PHP date reformat function

Question

I am currently working on an app and have some issues with the date handling. Found a simple solution, and want your opinion. First thing, that I want to achieve:

1. I have 2 date format inputs, one is like 2013年09月30日 14:20:00 and the other is 30/09/2013 1420
2. Time stamp is given with no day light saving time.

So, I have to store my date/time in DB with the same format in order to compare one with each other, and also I need to adjust the time stamp +1 hour if it is in the DST period. For this, I made the following function:

function format_date($date_string, $date_format)
{
$unix = mktime( substr($date_string, strpos($date_format, 'HH'), 2),
 (strpos($date_format, 'ii'))? substr($date_string, strpos($date_format, 'ii'), 2) : '00',
 (strpos($date_format, 'ss'))? substr($date_string, strpos($date_format, 'ss'), 2) : '00',
 substr($date_string, strpos($date_format, 'MM'), 2),
 substr($date_string, strpos($date_format, 'DD'), 2),
 substr($date_string, strpos($date_format, 'YYYY'), 4)
 ) ;
$human = date('Y-m-d H:i:s', $unix);
$dst = date('I', $unix);
return (object)array(
 'unix' => $unix,
 'human' => $human,
 'dst' => $dst
 );
}
//Usage:
$date1 = format_date('2013-09-30 14:20','YYYY-MM-DD HH:ii');
$date2 = format_date('30/09/2013 1420','DD/MM/YYYY HHii');
echo $date1->human ;
echo '<br />';
echo $date2->human ;
echo '<br />';
// $date1->human is the same with $date1->human, also ->unix

Maybe this will help others, but if you find something not right in this function please let me know before I put it in production.

Update: (thank you Glavić)

function format_date1($date_string, $date_format)
{
$date_build = DateTime::createFromFormat ( $date_format , $date_string );
return (object)array(
 'unix' => $date_build->format('U'),
 'human' => $date_build->format('Y-m-d H:i:s'),
 'dst' => $date_build->format('I')
 );
}
$make_date = format_date1('30/09/2013 1420', 'd/m/Y Hi');
print_r($make_date); 
//returns stdClass Object ( [unix] => 1380540000 [human] => 2013年09月30日 14:20:00 [dst] => 1 )
//Use: $make_date->unix | $make_date->human | $make_date->dst

• 1ed: You should take a look at DateTime::createFromFormat and DateTime::format
• BogdanD: Aha! good point.

Answer 1

Use DateTime::createFromFormat method to convert datetime strings to DateTime object:

$date1 = DateTime::createFromFormat('Y-m-d H:i', '2013-09-30 14:20');
$date2 = DateTime::createFromFormat('d/m/Y Hi', '30/09/2013 1420');

Now you can just format your output:

echo 'unix : ' . $date1->format('U') . "\n";
echo 'human : ' . $date1->format('Y-m-d H:i:s') . "\n";
echo 'dst : ' . $date1->format('I') . "\n";

And you don't need to adjust timestamp for +1 hour if in DST, DateTime can handle leap years and DST correctly. Set timezone when you create DateTime object, or change timezone after.

• BogdanD: I can not make the correction DST work as desired... My input date is in let`s say GMT+2 (which means no DST) when in DST it is +1 hour, the output should be +1h
• Glavić: DateTime objects work with timezones. Every timezone chooses to follow DST or not. How to find out if timezone observes DST or not? Here is also a good read.
• Glavić: Example of DST change for UTC (no DST) and Europe/Berlin (with DST).