Check if specific time is "now"?

[Gawan]

Hi,

I would like to compare the actual time with a timestamp I get from a database.
The timestamp is in the format "00:10" and it is stored in a global variable "ExecutionTime" as a string.

How do I compare this value in a function node with the actual system time ?

IF (global.get("ExecutionTime") == ???) ... do cool stuff ...

All I tried so far failed

BR
Gawan

[Steve-Mcl]

What are you trying to achieve?

Are you polling every second / every minute until it matches a time set in a a database - then when it matches, you do something?

Is this "time" supposed to be like a daily schedule or a one time thing?

[Gawan]

the plan is to compare the actual time with the "ExecutionTime" every 30sec and if it fits and an additional specific parameter is set , I will trigger a MQTT Message

The "ExecutionTime" is a timestamp that will be calculated in a SQL database outside NodeRed once a day to optimize the best trigger time for this specific event

[Steve-Mcl]

So essentially you will perform 2880 polls per day to look for a "time"

Since Node-RED is event based, a better solution is, when reading the database, generate a cron-plus schedule that will execute exactly at the right time.

Demo

look maa, no poling what-so-ever

[{"id":"60d8d1917dfe26e4","type":"cronplus","z":"c2233fc1d8cc5c3b","name":"","outputField":"payload","timeZone":"","persistDynamic":false,"commandResponseMsgOutput":"output1","defaultLocation":"","defaultLocationType":"default","outputs":1,"options":[],"x":1340,"y":700,"wires":[["2c6cb603de9c263c"]]},{"id":"9c72718894e9fbc4","type":"inject","z":"c2233fc1d8cc5c3b","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":1235,"y":580,"wires":[["e854ed1d3954a62d"]],"l":false},{"id":"e854ed1d3954a62d","type":"function","z":"c2233fc1d8cc5c3b","name":"fake database call (12:25)","func":"msg.payload = [\n    { executionTime: '12:25' }\n]\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1390,"y":580,"wires":[["4e65d37261007173"]]},{"id":"fcdcccf1f8dbcffd","type":"inject","z":"c2233fc1d8cc5c3b","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":1235,"y":620,"wires":[["12948bb6ae62e0e7"]],"l":false},{"id":"12948bb6ae62e0e7","type":"function","z":"c2233fc1d8cc5c3b","name":"fake database call (17:12)","func":"msg.payload = [\n    { executionTime: '17:12' }\n]\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1390,"y":620,"wires":[["4e65d37261007173"]]},{"id":"4e65d37261007173","type":"function","z":"c2233fc1d8cc5c3b","name":"generate schedule","func":"\nconst time = msg.payload[0]?.executionTime\n\nif (time) {\n    const timeParts = time.split(':')\n    if (timeParts.length < 2) {\n        node.warn('invalid time value');\n        return\n    }\n    const hour = timeParts[0]\n    const minute = timeParts[1]\n    const seconds = (timeParts.length > 2) ? timeParts[2] : 0\n\n    msg.payload = [\n        {\"command\": \"remove-all\" },\n        {\n            \"command\": \"add\",\n            \"name\": `at ${time}`,\n            \"expression\": `${seconds} ${minute} ${hour} * * * *`,\n            \"expressionType\": \"cron\",\n            \"payloadType\": \"default\",\n            \"limit\": 3 \n        }\n    ]\n    return msg;\n}","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1650,"y":600,"wires":[["60d8d1917dfe26e4"]]},{"id":"2c6cb603de9c263c","type":"debug","z":"c2233fc1d8cc5c3b","name":"--> do cool stuff at specified time","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":1590,"y":700,"wires":[]}]

[Gawan]

that looks really nice - thats exactly the solution I was looking for, but due to insufficient knowledge I tried to realize my version

but there seem to be a mistake in your code ?

[Steve-Mcl]

@Gawan

but there seem to be a mistake in your code ?

No, it is valid code as of Node v14.

you are either using an old Node-RED (pre v2) - OR - have Monaco editor turned off (the old - soon to be removed ACE editor does not understand optional chaining

and/or NodeJS V < 14

---

What version of Node-RED are you using? what version of NodeJS is it running on?

[Gawan]

I am using 2.2.2
... bit afraid to upgrade as there was an issue with Node JS Version and SQL Database Node compatibility last time ...

[Steve-Mcl]

@Gawan

I am using 2.2.2

2.2.2 does support monaco editor but you need to enable it is settings.js

What version of NodeJS (you didnt say)?

[Steve-Mcl]

@Steve-Mcl

@Gawan

but there seem to be a mistake in your code ?

No, it is valid code as of Node v14.

you can change that line of code to NOT use optional chaining.

This is the alternative code line

const time = msg.payload[0] && msg.payload[0].executionTime

[Gawan]

it was this thread and as a result I postponed the update of my local node-red to ... somewhen in the fare future

--> Node-red-contrib-mssql-plus fails to install because of version mismatch?

[Steve-Mcl]

That is resolved now. Installing mssql-plus will work with node20

But, you could have simply installed node v18 anyhow.

[Gawan]

after upgrading to the latest versions (without any problems or issues) your code works fine and setting dynamic trigger timestamp works fine as well
thanks a lot for your support !