In many examples, a payload is used with GET requests, for example

curl -G -iX GET 'http://localhost:1026/ngsi-ld/v1/entities/urn:ngsi-ld:TemperatureSensor:001' \
-H 'Link: <http://context/ngsi-context.jsonld>; rel="http://www.w3.org/ns/json-ld#context"; type="application/ld+json"' \
-d 'attrs=temperature'

I think this should be avoided and all data should included as query parameters. Note that according to HTTP 1.1 RFC

A payload within a GET request message has no defined semantics; sending a payload body on a GET request might cause some existing implementations to reject the request

Tutorial examples use the verified property of property (e.g., the request in this example) However, this term is not included in the context file

As a matter of fact, if you replace the context url in that request with

https://raw.githubusercontent.com/FIWARE/tutorials.Getting-Started/NGSI-LD/data-models/ngsi-context.jsonld

and then put the output in json-ld playground, you will observe that "verified" property is ignored.

Proof of concept

I was integrating IoT Agent with orion-ld , by using [https://ngsi-ld-tutorials.readthedocs.io/en/latest/iot-agent.html]. i was trying request no 14 by using upsert API for sending the command to the device. please help me to do this.

Since the tutorial says

As it happens, there are existing Smart Data Models for both Building and Device

I think it is more appropriate to refer to Smart Data Models context for building properties instead of schema.org For example address instead of

"address": "schema:address"

Could be

"address":"https://smartdatamodels.org/address"

I guess something similar applies to "Device"

The tutorial says:

Many types of device reading (i.e. context data attributes) have been predefined within the SAREF ontology - so it is reasonable to use the URIs defining these attributes as a basis of extending our model.

• temperature (https://w3id.org/saref#temperature)
• fillingLevel (https://w3id.org/saref#fillingLevel)

However fillingLevel is not defined in https://ontology.tno.nl/saref/. Similarly, at some other point it uses:

"airPollution": "https://w3id.org/saref#airPollution",
"atmosphericPressure": "https://w3id.org/saref#atmosphericPressure",

But both airPollution and atmosphericPressure are not defined in https://ontology.tno.nl/saref/

As side note, as far as I could search bot airPollution and fillingLevel are not event defined in ETSI's SAREF ontology.

First, thank you for writing these tutorials, they are a great help in getting started with NGSI-LD.

I think the uniqueness of the full entity IDs is in question when following the tutorial.

Reading section "Creating Several Entities at Once" there is a paragraph that says:

In both cases we have encoded each entity id according to the NGSI-LD specification - the proposal is that each id is a URN
follows a standard format: urn:ngsi-ld::. This will mean that every id in the system will be unique.

Also important: probably better to name this 'service-id' or 'device-id' as the term entity-id can easily be confused with the entity's id itself.

The concern is that this does not make an entity's full id unique. There seems to be an assumption that there is a single creator of entities that can guarantee that 'entitiy-id' is unique for an entity-type. This is an incorrect assumption. In an IoT environment there can be multiple agents that publish a temperature for example, each agent will use its own entity-id but without central coordination there is a chance of duplication. Another example, in my test setup I have two zwave controllers. These controllers generate device-id's starting numbering at 1. Using various temperature sensors on both controllers show there are two sensors with device ID 2 simply because that is how the numbering per controller works out.

What seems to be missing is to include the unique ID of the publisher/agent that is responsible the entity creation.
The entity ID format would look like this:

urn:ngsi-ld:<entity-type>:<agent-id>:<device-id>[:...]

As long as agent-id's are unique the entity will be unique.
There are other ways to solve this problem but way leaves a nice breadcrumb of ownership in the entity's full id.

I've seen this issue in various documents including the ETSI specs so this concern is wider spread. The tutorials however seems like a good place to start.

I hope this helps somebody.
(updated to fix the entity ID presentation)

Hi ,

I am integrating IOT agent from FogFlow using orion broker . In this scenario IOT agent send the data to the Orion broker and FogFlow have subscribe to the Orion broker to get the data . FogFlow is getting the following data in the notification .

{
	"@context": "https://fiware.github.io/data-models/context.jsonld",
	"id": "urn:ngsi-ld:Device:water001",
	"type": "Device",
	"heartRate": {
		"type": "Property",
		"value": {
			"@type": "Intangible",
			"@value": null
		},
		"unitCode": "5K"
	},
	"status": {
		"type": "Property",
		"value": {
			"@type": "Intangible",
			"@value": null
		}
	},
	"location": {
		"type": "GeoProperty",
		"value": {
			"type": "Point",
			"coordinates": [0, 0]
		}
	},
	"controlledAsset": {
		"type": "Relationship",
		"object": "urn:ngsi-ld:Building:barn001"
	},
	"category": {
		"type": "Property",
		"value": "sensor"
	},
	"supportedProtocol": {
		"type": "Property",
		"value": "ul20"
	},
	"on_status": {
		"type": "Property",
		"value": {
			"@type": "commandStatus",
			"@value": "UNKNOWN"
		}
	},
	"on_info": {
		"type": "Property",
		"value": {
			"@type": "commandResult",
			"@value": " "
		}
	},
	"off_status": {
		"type": "Property",
		"value": {
			"@type": "commandStatus",
			"@value": "UNKNOWN"
		}
	},
	"off_info": {
		"type": "Property",
		"value": {
			"@type": "commandResult",
			"@value": " "
		}
	},
	"on": {
		"type": "command",
		"value": ""
	},
	"off": {
		"type": "command",
		"value": ""
	}
}

This data has @type and @value at some places. I am confused whether this data is correct or not , because if we use same data to create entity i am getting error of "NOT A VALID JSON" Scorpio broker .

https://ngsi-ld-tutorials.readthedocs.io/en/latest/iot-agent-json.html shows:
git clone https://github.com/FIWARE/tutorials.IoT-Agent.git
should be changed to
git clone https://github.com/FIWARE/tutorials.IoT-Agent-JSON.git

But for the tutorials.IoT-Agent-JSON repository the issue was already fixed (see also FIWARE/tutorials.IoT-Agent-JSON#3).

Given that tutorials.IoT-Agent-JSON is a submodule of tutorials.NGSI-LD, perhaps it's missing a submodule update? (i.e. point tutorials.IoT-Agent-JSON to latest version)

The Temporal Operations page states: "The tutorial activates the IoT collars for connected animals in the previous tutorial and links to the IoT-Agent tutorials page, which is inconsistent when you come from the subscriptions tutorial and have clicked on the 'Next' button at the bottom of the page.

In addition, I followed the IoT-Agent tutorial but didn't see anything that corresponded to collar activation.

Hi ,

I am getting the following issue while installing setup with Scorpio broker .

Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected
Template parsing error: template: :1:8: executing "" at <.State.Health.Status>: map has no entry for key "Health"
./services: line 90: [: ==: unary operator expected

my docker-compose version is 1.29.2

Please help to resolve this issue

In section "Entity Relationships", at subsection "RELATIONSHIPS OF PROPERTIES", the document showed how to retrieve the temperature of a barn (the data has been duplicated from the TemperatureSensor to the Building), but didn't provide information about how the data was duplicated or whether the data has been duplicated automatically or has been copied manually by users.

I am working through the "step-by-step" tutorial. The section "Start Up" on this page doesn't include any instructions, where to get the code from.

I compared this with the NGSI-v2 tutorial, where the instructions tell the reader to clone a repo and run the docker-compose.