Returning Neo4j map projection with WebFlux - neo4j

Question

I have the nodes user and game with some relationships between them.
My REST API should return all relationships between the games and 1 user.
The cypher query i use is:
MATCH (u:User {id: '1234'} ) -[rel]- (game:Game) return game{.*, relationships: collect(DISTINCT rel)}
In my Neo4j Browser, everything works as expected and i see all properties i need.
But the GetMapping retuns everything except the relationship properties.
Neo4j Browser
{
"relationships": [
{
"identity": 54,
"start": 9,
"end": 8,
"type": "OWNED",
"properties": {
"ownedDate": "2021-07-03"
}
},
{
"identity": 45,
"start": 9,
"end": 8,
"type": "PLAYED",
"properties": {
"times": 5
}
}
],
"name": "Blood Rage",
"state": "ACTIVE",
"id": "1c152c91-4044-41f0-9208-0c436d6f6480",
"gameUrl": "https://asmodee.de/blood-rage"
}
GetMapping result (As you can see, the relationships are empty, but i have more empty JsonObjects, when there are more Relationships
{
"game": {
"relationships": [
{},
{}
],
"name": "Blood Rage",
"gameUrl": "https://asmodee.de/blood-rage",
"state": "ACTIVE",
"id": "1c152c91-4044-41f0-9208-0c436d6f6480"
}
}
The GetMapping is:
...
final ReactiveNeo4jClient client;
...
...
...
#GetMapping(value = { "/{id}/games"})
#RolesAllowed({"user", "admin"})
Flux<Map<String, Object>> findGamesByUser(#PathVariable String id){
String query = "MATCH (uuser:User {id: '" + id + "'} ) -[rel]- (game:Game) return game{.*, relationships: collect(DISTINCT rel)}";
return client.query(query).fetch().all();
}
A RelationshipProperty-Example
#RelationshipProperties
#Data
#Builder
public class PlayedGame {
#Id
#GeneratedValue
private Long relationshipId;
#Property
int times = 0;
#TargetNode private GameEntity game;
public int addPlay(){
this.times = this.times + 1;
return this.times;
}
}
What do i have to change in my GetMapping to show the relationship-properties?
Thank you,
Kevin

Answer 1

You need to return the actual nodes and relationships, otherwise you're missing the id-mapping.
There should be examples in the SDN docs.
Best if you have a small reproducible example (e.g. with the default movies graph).
Not sure if there is something off in your SDN setup, in general for such simple queries you should be able to just use a repository and not need to write cypher queries by hand.

Answer 2

The general information given by Michael is correct but there is more in you question:
First of all the meta domain model is completely ignored if you are using the Neo4jClient. It does not automatically map anything back but uses the driver's types.
As a result you will end up with an (current state of this answer) InternalRelationship which does not have any getter-methods.
I assume that you are serializing the result in the application with Jackson. This is the reason why you see objects that represent the relationships but without any content within.
If you want to get things mapped for you, create also the domain objects properly and use (at least) the Neo4jTemplate with your query.
If you model User, Game, and the relationship properties like PlayedGame correctly, a
neo4jTemplate.findAll("MATCH (u:User)<-[rel]-(g:Game) return u, collect(rel), collect(g)", User.class)
will map the results properly. Also if this is all you have, you could also skip the custom query at all and use
neo4jTemplate.findAll(User.class)
or
neo4jTemplate.findById(useId, User.class)