Neo4j Executing cypher query via rest

Question

Good Morning, I set up a local Neo4j database and want to model a graph of maven dependencies. When I execute the following statement via the webconsole, everything works fine:

start root = node(1)
create unique root -[:ROOT]-> (n{groupId:'fancyStuff',artifactId:'somewhat', version:'1.4'})
return n

(note: rootnode is there for debugging purposes, will be replaced by actual structure later) So, here everything works fine, no matter of how much whitespaces I take or replacing ' with "

In my java application i have the following function:

private static URI getOrCreate(Artifact artifact){
        String cypherUri = SERVER_ROOT_URI + "cypher";

        String cypherStatement="{\"query\" : \"start x  = node(1) " +
                "create unique x -[:ROOT]-> (artifact{groupId:\"" + artifact.getGroupID() +
                "\", artifactId:\"" + artifact.getArtifactID() +
                "\", version: \"" + artifact.getVersion() +
                "\"}) return artifact ,\"params\" : {}}";

        WebResource resource = Client.create()
                .resource( cypherUri );
        ClientResponse response = resource.accept( MediaType.APPLICATION_JSON_TYPE )
                .type( MediaType.APPLICATION_JSON_TYPE )
                .entity( cypherStatement )
                .post( ClientResponse.class );

        System.out.println( String.format( "POST to [%s], status code [%d]",
                cypherUri, response.getStatus() ) );

        response.close();
        return response.getLocation();
    }

so basically I post a json file looking like

{"query" : "start root = node(1) create unique root-[:ROOT]->(artifact{groupId:'{"query" : "start root = node(1) create unique root-[:ROOT]->(artifact{groupId:'lol',artifactId:'somewhat',version:'1.4'}) return artifact","params" : {}}

also no matter what whitespacing or "/' I use I get an http 500 error, saying the first - of the relationship -[:ROOT]-> is invalid.

Posting new nodes directly via

final String nodeEntryPointUri = SERVER_ROOT_URI + "node";
WebResource resource = Client.create().resource( nodeEntryPointUri );
ClientResponse response = resource.accept( MediaType.APPLICATION_JSON_TYPE )
         .type( MediaType.APPLICATION_JSON_TYPE )
         .entity( /*some json*/)
         .post(ClientResponse.class);

(Disclaimer: I will move the params to the right place asap this version works ;) )

I could bet it's some totally trivial error, but I'm staring at this for over half a workday right now and none of my variations want to work. Would be awesome if somebody knows an answer.

Greetings, Florian Rohm

Answer 1

The problem is you have invalid JSON. You repeat query twice. If you delete the part between stars, does it work?

**{"query" : 
    "start root = node(1) 
    create unique root-[:ROOT]->(artifact{groupId:'**
{"query" : "start root = node(1) 
  create unique root-[:ROOT]->(artifact{groupId:'lol',artifactId:'somewhat',version:'1.4'}) 
  return artifact",
 "params" : {}
}

Answer 2

Ok, i don't know what's different with this statement but this works (I tried the param split in the above code, too):

String cypherUri = SERVER_ROOT_URI + "cypher";        
JSONObject jObject = new JSONObject();
        try {
            Map<String, String> params = new HashMap<String, String>();
            params.put("groupId", artifact.getGroupID());
            params.put("artifactId", artifact.getArtifactID());
            params.put("version", artifact.getVersion());
            String query = "start x  = node(1) create unique x-[:ROOT]->(n{groupId:{groupId},artifactId:{artifactId},version:{version} }) return n";
            jObject.put("query", query);
            jObject.put("params", params);
        } catch (Exception e) {
            e.printStackTrace();
        }

        WebResource resource = Client.create()
                .resource( cypherUri );
        ClientResponse response = resource.accept( MediaType.APPLICATION_JSON_TYPE )
                .type(MediaType.APPLICATION_JSON_TYPE)
                .entity(jObject.toString())
                .post(ClientResponse.class);

But anyways, the second attempt is nicer and I won't complain :D It just bugs me not to know what's going on there...