Local Requests

Worker APIs

Overview

Purpose	Message Type	Icon Glyph	File Prefix
Send message to self	Asynchronous		rql_

The images below are taken from the Workers Fundamentals example project.

Local Request Purpose

A Local Request is a message that a Worker can send to itself. You can use Local Request VIs to send a message from a Worker's EHL to its MHL, or between MHL cases of the same Worker.

A local request is a message that a Worker can only send to itself

Local Request usage example

The image below demonstrates the use of a Local Request VI sending a message from the EHL to the MHL of this Worker's QMH, and from the MHL case to another MHL case of the same Worker.

Worker A : Main.vi - Local Request VI example

Local Request VI

A Local Request VI is required to be wired inline with a Worker's Main Data Wire, and can be used from within a Worker's EHL or MHL. This VI will send a message to the Worker's MHL case that has the same name as the Request VI.

Every Local Request VI filename takes the prefix: rql_ (request local). Every Local Request VI icon contains a blue glyph in its bottom-right corner. An example of a Local Request VI is shown below.

Worker A : rql_Send String.vi

Data in

Data that will be sent along with the message. By default, this is a typedef that has the same filename as the Local Request VI.

Message Priority

The priority of the message (default is Normal) can be set to either Low, Normal or High.

Show in Debugger?

When this flag is TRUE, then meta-data about this message will be sent to the Workers Debug Server.

Local Request Typedef

Local Request typedefs are created with the same icon and filename as their matching Local Request VI. Their purpose is to provide a custom container (cluster) for the data that will be sent along with the message to the Local Request's MHL case.

Local Request MHL Cases

For every Local Request, a MHL case will be created to receive the message sent by the Local Request VI. Local Request MHL cases will automatically be added to the Worker's case structure section called --- LOCAL API CASES ---. To convert the data sent with the message to its specific data type, a Variant to Data node is required at the beginning of every Local Request MHL case (this will automatically be added to the MHL case when the MHL case is created by the Create MHL Case tool).

Worker A : Main.vi - Local Request MHL cases

Local Request Folders

Local Request VIs created by the Create MHL Case tool are added to a Worker's Local API >> Requests folder. Their scope is set to protected because they are designed to be used only from within the Worker that owns them.

Local Request folder structure within a Worker