Server Time Issue

[Charles Hoens]

I am currently using a VPS server at GoDaddy, which is located in Arizona. For me here in the East, that's a two hour time difference. So this creates a problem which I don't know how to solve. I know that many of you out there have users in different time zones. So, when you have programs that rely on time or display of time such as login/logout out, etc., how do you handle this? Does Alpha offer some sort of a setting that would translate the server time to the user time?

I hope you can see where I am going with this and would be happy for any ideas or workarounds.

Charlie

[madtowng]

Re: Server Time Issue

I think most browsers display time in local time.
That said, I have been working on a system that I convert a given time to UTC,
then apply offset and DST as necessary.

[Charles Hoens]

Re: Server Time Issue

It's not the browser display time, but rather the time (using now() or time()) that gets put into and displayed from the database. My first idea is to find out what time zone the user is in and then use that as an offset. But I am looking for other ideas.

[madtowng]

Re: Server Time Issue

ok...here comes the fun

assuming your vps is hosted in Phoenix AZ, your server uses MST(UTC-7) and does not observe daylight savings time.
Princeton, NJ uses EST(UTC-5) and does recognize daylight savings time.

For this example, I am going to use a time of 13:00 MST.
The code below will convert MST time to EDT time.
I can get more detailed to cover other timezones, but this shows the basics.

The one thing this assumes is that people know what time zone they are really in.
You would be surprised how many people/companies say "Eastern Standard Time" when
they really mean "Eastern Daylight Time".

Hope this helps

dim offset as n = -5
dim hour as n = 3600
dim dstcode as n = 0
dim dst_recognized as c 
dim vpstime as t = convert_type("09/11/2012 13:00","T")
dim vpsutc as t = vpstime + (7*3600) 

'set dst_recognized to "y" for NJ
dst_recognized = "Y"

dstcode=if(dst_recognized = "Y",1,0)
njtime = vpsutc +  (offset*hour)+(dstcode*hour)
?njtime

[Steve Workings]

Re: Server Time Issue

Yeah, IMHO, there's a fair amount of work to assemble a complete user/timezone management system. But once done, it's quite portable -- I built one a couple years ago and have just implemented it with a few minor changes in a new app. As Gregg suggests, there's lots to consider including figuring DST, getting the user to (properly) select their timezone, etc. And then, I don't use the Date(), Time() or Now() functions. They're all replaced with LocalDate(), LocalTime() and LocalDT() that take into account all the timezone considerations including the server's own timezone location.

[madtowng]

Re: Server Time Issue

Steve,

Are the LocalDate(), LocalTime() and LocalDT() functions UDFs ?

[Steve Workings]

Re: Server Time Issue

They're UDFs that consider the user's timezone, the offset, DST, server vs. GMT -- that sort of thing. My current app is just getting rolling, with first users in the Eastern U.S. Next group will be in Singapore so a complete implementation of this is a must.

[madtowng]

Re: Server Time Issue

wow..makes me glad I only have to deal with North America (at least until we find a way to drive across the oceans).

The image I show is from an order entry screen.
The company I work for is in Milwaukee, WI.
I "assume" local time for the pickups and deliveries.
In this case, I used a pickup in Saskatoon, SK (They are always on utc-6) and a delivery to Greenville, TN (currently UTC-4)
A question we often run into is "what time is that in Milwaukee?", which explains the CDT (UTC-5) times above the
pickup and delivery times.

I can only imagine the hassles of needing to check the summer/winter time rules across the globe.

[2ninerniner2]

Re: Server Time Issue

... I used a pickup in Saskatoon, SK

Yeah, I did too a few times ... a 1982 Ford F-250 as I recall! ... sorry, couldn't help it when I saw ToonTown mentioned as I was born there! :)