/image/block-image-processor.ts

@@ -10,7 +10,7 @@ class BlockImageProcessor extends InlineImageProcessor {
         super();
     }
 
-    override renderFn(imageUrl: string) {
+    override renderFn(imageUrl: string): string {
         const inlineHtml = super.render(imageUrl);
         return DOMPurify.sanitize(`<div>${inlineHtml}</div>`);
     }

backend/src/services/learning-objects/processing/image/inline-image-processor.ts

@@ -13,7 +13,7 @@ class InlineImageProcessor extends StringProcessor {
         super(contentType);
     }
 
-    override renderFn(imageUrl: string) {
+    override renderFn(imageUrl: string): string {
         if (!isValidHttpUrl(imageUrl)) {
             throw new ProcessingError(`Image URL is invalid: ${imageUrl}`);
         }

backend/src/services/learning-objects/processing/markdown/markdown-processor.ts

@@ -14,26 +14,24 @@ class MarkdownProcessor extends StringProcessor {
         super(DwengoContentType.TEXT_MARKDOWN);
     }
 
-    override renderFn(mdText: string) {
-        let html = '';
-        try {
-            marked.use({ renderer: dwengoMarkedRenderer });
-            html = marked(mdText, { async: false });
-            html = this.replaceLinks(html); // Replace html image links path
-        } catch (e: any) {
-            throw new ProcessingError(e.message);
-        }
-        return html;
-    }
-
-    replaceLinks(html: string) {
+    static replaceLinks(html: string): string {
         const proc = new InlineImageProcessor();
         html = html.replace(
             /<img.*?src="(.*?)".*?(alt="(.*?)")?.*?(title="(.*?)")?.*?>/g,
-            (match: string, src: string, alt: string, altText: string, title: string, titleText: string) => proc.render(src)
+            (_match: string, src: string, _alt: string, _altText: string, _title: string, _titleText: string) => proc.render(src)
         );
         return html;
     }
+
+    override renderFn(mdText: string): string {
+        try {
+            marked.use({ renderer: dwengoMarkedRenderer });
+            const html = marked(mdText, { async: false });
+            return MarkdownProcessor.replaceLinks(html); // Replace html image links path
+        } catch (e: unknown) {
+            throw new ProcessingError('Unknown error while processing markdown: ' + e);
+        }
+    }
 }
 
 export { MarkdownProcessor };

backend/src/services/learning-objects/processing/pdf/pdf-processor.ts

@@ -15,7 +15,7 @@ class PdfProcessor extends StringProcessor {
         super(DwengoContentType.APPLICATION_PDF);
     }
 
-    override renderFn(pdfUrl: string) {
+    override renderFn(pdfUrl: string): string {
         if (!isValidHttpUrl(pdfUrl)) {
             throw new ProcessingError(`PDF URL is invalid: ${pdfUrl}`);
         }

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

@@ -21,7 +21,7 @@ const EMBEDDED_LEARNING_OBJECT_PLACEHOLDER = /<learning-object hruid="([^"]+)" l
 const LEARNING_OBJECT_DOES_NOT_EXIST = "<div class='non-existing-learning-object' />";
 
 class ProcessingService {
-    private processors!: Map<DwengoContentType, Processor<any>>;
+    private processors!: Map<DwengoContentType, Processor<DwengoContentType>>;
 
     constructor() {
         const processors = [

backend/src/services/learning-objects/processing/processor.ts

@@ -9,7 +9,9 @@ import { DwengoContentType } from './content-type.js';
  * Based on https://github.com/dwengovzw/Learning-Object-Repository/blob/main/app/processors/processor.js
  */
 abstract class Processor<T> {
-    protected constructor(public contentType: DwengoContentType) {}
+    protected constructor(public contentType: DwengoContentType) {
+        // Do nothing
+    }
 
     /**
      * Render the given object.

backend/src/services/learning-objects/processing/text/text-processor.ts

@@ -11,7 +11,7 @@ class TextProcessor extends StringProcessor {
         super(DwengoContentType.TEXT_PLAIN);
     }
 
