unsubscribe

[ Function ]

public static unsubscribe(
    requestId: number,
    callback?: null | (
        (data: TcHmi.Server.IResultObject) => void
    )
): number | null;

Cancels an existing subscription.

Parameter

Name

Type

Description

requestId

number

The request ID of the subscription that is to be terminated.

callback [ optional ]

null, (data: TcHmi.Server.IResultObject) => void

Asynchronous callback function that is triggered when the operation was terminated.

Return value

Type

Description

number, null

The request ID as number or null in the event of an error.

unsubscribe 1:

Available from version 1.10

Sample - JavaScript

var commands = [
    {
        'symbol': 'PLC1.MAIN.bTest'
    },{
        'symbol': 'PLC1.MAIN.nTest'
    }
];

var requestId = TcHmi.Server.subscribe(
    commands,
    500,
    function (data) {
        // ...
    }
);

setTimeout(function () {
    if (requestId === null) {
        return;
    }
    TcHmi.Server.unsubscribe(
        requestId,
        function (data) {
            if (data.error !== TcHmi.Errors.NONE) {
                // Handle TcHmi.Server class level error here.
                return;
            }
            var response = data.response;
            if (!response || response.error !== undefined) {
                // Handle TwinCAT HMI Server response level error here.
                return;
            }

            var commands = response.commands;
            if (commands === undefined) {
                return;
            }
            var command = commands[0];
            if (command === undefined) {
                return;
            }

            if (command.error !== undefined) {
                TcHmi.Log.debugEx('Unsubscribe for subscription with request id=', requestId, ' failed.');
            } else {
                TcHmi.Log.debugEx('Unsubscribe for subscription with request id=', requestId, ' finished.');
            }
        }
    );
}, 500);