Improve EXIF timestamp handling with timezone support

src/wp-admin/includes/image.php

@@ -805,6 +805,25 @@ function wp_exif_frac2dec( $str ) {
 	return $numerator / $denominator;
 }
 
+/**
+ * Convert the exif date format to DateTime object
+ *
+ * @since 6.8.0
+ *
+ * @param string $str      A date string expected to be in Exif format (Y:m:d H:i:s).
+ * @param string $timezone Optional. Timezone or offset string.
+ * @return DateTimeImmutable|false Return false if not valid date
+ */
+function wp_exif_datetime( $str, $timezone = null ) {
+	try {
+		$timezone = ( $timezone ) ? new DateTimeZone( $timezone ) : wp_timezone();
+		$datetime = new DateTimeImmutable( $str, $timezone );
+		return $datetime;
+	} catch ( Exception $e ) {
+		return false;
+	}
+}
+
 /**
  * Converts the exif date format to a unix timestamp.
  *
@@ -814,10 +833,11 @@ function wp_exif_frac2dec( $str ) {
  * @return int|false The unix timestamp, or false on failure.
  */
 function wp_exif_date2ts( $str ) {
-	list( $date, $time ) = explode( ' ', trim( $str ) );
-	list( $y, $m, $d )   = explode( ':', $date );
-
-	return strtotime( "{$y}-{$m}-{$d} {$time}" );
+	$datetime = wp_exif_datetime( $str );
+	if ( $datetime ) {
+		return $datetime->getTimestamp();
+	}
+	return false;
 }
 
 /**
@@ -921,7 +941,11 @@ function wp_read_image_metadata( $file ) {
 			}
 
 			if ( ! empty( $iptc['2#055'][0] ) && ! empty( $iptc['2#060'][0] ) ) { // Created date and time.
-				$meta['created_timestamp'] = strtotime( $iptc['2#055'][0] . ' ' . $iptc['2#060'][0] );
+				$datetime = new DateTimeImmutable( $iptc['2#055'][0] . ' ' . $iptc['2#060'][0] );
+				// Store as a RFC3339 formatted timestring as this includes both date, time, and timezone.
+				$meta['created'] = $datetime->format( DATE_RFC3339 );
+				// Retain the original created timestamp for backcompat.
+				$meta['created_timestamp'] = $datetime->getTimestamp();
 			}
 
 			if ( ! empty( $iptc['2#116'][0] ) ) { // Copyright.
@@ -1029,7 +1053,17 @@ function wp_read_image_metadata( $file ) {
 			$meta['camera'] = trim( $exif['Model'] );
 		}
 		if ( empty( $meta['created_timestamp'] ) && ! empty( $exif['DateTimeDigitized'] ) ) {
-			$meta['created_timestamp'] = wp_exif_date2ts( $exif['DateTimeDigitized'] );
+			$timezone = null;
+			if ( ! empty( $exif['UndefinedTag:0x9012'] ) ) {
+				$timezone = $exif['UndefinedTag:0x9012'];
+			}
+
+			$datetime = wp_exif_datetime( $exif['DateTimeDigitized'], $timezone );
+
+			// Store as a RFC3339 formatted timestring as this includes both date, time, and timezone.
+			$meta['created'] = $datetime->format( DATE_RFC3339 );
+			// Retain the original created timestamp for backcompat.
+			$meta['created_timestamp'] = $datetime->getTimestamp();
 		}
 		if ( ! empty( $exif['FocalLength'] ) ) {
 			$meta['focal_length'] = (string) $exif['FocalLength'];

tests/phpunit/tests/date/exifDate.php

@@ -0,0 +1,78 @@
+<?php
+
+/**
+ * @group date
+ * @group datetime
+ */
+class Tests_Date_Exif extends WP_UnitTestCase {
+
+	/**
+	 * @dataProvider data_wp_exif_datetime
+	 *
+	 * @ticket 49413
+	 *
+	 * @param string      $date_string Date string in EXIF format (Y:m:d H:i:s).
+	 * @param string|null $timezone    Optional. Timezone or offset string.
+	 * @param string|bool $expected    Expected RFC3339 formatted date string or false for invalid input.
+	 */
+	public function test_wp_exif_datetime( $date_string, $timezone, $expected ) {
+		$datetime = wp_exif_datetime( $date_string, $timezone );
+		if ( false === $expected ) {
+			$this->assertFalse( $datetime );
+		} else {
+			$this->assertInstanceOf( 'DateTimeImmutable', $datetime );
+			$this->assertSame( $expected, $datetime->format( DATE_RFC3339 ) );
+		}
+	}
+
+	public function data_wp_exif_datetime() {
+		return array(
+			'valid date without timezone' => array(
+				'2004:07:22 17:14:35',
+				null,
+				'2004-07-22T17:14:35+00:00',
+			),
+			'valid date with timezone'    => array(
+				'2004:07:22 17:14:35',
+				'+05:30',
+				'2004-07-22T17:14:35+05:30',
+			),
+			'invalid date format'         => array(
+				'not a date',
+				null,
+				false,
+			),
+			'invalid timezone'            => array(
+				'2004:07:22 17:14:35',
+				'Invalid/Timezone',
+				false,
+			),
+		);
+	}
+
+	/**
+	 * @dataProvider data_wp_exif_date2ts
+	 *
+	 * @ticket 49413
+	 *
+	 * @param string    $date_string Date string in EXIF format (Y:m:d H:i:s).
+	 * @param int|bool  $expected    Expected Unix timestamp or false for invalid input.
+	 */
+	public function test_wp_exif_date2ts( $date_string, $expected ) {
+		$timestamp = wp_exif_date2ts( $date_string );
+		$this->assertSame( $expected, $timestamp );
+	}
+
+	public function data_wp_exif_date2ts() {
+		return array(
+			'valid date'          => array(
+				'2004:07:22 17:14:35',
+				1090516475,
+			),
+			'invalid date format' => array(
+				'not a date',
+				false,
+			),
+		);
+	}
+}

tests/phpunit/tests/image/meta.php

@@ -217,6 +217,7 @@ public function data_stream() {
 					'title'             => 'IPTC Headline',
 					'orientation'       => '0',
 					'keywords'          => array(),
+					'created'           => '2004-07-22T17:14:35+00:00',
 				),
 			),
 			'Exif from a DMC-LX2 camera with keywords' => array(
@@ -234,6 +235,7 @@ public function data_stream() {
 					'title'             => 'Photoshop Document Ttitle',
 					'orientation'       => '1',
 					'keywords'          => array( 'beach', 'baywatch', 'LA', 'sunset' ),
+					'created'           => '2011-05-25T09:22:07+00:00',
 				),
 			),
 		);