-    override renderFn(text: string) {
+    override renderFn(text: string): string {
         // Sanitize plain text to prevent xss.
         return DOMPurify.sanitize(text);
     }

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

@@ -18,14 +18,14 @@ async function getLearningObjectsForNodes(nodes: LearningPathNode[]): Promise<Ma
     // Its corresponding learning object.
     const nullableNodesToLearningObjects = new Map<LearningPathNode, FilteredLearningObject | null>(
         await Promise.all(
-            nodes.map((node) =>
+            nodes.map(async (node) =>
                 learningObjectService
                     .getLearningObjectById({
                         hruid: node.learningObjectHruid,
                         version: node.version,
                         language: node.language,
                     })
-                    .then((learningObject) => <[LearningPathNode, FilteredLearningObject | null]>[node, learningObject])
+                    .then((learningObject) => [node, learningObject] as [LearningPathNode, FilteredLearningObject | null])
             )
         )
     );
@@ -117,7 +117,7 @@ async function convertNodes(
     nodesToLearningObjects: Map<LearningPathNode, FilteredLearningObject>,
     personalizedFor?: PersonalizationTarget
 ): Promise<LearningObjectNode[]> {
-    const nodesPromise = Array.from(nodesToLearningObjects.entries()).map((entry) =>
+    const nodesPromise = Array.from(nodesToLearningObjects.entries()).map(async (entry) =>
         convertNode(entry[0], entry[1], personalizedFor, nodesToLearningObjects)
     );
     return await Promise.all(nodesPromise);
@@ -152,7 +152,7 @@ function convertTransition(
         throw new Error(`Learning object ${transition.next.learningObjectHruid}/${transition.next.language}/${transition.next.version} not found!`);
     } else {
         return {
-            _id: '' + index, // Retained for backwards compatibility. The index uniquely identifies the transition within the learning path.
+            _id: String(index), // Retained for backwards compatibility. The index uniquely identifies the transition within the learning path.
             default: false, // We don't work with default transitions but retain this for backwards compatibility.
             next: {
                 _id: nextNode._id + index, // Construct a unique ID for the transition for backwards compatibility.
@@ -179,11 +179,11 @@ const databaseLearningPathProvider: LearningPathProvider = {
     ): Promise<LearningPathResponse> {
         const learningPathRepo = getLearningPathRepository();
 
-        const learningPaths = (await Promise.all(hruids.map((hruid) => learningPathRepo.findByHruidAndLanguage(hruid, language)))).filter(
+        const learningPaths = (await Promise.all(hruids.map(async (hruid) => learningPathRepo.findByHruidAndLanguage(hruid, language)))).filter(
             (learningPath) => learningPath !== null
         );
         const filteredLearningPaths = await Promise.all(
-            learningPaths.map((learningPath, index) => convertLearningPath(learningPath, index, personalizedFor))
+            learningPaths.map(async (learningPath, index) => convertLearningPath(learningPath, index, personalizedFor))
         );
 
         return {
@@ -200,7 +200,7 @@ const databaseLearningPathProvider: LearningPathProvider = {
         const learningPathRepo = getLearningPathRepository();
 
         const searchResults = await learningPathRepo.findByQueryStringAndLanguage(query, language);
-        return await Promise.all(searchResults.map((result, index) => convertLearningPath(result, index, personalizedFor)));
+        return await Promise.all(searchResults.map(async (result, index) => convertLearningPath(result, index, personalizedFor)));
     },
 };
 

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

@@ -1,11 +1,11 @@
 import { LearningPath, LearningPathResponse } from '../../interfaces/learning-content.js';
 import dwengoApiLearningPathProvider from './dwengo-api-learning-path-provider.js';
 import databaseLearningPathProvider from './database-learning-path-provider.js';
-import { EnvVars, getEnvVar } from '../../util/envvars.js';
+import { envVars, getEnvVar } from '../../util/envVars.js';
 import { Language } from '../../entities/content/language.js';
 import { PersonalizationTarget } from './learning-path-personalization-util.js';
 
