Create and use event listener and event trigger

Prerequisites

You are familiar with scripts
You are familiar with the App Designer
You have understood the basics of Events

Procedure

The purpose of this guide is to show you how the neptune.events.Trigger and neptune.events.Listener work together. In this guide we will create two Events where, the event listerner will run custom functions be triggered once the trigger event initiates. In this simple setup, we will have an event

Step 1. Set up first event

Open Events and select add
Give it a name. In this example, the name is ListenerExample
Set Event Action to App

This Event will work as a "listener" and will trigger custom actions that we will set.

event listener

Step 2. Set up script for the second event

Open a Project and add a new script
Give it a name. In this example, the name is app.js
Add the logic

The script will accept the payload and update a given table. Once that is done, we can pass data to the ListenerExample Event and process it anyway we desire.

try {

    const eventResponse = {
        process: payload.process,
        data: null,
    }

    switch (payload.process) {
        case "updateTable":
            await entities.inspections_terry.createQueryBuilder()
                .update()
                .set(payload.data.change)
                .where("id = :id", { id: payload.data.id })
                .execute();
            eventResponse.data = {"status":"Update happended!"}
            break;
        default:
            log.error("Process not handled:", payload.process);
            break;
    }

    await p9.events.publish("ListenerExample", eventResponse) // this function initiates the event listener
    complete();

} catch (err) {
    log.error(err)
    complete();
}

In this example, we have dragged and dropped a Table in the script

Step 3. Create the second event

Open Events and select add
Give it a name. In this example, the name is TriggerExample
Set Event Action to Script
Select the script you have just created

event trigger

Set up the neptune.events components

For the neptune.events.Trigger:

In the App Designer, drag and drop a neptune.events.Trigger in Resources
At event, select the trigger event. In this case, it is TriggerExample

For the neptune.events.Listener:

Drag and drop a neptune.events.Listener in Resources
At event, select the listener event. In this case, it is ListenerExample

Regarding how we handle the response we pass back to the ListenerExample, we will define a function that will be triggered each time ListenerExample is called.

In a script past the below:

function handleData(payload)  {
    switch (payload.process) {
        case "updateTable":
            const data = payload.data
            console.log("Response data from script: ",data)
            break;
        default:
            console.log("Not handled");
            break;
    }
}

Now, we need to refer this function in the actions of the neptune.events.Listener.

event listener action

Execution

There are many ways to trigger this process. In this example, a button once selected will trigger the TriggerExample Event and pass data.

In the Press Event add the following:

var payload = {
    process:"updateTable",
    data: {
        id:"EDC4F5BA-3DE0-4BE7-9B50-010D667CC684", // id of an entry located in the table
        change: {
            "status" : "Pending"   // altering "status"
        }
    }
}
triggerEventTrigger(payload);

Results

After selecting the button, the table will update and the function we defined will be triggered.

Button that triggers the progress

Response from the handleData() function

event logs

Table before selection

event table before

Table after selection

event table after