WordPress Function for Automatically Updating Copyright Years

Well, I gave away the whole point of this post in the title. Before we dive in and look at the whole code, I’ll explain the purpose of this function. A lot of posts will recommend you simply put <?php echo date( 'Y' ); ?> where the year is hardcoded into footer.php. That’s fine, but it only gives you this year in your footer. It’s better to put the range of years that your site’s content spans, not merely the current year. The function we’ll look at here will display the entire range of years for all the posts and pages published on your site.

Get the raw code from this Github gist.

Let’s take a look at the code you’ll need to copy into your theme’s functions.php file (without the open/close PHP tags):

<?php
if ( ! function_exists( 'get_copyright_years' ) ) {
  function get_copyright_years( $earliest_id = null ) {
    $earliest_args = array(
      'post_type'   => array( 'any' ),
      'numberposts' => 1,
      'orderby'     => 'date',
      'order'       => 'ASC'
    );
    $get_post      = $earliest_id
                   ? get_post( $earliest_id )
                   : null;
    if ( ! $get_post ) {
      $get_post = array_shift( get_posts( $earliest_args ) );
    }
    $earliest_date = date( 'Y', strtotime( $get_post->post_date ) );
    $current_date  = date( 'Y' );
    return $earliest_date == $current_date
           ? $current_date
           : $earliest_date . '&ndash;' . $current_date;
  }
}

if ( ! function_exists( 'copyright_years' ) ) {
  function copyright_years( $earliest_id = null ) {
    echo get_copyright_years( $earliest_id );
  }
}
?>

After you’ve added those two functions to functions.php, open footer.php and delete the year if it’s hardcoded in. Replace it with <?php copyright_years(); ?>. This function only shows the years, no © or other text: you can keep whatever copyright / “all rights reserved” text you like.

The first thing I should point out is that there are actually two functions here. The first function is get_copyright_years() and only returns the date range. The second function is copyright_years() and echoes the date range. If you’re going to use this function in plain HTML in your footer file, use <?php copyright_years(); ?>:

<footer class="site-footer">
	<p class="footer-credits">&copy; <?php copyright_years(); ?>. All Rights Reserved.</p>
</footer>
<?php wp_footer();?>

If you’re going to use this function in a line of PHP in your footer file, use get_copyright_years() instead. The following code shows how you might use it inside a translatable string function:

<footer class="site-footer">
	<p class="footer-credits">
		<?php printf( __( '&copy; %s. All Rights Reserved.', 'text-domain' ), get_copyright_years() ); ?>
	</p>
</footer>
<?php wp_footer();?>

Technically you’re done now, you can quit reading this post. But if you’re curious how this function works, stay with me.

So now that you know the basics of using this function, let’s look under the hood and learn how it works.

Getting the earliest post

You may have noticed this function takes a single argument: $earliest_id. Normally the function returns the publication date for the earliest post or page published, but if you want to override that by specifying a specific post or page as the “earliest published,” pass its ID in the function in footer.php.

The first thing in the function is $earliest_args: an array of get_posts() args. If you haven’t specified an override $earliest_id, the function will use these arguments to query the oldest post or page from the database.

The $get_post declaration uses PHP ternary logic. If $earliest_id is set, $get_post will contain the output of the function get_post( $earliest_id ), otherwise, it will be null.

At this point, $get_post will either be a single post object (if you specified a valid $earliest_id) or null (if you specified an invalid ID or none at all). If it’s null, we’ll run our fallback get_posts( $earliest_args ) function. This will return an array containing a single post objects. We only want the post object, so we’ll wrap get_posts() in array_shift(). The PHP function array_shift() will return only the first object in the array. Note: array_pop() would’ve done the same thing, since there’s only one object in the array.

Comparing the years

Now no matter what argument you did or didn’t pass into the function, $get_post is a WordPress post object containing the post or page we want to use for the earliest piece of published content.

The next two variables ($earliest_date and $current_date) use the PHP date function to get the year from $get_post and the current year.

The return statement uses ternary logic again. If $earliest_date and $current_date are the same, the function will return only the current year. If they’re different, it will return the earliest year, a dash (–), then the current year.

Conclusion

Put these functions in your theme functions.php and call the right function from footer.php, and you’ve now got an always-correct copyright date range in the footer of your site. No more January updates for you! (Unless, of course, you change your theme: in that case, you’ll need to put these functions where they belong in that theme too.)

Get the raw code from this Github gist.