[wp-trac] [WordPress Trac] #47717: Attached JPEGs potentially have an incorrect 'localized' timestamp

[WordPress Trac]

#47717: Attached JPEGs potentially have an incorrect 'localized' timestamp
--------------------------+-----------------------------
 Reporter:  githue        |      Owner:  (none)
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Media         |    Version:  5.2.2
 Severity:  normal        |   Keywords:
  Focuses:                |
--------------------------+-----------------------------
 When you upload a JPEG to the WP media library, WP generates a UNIX
 timestamp for the `created_timestamp` meta value. I want to use this
 timestamp to display a "Date Taken" on my photography site, however
 sometimes the time is off by 10 hours. Other software like Windows and
 Photoshop show the correct localized time.

 WP uses two IPTC fields to generate the timestamp (in `/wp-
 admin/includes/image.php`):

 `$meta['created_timestamp'] = strtotime( $iptc['2#055'][0] . ' ' .
 $iptc['2#060'][0] )`

 The value of the second IPTC field `[2#060]` can be "141433'''+1000'''" or
 "141433'''+0000'''", etc. The result is that the `created_timestamp` can
 sometimes be UTC+10 or UTC+0, which makes it pretty unreliable. For
 example I'm using the timestamp to display a "Date Taken" on my website
 for thousands of photos, but there's no way to know if the timestamp has
 already been localized or not. I don't know much about date formats, but
 I'd expect timestamps to always be UTC+0.

 One way to solve this is to strip out the offset from the time string
 before `strtotime()`, I've been using the `wp_read_image_metadata` filter
 to do this.

 Here's a quick test I made using two images with different timezone values
 (see attached).

 {{{
 <?php
 function read_jpeg($path)
 {
         getimagesize($path, $info);
         if (isset($info['APP13'])) {
                 $iptc = iptcparse($info['APP13']);
                 $date = $iptc['2#055'][0];
                 $time = $iptc['2#060'][0];
                 $timeNoOffset = explode("+", $time)[0];

                 $wp_timestamp = strtotime($date . ' ' . $time);
                 $utc_timestamp = strtotime($date . ' ' . $timeNoOffset);

                 echo "WP: " . date("h:i:s A, D", $wp_timestamp);
                 echo " | Excluding offset: " . date("h:i:s A, D",
 $utc_timestamp);
                 echo "<hr />";
                 var_dump($iptc);
         }
 }
 date_default_timezone_set('UTC');
 echo date_default_timezone_get();
 ?>
 <hr />
 <br />
 <?php
 // Correct localized time: 12:00:00 AM, Wed
 read_jpeg('./date_created+0.jpg');
 ?>
 <hr />
 <br />
 <?php
 // Correct localized time: 02:14:33 PM, Sun
 read_jpeg('./date_created+1000.jpg');
 ?>
 }}}

 I searched for related issues but I dont think they were related to this
 specific issue with `$meta[created_time]`.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/47717>
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