Programming exercises: Notify active editors when new changes are saved by another user

src/main/java/de/tum/cit/aet/artemis/exercise/service/ExerciseVersionService.java

@@ -3,8 +3,11 @@
 import static de.tum.cit.aet.artemis.core.config.Constants.PROFILE_CORE;
 
 import java.util.EnumSet;
+import java.util.List;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -18,12 +21,15 @@
 import de.tum.cit.aet.artemis.exercise.domain.ExerciseType;
 import de.tum.cit.aet.artemis.exercise.domain.ExerciseVersion;
 import de.tum.cit.aet.artemis.exercise.dto.versioning.ExerciseSnapshotDTO;
+import de.tum.cit.aet.artemis.exercise.dto.versioning.ProgrammingExerciseSnapshotDTO;
 import de.tum.cit.aet.artemis.exercise.repository.ExerciseVersionRepository;
 import de.tum.cit.aet.artemis.fileupload.repository.FileUploadExerciseRepository;
 import de.tum.cit.aet.artemis.modeling.repository.ModelingExerciseRepository;
 import de.tum.cit.aet.artemis.programming.domain.RepositoryType;
+import de.tum.cit.aet.artemis.programming.domain.SynchronizationTarget;
 import de.tum.cit.aet.artemis.programming.repository.ProgrammingExerciseRepository;
 import de.tum.cit.aet.artemis.programming.service.GitService;
+import de.tum.cit.aet.artemis.programming.service.ProgrammingExerciseSynchronizationService;
 import de.tum.cit.aet.artemis.quiz.repository.QuizExerciseRepository;
 import de.tum.cit.aet.artemis.text.repository.TextExerciseRepository;
 
@@ -53,9 +59,12 @@ public class ExerciseVersionService {
 
     private final UserRepository userRepository;
 
+    private final ProgrammingExerciseSynchronizationService programmingExerciseSynchronizationService;
+
     public ExerciseVersionService(ExerciseVersionRepository exerciseVersionRepository, GitService gitService, ProgrammingExerciseRepository programmingExerciseRepository,
             QuizExerciseRepository quizExerciseRepository, TextExerciseRepository textExerciseRepository, ModelingExerciseRepository modelingExerciseRepository,
-            FileUploadExerciseRepository fileUploadExerciseRepository, UserRepository userRepository) {
+            FileUploadExerciseRepository fileUploadExerciseRepository, UserRepository userRepository,
+            ProgrammingExerciseSynchronizationService programmingExerciseSynchronizationService) {
         this.exerciseVersionRepository = exerciseVersionRepository;
         this.gitService = gitService;
         this.programmingExerciseRepository = programmingExerciseRepository;
@@ -64,6 +73,7 @@ public ExerciseVersionService(ExerciseVersionRepository exerciseVersionRepositor
         this.modelingExerciseRepository = modelingExerciseRepository;
         this.fileUploadExerciseRepository = fileUploadExerciseRepository;
         this.userRepository = userRepository;
+        this.programmingExerciseSynchronizationService = programmingExerciseSynchronizationService;
     }
 
