Draft: Split logic of ExerciseResource into endpoints per exercise-type

src/main/java/de/tum/cit/aet/artemis/exam/web/ExamResource.java

@@ -51,6 +51,7 @@
 import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
 
 import de.tum.cit.aet.artemis.assessment.domain.TutorParticipation;
+import de.tum.cit.aet.artemis.assessment.repository.GradingCriterionRepository;
 import de.tum.cit.aet.artemis.assessment.repository.TutorParticipationRepository;
 import de.tum.cit.aet.artemis.assessment.service.AssessmentDashboardService;
 import de.tum.cit.aet.artemis.communication.domain.conversation.Channel;
@@ -107,6 +108,7 @@
 import de.tum.cit.aet.artemis.exam.service.ExamSessionService;
 import de.tum.cit.aet.artemis.exam.service.ExamUserService;
 import de.tum.cit.aet.artemis.exam.service.StudentExamService;
+import de.tum.cit.aet.artemis.exercise.api.ExerciseApi;
 import de.tum.cit.aet.artemis.exercise.domain.Exercise;
 import de.tum.cit.aet.artemis.exercise.domain.Submission;
 import de.tum.cit.aet.artemis.exercise.dto.ExerciseForPlagiarismCasesOverviewDTO;
@@ -178,12 +180,17 @@ public class ExamResource {
 
     private final ExamUserService examUserService;
 
+    private final GradingCriterionRepository gradingCriterionRepository;
+
+    private final ExerciseApi exerciseApi;
+
     public ExamResource(UserRepository userRepository, CourseRepository courseRepository, ExamService examService, ExamDeletionService examDeletionService,
             ExamAccessService examAccessService, InstanceMessageSendService instanceMessageSendService, ExamRepository examRepository, SubmissionService submissionService,
             AuthorizationCheckService authCheckService, ExamDateService examDateService, TutorParticipationRepository tutorParticipationRepository,
             AssessmentDashboardService assessmentDashboardService, ExamRegistrationService examRegistrationService, ExamImportService examImportService,
             CustomAuditEventRepository auditEventRepository, ChannelService channelService, ChannelRepository channelRepository, ExerciseRepository exerciseRepository,
-            ExamSessionService examSessionRepository, ExamLiveEventsService examLiveEventsService, StudentExamService studentExamService, ExamUserService examUserService) {
+            ExamSessionService examSessionRepository, ExamLiveEventsService examLiveEventsService, StudentExamService studentExamService, ExamUserService examUserService,
+            GradingCriterionRepository gradingCriterionRepository, ExerciseApi exerciseApi) {
         this.userRepository = userRepository;
         this.courseRepository = courseRepository;
         this.examService = examService;
@@ -206,6 +213,8 @@ public ExamResource(UserRepository userRepository, CourseRepository courseReposi
         this.examLiveEventsService = examLiveEventsService;
         this.studentExamService = studentExamService;
         this.examUserService = examUserService;
+        this.gradingCriterionRepository = gradingCriterionRepository;
+        this.exerciseApi = exerciseApi;
     }
 
     /**
@@ -303,6 +312,45 @@ public ResponseEntity<Exam> updateExam(@PathVariable Long courseId, @RequestBody
         return ResponseEntity.ok(savedExam);
     }
 
+    /**
+     * GET /exercises/:exerciseId : get an exam exercise by id.
+     * Users with at least editor rights can always access the exercise.
+     * Users with at least tutor rights can only access the exercise after the it has been finished.
+     * Students cannot see the exercise.
+     *
+     * @param exerciseId the exerciseId of the exercise to retrieve
+     * @return the ResponseEntity with status 200 (OK) and with body the exercise, or with status 404 (Not Found)
+     */
+    @GetMapping("exam/exercises/{exerciseId}")
+    @EnforceAtLeastEditor
+    public ResponseEntity<Exercise> getExamExercise(@PathVariable Long exerciseId) {
+        log.debug("REST request to get Exam Exercise : {}", exerciseId);
+
+        User user = userRepository.getUserWithGroupsAndAuthorities();
+        Exercise exercise = exerciseRepository.findByIdWithCategoriesAndTeamAssignmentConfigElseThrow(exerciseId);
+
+        Exam exam = exercise.getExerciseGroup().getExam();
+        if (authCheckService.isAtLeastEditorForExercise(exercise, user)) {
+            // instructors editors and admins should always be able to see exam exercises
+            // continue
+        }
+        else if (authCheckService.isAtLeastTeachingAssistantForExercise(exercise, user)) {
+            // tutors should only be able to see exam exercises when the exercise has finished
+            ZonedDateTime latestIndividualExamEndDate = examDateService.getLatestIndividualExamEndDate(exam);
+            if (latestIndividualExamEndDate == null || latestIndividualExamEndDate.isAfter(ZonedDateTime.now())) {
+                // When there is no due date or the due date is in the future, we return forbidden here
+                throw new AccessForbiddenException();
+            }
+        }
+        else {
+            // Students should never access exercises
+            throw new AccessForbiddenException();
+        }
+
+        exerciseApi.setGradingCriteria(exercise);
+        return ResponseEntity.ok(exercise);
+    }
+
     /**
      * PATCH /courses/{courseId}/exams/{examId}/working-time : Update the working time of all exams
      *

