Data Operations · NGSI-LD and Stellio

Stellio Entities

The node bundles the most important entity operations of the Stellio context broker: querying by type, filter and id pattern, reading a single entity, counting matches and deleting individually or in batches. The operation can be fixed in the dialog or controlled per message via msg.operation. A Browser tab shows entities directly in the editor.

Query
Delete
NGSI-LD

Node type: stellio-entities
Package: @htag/node-red-contrib-hypertegrity-ngsi-ld
Inputs / outputs: 1 / 1
Target: Stellio context broker (NGSI-LD)

When to use this node

After publishing entities you usually want to check what is stored in the broker, look up individual records or remove outdated entities. Stellio Entities covers these tasks with one node and saves you from assembling HTTP requests, headers and query parameters by hand.

Typical use cases are:

Quality control after an import: query all entities of a type and compare them with the source.
Dashboards and enrichment: read an entity by id and reuse its attributes in a flow.
Monitoring: count the entities of a type and raise an alert on deviations.
Clean-up: find entities by id pattern and remove them via batch delete.

How the node works

Determine operation

msg.operation or the configured action decides whether to query, get, count or delete.

Build request

Connection (API URL, tenant, context) and parameters (type, q, id pattern, attrs, limit, offset, entity id) are merged from msg and configuration.

Call the broker

The node calls /ngsi-ld/v1/entities or /entityOperations/delete with NGSILD-Tenant and Link headers.

Emit response

Response body, status code, headers and, where available, the result count are written into the message.

Result: Entities, a single entity, a count or the result of a deletion in msg.payload.

The node is message-driven. Every incoming message triggers exactly one request. The Browser tab in the dialog works independently: it uses the admin endpoints of the Node-RED server to list entities in the editor, show details and delete entities directly.

Configuration

The dialog has the tabs Aktion (action) and Browser. All stored fields are on the action tab.

Action tab

Field	Type	Default	Meaning
Name	Text	empty	Display name of the node in the flow. Without a name the node shows `Entities: <action>`.
API URL	Text	`${STELLIO_API_URL}`	Base URL of the broker. Placeholders `${VAR}` are replaced from environment variables at runtime; a trailing slash is removed. Empty: falls back to the environment variable `STELLIO_API_URL`.
Tenant	Text	empty	Value of the `NGSILD-Tenant` header. Empty: the header is not sent (default tenant of the broker).
Context	Text	see below	JSON-LD context sent as `Link` header. It determines how type and attribute names are abbreviated in the response.
Aktion (action)	Select	`Query`	`Query` (search entities), `Get` (single entity by id), `Count` (determine number), `Delete` (delete entity), `Batch Delete` (array of ids from `msg.payload`).
Type	Text	empty	Entity type(s) for Query and Count, comma-separated, for example `Device,WeatherObserved`.
q-Filter	Text	empty	NGSI-LD filter expression (example below).
ID Pattern	Text	empty	Regular expression on the entity id, for example `urn:ngsi-ld:Device:.*`.
Attrs	Text	empty	Return only these attributes, comma-separated. Also applies to Get.
Limit	Number	`100`	Maximum number of results per response (Query).
Offset	Number	empty	Number of results to skip for paging.
Entity ID	Text	empty	Full URN for Get and Delete, for example `urn:ngsi-ld:Device:001`.

Example of a q filter:

temperature>20;category=="urban"

Default values of the URL fields:

Context: https://context.${DOMAIN}/main-context.jsonld

Which fields are visible depends on the selected action: Type, q-Filter, ID Pattern, Attrs, Limit and Offset appear for Query and Count, Entity ID for Get and Delete, and a hint about msg.payload for Batch Delete.

Browser tab

The tab uses the connection from the action tab. You can search by type and q-filter, set a limit, list results with Laden (load), show details as JSON and delete single entities after confirmation. The browser fields are not stored.

Deleting from the editor

Deleting in the Browser tab takes effect on the broker immediately, without deploying the flow. It requires the Node-RED permission stellio.write.

Input

Values from the message take precedence over the configuration.

Property	Type	Meaning
`msg.operation`	string	`query`, `get`, `count`, `delete` or `batchDelete`. Unknown values are treated as `query`.
`msg.apiUrl`	string	Overrides the API URL.
`msg.tenant`	string	Overrides the tenant.
`msg.contextUrl`	string	Overrides the context (Link header).
`msg.type`	string	Overrides Type (Query, Count).
`msg.q`	string	Overrides the q-filter (Query, Count).
`msg.idPattern`	string	Overrides the ID Pattern (Query, Count).
`msg.attrs`	string	Overrides Attrs (Query, Count, Get).
`msg.limit`	number	Overrides the limit (Query).
`msg.offset`	number	Overrides the offset (Query, Count).
`msg.entityId`	string	Overrides the Entity ID (Get, Delete; fallback for Batch Delete).
`msg.payload`	array of strings	`batchDelete` only: list of URNs to delete. If the payload is not an array, the Entity ID is used as a single element instead.

If a query contains neither type, q-filter nor id pattern, the node automatically sets idPattern=.* so that the broker returns all entities.

Output

The message is extended with the broker response. For query with type WeatherObserved, msg.payload looks like this:

[
  {
    "id": "urn:ngsi-ld:WeatherObserved:exampletown:station-042",
    "type": "WeatherObserved",
    "temperature": {
      "type": "Property",
      "value": 14.2,
      "observedAt": "2026-10-01T06:00:00.000Z"
    },
    "location": {
      "type": "GeoProperty",
      "value": {"type": "Point", "coordinates": [7.3322, 50.3315]}
    },
    "@context": ["https://context.exampletown.example/main-context.jsonld"]
  }
]

Field	Meaning
`msg.payload`	`query`: array of entities. `get`: one entity object. `count`: object `{"count": n}`. `delete`: usually empty (`204`). `batchDelete`: result object of the broker with successful and failed ids.
`msg.statusCode`	HTTP status code of the response.
`msg.headers`	Response headers, including `ngsi-ld-results-count` for count queries.
`msg.count`	Result count from the `NGSILD-Results-Count` header, if the broker sends it for `query`.

Example flow

The package ships with a shared example flow for several Stellio nodes. You can import it in Node-RED via Menu → Import → Examples → @htag/node-red-contrib-hypertegrity-ngsi-ld → stellio-helper-nodes. The Stellio Entities node is included in this shared example, but it is not wired as a complete Inject-Entities-Debug flow; the following excerpt therefore shows a minimal wiring of this node. Alternatively, download stellio-helper-nodes.json and import it via Menu → Import.

Step 1

Inject

An Inject node triggers the query manually or at a fixed interval.

Step 2