-const userContentPrefix = getEnvVar(EnvVars.UserContentPrefix);
+const userContentPrefix = getEnvVar(envVars.UserContentPrefix);
 const allProviders = [dwengoApiLearningPathProvider, databaseLearningPathProvider];
 
 /**
@@ -49,7 +49,9 @@ const learningPathService = {
      * Search learning paths in the data source using the given search string.
      */
     async searchLearningPaths(query: string, language: Language, personalizedFor?: PersonalizationTarget): Promise<LearningPath[]> {
-        const providerResponses = await Promise.all(allProviders.map((provider) => provider.searchLearningPaths(query, language, personalizedFor)));
+        const providerResponses = await Promise.all(
+            allProviders.map(async (provider) => provider.searchLearningPaths(query, language, personalizedFor))
+        );
         return providerResponses.flat();
     },
 };

backend/src/services/questions.ts

@@ -2,11 +2,9 @@ import { getAnswerRepository, getQuestionRepository } from '../data/repositories
 import { mapToQuestionDTO, mapToQuestionId, QuestionDTO, QuestionId } from '../interfaces/question.js';
 import { Question } from '../entities/questions/question.entity.js';
 import { Answer } from '../entities/questions/answer.entity.js';
-import { mapToAnswerDTO, mapToAnswerId } from '../interfaces/answer.js';
+import { AnswerDTO, AnswerId, mapToAnswerDTO, mapToAnswerId } from '../interfaces/answer.js';
 import { QuestionRepository } from '../data/questions/question-repository.js';
 import { LearningObjectIdentifier } from '../entities/content/learning-object-identifier.js';
-import { mapToUser } from '../interfaces/user.js';
-import { Student } from '../entities/users/student.entity.js';
 import { mapToStudent } from '../interfaces/student.js';
 
 export async function getAllQuestions(id: LearningObjectIdentifier, full: boolean): Promise<QuestionDTO[] | QuestionId[]> {
@@ -47,7 +45,7 @@ export async function getQuestion(questionId: QuestionId): Promise<QuestionDTO |
     return mapToQuestionDTO(question);
 }
 
-export async function getAnswersByQuestion(questionId: QuestionId, full: boolean) {
+export async function getAnswersByQuestion(questionId: QuestionId, full: boolean): Promise<AnswerDTO[] | AnswerId[]> {
     const answerRepository = getAnswerRepository();
     const question = await fetchQuestion(questionId);
 
@@ -70,7 +68,7 @@ export async function getAnswersByQuestion(questionId: QuestionId, full: boolean
     return answersDTO.map(mapToAnswerId);
 }
 
-export async function createQuestion(questionDTO: QuestionDTO) {
+export async function createQuestion(questionDTO: QuestionDTO): Promise<QuestionDTO | null> {
     const questionRepository = getQuestionRepository();
 
     const author = mapToStudent(questionDTO.author);
@@ -81,14 +79,14 @@ export async function createQuestion(questionDTO: QuestionDTO) {
             author,
             content: questionDTO.content,
         });
-    } catch (e) {
+    } catch (_) {
         return null;
     }
 
     return questionDTO;
 }
 
-export async function deleteQuestion(questionId: QuestionId) {
+export async function deleteQuestion(questionId: QuestionId): Promise<QuestionDTO | null> {
     const questionRepository = getQuestionRepository();
 
     const question = await fetchQuestion(questionId);
@@ -99,7 +97,7 @@ export async function deleteQuestion(questionId: QuestionId) {
 
     try {
         await questionRepository.removeQuestionByLearningObjectAndSequenceNumber(questionId.learningObjectIdentifier, questionId.sequenceNumber);
-    } catch (e) {
+    } catch (_) {
         return null;
     }
 

backend/src/services/students.ts

@@ -1,12 +1,11 @@
 import { getClassRepository, getGroupRepository, getStudentRepository, getSubmissionRepository } from '../data/repositories.js';
-import { Class } from '../entities/classes/class.entity.js';
-import { Student } from '../entities/users/student.entity.js';
 import { AssignmentDTO } from '../interfaces/assignment.js';
 import { ClassDTO, mapToClassDTO } from '../interfaces/class.js';
 import { GroupDTO, mapToGroupDTO, mapToGroupDTOId } from '../interfaces/group.js';
 import { mapToStudent, mapToStudentDTO, StudentDTO } from '../interfaces/student.js';
 import { mapToSubmissionDTO, mapToSubmissionDTOId, SubmissionDTO, SubmissionDTOId } from '../interfaces/submission.js';
 import { getAllAssignments } from './assignments.js';
+import { getLogger } from '../logging/initalize.js';
 
