How do I get date function to return date according to current system date? Right now, with the code snippet below, it always returns UK time, not the current system date.
<calculate>
<script>$ = concat( num2date(date(), DateFmt()), " ", num2Time(Time(), TimeFmt()) )</script>
Any help is appreciated!
It's probably not UK time exactly, but rather GMT (or UTC, to use a more precise term). The UK happens to be aligned to GMT in the winter, but in the summer it advances one hour to BST for daylight saving time.
Now, I've never used LiveCycle myself, but nonetheless, I've read through the somewhat minimal docs for LiveCycle FormCalc Date and Time Functions, and the spec, and it appears to me that a few critical mistakes were made.
The date and time functions return UTC-based values, but only the time-related functions have been made aware of the local time zone. That is, there are separate Num2Time and Num2GMTime functions, but there is only one Num2Date function.
The Num2Date function works in terms of whole integer days, and thus they are simply days since 1900-01-01. Therefore, the number being passed in to the function must already be representative of the desired time zone. However, the Date function only gets the current GMT date. There does not appear to be a function to get the current local date.
It's different on the time side, because of the millisecond precision involved. However, there's yet another flaw here. Despite the docs saying that the Time function returning "the number of milliseconds since the epoch", its actually returning only the number of milliseconds since midnight GMT. There is no day-over-day accumulation of milliseconds from the date part. The docs here are even lying in their sample code which says:
Returns the current system time as the number of milliseconds since the epoch.
Time() => 71533235 at precisely 3:52:15 P.M. on September 15th, 2003 to a user in the Eastern Standard Time (EST) zone.
If that was indeed the case (and ensuring to use their 1900-01-01 epoch), the value would actually include an additional 3272572800000 milliseconds representing the days between 1900-01-01 and 2003-09-15, bringing the total timestamp to 3272644333235. Additionally, there's a typo there, because the timestamp they give is 3:52:13, not 3:52:15. Clearly nobody paid close attention to these docs!
The real problem is that one cannot be certain that the number of milliseconds since midnight of the current day in the local time zone is the same on every day. If instead of getting the current time, you were working with past stored time values, you might be an hour off (+ or -) if the current offset is different due to daylight saving time. Example: Eastern time might be UTC-5 or UTC-4, but only the offset currently in effect will be used by the Num2Time function, even if the date you're working with is using the other offset.
So, in summary, the Date function is insufficient, leading to your observations, and the date/time functionality in general is poorly designed. Given the constraints of this API, I can't even recommend a workaround. There would have to be a LocalDate function of some kind to be used instead of the Date function, but it doesn't exist.
The only advice I can offer is that it appears (from my research, not experience) that LiveCycle can use either FormCalc or JavaScript. So - use JavaScript instead.