src/main/java/de/tum/cit/aet/artemis/exercise/api/ExerciseApi.java

@@ -0,0 +1,84 @@
+package de.tum.cit.aet.artemis.exercise.api;
+
+import java.util.Set;
+
+import org.springframework.stereotype.Controller;
+
+import de.tum.cit.aet.artemis.assessment.domain.ExampleSubmission;
+import de.tum.cit.aet.artemis.assessment.domain.GradingCriterion;
+import de.tum.cit.aet.artemis.assessment.repository.ExampleSubmissionRepository;
+import de.tum.cit.aet.artemis.assessment.repository.GradingCriterionRepository;
+import de.tum.cit.aet.artemis.communication.domain.conversation.Channel;
+import de.tum.cit.aet.artemis.communication.repository.conversation.ChannelRepository;
+import de.tum.cit.aet.artemis.core.domain.User;
+import de.tum.cit.aet.artemis.core.service.AuthorizationCheckService;
+import de.tum.cit.aet.artemis.exercise.domain.Exercise;
+import de.tum.cit.aet.artemis.exercise.service.ExerciseService;
+
+// This is a very simple implementation, and should pbl be split up
+@Controller
+public class ExerciseApi {
+
+    // ToDo: Should be some kind of ChannelApi
+    private final ChannelRepository channelRepository;
+
+    // ToDo: Should be some kind of AssessmentApi
+    private final GradingCriterionRepository gradingCriterionRepository;
+
+    // ToDo: Should be some kind of AssessmentApi
+    private final ExampleSubmissionRepository exampleSubmissionRepository;
+
+    private final AuthorizationCheckService authCheckService;
+
+    private final ExerciseService exerciseService;
+
+    public ExerciseApi(AuthorizationCheckService authCheckService, ChannelRepository channelRepository, GradingCriterionRepository gradingCriterionRepository,
+            ExerciseService exerciseService, ExampleSubmissionRepository exampleSubmissionRepository) {
+        this.authCheckService = authCheckService;
+        this.channelRepository = channelRepository;
+        this.gradingCriterionRepository = gradingCriterionRepository;
+        this.exerciseService = exerciseService;
+        this.exampleSubmissionRepository = exampleSubmissionRepository;
+    }
+
+    public boolean isStudentAllowedToSee(Exercise exercise) {
+        return isStudentAllowedToSee(exercise, null);
+    }
+
+    public boolean isStudentAllowedToSee(Exercise exercise, User user) {
+        if (exercise.isExamExercise()) {
+            return false;
+        }
+
+        return authCheckService.isAllowedToSeeExercise(exercise, user);
+    }
+
+    public boolean isCorrectExerciseType(Exercise exercise, Class<? extends Exercise> expectedExerciseClass) {
+        return expectedExerciseClass.isInstance(exercise);
+    }
+
+    public void setChannelName(Exercise exercise) {
+        Channel channel = channelRepository.findChannelByExerciseId(exercise.getId());
+        if (channel != null) {
+            exercise.setChannelName(channel.getName());
+        }
+    }
+
+    public void setGradingCriteria(Exercise exercise) {
+        Set<GradingCriterion> gradingCriteria = gradingCriterionRepository.findByExerciseIdWithEagerGradingCriteria(exercise.getId());
+        exercise.setGradingCriteria(gradingCriteria);
+    }
+
+    public void checkExerciseIfStructuredGradingInstructionFeedbackUsed(Set<GradingCriterion> gradingCriteria, Exercise exercise) {
+        exerciseService.checkExerciseIfStructuredGradingInstructionFeedbackUsed(gradingCriteria, exercise);
+    }
+
+    public void setExampleSubmissions(Exercise exercise) {
+        Set<ExampleSubmission> exampleSubmissions = this.exampleSubmissionRepository.findAllWithResultByExerciseId(exercise.getId());
+        exercise.setExampleSubmissions(exampleSubmissions);
+    }
+
+    public void filterSensitiveData(Exercise exercise) {
+        exercise.filterSensitiveInformation();
+    }
+}

src/main/java/de/tum/cit/aet/artemis/exercise/web/ExerciseResource.java

@@ -2,6 +2,7 @@
 
 import static de.tum.cit.aet.artemis.core.config.Constants.PROFILE_CORE;
 
