Create a subject

At this point, we are capable of tracking the life cycle of our wine bottles through Wine type subjects, which are defined in our Kore network. Additionally, we have the entity Premium Wines, which will be responsible for carrying out this action.

Let’s start by launching a genesis event to create our first Wine type subject:

curl --request POST 'http://localhost:3001/event-requests' \
--header 'Content-Type: application/json' \
--data-raw '{
    "request": {
        "Create": {
        "governance_id": "{{GOVERNANCE-ID}}",
        "schema_id": "Wine",
        "namespace": "",
        "name": "Wine"
        }
    }
}'

Upon performing this action, we will receive a request-id, which we need to copy and use in the following command:

curl --request GET 'http://localhost:3001/event-requests/{{REQUEST-ID}}/state'

The last command will provide a response like the following:

{
    "id": "{{REQUEST-ID}}",
    "subject_id": "{{SUBJECT-ID}}",
    "sn": 0,
    "state": "finished",
    "success": true
}

INFO

Keep the subject_id of the subject, as we’ll need it in later steps of the tutorial.

We can query the created subject using the following command:

curl --request GET 'http://localhost:3001/subjects/{{SUBJECT-ID}}'

{
    "subject_id": "{{SUBJECT-ID}}",
    "governance_id": "{{GOVERNANCE-ID}}",
    "sn": 0,
    "public_key": "E-_PigfpbWeFsQzMXENgEQPQR5ea4FfoSFAqdZtx7lS0",
    "namespace": "",
    "name": "Wine",
    "schema_id": "Wine",
    "owner": "{{CONTROLLER-ID}}",
    "creator": "{{CONTROLLER-ID}}",
    "properties": {
        "grape": null,
        "harvest": 0,
        "organic_certified": null,
        "origin": "",
        "temperature_control": {
            "last_check": 0,
            "temperature_ok": true
        }
    },
    "active": true
}

Now that we have reached this point, the first subject has been created. However, as we can see in the previous information block, it has a default initialization with the body we defined in the genesis event. Therefore, our next step will be to modify the basic characteristics of the subject to represent the production of a wine bottle produced by Premium Wines. We’ll achieve this through the Init event we declared in the contract of Wine subjects.

The characteristics we want our bottle to have are as follows:

Harvest number: 1
Grape type: Cabernet Sauvignon
Origin: Spain

Therefore, the command we need to execute is the following:

curl --request POST 'http://localhost:3001/event-requests' \
--header 'Content-Type: application/json' \
--data-raw '{
    "request": {
        "Fact": {
            "subject_id": "{{SUBJECT-ID}}",
            "payload": {
                "Init": {
                    "harvest": 1,
                    "grape": "CabernetSauvignon",
                    "origin": "spain"
                }
            }
        }
    }
}'

If everything has gone correctly, running the following command should update the subject with an sn value of 1 and reflect the changes mentioned above:

curl --request GET 'http://localhost:3001/subjects/{{SUBJECT-ID}}'

{
    "subject_id": "{{SUBJECT-ID}}",
    "governance_id": "{{GOVERNANCE-ID}}",
    "sn": 1,
    "public_key": "E-_PigfpbWeFsQzMXENgEQPQR5ea4FfoSFAqdZtx7lS0",
    "namespace": "",
    "name": "Wine",
    "schema_id": "Wine",
    "owner": "{{CONTROLLER-ID}}",
    "creator": "{{CONTROLLER-ID}}",
    "properties": {
        "grape": "CabernetSauvignon",
        "harvest": 1,
        "organic_certified": null,
        "origin": "spain",
        "temperature_control": {
            "last_check": 0,
            "temperature_ok": true
        }
    },
    "active": true
}