How to deliver variable value to different flow when ui-button is pressed

General
1

Good day Guys. The first 3 image represents that I am trying to initialise a global variable "a" to be 1 whenever i press the button. And the value represented by variable "a" will be stored as "msg.test" and to be used in other FLOW.

The last 3 image shows the other flow that I am trying to obtain the variable "a" value into this flow.

But when i press the button on the dashboard, I want this flow to show its message on debug node right away WITHOUT clicking on the inject node.

P/S: The reason why im using global variable is because in my main flow, both the msg.topic and msg.payload is occupied with the constantly generated value from OPCUA client.

And i want it such that when i press the button, I want these data to be saved into MySQL database. Therefore, im doing some testing here to make sure that i can pass on the global variable instead of letting my msg.topic or msg.payload overwrite by the value sent from the "ui-button" when its pressed.

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2

A flow will not run until something triggers it. Having a function node at the start of a flow will never run the flow, a msg has to be fed into the function node.

Why not also have a switch node connected to the button. Have it check the 'topic' ad iff it is a yes have the optput of the switch go to a link-out node. Have the link-out node connect to link-in nodes connected to the flows you need to run.

3

Sorry for the misunderstanding, As you can see from my overall flow here, the button node here is suppose to act like a gate which before it is pressed, no value will be able to pass through it to the function and save it to the MySQL data base.

please have a look at the code in this function node(after button node) , there is 1 line which consist both msg.topic and msg.payload.

Since button can only send msg.topic and msg.payload, lets say if i were to write the code like this:-

if(msg.topic=='pressed')
{
msg.topic = "INSERT INTO table1(value)VALUES(' " + msg.payload + " ');";

}

return msg;

i wont get the value that i desired if i do if(msg.topic=='pressed') condition, my value will become a random string number in mySQL database

or the value turns out to be just "pressed" if i use if(msg.payload=="pressed") condition.

However, if i were to remove this button node, everything works fine.

This is my concept,I am planning to implement a dashboard whereby, if the end-user wants to record this reading, they just have to press the button and the data will be saved in a MYSQL database.

Once again, so sorry for causing a confusion.

Please refer to the image shown in this link.

4

So just have the button attached to the nodes that builds the query and runs it. I don't see what is so hard about this.
Screen Shot 2022-07-14 at 8.55.13 AM

5

Or do you mean that you want to allow messages through or block them, by using a button? If so then have a look at node-red-contrib-simple-gate which can do that.

6

my primary concern is that , this button can only send msg.topic & msg.payload value right?

But both of these (msg.topic & msg.payload) exist in my function node(after the button node) as shown below:-

msg.topic = "INSERT INTO table1(value) VALUES( ' " + msg.payload + " ');";"

So lets say if i were to use "if" condition , i can only choose either to send Payload or Topic value when it is pressed. Which is what i dont want as this will overwrite the data in msg.payload and msg.topic that is to be stored into MySQL database.

7

I’m building an inventory system. On the input page in the dashboard I’ll enter data in some ui-text nodes. Each node sends its msg to a change node that stored it in a flow variable.

When the button is pressed a msg is passed to a change node. The change node will move all the flow variables to msg.payload as a object. That is passed to a template node that builds the query and puts it into msg.topic and then it is sent to the sql node.

8

Hi, thanks for your suggestion. I will give it a try when I get to my office tomorrow. Sorry I am running on on asia time zone here. I will update again tomorrow.

9

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