How to retrieve all Variables from a Twig Template?

Question

Is it possible to retrieve all variables inside a Twig template with PHP?

Example someTemplate.twig.php:

Hello {{ name }}, 
your new email is {{ ema         


        

Answer 1

I think 19Gerhard85's answer is pretty good, although it might need some tweaking because it matched some empty strings for me. I like using existing functions where possible and this is an approach mostly using twig's functions. You need access to your application's twig environment.

/**
 * @param $twigTemplateName
 * @return array
 */
public function getRequiredKeys($twigTemplateName)
{
    $twig = $this->twig;
    $source = $twig->getLoader()->getSource($twigTemplateName);
    $tokens = $twig->tokenize($source);
    $parsed = $twig->getParser()->parse($tokens);
    $collected = [];
    $this->collectNodes($parsed, $collected);

    return array_keys($collected);
}

And the only custom part of it is the recursive function to collect only certain types of nodes:

/**
 * @param \Twig_Node[] $nodes
 * @param array $collected
 */
private function collectNodes($nodes, array &$collected)
{
    foreach ($nodes as $node) {
        $childNodes = $node->getIterator()->getArrayCopy();
        if (!empty($childNodes)) {
            $this->collectNodes($childNodes, $collected); // recursion
        } elseif ($node instanceof \Twig_Node_Expression_Name) {
            $name = $node->getAttribute('name');
            $collected[$name] = $node; // ensure unique values
        }
    }
}