userguide.md

Introduction

This operator allows you to use any Orion Context Broker server as source of data. This is accomplished by creating a subscription to obtain real time notifications about changes on the entities of interest.

NOTE: This WireCloud operator is based on ngsi-source-operator created by CoNWeT Lab., Universidad Politecnica de Madrid and Future Internet Consulting and Development Solutions S.L..

Settings

• NGSI server URL: URL of the Orion Context Broker to use for retrieving entity information.
• NGSI proxy URL: URL of the Orion Context Broker proxy to use for receiving notifications about changes.
• Use the FIWARE credentials of the user: Use the FIWARE credentials of the user logged into WireCloud. Take into account this option cannot be enabled if you want to use this widget in a public workspace as anonoymous users doesn't have a valid FIWARE auth token. As an alternative, you can make use of the "Use the FIWARE credentials of the workspace owner" preference.
• Use the FIWARE credentials of the dashboard owner: Use the FIWARE credentials of the owner of the workspace. This preference takes preference over "Use the FIWARE credentials of the user".
• Tenant: Tenant/service to use when connecting to the context broker. Must be a string of alphanumeric characters (lowercase) and the _ symbol. Maximum length is 50 characters. If empty, the default tenant will be used.
• Service path: Scope/path to use when connecting to the context broker. Must be a string of alphanumeric characters (lowercase) and the _ symbol separated by / slashes. Maximum length is 50 characters. If empty, the default service path will be used: /
• NGSI entity types: A comma separated list of entity types to use for filtering entities from the Orion Context broker. Leave this field empty If you don't want to filter entities by type.
• Id pattern: Id pattern for filtering entities. This preference can be empty, in that case, entities won't be filtered by id.
• Query: Filter entities by providing a query using the Simple Query Language.
• Monitored NGSI Attributes: Attributes to monitor for updates. those changes are tracked by creating a subscription inside the context broker. If this list is empty, that subscription won't be created.
• attributes format ('keyValues', 'normalized' or 'values'): Specifies how the entities are represented in notifications. Accepted values are 'normalized' (default), 'keyValues' or 'values'.

Wiring

Input Endpoints:

• This widget has no input endpoint

Output Endpoints:

• Entities: This endpoint is used for sending initial entities as well as any updates received as part of the created subscription. This endpoint provides such entities updates using chunks of entities using the keyValues format. E.g:

  :::json
  [
      {
          "id": "van4",
          "type": "Vehicle",
          "location": {
              "type": "Point",
              "coordinates": [-3.7967205, 43.47173]
          }
      },
      {
          "id": "van10",
          "type": "Vehicle",
          "location": {
              "type": "Point",
              "coordinates": []
          }
      }
  ]
  

• Normalized Entities: This endpoint is used for sending initial entities as well as any updates received as part of the created subscription. This endpoint provides such entities updates using chunks of entities using the normalized format. E.g:

  :::json
  [
      {
          "id": "madrid-bici-2",
          "type": "BikeHireDockingStation",
          "address": {
              "type": "Text",
              "value": "Puerta del Sol n\u00ba 1",
              "metadata": {}
          },
          "availableBikeNumber": {
              "type": "Number",
              "value": 22,
              "metadata": {}
          },
          "freeSlotNumber": {
              "type": "Number",
              "value": 2,
              "metadata": {}
          },
          "location": {
              "type": "geo:json",
              "value": {
                  "type": "Point",
                  "coordinates": [
                      -3.7024207,
                      40.4170009
                  ]
              },
              "metadata": {}
          }
      },
      {
          "id": "madrid-bici-1",
          "type": "BikeHireDockingStation",
          "address": {
              "type": "Text",
              "value": "Puerta del Sol n\u00ba 1",
              "metadata": {}
          },
          "availableBikeNumber": {
              "type": "Number",
              "value": 17,
              "metadata": {}
          },
          "freeSlotNumber": {
              "type": "Number",
              "value": 6,
              "metadata": {}
          },
          "location": {
              "type": "geo:json",
              "value": {
                  "type": "Point",
                  "coordinates": [
                      -3.7024255,
                      40.4168961
                  ]
              },
              "metadata": {}
          }
      }
  ]
  

References

• Orion Context Broker