+import java.io.IOException;
 import java.time.ZonedDateTime;
 import java.util.Collections;
 import java.util.HashSet;
@@ -10,6 +11,11 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
+import jakarta.servlet.RequestDispatcher;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.context.annotation.Profile;
@@ -38,10 +44,9 @@
 import de.tum.cit.aet.artemis.core.security.annotations.EnforceAtLeastInstructor;
 import de.tum.cit.aet.artemis.core.security.annotations.EnforceAtLeastStudent;
 import de.tum.cit.aet.artemis.core.security.annotations.EnforceAtLeastTutor;
+import de.tum.cit.aet.artemis.core.security.annotations.enforceRoleInExercise.EnforceAtLeastStudentInExercise;
 import de.tum.cit.aet.artemis.core.service.AuthorizationCheckService;
-import de.tum.cit.aet.artemis.exam.domain.Exam;
 import de.tum.cit.aet.artemis.exam.service.ExamAccessService;
-import de.tum.cit.aet.artemis.exam.service.ExamDateService;
 import de.tum.cit.aet.artemis.exercise.domain.Exercise;
 import de.tum.cit.aet.artemis.exercise.domain.participation.StudentParticipation;
 import de.tum.cit.aet.artemis.exercise.dto.ExerciseDetailsDTO;
@@ -86,8 +91,6 @@ public class ExerciseResource {
 
     private final TutorParticipationService tutorParticipationService;
 
-    private final ExamDateService examDateService;
-
     private final GradingCriterionRepository gradingCriterionRepository;
 
     private final ExampleSubmissionRepository exampleSubmissionRepository;
@@ -107,7 +110,7 @@ public class ExerciseResource {
     private final ExerciseHintService exerciseHintService;
 
     public ExerciseResource(ExerciseService exerciseService, ExerciseDeletionService exerciseDeletionService, ParticipationService participationService,
-            UserRepository userRepository, ExamDateService examDateService, AuthorizationCheckService authCheckService, TutorParticipationService tutorParticipationService,
+            UserRepository userRepository, AuthorizationCheckService authCheckService, TutorParticipationService tutorParticipationService,
             ExampleSubmissionRepository exampleSubmissionRepository, ProgrammingExerciseRepository programmingExerciseRepository,
             GradingCriterionRepository gradingCriterionRepository, ExerciseRepository exerciseRepository, QuizBatchService quizBatchService,
             ParticipationRepository participationRepository, ExamAccessService examAccessService, Optional<IrisSettingsService> irisSettingsService,
@@ -120,7 +123,6 @@ public ExerciseResource(ExerciseService exerciseService, ExerciseDeletionService
         this.tutorParticipationService = tutorParticipationService;
         this.exampleSubmissionRepository = exampleSubmissionRepository;
         this.gradingCriterionRepository = gradingCriterionRepository;
-        this.examDateService = examDateService;
         this.exerciseRepository = exerciseRepository;
         this.programmingExerciseRepository = programmingExerciseRepository;
         this.quizBatchService = quizBatchService;
@@ -138,47 +140,19 @@ public ExerciseResource(ExerciseService exerciseService, ExerciseDeletionService
      * @return the ResponseEntity with status 200 (OK) and with body the exercise, or with status 404 (Not Found)
      */
     @GetMapping("exercises/{exerciseId}")
-    @EnforceAtLeastStudent
-    public ResponseEntity<Exercise> getExercise(@PathVariable Long exerciseId) {
-
-        log.debug("REST request to get Exercise : {}", exerciseId);
+    @EnforceAtLeastStudentInExercise
+    public ResponseEntity<Exercise> getExercise(@PathVariable Long exerciseId, HttpServletRequest request, HttpServletResponse response) {
 
