FriendsOfTYPO3 · linawolf · Mar 10, 2026
diff --git a/Classes/Command/Input/Question/ChooseExtensionKeyQuestion.php b/Classes/Command/Input/Question/ChooseExtensionKeyQuestion.php
@@ -36,6 +36,7 @@
 #[AutoconfigureTag('ext-kickstarter.command.question.type-converter')]
 #[AutoconfigureTag('ext-kickstarter.command.question.upgrade-wizard')]
 #[AutoconfigureTag('ext-kickstarter.command.question.validator')]
+#[AutoconfigureTag('ext-kickstarter.command.question.view-helper')]
 readonly class ChooseExtensionKeyQuestion extends AbstractQuestion
 {
     public const ARGUMENT_NAME = 'choose_extension';

diff --git a/Classes/Command/ViewHelperCommand.php b/Classes/Command/ViewHelperCommand.php
@@ -0,0 +1,247 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the package friendsoftypo3/kickstarter.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace FriendsOfTYPO3\Kickstarter\Command;
+
+use FriendsOfTYPO3\Kickstarter\Command\Input\Question\ChooseExtensionKeyQuestion;
+use FriendsOfTYPO3\Kickstarter\Command\Input\QuestionCollection;
+use FriendsOfTYPO3\Kickstarter\Context\CommandContext;
+use FriendsOfTYPO3\Kickstarter\Information\ViewHelperInformation;
+use FriendsOfTYPO3\Kickstarter\Service\Creator\ViewHelperCreatorService;
+use FriendsOfTYPO3\Kickstarter\Traits\AskForExtensionKeyTrait;
+use FriendsOfTYPO3\Kickstarter\Traits\CreatorInformationTrait;
+use FriendsOfTYPO3\Kickstarter\Traits\ExtensionInformationTrait;
+use FriendsOfTYPO3\Kickstarter\Traits\TryToCorrectClassNameTrait;
+use Psr\Http\Message\UploadedFileInterface;
+use Symfony\Component\Console\Attribute\AsCommand;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Console\Style\SymfonyStyle;
+use TYPO3\CMS\Core\Attribute\AsNonSchedulableCommand;
+use TYPO3\CMS\Core\Resource\FileReference;
+use TYPO3\CMS\Extbase\Persistence\ObjectStorage;
+
+#[AsCommand('make:view-helper', 'Create a new ViewHelper. See also https://docs.typo3.org/permalink/t3coreapi:fluid-custom-viewhelper')]
+#[AsNonSchedulableCommand]
+class ViewHelperCommand extends Command
+{
+    use AskForExtensionKeyTrait;
+    use CreatorInformationTrait;
+    use ExtensionInformationTrait;
+    use TryToCorrectClassNameTrait;
+
+    public function __construct(
+        private readonly ViewHelperCreatorService $viewHelperCreatorService,
+        private readonly QuestionCollection $questionCollection,
+    ) {
+        parent::__construct();
+    }
+
+    protected function configure(): void
+    {
+        $this->addArgument(
+            'extension_key',
+            InputArgument::OPTIONAL,
+            'Provide the extension key you want to extend',
+        );
+    }
+
+    protected function execute(InputInterface $input, OutputInterface $output): int
+    {
+        $commandContext = new CommandContext($input, $output);
+        $io = $commandContext->getIo();
+        $io->title('Welcome to the TYPO3 Extension Builder');
+
+        $io->text([
+            'We are here to assist you in creating a new Fluid ViewHelper. ',
+            'https://docs.typo3.org/permalink/t3coreapi:fluid-custom-viewhelper on how implement its functionality.',
+        ]);
+
+        $viewHelperInformation = $this->askForViewHelperInformation($commandContext);
+        $this->viewHelperCreatorService->create($viewHelperInformation);
+        $this->printCreatorInformation($viewHelperInformation->getCreatorInformation(), $commandContext);
+
+        return Command::SUCCESS;
+    }
+
+    private function askForViewHelperInformation(CommandContext $commandContext): ViewHelperInformation
+    {
+        $io = $commandContext->getIo();
+        $extensionInformation = $this->getExtensionInformation(
+            (string)$this->questionCollection->askQuestion(
+                ChooseExtensionKeyQuestion::ARGUMENT_NAME,
+                $commandContext,
