events without subprotocol might be causing unexpected behaviour #1281
Description
I use events primarily with HTTP SSE.
When I generate the TD without the subprotocol option within the event affordance, the node-wot client subscribes to the event multiple times.
The event afffordance (faulty) schema is as follows:
intensity_measurement_event": {
"forms": [
{
"href": "https://LAPTOP-F60CU35D:8083/spectrometer/ocean-optics/USB2000-plus/intensity/measurement-event",
"op": "subscribeevent",
"htv:methodName": "GET",
"contentType": "text/event-stream"
}
]
}The validator does not complain. When the client tries to subscribe to the event:
spectrometer.subscribeEvent("intensity_measurement_event", async(data : InteractionOutput) => {
const value = await data.value()
console.log("event", value, data)
}).then((subscription : any) => {
intensityMeasurementEvent = subscription
console.debug("subscribed to intensity measurement event")
})This somehow leads to 6 event subscriptions to the server side. I get the following output:
App.svelte:37 consumed thing description from spectrometer
App.svelte:43 updating state
App.svelte:59 action with value InteractionOutput {form: {…}, schema: undefined, dataUsed: false}
App.svelte:60 action with value undefined
MainView.svelte:45 subscribed to intensity measurement event
MainView.svelte:42 event undefined InteractionOutput {form: {…}, schema: undefined, dataUsed: false}
MainView.svelte:42 event undefined InteractionOutput {form: {…}, schema: undefined, dataUsed: false}
MainView.svelte:42 event undefined InteractionOutput {form: {…}, schema: undefined, dataUsed: false}
MainView.svelte:42 event undefined InteractionOutput {form: {…}, schema: undefined, dataUsed: false}
MainView.svelte:42 event undefined InteractionOutput {form: {…}, schema: undefined, dataUsed: false}
App.svelte:77 rescheduling property polling functionFrom server side:
count 42
DEBUG - 2024-05-02T20:29:03:171 - spectrometer/ocean-optics/USB2000-plus - starting measurement count 43
DEBUG - 2024-05-02T20:29:03:172 - HTTPServer|0.0.0.0:8083 - new data sent - intensity-measurement-event
DEBUG - 2024-05-02T20:29:03:173 - HTTPServer|0.0.0.0:8083 - new data sent - intensity-measurement-event
DEBUG - 2024-05-02T20:29:03:174 - HTTPServer|0.0.0.0:8083 - new data sent - intensity-measurement-event
DEBUG - 2024-05-02T20:29:03:175 - HTTPServer|0.0.0.0:8083 - new data sent - intensity-measurement-event
DEBUG - 2024-05-02T20:29:03:175 - HTTPServer|0.0.0.0:8083 - new data sent - intensity-measurement-event
DEBUG - 2024-05-02T20:29:03:176 - HTTPServer|0.0.0.0:8083 - new data sent - intensity-measurement-event
DEBUG - 2024-05-02T20:29:04:182 - spectrometer/ocean-optics/USB2000-plus - measurement taken at 02.05.2024 20:29:04.182 - measurement count 43
DEBUG - 2024-05-02T20:29:04:184 - spectrometer/ocean-optics/USB2000-plus - starting measurement count 44
DEBUG - 2024-05-02T20:29:04:185 - HTTPServer|0.0.0.0:8083 - new data sent - intensity-measurement-event
DEBUG - 2024-05-02T20:29:04:186 - HTTPServer|0.0.0.0:8083 - new data sent - intensity-measurement-event
DEBUG - 2024-05-02T20:29:04:187 - HTTPServer|0.0.0.0:8083 - new data sent - intensity-measurement-event
DEBUG - 2024-05-02T20:29:04:188 - HTTPServer|0.0.0.0:8083 - new data sent - intensity-measurement-event
DEBUG - 2024-05-02T20:29:04:188 - HTTPServer|0.0.0.0:8083 - new data sent - intensity-measurement-event
DEBUG - 2024-05-02T20:29:04:189 - HTTPServer|0.0.0.0:8083 - new data sent - intensity-measurement-event
DEBUG - 2024-05-02T20:29:05:196 - spectrometer/ocean-optics/USB2000-plus - measurement taken at 02.05.2024 20:29:05.196 - measurement count 44
The event is being sent, but there are 6 of them (each line claiming "new data sent" is a single event of same type). Also, I am not able to invoke further actions.
When adding the subprotocol field, the issue is solved. However, due to absence of schema the event value is undefined.
(#1280)
The TD document also says subprotocol is optional, may I know what is the default value?