 export async function getAllStudents(full: boolean): Promise<StudentDTO[] | string[]> {
     const studentRepository = getStudentRepository();
@@ -28,15 +27,9 @@ export async function getStudent(username: string): Promise<StudentDTO | null> {
 export async function createStudent(userData: StudentDTO): Promise<StudentDTO | null> {
     const studentRepository = getStudentRepository();
 
-    try {
-        const newStudent = studentRepository.create(mapToStudent(userData));
-        await studentRepository.save(newStudent);
-
-        return mapToStudentDTO(newStudent);
-    } catch (e) {
-        console.log(e);
-        return null;
-    }
+    const newStudent = mapToStudent(userData);
+    await studentRepository.save(newStudent, { preventOverwrite: true });
+    return mapToStudentDTO(newStudent);
 }
 
 export async function deleteStudent(username: string): Promise<StudentDTO | null> {
@@ -53,7 +46,7 @@ export async function deleteStudent(username: string): Promise<StudentDTO | null
 
         return mapToStudentDTO(user);
     } catch (e) {
-        console.log(e);
+        getLogger().error(e);
         return null;
     }
 }
@@ -87,9 +80,7 @@ export async function getStudentAssignments(username: string, full: boolean): Pr
     const classRepository = getClassRepository();
     const classes = await classRepository.findByStudent(student);
 
-    const assignments = (await Promise.all(classes.map(async (cls) => await getAllAssignments(cls.classId!, full)))).flat();
-
-    return assignments;
+    return (await Promise.all(classes.map(async (cls) => await getAllAssignments(cls.classId!, full)))).flat();
 }
 
 export async function getStudentGroups(username: string, full: boolean): Promise<GroupDTO[]> {

backend/src/services/submissions.ts

@@ -1,4 +1,4 @@
-import { getGroupRepository, getSubmissionRepository } from '../data/repositories.js';
+import { getSubmissionRepository } from '../data/repositories.js';
 import { Language } from '../entities/content/language.js';
 import { LearningObjectIdentifier } from '../entities/content/learning-object-identifier.js';
 import { mapToSubmission, mapToSubmissionDTO, SubmissionDTO } from '../interfaces/submission.js';
@@ -21,21 +21,26 @@ export async function getSubmission(
     return mapToSubmissionDTO(submission);
 }
 
-export async function createSubmission(submissionDTO: SubmissionDTO) {
+export async function createSubmission(submissionDTO: SubmissionDTO): Promise<SubmissionDTO | null> {
     const submissionRepository = getSubmissionRepository();
     const submission = mapToSubmission(submissionDTO);
 
     try {
-        const newSubmission = await submissionRepository.create(submission);
+        const newSubmission = submissionRepository.create(submission);
         await submissionRepository.save(newSubmission);
-    } catch (e) {
+    } catch (_) {
         return null;
     }
 
     return mapToSubmissionDTO(submission);
 }
 
-export async function deleteSubmission(learningObjectHruid: string, language: Language, version: number, submissionNumber: number) {
+export async function deleteSubmission(
+    learningObjectHruid: string,
+    language: Language,
+    version: number,
+    submissionNumber: number
+): Promise<SubmissionDTO | null> {
     const submissionRepository = getSubmissionRepository();
 
     const submission = getSubmission(learningObjectHruid, language, version, submissionNumber);

