Question

I get the Error sometime on Converting 12hour format time from a Timezone to new
TimeZone

Error:

Fatal error: Uncaught exception 'Exception' with message 'DateTime::__construct(): Failed to parse time string (00:00:31 AM) at position 9 (A): The timezone could not be found in the database' in C:\xampp\php\udp.php:105
Stack trace:
#0 C:\xampp\php\udp.php(105): DateTime->__construct('00:00:31 AM', Object(DateTimeZone))
#1 {main}  thrown in C:\xampp\php\udp.php on line 105

MyCodes:

// $gps_time = "9:43:52"; 
$gps_time      = $time_hour.":".$time_min.":".$time_sec;
// $time_received = "01:45:04 2012-07-28"; 
$time_received = date('H:i:s Y-m-d');

$utc = new DateTimeZone("UTC"); 
$moscow = new DateTimeZone("Europe/Moscow"); 

//Instantiate both AM and PM versions of your time 
$gps_time_am = new DateTime("$gps_time AM", $utc); 
$gps_time_pm = new DateTime("$gps_time PM", $utc); 

//Received time 
$time_received = new DateTime($time_received, $moscow); 

//Change timezone to Moscow 
$gps_time_am->setTimezone($moscow); 
$gps_time_pm->setTimezone($moscow); 

//Check the difference in hours. If it's less than 1 hour difference, it's the correct one. 
if ($time_received->diff($gps_time_pm)->h < 1) { 

$correct_time = $gps_time_pm->format("H:i:s Y-m-d");
} 
else { 

$correct_time = $gps_time_am->format("H:i:s Y-m-d");
}

echo $correct_time;

Question: Where’s the problem !!?
P.S: above Code is a part of my udp socket and run from php cli

Answer 1

Summary

Put simply, that PHP is trying (mistakenly, for your needs) to read AM as a timezone and AM is not a valid timezone.

---

Details

10:39:6 AM gets separated into the following pieces

• 10:39:6 it recognises as timelong24 (a 24-hour formatted time with seconds)
• AM it recognises as tz (timezone).

In contrast, for 10:39:06 AM it correctly parses the whole string as timelong12 (a 12-hour formatted time with seconds and AM/PM).

Boring bit

The reason for this strange behaviour lies in the date parsing logic (source). The relevant patterns are:

timelong24

't'?
[01]?[0-9] | "2"[0-4]              # hour24
[:.]
[0-5]?[0-9]                        # minute
[:.]
[0-5]?[0-9] | "60"                 # second;

timelong12

"0"?[1-9] | "1"[0-2]               # hour12
[:.]
[0-5]?[0-9]                        # minute
[:.]
[0-5][0-9] | "60"                  # secondlz
[ \t]*                             # space?
([AaPp] "."? [Mm] "."?) [\000\t ]  # meridian;

As you can see, to match the timelong12 format (which is what we really wanted), the seconds portion of the time must be double-digits.