Delete inactive sessions created by guests periodically

src/main/java/de/thm/arsnova/dao/CouchDBDao.java

@@ -1679,6 +1679,36 @@ public class CouchDBDao implements IDatabaseDao, ApplicationEventPublisherAware
 		}
 	}
 
+	@Override
+	public boolean deleteInactiveGuestSessions(long lastActivityBefore) {
+		try {
+			NovaView view = new NovaView("session/by_last_activity_for_guests");
+			view.setEndKey(lastActivityBefore);
+			List<Document> results = this.getDatabase().view(view).getResults();
+
+			final List<Document> newDocs = new ArrayList<Document>();
+			for (Document oldDoc : results) {
+				final Document newDoc = new Document();
+				newDoc.setId(oldDoc.getId());
+				newDoc.setRev(oldDoc.getJSONObject("value").getString("_rev"));
+				newDoc.put("_deleted", true);
+				newDocs.add(newDoc);
+				LOGGER.debug("Marked session document {} for deletion.", oldDoc.getId());
+			}
+
+			if (newDocs.size() > 0) {
+				getDatabase().bulkSaveDocuments(newDocs.toArray(new Document[newDocs.size()]));
+				LOGGER.info("Deleted {} inactive guest sessions.", newDocs.size());
+			}
+
+			return true;
+		} catch (IOException e) {
+			LOGGER.error("Could not delete inactive guest sessions.");
+		}
+
+		return false;
+	}
+
 	@Cacheable("lecturequestions")
 	@Override
 	public List<Question> getLectureQuestionsForUsers(final Session session) {

src/main/java/de/thm/arsnova/dao/IDatabaseDao.java

@@ -146,6 +146,8 @@ public interface IDatabaseDao {
 
 	void deleteSession(Session session);
 
+	boolean deleteInactiveGuestSessions(long lastActivityBefore);
+
 	List<Question> getLectureQuestionsForUsers(Session session);
 
 	List<Question> getLectureQuestionsForTeachers(Session session);

src/main/java/de/thm/arsnova/services/ISessionService.java

@@ -91,6 +91,8 @@ public interface ISessionService {
 	SessionFeature changeSessionFeatures(String sessionkey, SessionFeature features);
 
 	boolean lockFeedbackInput(String sessionkey, Boolean lock);
-	
+
 	boolean flipFlashcards(String sessionkey, Boolean flip);
+
+	void deleteInactiveSessions();
 }

src/main/java/de/thm/arsnova/services/SessionService.java

@@ -47,6 +47,7 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.context.ApplicationEventPublisherAware;
+import org.springframework.scheduling.annotation.Scheduled;
 import org.springframework.security.access.prepost.PreAuthorize;
 import org.springframework.stereotype.Service;
 
@@ -98,6 +99,9 @@ public class SessionService implements ISessionService, ApplicationEventPublishe
 		}
 	}
 
+	private static final long SESSION_INACTIVITY_CHECK_INTERVAL_MS = 30 * 60 * 1000L;
+	private static final long SESSION_INACTIVITY_THRESHOLD_MS = 90 * 24 * 60 * 60 * 1000L;
+
 	@Autowired
 	private IDatabaseDao databaseDao;
 
@@ -123,6 +127,14 @@ public class SessionService implements ISessionService, ApplicationEventPublishe
 
 	public static final Logger LOGGER = LoggerFactory.getLogger(SessionService.class);
 
+	@Scheduled(fixedDelay = SESSION_INACTIVITY_CHECK_INTERVAL_MS)
+	public void deleteInactiveSessions() {
+		LOGGER.info("Delete inactive sessions.");
+		long unixTime = System.currentTimeMillis();
+		long lastActivityBefore = unixTime - SESSION_INACTIVITY_THRESHOLD_MS;
+		databaseDao.deleteInactiveGuestSessions(lastActivityBefore);
+	}
+
 	public void setDatabaseDao(final IDatabaseDao newDatabaseDao) {
 		databaseDao = newDatabaseDao;
 	}

src/test/java/de/thm/arsnova/dao/StubDatabaseDao.java

@@ -345,6 +345,12 @@ public class StubDatabaseDao implements IDatabaseDao {
 		// TODO Auto-generated method stub
 	}
 
+	@Override
+	public boolean deleteInactiveGuestSessions(long lastActivityBefore) {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
 	@Override
 	public void deleteAllQuestionsWithAnswers(Session session) {
 		// TODO Auto-generated method stub