Expiration date for some database entries - php

Question

I am trying to set an expiration on DB entries. I've set the field to datetime and entered some values manually through MySQL
I take the value from the table and convert it to strtotime(). then I get the current time using strtotime("now"); or time(); they seemed to return the same value.
I then take the future date(the one from the db) and with if statement check if its smaller then current time if so I set it as expired. if it's still bigger then current time I return how much time left..
Here is the code for that:
$time_left = "";
$value['ex_date'] = '2012-11-22 18:17:33';// this is whats in the DB now.
$future_time = strtotime($value['ex_date']);
$now_time = strtotime('now');
if($deal_end < $now_time){
$time_left = 'Expired';
}else{
$seconds = $future_time - $now_time;
$days = floor($seconds / 86400);
$seconds %= 86400;
$hours = floor($seconds / 3600);
$seconds %= 3600;
$minutes = floor($seconds / 60);
$seconds %= 60;
if($days >= 1) {$time_left .= "D:$day ";}
if($hours >= 1) {$time_left .= "H:$hours ";}
if($minutes >= 1) {$time_left .= "M:$minutes ";}
if($seconds >= 1) {$time_left .= "S:$seconds ";}
For some reason the above doesn't work well. its like there is some time gap.
my question is: is there a way to check server time vs database time ?
because the strtotime('now'); time seems different then current timestemp by like 2/3 hours for some reason.

Answer 1

I can suggest two other approaches:
a. Select from the database rows that did not expire yet adding the logic to the query itself
b. run cron/mysql schedule every minute that will clear the database entries that had expired
SELECT * from TABLE where X = Y and NOW() < expiredField
Besides, PHP has a built in class just for the operations with date you are trying to perform.
It's called DateTime.
$dt = new DateTime('2012-11-22 18:17:33');
$dtNow = new DateTime();
$interval = $dtNow->diff($dt); // php.net/DateInterval
if($interval->invert)
echo 'expired';
else
echo $interval->format('%m month, %d days, %h hours, %s seconds');
To your original question
Checking the server time is
echo time();
Checking database time is
SELECT NOW();

Answer 2

You can find server(linux) time zone using following at command line:
$ date +%Z
Or following in php:
$ echo system('date +%Z');
In php you can use date_default_timezone_get function.
Most probably your system and php timezones will be different.
You can change php timezone by using date_default_timezone_set function.

Answer 3

In-case anyone is curious about how i solved it:
$result = mysql_query("select CURRENT_TIMESTAMP;");
$row = mysql_fetch_array( $result );
$DB_now = $row['CURRENT_TIMESTAMP'];
$deal_end = strtotime($value['ex_date']);
$now_time = strtotime($DB_now);
I just use database's current timestamp as "now"
Not sure if that's the best solution but it works