help with some php code

tdnnash25 · 06-04-2010, 12:50 PM

Sorry if this is not the appropriate forum. Experienced PHP developers, please advise:

My server is in Kansas (Central time). Right now, due to DST, we are
GMT -5...in the Winter GMT -6

my form gives users the option to select a date, time, and timezone
for a specific event to occur. So, say the user is in California and
they choose 8:00AM, January 1st 2011, Pacific Time (2 hours behind
us).

Well, I want my script to take the date, time, and timezone they
choose and convert it to central time so I can timestamp it on my
server ... so for this example, I'd timestamp the file 10:00AM,
January 1st 2011 ... then on that date, the event would occur at
10:00AM my time, 8:00AM their time.

I've got some code that is getting close to accomplishing this....do
you have any experience with timezone stuff?

my code:

$userTimezone = new DateTimeZone($tz);
$myDateTime = new DateTime($time);
$cstTimeZone = new DateTimeZone('CST');
$myDateTime = new DateTime($time, $userTimezone);

echo $myDateTime->format('r'); // browser prints this: Sat, 01 Jan
2011 08:00:00 -0800
$offset = $cstTimeZone->getOffset($myDateTime);
echo "<br />";
echo $offset; // browser prints this: -21600
echo "<br />";
echo date('Y-m-d H:i:s', $myDateTime->format('U') + $offset); //
browser prints this: 2011-01-01 04:00:00
echo "<br />";

so, the first echo is correct...it prints the date and time the user
chose ... plus the GMT time

I'm going off of an article I found here(http://blog.boxedice.com/
2009/03/21/handling-timezone-conversion-with-php-datetime/), but I
must be doing something wrong b/c the last echo certainly doesn't
print out the correct time I'm looking for.

eSelix · 06-04-2010, 03:30 PM

Check this:

PHP Code:


			
$aMyTimeZone = "CST";

$aUserTimeZone = "US/Pacific";

$aUserTime = "2011-01-01 08:00";



$MyTimeZone = new DateTimeZone($aMyTimeZone);

$UserTimeZone = new DateTimeZone($aUserTimeZone);

$UserTime = new DateTime($aUserTime, $UserTimeZone);



$MyTime = new DateTime('@'.(string)$UserTime->format('U'));

$MyTime->setTimeZone($MyTimeZone);



echo 'USER:<br>';

echo $UserTime->format('r').'<br><br>';

echo 'MY:<br>';

echo $MyTime->format('r').'<br>';

If you have PHP >= 5.3 you can use DateTime::getTimestamp() and DateTime::createFromFormat().
Also I don't known why

PHP Code:


			
$MyTime = new DateTime('@'.(string)$UserTime->format('U'), $MyTimeZone);

does not set timezone, but compute it.

tdnnash25 · 06-04-2010, 03:41 PM

Quote:

Originally Posted by eSelix

Check this:

PHP Code:


			
$aMyTimeZone = "CST";

$aUserTimeZone = "US/Pacific";

$aUserTime = "2011-01-01 08:00";



$MyTimeZone = new DateTimeZone($aMyTimeZone);

$UserTimeZone = new DateTimeZone($aUserTimeZone);

$UserTime = new DateTime($aUserTime, $UserTimeZone);



$MyTime = new DateTime('@'.(string)$UserTime->format('U'));

$MyTime->setTimeZone($MyTimeZone);



echo 'USER:<br>';

echo $UserTime->format('r').'<br><br>';

echo 'MY:<br>';

echo $MyTime->format('r').'<br>';

If you have PHP >= 5.3 you can use DateTime::getTimestamp() and DateTime::createFromFormat().
Also I don't known why

PHP Code:


			
$MyTime = new DateTime('@'.(string)$UserTime->format('U'), $MyTimeZone);

does not set timezone, but compute it.

thank you so much ... I think it is working as expected, I will test it out for a while and post back here if I have any other questions. I *really* appreciate your feedback

tdnnash25 · 06-04-2010, 03:54 PM

How would I get this:
MY:
Thu, 24 Jun 2010 14:20:00 -0500

to look like this:
My:
20100624142000

?

tdnnash25 · 06-04-2010, 04:05 PM

also, I'm not familiar with this: '@'.(string)

what does it mean?

eSelix · 06-04-2010, 07:00 PM

Look at the possible formats of date and time.
Ex. echo $MyTime->format('YmdHis');

About '@' look at http://pl2.php.net/manual/en/datetim...s.compound.php
It tells DateTime constructor that its parameter is an Unix Timestamp.

The '(string)' convert variable to string type, for safety to concatenation. It is not required here, it's just my style of programming.