WordPress Function to get EXIF date of attachment

sjf_deh_get_exif_date.php

<?php

/**
 * Return the EXIF date for a jpeg attachment post.
 * 
 * @return string The Exif time on which the image was taken.
 */
 function sjf_deh_get_exif_date() {
 	
 	// Grab the current post.
 	$post = get_post();

 	// If this isn't an attachment, bail.
 	if( $post->post_type != 'attachment' ) { return false; }

 	// If this isn't an jpeg, bail.
	$mime = get_post_mime_type();
 	if( $mime != 'image/jpeg' ) { return false; }

 	// Get the path to the attachment file.
 	$path = get_attached_file( $post->ID );
 	if( empty( $path ) ) { return false; }

 	// Get the exif data.
	$exif = exif_read_data( $path );
	

	// Get the exif time.
	if( isset( $exif[ 'DateTimeOriginal' ] ) ) {
		$exif_time = $exif[ 'DateTimeOriginal' ];
	
	// If there is no exif time, bail.
	} else {
		return false;
	}

	// Convert the time to Unix time.
	$unix_time = strtotime( $exif_time );

	// If the time seems like the Unix epoch, which it might be if strtotime gets an oddball value, bail.	
	if( stristr( '1970-01-01', $exif_time ) ) { return false; }

	// Convert the time back to the format used by WordPress $post->post_date.
	$time = date( 'Y-m-d H:i:s', $unix_time );

	return $time;
 
 }