datetime - Return local time from unix timestamp with timezone identifier in php

Question

I have a dropdown box on a webpage that takes a timezone identifier as the value (however I can change it to save the GMT offset if that is a better choice). Currently a user would be saving something like "America/Denver" as his / her time zone.

I need to convert a unix timestamp into the user's local time for display in another portion of the page. What is the best way to accomplish this?

Would it be better to store the GMT offset in the database and use that for a time calculation? Can someone please point me in the right direction here?

Thanks!

Answer 1

The easiest approach would be to use DateTime with:

$t = new DateTime();
$t->setTimestamp( $time=time() );
$t->setTimeZone(new DateTimeZone("America/Denver"));
print $t->format(DateTime::RFC850);

The timezone can be changed at will to cause the format function to recalculate the local time.