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 {{ email }}

Now I want to do something like this:

$template = $twig->loadTemplate('someTemplate');
$variables = $template->getVariables();

$variables should now contain "name" and "email".

The reason I want to do this is that I am working on a CMS system where my twig templates and variables are dynamically set by my users and they also fill the variables through an API.

I want to set default values to not-set variables and therefore I need a list of all variables that exist inside the template…

Answer 1

After using duncan's answer for quite some time I finally found the "right" way to dump all twig variables of a template:

{% dump %}

That's it. All the variables available in the template will be dumped and in the dump section of the profiler, not in the middle of your html like with {{ dump() }}.

if you put the contents of dump() into a variable:

{% set d = dump() %}

you 'll get all the variables but in "dump ready" html so it would be a pain to parse it.

Hope that helps.

Answer 2

If you need all Twig elements inside of a text, just use:

preg_match_all('/\{\%\s*(.*)\s*\%\}|\{\{(?!%)\s*((?:[^\s])*)\s*(?<!%)\}\}/i', $text, $matches);

I had a issue where the WSIWYG editor placed HTML tags inside of Twig variables. I filter them with:

public function cleanHTML($text)
{
    preg_match_all('/\{\%\s*(.*)\s*\%\}|\{\{(?!%)\s*((?:[^\s])*)\s*(?<!%)\}\}/i', $text, $matches);

    if (isset($matches[0]) && count($matches[0])) {
        foreach ($matches[0] as $match) {
            $clean_match = strip_tags($match);

            $text = str_replace($match, $clean_match, $text);
        }
    }

    return $text;
}

UPDATE

Use this expression to find all {{ }} and {% %}

preg_match_all('/\{\%\s*([^\%\}]*)\s*\%\}|\{\{\s*([^\}\}]*)\s*\}\}/i', $text, $matches);

Answer 3

$loader1 = new Twig_Loader_Array([
    'blub.html' => '{{ twig.template.code }}',
]);
$twig = new Twig_Environment($loader1);
$tokens = $twig->tokenize($loader1->getSource('blub.html'));
$nodes = $twig->getParser()->parse($tokens);

var_dump($this->getTwigVariableNames($nodes));


function getTwigVariableNames($nodes): array
{
    $variables = [];
    foreach ($nodes as $node) {
        if ($node instanceof \Twig_Node_Expression_Name) {
            $name = $node->getAttribute('name');
            $variables[$name] = $name;
        } elseif ($node instanceof \Twig_Node_Expression_Constant && $nodes instanceof \Twig_Node_Expression_GetAttr) {
            $value = $node->getAttribute('value');
            if (!empty($value) && is_string($value)) {
                $variables[$value] = $value;
            }
        } elseif ($node instanceof \Twig_Node_Expression_GetAttr) {
            $path = implode('.', $this->getTwigVariableNames($node));
            if (!empty($path)) {
                $variables[$path] = $path;
            }
        } elseif ($node instanceof \Twig_Node) {
            $variables += $this->getTwigVariableNames($node);
        }
    }
    return $variables;
}

have fun :-)

Answer 4

Here is the best way and easiest way to dump all variables :

{{ dump () }}

Source : https://www.drupal.org/docs/8/theming/twig/discovering-and-inspecting-variables-in-twig-templates

Answer 5

UPDATE 2019

Although {{ dump() }} does work, in some circumstances it may result in a "memory exhausted" error from PHP if it generates too much information (for example, due to recursion). In this case, try {{ dump(_context|keys) }} to get a list of the defined variables by name without dumping their contents.

UPDATE 2017

It is possible by using {{ dump() }} filter. Thanks for pointing that out in the comments!

---

OUTDATED

It is not possible.

You can look for these variable in twig templates and add |default('your_value') filter to them. It will check if variable is defined and is not empty, and if no - will replace it with your value.

Answer 6

This is useful I find to get all the top-level keys available in the current context:

<ol>
    {% for key, value in _context  %}
      <li>{{ key }}</li>
    {% endfor %}
</ol>

Thanks to https://www.drupal.org/node/1906780