Why might the Canonical plugin not work?

Question

MODX

Installed the Canonical add-on on ModX Revo ( https://docs.modx.com/extras/revo/canonical), inside the ... section added a call to the snippet. The result of the work is an empty line in the html code. What could be the problem?

Answer 1

The condition in the snippet fails - this page doesn't need link=canonical.

The code

$docId = $modx->resource->get('id');
$query = $modx->newQuery("modSymLink");

$query->select(array(
    'id',
    'class_key',
    'content',
));
$query->where(array(
    'id' => $docId,
    'class_key' => 'modSymLink'
));

if ($query->prepare() && $query->stmt->execute()) {
    $results = $query->stmt->fetchAll(PDO::FETCH_ASSOC);
}

if (!empty($results)) {
    $id = (integer) $results[0]['content'];
    $url = $modx->makeUrl($id, '', '', 'full');
    return '<link rel="canonical" href="' . $url . '" />';
}
return '';