Tutorial: Create a daily job with a Cron handler

Now that we're storing requests, we can use a scheduled job (a "Cron", named after the Unix cron utility) to create a report of all requests per day.

1. Hit the plus (+) button (or use the omnibox) to create a new Cron. Set it to run daily, and with the name DailyReport.

2. To know if a request was executed today, we compare it to the current time. Let's assign the current time in seconds to a variable timeSeconds. The current time in seconds is Date::now, piped into Date::toSeconds. (Note: to create a pipe, type |> after the Date::now function).

   Run the Date::now function to see a live value for your code.

3. Next, we'll need to filter the reports to just today's reports. Set allRequests to DB::getAll Requests. Run the function to the live value for allRequests.

4. To see only today's requests, use List::filter. List::filter takes two arguments - the list to filter (in this case allRequests) and an anonymous function that determines if each element of the list element should be includes in the new list. List::filter is similar to List::map and the concept is explained in more detail here.

5. We want to keep only reports that occurred today, meaning we want to compare the report's time to timeSeconds that we created earlier. Let's convert the time of the request into seconds so that both times have the same units.

6. Next, we calculate the difference from the current time; this tells us if it happened today (in the last 86,400 seconds).

7. To see this work, it's helpful to have a recent request. If you paused in the tutorial, re-run the HttpClient::post function from the REPL. Then, when you place your cursor in todayRequests or List::filter you'll see a list of requests from the last 24 hours.

8. Finally, let's emit today's requests to a background worker, using the emit keyword. emit takes two arguments, and in this case we're sending todayRequests to a not-yet-created worker named storeReport.

9. To have our first report run, hit the "replay" button in the upper right of the Cron. This creates a 404 in the sidebar for the Worker storeReport.