Gremlin API

8.1 Gremlin

8.1.1 Send a Gremlin statement to HugeGraphServer (GET), synchronously

Params

• gremlin: The Gremlin statement to execute on HugeGraphServer.
• bindings: Parameter bindings with string keys and string or numeric values, similar to MySQL prepared statements, to speed up execution.
• language: Statement language, defaulting to gremlin-groovy.
• aliases: Adds aliases for existing variables in a graph space.

This REST proxy cannot reliably carry a JSON-braced aliases parameter in GET queries. Current graph binding names contain hyphens and cannot be used directly as Groovy variables. This GET example uses a simple expression; use the POST example with aliases below to select a graph for traversal.

Method & Url

1curl --compressed --get \
2  --data-urlencode "gremlin=1+1" \
3  http://127.0.0.1:8080/gremlin

Response Status

1200

Response Body

1{
2	"requestId": "<request_id>",
3	"status": {"message": "", "code": 200, "attributes": {}},
4	"result": {"data": [2], "meta": {}}
5}

8.1.2 Send a Gremlin statement to HugeGraphServer (POST), synchronously

Count vertices

Runnable request

1curl --compressed -sS -X POST http://127.0.0.1:8080/gremlin \
2  -H 'Content-Type: application/json' \
3  --data-binary '{"gremlin":"g.V().count()","aliases":{"g":"__g_DEFAULT-hugegraph"}}'

/gremlin is a top-level endpoint. The traversal source for graph hugegraph in graph space DEFAULT is __g_DEFAULT-hugegraph; aliases maps it to script variable g. Adjust the alias to the Server binding name for another graph or graph space. Batch responses can use gzip; curl --compressed decompresses them automatically.

Response Status

1200

Response Body

1{
2	"requestId": "<request_id>",
3	"status": {"message": "", "code": 200, "attributes": {}},
4	"result": {"data": [6], "meta": {}}
5}

Vertex count depends on current graph data; 6 above is an example result.

The response structure differs from the Vertex and Edge REST APIs; clients may need to parse it explicitly.

Query edges

Request Body

1{
2	"gremlin": "g.E().hasLabel('created').limit(1)",
3	"bindings": {},
4	"language": "gremlin-groovy",
5	"aliases": {
6		"g": "__g_DEFAULT-hugegraph"
7	}
8}

Response Status

1200

Response Body

 1{
 2	"requestId": "<request_id>",
 3	"status": {
 4		"message": "",
 5		"code": 200,
 6		"attributes": {}
 7	},
 8	"result": {
 9		"data": [{
10			"id": "<edge_id>",
11			"label": "created",
12			"type": "edge",
13			"outVLabel": "person",
14			"inVLabel": "software",
15			"outV": "<source_vertex_id>",
16			"inV": "<target_vertex_id>",
17			"properties": {
18				"weight": 0.4,
19				"date": "<date>"
20			}
21		}],
22		"meta": {}
23	}
24}

Edge IDs, endpoints, and properties depend on current graph data.

8.1.3 Send a Gremlin statement to HugeGraphServer (POST), asynchronously

Method & Url

1POST http://localhost:8080/graphspaces/DEFAULT/graphs/hugegraph/jobs/gremlin

Query vertices

Request Body

1{
2	"gremlin": "g.V('1:marko')",
3	"bindings": {},
4	"language": "gremlin-groovy",
5	"aliases": {}
6}

Note:

Asynchronous requests cannot supply aliases. Server automatically binds graph to the current graph and g to its traversal source, and adds the URL graph name as an alias for graph. Scripts can use graph, g, or that graph name.

Response Status

1201

Response Body

1{
2	"task_id": 1
3}

Note:

Query task status with GET http://localhost:8080/graphspaces/DEFAULT/graphs/hugegraph/tasks/1, where 1 is the task ID. See the asynchronous task REST API.

Query edges

Request Body

1{
2	"gremlin": "g.E().hasLabel('created').limit(1)",
3	"bindings": {},
4	"language": "gremlin-groovy",
5	"aliases": {}
6}

Response Status

1201

Response Body

1{
2	"task_id": 2
3}

Note:

Query task status with GET http://localhost:8080/graphspaces/DEFAULT/graphs/hugegraph/tasks/2, where 2 is the task ID. See the asynchronous task REST API.