I can't stop the job

[nsnhan127]

I created a function to handle click button like this

const [published, setPublished] = useState(false);
const handlePublishFlows = async () => {
    const newPublished = !published; 
    setPublished(newPublished); 

    await axios
      .get(`/api/schedule?published=${newPublished}`, {})
      .then((res) => {
        toast.success(res.data.message);
      });
  };

And this is an api

export async function GET(request) {
  const { searchParams } = new URL(request.url);
  const published = searchParams.get("published") === "true";
  console.log(published);
  console.log("Before job instantiation");
  const job = new CronJob("* * * * * *", function () {
    const d = new Date();
    console.log("Every second:", d);
  });
  
  if (published){
    job.start();
    return NextResponse.json({
        message: "Schedule started",
      });
  }
  else{
    job.stop();
    return NextResponse.json({
        message: "Schedule stopped",
      });
  }
}

My problem is the job still running when i click button to change "published" to "false". How can i fix it ?

[sheerlox]

Looks like you're creating a new job on every button click. You would need a way to manage the jobs in your backend so you can find the right one and call the stop/start methods on it. If you have only one job to manage, maybe moving the job instantiation outside of the GET function declaration would do the trick, though not in a very clean way.

[nsnhan127]

I tested it outside, it seemed to work. But can I assign the property and call the fireOnTick method like this?

import { NextResponse } from "next/server";
import { CronJob } from "cron";
const job = new CronJob();
export async function GET(request) {
  const { params } = new URL(request.url);
  job.cronTime = "* * * * * *";
  job.fireOnTick(()=>{
//do something
})

  if (published) {
    job.start();
    return NextResponse.json({
      message: "Schedule started",
    });
  } else {
    job.stop();
    return NextResponse.json({
      message: "Schedule stopped",
    });
  }
}

I I tried, but it doesn't seem to work. How can I write an event handler inside the onTick with values taken from the query or body in api?

[sheerlox]

You can actually add multiple callbacks (onTicks) to the same CronJob. So you could instantiate the CronJob with a dummy callback (() => {}, since you're required to provide at least one), then from within the GET function you could use job.addCallback(yourFunc).

The issue with this approach is that you cannot reset the callbacks, as they are stored in a private property and there is no method on the CronJob class to do this (which would make a great feature request, IIRC that was already mentioned some time ago).

One workaround in this case would be to declare your job with let, and override it from the GET method everytime it's called.

Remember to call job.stop() before, because reassigning the variable only means you lose reference to the job, not that it's actually destroyed.

[nsnhan127]

So I can't update cron time again, but only update another function in onTick via callback, right?

[sheerlox]

You can definitely update the cron time using setTime. What you cannot do is override existing callbacks (onTicks if you prefer). The only way to do this is to stop the current job, and replace it by a new one. Please let me know if what I'm saying is unclear and I'll try my best to reformulate!

[nsnhan127]

thank you very much for supporting