Align Spring Session MongoDB with WebSession API.

Only perform a save after verifying the MongoSession already exists in MongoDB. Otherwise, throw an IllegalStateException.

Resolved #47.

Author: gregturn

src/main/java/org/springframework/session/data/mongo/ReactiveMongoOperationsSessionRepository.java

@@ -107,8 +107,9 @@ public Mono<MongoSession> createSession() {
 	@Override
 	public Mono<Void> save(MongoSession session) {
 
-		return this.mongoOperations
-			.save(convertToDBObject(this.mongoSessionConverter, session), this.collectionName)
+		return findSession(session.getId())
+			.map(document -> this.mongoOperations.save(convertToDBObject(this.mongoSessionConverter, session), this.collectionName))
+			.switchIfEmpty(Mono.error(new IllegalStateException("Session was invalidated")))
 			.then();
 	}
 

src/test/java/org/springframework/session/data/mongo/ReactiveMongoOperationsSessionRepositoryTest.java

@@ -23,6 +23,7 @@
 import static org.mockito.BDDMockito.mock;
 import static org.mockito.BDDMockito.times;
 import static org.mockito.Mockito.verify;
+import static org.springframework.session.data.mongo.ReactiveMongoOperationsSessionRepository.DEFAULT_COLLECTION_NAME;
 
 import java.util.UUID;
 
@@ -114,8 +115,12 @@ public void shouldSaveSession() {
 
 		// given
 		MongoSession session = new MongoSession();
+		Document sessionDocument = new Document();
 		BasicDBObject dbSession = new BasicDBObject();
 
+		given(this.mongoOperations.findById(session.getId(), Document.class,
+			DEFAULT_COLLECTION_NAME)).willReturn(Mono.just(sessionDocument));
+
 		given(this.converter.convert(session,
 				TypeDescriptor.valueOf(MongoSession.class),
 				TypeDescriptor.valueOf(DBObject.class))).willReturn(dbSession);
@@ -127,7 +132,35 @@ public void shouldSaveSession() {
 			.as(StepVerifier::create)
 			.verifyComplete();
 
-		verify(this.mongoOperations).save(dbSession, ReactiveMongoOperationsSessionRepository.DEFAULT_COLLECTION_NAME);
+		verify(this.mongoOperations).findById(session.getId(), Document.class, DEFAULT_COLLECTION_NAME);
+		verify(this.mongoOperations).save(dbSession, DEFAULT_COLLECTION_NAME);
+		verifyNoMoreInteractions(this.mongoOperations);
+	}
+
+	@Test
+	public void shouldFailSaveWhenSessionDoesntExist() {
+
+		// given
+		MongoSession session = new MongoSession();
+		Document sessionDocument = new Document();
+		BasicDBObject dbSession = new BasicDBObject();
+
+		given(this.mongoOperations.findById(session.getId(), Document.class,
+			DEFAULT_COLLECTION_NAME)).willReturn(Mono.empty());
+
+		given(this.converter.convert(session,
+			TypeDescriptor.valueOf(MongoSession.class),
+			TypeDescriptor.valueOf(DBObject.class))).willReturn(dbSession);
+
+		given(this.mongoOperations.save(dbSession, "sessions")).willReturn(Mono.just(dbSession));
+
+		// when
+		this.repository.save(session)
+			.as(StepVerifier::create)
+			.verifyErrorMessage("Session was invalidated");
+
+		verify(this.mongoOperations).findById(session.getId(), Document.class, DEFAULT_COLLECTION_NAME);
+		verifyNoMoreInteractions(this.mongoOperations);
 	}
 
 	@Test
@@ -138,7 +171,7 @@ public void shouldGetSession() {
 		Document sessionDocument = new Document();
 
 		given(this.mongoOperations.findById(sessionId, Document.class,
-			ReactiveMongoOperationsSessionRepository.DEFAULT_COLLECTION_NAME)).willReturn(Mono.just(sessionDocument));
+			DEFAULT_COLLECTION_NAME)).willReturn(Mono.just(sessionDocument));
 
 		MongoSession session = new MongoSession();
 
@@ -160,9 +193,9 @@ public void shouldHandleExpiredSession() {
 		Document sessionDocument = new Document();
 
 		given(this.mongoOperations.findById(sessionId, Document.class,
-			ReactiveMongoOperationsSessionRepository.DEFAULT_COLLECTION_NAME)).willReturn(Mono.just(sessionDocument));
+			DEFAULT_COLLECTION_NAME)).willReturn(Mono.just(sessionDocument));
 
-		given(this.mongoOperations.remove(sessionDocument, ReactiveMongoOperationsSessionRepository.DEFAULT_COLLECTION_NAME))
+		given(this.mongoOperations.remove(sessionDocument, DEFAULT_COLLECTION_NAME))
 			.willReturn(Mono.just(DeleteResult.acknowledged(1)));
 
 		MongoSession session = mock(MongoSession.class);
@@ -177,8 +210,7 @@ public void shouldHandleExpiredSession() {
 			.verifyComplete();
 
 		// then
-		verify(this.mongoOperations).remove(any(Document.class),
-			eq(ReactiveMongoOperationsSessionRepository.DEFAULT_COLLECTION_NAME));
+		verify(this.mongoOperations).remove(any(Document.class), eq(DEFAULT_COLLECTION_NAME));
 	}
 
 	@Test
@@ -189,7 +221,7 @@ public void shouldDeleteSession() {
 		Document sessionDocument = new Document();
 
 		given(this.mongoOperations.findById(sessionId, Document.class,
-			ReactiveMongoOperationsSessionRepository.DEFAULT_COLLECTION_NAME)).willReturn(Mono.just(sessionDocument));
+			DEFAULT_COLLECTION_NAME)).willReturn(Mono.just(sessionDocument));
 
 		given(this.mongoOperations.remove(sessionDocument, "sessions"))
 			.willReturn(Mono.just(DeleteResult.acknowledged(1)));
@@ -204,9 +236,7 @@ public void shouldDeleteSession() {
 			.as(StepVerifier::create)
 			.verifyComplete();
 
-		verify(this.mongoOperations).remove(any(Document.class),
-			eq(ReactiveMongoOperationsSessionRepository.DEFAULT_COLLECTION_NAME));
-
+		verify(this.mongoOperations).remove(any(Document.class), eq(DEFAULT_COLLECTION_NAME));
 		verify(this.eventPublisher).publishEvent(any(SessionDeletedEvent.class));
 	}
 
@@ -225,5 +255,8 @@ public void shouldInvokeMethodToCreateIndexesImperatively() {
 		// then
 		verify(this.blockingMongoOperations, times(1)).indexOps((String) any());
 		verify(this.converter, times(1)).ensureIndexes(indexOperations);
+		
+		verifyNoMoreInteractions(this.blockingMongoOperations);
+		verifyNoMoreInteractions(this.converter);
 	}
 }