     public boolean isRepositoryTypeVersionable(RepositoryType repositoryType) {
@@ -122,6 +132,7 @@ public void createExerciseVersion(Exercise targetExercise, User author) {
             }
             exerciseVersion.setExerciseSnapshot(exerciseSnapshot);
             ExerciseVersion savedExerciseVersion = exerciseVersionRepository.save(exerciseVersion);
+            this.determineSynchronizationForActiveEditors(exercise.getId(), exerciseSnapshot, previousVersion.map(ExerciseVersion::getExerciseSnapshot).orElse(null));
             log.info("Exercise version {} has been created for exercise {}", savedExerciseVersion.getId(), exercise.getId());
         }
         catch (Exception e) {
@@ -152,4 +163,62 @@ private Exercise fetchExerciseEagerly(Exercise exercise) {
             case FILE_UPLOAD -> fileUploadExerciseRepository.findForVersioningById(exercise.getId()).orElse(null);
         };
     }
+
+    /**
+     * Compare two exercise snapshots and return the change that should be broadcast to clients.
+     *
+     * @param exerciseId       the exercise id
+     * @param newSnapshot      the new snapshot
+     * @param previousSnapshot the previous snapshot (optional)
+     */
+    private void determineSynchronizationForActiveEditors(Long exerciseId, ExerciseSnapshotDTO newSnapshot, ExerciseSnapshotDTO previousSnapshot) {
+        if (previousSnapshot == null || newSnapshot.programmingData() == null || previousSnapshot.programmingData() == null) {
+            return;
+        }
+
+        var newProgrammingData = newSnapshot.programmingData();
+        var previousProgrammingData = previousSnapshot.programmingData();
+        SynchronizationTarget target = null;
+        Long auxiliaryRepositoryId = null;
+
+        if (commitIdChanged(previousProgrammingData.templateParticipation(), newProgrammingData.templateParticipation())) {
+            target = SynchronizationTarget.TEMPLATE_REPOSITORY;
+        }
+        else if (commitIdChanged(previousProgrammingData.solutionParticipation(), newProgrammingData.solutionParticipation())) {
+            target = SynchronizationTarget.SOLUTION_REPOSITORY;
+        }
+        else if (!Objects.equals(previousProgrammingData.testsCommitId(), newProgrammingData.testsCommitId())) {
+            target = SynchronizationTarget.TESTS_REPOSITORY;
+        }
+        else {
+            var previousAuxiliaries = Optional.ofNullable(previousProgrammingData.auxiliaryRepositories()).orElseGet(List::of).stream().collect(
+                    Collectors.toMap(ProgrammingExerciseSnapshotDTO.AuxiliaryRepositorySnapshotDTO::id, ProgrammingExerciseSnapshotDTO.AuxiliaryRepositorySnapshotDTO::commitId));
+            for (var auxiliary : Optional.ofNullable(newProgrammingData.auxiliaryRepositories()).orElseGet(List::of)) {
+                var previousCommitId = previousAuxiliaries.get(auxiliary.id());
+                if (!Objects.equals(previousCommitId, auxiliary.commitId())) {
+                    target = SynchronizationTarget.AUXILIARY_REPOSITORY;
+                    auxiliaryRepositoryId = auxiliary.id();
+                    break;
+                }
+            }
+        }
+
+        if (target == null && !Objects.equals(previousSnapshot.problemStatement(), newSnapshot.problemStatement())) {
+            target = SynchronizationTarget.PROBLEM_STATEMENT;
+        }
+
+        if (target != null) {
+            programmingExerciseSynchronizationService.broadcastChange(exerciseId, target, auxiliaryRepositoryId);
+        }
+    }
+
+    private boolean commitIdChanged(ProgrammingExerciseSnapshotDTO.ParticipationSnapshotDTO previousParticipation,
+            ProgrammingExerciseSnapshotDTO.ParticipationSnapshotDTO newParticipation) {
+        if (previousParticipation == null && newParticipation == null) {
+            return false;
+        }
+        var previousCommitId = previousParticipation == null ? null : previousParticipation.commitId();
+        var newCommitId = newParticipation == null ? null : newParticipation.commitId();
+        return !Objects.equals(previousCommitId, newCommitId);
+    }
 }

src/main/java/de/tum/cit/aet/artemis/programming/domain/SynchronizationTarget.java

@@ -0,0 +1,8 @@
+package de.tum.cit.aet.artemis.programming.domain;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+
+@JsonInclude(JsonInclude.Include.NON_EMPTY)
+public enum SynchronizationTarget {
+    PROBLEM_STATEMENT, TEMPLATE_REPOSITORY, SOLUTION_REPOSITORY, TESTS_REPOSITORY, AUXILIARY_REPOSITORY
+}

src/main/java/de/tum/cit/aet/artemis/programming/dto/ProgrammingExerciseSynchronizationDTO.java

@@ -0,0 +1,11 @@
+package de.tum.cit.aet.artemis.programming.dto;
+
+import org.jspecify.annotations.Nullable;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+
+import de.tum.cit.aet.artemis.programming.domain.SynchronizationTarget;
+
+@JsonInclude(JsonInclude.Include.NON_EMPTY)
+public record ProgrammingExerciseSynchronizationDTO(SynchronizationTarget target, @Nullable Long auxiliaryRepositoryId, @Nullable String clientInstanceId) {
+}

src/main/java/de/tum/cit/aet/artemis/programming/service/ProgrammingExerciseSynchronizationService.java

