SEO

With the help of YOAST it is possible to display the product description as a meta description. This is done in the programmatic way as follows:

Insert the following code as a snippet in functions.php of the theme or using a plugin.

// callback für Ersetzung in YOAST SEO 
function get_fullDescription() {
    global $post;
    return $post != null ? $post->post_content : "";
}

// Registriere eigene YOAST-Variablenersetzung
function register_custom_yoast_variables() {
    wpseo_register_var_replacement( '%%fulldes%%', 'get_fullDescription', 'advanced', 'Full Description' );
}

// YOAST-Variablenersetzung bekannt machen
add_action('wpseo_register_extra_replacements', 'register_custom_yoast_variables');

Then under WordPress -> SEO -> Presentation in search results -> Enter products %%fulldes%% under meta description. Don’t forget to save!

But now the complete description is used. However, it would be better to observe the length specification for meta descriptions of the search engines. This is a maximum of 160 characters.

For this we need two more functions. With the replaceHtmlTags function below, we replace any existing HTML tags in the description, because we don’t want them in our meta description. With the second function wordTruncate we reach the length specification. The code ensures that it is not just separated after 160 characters and thus possibly cut off in the middle of the word, but that it is cut off after the last word that is still within the 160 characters.

function replaceHtmlTags($string) {
	return preg_replace("/<.*?>/", "", $string);
}

function wordTruncate($string, $desired_max_width) {
  $parts = preg_split('/([\s\n\r]+)/u', $string, -1, PREG_SPLIT_DELIM_CAPTURE);
  $parts_count = count($parts);

  $length = 0;
  $last_part = 0;
  for (; $last_part < $parts_count; ++$last_part) {
    $length += strlen($parts[$last_part]);
    if ($length > $desired_max_width) { break; }
  }

  return implode(array_slice($parts, 0, $last_part));
}

The routine get_fullDescription from the code above is modified again a bit and looks like this:

// callback für Ersetzung in YOAST SEO 
function get_fullDescription() {
    global $post;
    return wordTruncate(replaceHtmlTags($post->post_content), 160);
}

The complete code looks like this:

// callback für Ersetzung in YOAST SEO 
function get_fullDescription() {
    global $post;
    return wordTruncate(replaceHtmlTags($post->post_content), 160);
}

// Registriere eigene YOAST-Variablenersetzung
function register_custom_yoast_variables() {
    wpseo_register_var_replacement( '%%fulldes%%', 'get_fullDescription', 'advanced', 'Full Description' );
}

// YOAST-Variablenersetzung bekannt machen
add_action('wpseo_register_extra_replacements', 'register_custom_yoast_variables');

function replaceHtmlTags($string) {
	return preg_replace("/<.*?>/", "", $string);
}

function wordTruncate($string, $desired_max_width) {
  $parts = preg_split('/([\s\n\r]+)/u', $string, -1, PREG_SPLIT_DELIM_CAPTURE);
  $parts_count = count($parts);

  $length = 0;
  $last_part = 0;
  for (; $last_part < $parts_count; ++$last_part) {
    $length += strlen($parts[$last_part]);
    if ($length > $desired_max_width) { break; }
  }

  return implode(array_slice($parts, 0, $last_part));
}

Thus, without the chargeable YOAST SEO WooCommerce extension, we have managed to display the product description as a meta description.

WooCommerce short description as meta description

If, on the other hand, you want to use the short description as a meta description, YOAST SEO offers the function in the free version, albeit a bit hidden.

To use the short description as a meta description, under SEO -> Presentation in search results -> Products include the %%wc_shortdesc%% variable.