backend/src/services/teachers.ts

@@ -1,18 +1,10 @@
-import {
-    getClassRepository,
-    getLearningObjectRepository,
-    getQuestionRepository,
-    getStudentRepository,
-    getTeacherRepository,
-} from '../data/repositories.js';
-import { Teacher } from '../entities/users/teacher.entity.js';
+import { getClassRepository, getLearningObjectRepository, getQuestionRepository, getTeacherRepository } from '../data/repositories.js';
 import { ClassDTO, mapToClassDTO } from '../interfaces/class.js';
 import { getClassStudents } from './classes.js';
 import { StudentDTO } from '../interfaces/student.js';
 import { mapToQuestionDTO, mapToQuestionId, QuestionDTO, QuestionId } from '../interfaces/question.js';
-import { mapToUser } from '../interfaces/user.js';
 import { mapToTeacher, mapToTeacherDTO, TeacherDTO } from '../interfaces/teacher.js';
-import { teachersOnly } from '../middleware/auth/auth.js';
+import { getLogger } from '../logging/initalize.js';
 
 export async function getAllTeachers(full: boolean): Promise<TeacherDTO[] | string[]> {
     const teacherRepository = getTeacherRepository();
@@ -34,15 +26,10 @@ export async function getTeacher(username: string): Promise<TeacherDTO | null> {
 export async function createTeacher(userData: TeacherDTO): Promise<TeacherDTO | null> {
     const teacherRepository = getTeacherRepository();
 
-    try {
-        const newTeacher = teacherRepository.create(mapToTeacher(userData));
-        await teacherRepository.save(newTeacher);
+    const newTeacher = mapToTeacher(userData);
+    await teacherRepository.save(newTeacher, { preventOverwrite: true });
 
-        return mapToTeacherDTO(newTeacher);
-    } catch (e) {
-        console.log(e);
-        return null;
-    }
+    return mapToTeacherDTO(newTeacher);
 }
 
 export async function deleteTeacher(username: string): Promise<TeacherDTO | null> {
@@ -59,7 +46,7 @@ export async function deleteTeacher(username: string): Promise<TeacherDTO | null
 
         return mapToTeacherDTO(user);
     } catch (e) {
-        console.log(e);
+        getLogger().error(e);
         return null;
     }
 }

backend/src/sqlite-autoincrement-workaround.ts

@@ -14,7 +14,7 @@ import { EntityProperty, EventArgs, EventSubscriber } from '@mikro-orm/core';
  *   the sequence number will not be filled in.
  */
 export class SqliteAutoincrementSubscriber implements EventSubscriber {
-    private sequenceNumbersForEntityType: Map<string, number> = new Map();
+    private sequenceNumbersForEntityType = new Map<string, number>();
 
     /**
      * When an entity with an autoincremented property which is part of the composite private key is created,
@@ -27,14 +27,14 @@ export class SqliteAutoincrementSubscriber implements EventSubscriber {
 
         for (const prop of Object.values(args.meta.properties)) {
             const property = prop as EntityProperty<T>;
-            if (property.primary && property.autoincrement && !(args.entity as Record<string, any>)[property.name]) {
+            if (property.primary && property.autoincrement && !(args.entity as Record<string, unknown>)[property.name]) {
                 // Obtain and increment sequence number of this entity.
                 const propertyKey = args.meta.class.name + '.' + property.name;
                 const nextSeqNumber = this.sequenceNumbersForEntityType.get(propertyKey) || 0;
                 this.sequenceNumbersForEntityType.set(propertyKey, nextSeqNumber + 1);
 
                 // Set the property accordingly.
-                (args.entity as Record<string, any>)[property.name] = nextSeqNumber + 1;
+                (args.entity as Record<string, unknown>)[property.name] = nextSeqNumber + 1;
             }
         }
     }

backend/src/util/api-helper.ts

@@ -1,5 +1,6 @@
 import axios, { AxiosRequestConfig } from 'axios';
 import { getLogger, Logger } from '../logging/initalize.js';
+import { LearningObjectIdentifier } from '../interfaces/learning-content.js';
 
 const logger: Logger = getLogger();
 