@@ -0,0 +1,66 @@
+package de.tum.cit.aet.artemis.programming.service;
+
+import static de.tum.cit.aet.artemis.core.config.Constants.PROFILE_CORE;
+
+import org.jspecify.annotations.Nullable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.context.annotation.Lazy;
+import org.springframework.context.annotation.Profile;
+import org.springframework.stereotype.Service;
+import org.springframework.web.context.request.RequestAttributes;
+import org.springframework.web.context.request.RequestContextHolder;
+import org.springframework.web.context.request.ServletRequestAttributes;
+
+import de.tum.cit.aet.artemis.communication.service.WebsocketMessagingService;
+import de.tum.cit.aet.artemis.programming.domain.SynchronizationTarget;
+import de.tum.cit.aet.artemis.programming.dto.ProgrammingExerciseSynchronizationDTO;
+
+@Profile(PROFILE_CORE)
+@Lazy
+@Service
+public class ProgrammingExerciseSynchronizationService {
+
+    private static final Logger log = LoggerFactory.getLogger(ProgrammingExerciseSynchronizationService.class);
+
+    public static final String CLIENT_INSTANCE_HEADER = "X-Artemis-Client-Instance-ID";
+
+    private final WebsocketMessagingService websocketMessagingService;
+
+    public ProgrammingExerciseSynchronizationService(WebsocketMessagingService websocketMessagingService) {
+        this.websocketMessagingService = websocketMessagingService;
+    }
+
+    public static String getSynchronizationTopic(long exerciseId) {
+        return "/topic/programming-exercises/" + exerciseId + "/synchronization";
+    }
+
+    /**
+     * Retrieves the client instance id from the current request, if available.
+     *
+     * @return the client instance id or null if no request context is available
+     */
+    public static String getClientInstanceId() {
+        RequestAttributes attributes = RequestContextHolder.getRequestAttributes();
+        if (attributes instanceof ServletRequestAttributes servletRequestAttributes) {
+            return servletRequestAttributes.getRequest().getHeader(CLIENT_INSTANCE_HEADER);
+        }
+        return null;
+    }
+
+    /**
+     * Broadcast a single change to all active editors.
+     *
+     * @param exerciseId            the exercise id
+     * @param target                the target data type associated with this change (e.g. template repository, solution repository, auxiliary repository, problem statement)
+     * @param auxiliaryRepositoryId (optional) the id of the auxiliary repository associated with this change
+     */
+    public void broadcastChange(long exerciseId, SynchronizationTarget target, @Nullable Long auxiliaryRepositoryId) {
+        var payload = new ProgrammingExerciseSynchronizationDTO(target, auxiliaryRepositoryId, getClientInstanceId());
+        websocketMessagingService.sendMessage(getSynchronizationTopic(exerciseId), payload).exceptionally(exception -> {
+            log.warn("Cannot send synchronization message for exercise {}", exerciseId, exception);
+            return null;
+        });
+    }
+
+}

src/main/java/de/tum/cit/aet/artemis/programming/web/repository/AuxiliaryRepositoryResource.java

@@ -39,11 +39,13 @@
 import de.tum.cit.aet.artemis.programming.domain.FileType;
 import de.tum.cit.aet.artemis.programming.domain.ProgrammingExercise;
 import de.tum.cit.aet.artemis.programming.domain.Repository;
+import de.tum.cit.aet.artemis.programming.domain.SynchronizationTarget;
 import de.tum.cit.aet.artemis.programming.dto.FileMove;
 import de.tum.cit.aet.artemis.programming.dto.RepositoryStatusDTO;
 import de.tum.cit.aet.artemis.programming.repository.AuxiliaryRepositoryRepository;
 import de.tum.cit.aet.artemis.programming.repository.ProgrammingExerciseRepository;
 import de.tum.cit.aet.artemis.programming.service.GitService;
+import de.tum.cit.aet.artemis.programming.service.ProgrammingExerciseSynchronizationService;
 import de.tum.cit.aet.artemis.programming.service.RepositoryAccessService;
 import de.tum.cit.aet.artemis.programming.service.RepositoryService;
 import de.tum.cit.aet.artemis.programming.service.localvc.LocalVCRepositoryUri;
@@ -62,8 +64,9 @@ public class AuxiliaryRepositoryResource extends RepositoryResource {
 
     public AuxiliaryRepositoryResource(UserRepository userRepository, AuthorizationCheckService authCheckService, GitService gitService, RepositoryService repositoryService,
             ProgrammingExerciseRepository programmingExerciseRepository, RepositoryAccessService repositoryAccessService, Optional<LocalVCServletService> localVCServletService,
-            AuxiliaryRepositoryRepository auxiliaryRepositoryRepository) {
-        super(userRepository, authCheckService, gitService, repositoryService, programmingExerciseRepository, repositoryAccessService, localVCServletService);
+            AuxiliaryRepositoryRepository auxiliaryRepositoryRepository, ProgrammingExerciseSynchronizationService programmingExerciseSynchronizationService) {
+        super(userRepository, authCheckService, gitService, repositoryService, programmingExerciseRepository, repositoryAccessService, programmingExerciseSynchronizationService,
+                localVCServletService);
         this.auxiliaryRepositoryRepository = auxiliaryRepositoryRepository;
     }
 