-        User user = userRepository.getUserWithGroupsAndAuthorities();
-        Exercise exercise = exerciseRepository.findByIdWithCategoriesAndTeamAssignmentConfigElseThrow(exerciseId);
+        log.debug("REST request to get generic Exercise : {}", exerciseId);
 
         // Exam exercise
+        Exercise exercise = exerciseRepository.findByIdElseThrow(exerciseId);
         if (exercise.isExamExercise()) {
-            Exam exam = exercise.getExerciseGroup().getExam();
-            if (authCheckService.isAtLeastEditorForExercise(exercise, user)) {
-                // instructors editors and admins should always be able to see exam exercises
-                // continue
-            }
-            else if (authCheckService.isAtLeastTeachingAssistantForExercise(exercise, user)) {
-                // tutors should only be able to see exam exercises when the exercise has finished
-                ZonedDateTime latestIndividualExamEndDate = examDateService.getLatestIndividualExamEndDate(exam);
-                if (latestIndividualExamEndDate == null || latestIndividualExamEndDate.isAfter(ZonedDateTime.now())) {
-                    // When there is no due date or the due date is in the future, we return forbidden here
-                    throw new AccessForbiddenException();
-                }
-            }
-            else {
-                // Students should never access exercises
-                throw new AccessForbiddenException();
-            }
-        }
-        // Normal exercise
-        else {
-            if (!authCheckService.isAllowedToSeeExercise(exercise, user)) {
-                throw new AccessForbiddenException();
-            }
-            if (!authCheckService.isAtLeastTeachingAssistantForExercise(exercise, user)) {
-                exercise.filterSensitiveInformation();
-            }
+            return forwardToExamExerciseURL(request, response, exerciseId);
         }
 
-        Set<GradingCriterion> gradingCriteria = gradingCriterionRepository.findByExerciseIdWithEagerGradingCriteria(exerciseId);
-        exercise.setGradingCriteria(gradingCriteria);
-        return ResponseEntity.ok(exercise);
+        // Regular exercise
+        return forwardToExerciseURL(request, response, exercise);
     }
 
     /**
@@ -387,4 +361,48 @@ public ResponseEntity<ZonedDateTime> getLatestDueDate(@PathVariable Long exercis
         authCheckService.checkHasAtLeastRoleForExerciseElseThrow(Role.STUDENT, exercise, null);
         return ResponseEntity.ok(participationRepository.findLatestIndividualDueDate(exerciseId).orElse(exercise.getDueDate()));
     }
+
+    private ResponseEntity<Exercise> forwardToExamExerciseURL(HttpServletRequest request, HttpServletResponse response, Long exerciseId) {
+        String url = String.format("/api/exams/exercises/%s", exerciseId);
+        return forwardToUrl(request, response, url);
+    }
+
+    /**
+     * Handles the forwarding to the correct exercise URL based on the exercise type.
+     * ToDo: Consider already throwing an error here, if a module is not present. Otherwise, it produces a 404
+     */
+    private ResponseEntity<Exercise> forwardToExerciseURL(HttpServletRequest request, HttpServletResponse response, Exercise exercise) {
+        Long exerciseId = exercise.getId();
+        String url = switch (exercise.getExerciseType()) {
+            case PROGRAMMING -> "/api/programming-exercises/" + exerciseId;
+            case QUIZ -> "/api/quiz-exercises/" + exerciseId;
+            case MODELING -> "/api/modeling-exercises/" + exerciseId;
+            case TEXT -> "/api/text-exercises/" + exerciseId;
+            case FILE_UPLOAD -> "/api/file-upload-exercises/" + exerciseId;
+        };
+
+        // For students, call a separate endpoint
+        if (!authCheckService.isAtLeastTeachingAssistantInExercise(exerciseId)) {
+            url += "/for-students";
+        }
+
+        return forwardToUrl(request, response, url);
+    }
+
+    // ToDo: Move to common class
+    // ToDo: Consider using redirects (302) instead of internal forwards. An exercise with the same ID won't change its type
+    private <T> ResponseEntity<T> forwardToUrl(HttpServletRequest request, HttpServletResponse response, String url) {
+        RequestDispatcher dispatcher = request.getRequestDispatcher(url);
+        try {
+            dispatcher.forward(request, response);
+        }
+        catch (ServletException e) {
+            throw new RuntimeException(e); // ToDo: Handle gracefully
+        }
+        catch (IOException e) {
+            throw new RuntimeException(e); // ToDo: Handle gracefully
+        }
+
+        return null; // Will be overridden by response
+    }
 }