The responsibility of the Extractor component is to get translation keys from the source code.

Installation and Usage

Install the extractor component with Composer

composer require php-translation/extractor

When the extractor is downloaded you may use it by doing the following:

require "vendor/autoload.php";

use Translation\Extractor\Visitor\Php\Symfony as Visitor;

// Create extractor for PHP files
$fileExtractor = new PHPFileExtractor()

// Add visitors
$fileExtractor->addVisitor(new Visitor\ContainerAwareTrans());
$fileExtractor->addVisitor(new Visitor\ContainerAwareTransChoice());
$fileExtractor->addVisitor(new Visitor\FlashMessage());
$fileExtractor->addVisitor(new Visitor\FormTypeChoices());

// Add the file extractor to Extractor
$extractor = new Extractor();

//Start extracting files
$sourceCollection = $extractor->extractFromDirectory('/foo/bar');

// Print the result
foreach ($sourceCollection as $source) {
  echo sprintf('Key "%s" found in %s at line %d', $source->getMessage(), $source->getPath(), $source->getLine());


There is a lot of things happening the the code example above. Everything is very SOLID so it is easy to add your own extractors if you have custom features that you need to translate.

The class that we interact with after when we want to extract translations is the Extractor class. It supports Extractor::extractFromDirectory(string) and the more flexible Extractor::extract(Finder). The Extractor looks at all files in the directory and checks the type/extension. The extractor then executes all FileExtractor for this file type.

There is a few FileExtractor that comes with this component. They are PHPFileExtractor, TwigFileExtractor and BladeExtractor. As you may guess they extract translations from PHP files, Twig files and Blade files respectively. The most interesting ones are PHPFileExtractor and TwigFileExtractor because they are using the Visitor pattern to parse all the nodes in the document.

Let’s focus on the PHPFileExtractor only for a moment. We are using the Nikic PHP Parser to split the PHP source into an abstract syntax tree which enables us to statically analyze the source. Read more about this in the nikic/php-parser documentation. When you add a visitor to the PHPFileExtractor it will be called for each node in the syntax tree.

The visitors is very specific with what they are looking for. The FlashMessage visitor is searching for a pattern like $this->addFlash(). If that string is found it will add a new SourceLocation to the SourceCollection model.

When all visitors and FileExtractor has been executed an instance of the SourceCollection will be returned.


If you want to add functionality to the extractor you are most likely to add a new visitor. See Adding extractors for more information.

Special extractors

We have common extractors for Symfony, Twig and Blade. They all are doing static analysis on the source files to find translation strings. But in some situations you need to specify translation dynamically. You may achieve this by implementing TranslationSourceLocationContainer.

use Translation\Extractor\Model\SourceLocation;
use Translation\Extractor\TranslationSourceLocationContainer;
use Symfony\Component\Form\AbstractType;

class MyCustomFormType extends AbstractType implements TranslationSourceLocationContainer
    // ...
    public static function getTranslationSourceLocations()
        $options = // Get options
        $data = [];
        foreach ($options as $option) {
            $data[] = SourceLocation::createHere('option.'.$option);

        return $data;