@@ -118,31 +121,39 @@ public ResponseEntity<byte[]> getFile(@PathVariable Long auxiliaryRepositoryId,
     @EnforceAtLeastTutor
     @FeatureToggle(Feature.ProgrammingExercises)
     public ResponseEntity<Void> createFile(@PathVariable Long auxiliaryRepositoryId, @RequestParam("file") String filePath, HttpServletRequest request) {
-        return super.createFile(auxiliaryRepositoryId, filePath, request);
+        var response = super.createFile(auxiliaryRepositoryId, filePath, request);
+        broadcastAuxiliaryRepositoryChange(auxiliaryRepositoryId);
+        return response;
     }
 
     @Override
     @PostMapping(value = "{auxiliaryRepositoryId}/folder", produces = MediaType.APPLICATION_JSON_VALUE)
     @EnforceAtLeastTutor
     @FeatureToggle(Feature.ProgrammingExercises)
     public ResponseEntity<Void> createFolder(@PathVariable Long auxiliaryRepositoryId, @RequestParam("folder") String folderPath, HttpServletRequest request) {
-        return super.createFolder(auxiliaryRepositoryId, folderPath, request);
+        var response = super.createFolder(auxiliaryRepositoryId, folderPath, request);
+        broadcastAuxiliaryRepositoryChange(auxiliaryRepositoryId);
+        return response;
     }
 
     @Override
     @PostMapping(value = "{auxiliaryRepositoryId}/rename-file", produces = MediaType.APPLICATION_JSON_VALUE)
     @EnforceAtLeastTutor
     @FeatureToggle(Feature.ProgrammingExercises)
     public ResponseEntity<Void> renameFile(@PathVariable Long auxiliaryRepositoryId, @RequestBody FileMove fileMove) {
-        return super.renameFile(auxiliaryRepositoryId, fileMove);
+        var response = super.renameFile(auxiliaryRepositoryId, fileMove);
+        broadcastAuxiliaryRepositoryChange(auxiliaryRepositoryId);
+        return response;
     }
 
     @Override
     @DeleteMapping(value = "{auxiliaryRepositoryId}/file", produces = MediaType.APPLICATION_JSON_VALUE)
     @EnforceAtLeastTutor
     @FeatureToggle(Feature.ProgrammingExercises)
     public ResponseEntity<Void> deleteFile(@PathVariable Long auxiliaryRepositoryId, @RequestParam("file") String filename) {
-        return super.deleteFile(auxiliaryRepositoryId, filename);
+        var response = super.deleteFile(auxiliaryRepositoryId, filename);
+        broadcastAuxiliaryRepositoryChange(auxiliaryRepositoryId);
+        return response;
     }
 
     @Override
@@ -165,7 +176,9 @@ public ResponseEntity<Void> commitChanges(@PathVariable Long auxiliaryRepository
     @EnforceAtLeastTutor
     @FeatureToggle(Feature.ProgrammingExercises)
     public ResponseEntity<Void> resetToLastCommit(@PathVariable Long auxiliaryRepositoryId) {
-        return super.resetToLastCommit(auxiliaryRepositoryId);
+        var response = super.resetToLastCommit(auxiliaryRepositoryId);
+        broadcastAuxiliaryRepositoryChange(auxiliaryRepositoryId);
+        return response;
     }
 
     @Override
@@ -209,6 +222,21 @@ public ResponseEntity<Map<String, String>> updateAuxiliaryFiles(@PathVariable("a
             FileSubmissionError error = new FileSubmissionError(auxiliaryRepositoryId, "checkoutFailed");
             throw new ResponseStatusException(HttpStatus.SERVICE_UNAVAILABLE, error.getMessage(), error);
         }
-        return saveFilesAndCommitChanges(auxiliaryRepositoryId, submissions, commit, repository);
+        var response = saveFilesAndCommitChanges(auxiliaryRepositoryId, submissions, commit, repository);
+        if (!commit && !submissions.isEmpty()) {
+            this.broadcastAuxiliaryRepositoryChange(auxiliaryRepositoryId);
+        }
+        return response;
+    }
+
+    private void broadcastAuxiliaryRepositoryChange(Long auxiliaryRepositoryId) {
+        try {
+            AuxiliaryRepository auxiliaryRepository = auxiliaryRepositoryRepository.findByIdElseThrow(auxiliaryRepositoryId);
+            ProgrammingExercise exercise = auxiliaryRepository.getExercise();
+            this.broadcastRepositoryUpdates(exercise.getId(), SynchronizationTarget.AUXILIARY_REPOSITORY, auxiliaryRepositoryId);
+        }
+        catch (Exception e) {
+            log.debug("Could not broadcast auxiliary repository change for {}: {}", auxiliaryRepositoryId, e.getMessage());
+        }
     }
 }