@@ -17,8 +18,8 @@ export async function fetchWithLogging<T>(
     url: string,
     description: string,
     options?: {
-        params?: Record<string, any>;
-        query?: Record<string, any>;
+        params?: Record<string, unknown> | LearningObjectIdentifier;
+        query?: Record<string, unknown>;
         responseType?: 'json' | 'text';
     }
 ): Promise<T | null> {
@@ -26,18 +27,21 @@ export async function fetchWithLogging<T>(
         const config: AxiosRequestConfig = options || {};
         const response = await axios.get<T>(url, config);
         return response.data;
-    } catch (error: any) {
-        if (error.response) {
-            if (error.response.status === 404) {
-                logger.debug(`❌ ERROR: ${description} not found (404) at "${url}".`);
+    } catch (error: unknown) {
+        if (axios.isAxiosError(error)) {
+            if (error.response) {
+                if (error.response.status === 404) {
+                    logger.debug(`❌ ERROR: ${description} not found (404) at "${url}".`);
+                } else {
+                    logger.debug(
+                        `❌ ERROR: Failed to fetch ${description}. Status: ${error.response.status} - ${error.response.statusText} (URL: "${url}")`
+                    );
+                }
             } else {
-                logger.debug(
-                    `❌ ERROR: Failed to fetch ${description}. Status: ${error.response.status} - ${error.response.statusText} (URL: "${url}")`
-                );
+                logger.debug(`❌ ERROR: Network or unexpected error when fetching ${description}:`, error.message);
             }
-        } else {
-            logger.debug(`❌ ERROR: Network or unexpected error when fetching ${description}:`, error.message);
         }
+        logger.error(`❌ ERROR: Unknown error while fetching ${description}.`, error);
         return null;
     }
 }

backend/src/util/async.ts

@@ -6,7 +6,11 @@
  * @param regex
  * @param replacementFn
  */
-export async function replaceAsync(str: string, regex: RegExp, replacementFn: (match: string, ...args: string[]) => Promise<string>) {
+export async function replaceAsync(
+    str: string,
+    regex: RegExp,
+    replacementFn: (match: string, ...args: string[]) => Promise<string>
+): Promise<string> {
     const promises: Promise<string>[] = [];
 
     // First run through matches: add all Promises resulting from the replacement function

backend/src/util/envVars.ts

@@ -6,9 +6,13 @@ const TEACHER_IDP_PREFIX = IDP_PREFIX + 'TEACHER_';
 const CORS_PREFIX = PREFIX + 'CORS_';
 const LOGGING_PREFIX = PREFIX + 'LOGGING_';
 
-type EnvVar = { key: string; required?: boolean; defaultValue?: any };
+interface EnvVar {
+    key: string;
+    required?: boolean;
+    defaultValue?: number | string | boolean;
+}
 
-export const EnvVars: { [key: string]: EnvVar } = {
+export const envVars: Record<string, EnvVar> = {
     Port: { key: PREFIX + 'PORT', defaultValue: 3000 },
     LearningContentRepoApiBaseUrl: { key: PREFIX + 'LEARNING_CONTENT_REPO_API_BASE_URL', defaultValue: 'https://dwengo.org/backend/api' },
     FallbackLanguage: { key: PREFIX + 'FALLBACK_LANGUAGE', defaultValue: 'nl' },
@@ -52,7 +56,7 @@ export function getEnvVar(envVar: EnvVar): string {
     } else if (envVar.required) {
         throw new Error(`Missing environment variable: ${envVar.key}`);
     } else {
-        return envVar.defaultValue || '';
+        return String(envVar.defaultValue) || '';
     }
 }
 

backend/src/util/links.ts

@@ -4,12 +4,12 @@ export function isValidHttpUrl(url: string): boolean {
     try {
         const parsedUrl = new URL(url, 'http://test.be');
         return parsedUrl.protocol === 'http:' || parsedUrl.protocol === 'https:';
-    } catch (e) {
+    } catch (_) {
         return false;
     }
 }
 
-export function getUrlStringForLearningObject(learningObjectId: LearningObjectIdentifier) {
+export function getUrlStringForLearningObject(learningObjectId: LearningObjectIdentifier): string {
     let url = `/learningObject/${learningObjectId.hruid}/html?language=${learningObjectId.language}`;
     if (learningObjectId.version) {
         url += `&version=${learningObjectId.version}`;