+            ),
+            $commandContext
+        );
+
+        $name = $this->askForViewHelperName($io);
+
+        return new ViewHelperInformation(
+            extensionInformation: $extensionInformation,
+            name: $name,
+            arguments: $this->askForArguments($commandContext->getIo()),
+        );
+    }
+
+    private function askForArguments(SymfonyStyle $io): array
+    {
+        $arguments = [];
+
+        $typeMap = [
+            'string' => 'string',
+            'int' => 'int',
+            'bool' => 'bool',
+            'float' => 'float',
+            'array' => 'array',
+            'mixed' => 'mixed',
+            'DateTimeInterface' => \DateTimeInterface::class,
+            'FileReference (TYPO3)' => FileReference::class,
+            'UploadedFile (PSR-7)' => UploadedFileInterface::class,
+            'ObjectStorage (Extbase)' => ObjectStorage::class,
+            'Custom class' => 'custom',
+        ];
+
+        while (true) {
+            while (true) {
+                $name = (string)$io->ask('Argument name (leave empty to finish)');
+
+                if ($name === '') {
+                    break 2; // exit BOTH loops correctly
+                }
+
+                // already valid (strict Fluid-style)
+                if (preg_match('/^[a-z][a-zA-Z0-9]*$/', $name)) {
+                    break;
+                }
+
+                // try to suggest correction
+                $suggestion = $this->toLowerCamelCase($name);
+
+                if ($suggestion === '' || !preg_match('/^[a-z][a-zA-Z0-9]*$/', $suggestion)) {
+                    $io->error('Invalid argument name. Use lowerCamelCase (e.g. "emailAddress").');
+                    continue;
+                }
+
+                if ($io->confirm(sprintf('Invalid argument name. Use "%s" instead?', $suggestion), true)) {
+                    $name = $suggestion;
+                    break;
+                }
+
+                // otherwise: loop again
+            }
+
+            // prevent duplicates
+            if (in_array($name, array_column($arguments, 0), true)) {
+                $io->error('Argument already exists.');
+                continue;
+            }
+
+            // type selection
+            $typeLabel = $io->choice('Type', array_keys($typeMap), 'string');
+            $type = $typeMap[$typeLabel];
+
+            if ($type === 'custom') {
+                $type = $this->askForFqn($io);
+            }
+
+            $description = (string)$io->ask('Description');
+            $required = $io->confirm('Required?', true);
+
+            $argument = [$name, $type, $description, $required];
+
+            // default only if NOT required
+            if (!$required) {
+                $defaultInput = $io->ask('Default value (leave empty for none)');
+                if ($defaultInput !== null && $defaultInput !== '') {
+                    $argument[] = $this->normalizeDefaultValue($defaultInput, $type);
+                }
+            }
+
+            $arguments[] = $argument;
+        }
+
+        return $arguments;
+    }
+
+    private function askForFqn(SymfonyStyle $io): string
+    {
+        do {
+            $fqn = (string)$io->ask('Enter fully qualified class name (e.g. \\Vendor\\Package\\Model\\Foo)');
+
+            $isValid = preg_match('/^\\\\?[A-Za-z_][A-Za-z0-9_\\\\]*$/', $fqn);
+
+            if (!$isValid) {
+                $io->error('Invalid class name. Must be a valid FQN.');
+            }
+        } while (!$isValid);
+
+        return ltrim($fqn, '\\'); // normalize
+    }
+
+    private function toLowerCamelCase(string $input): string
+    {
+        $clean = preg_replace('/[^a-zA-Z0-9]+/', ' ', $input);
+
+        $words = explode(' ', trim($clean));
+        $words = array_filter($words);
+
+        if ($words === []) {
+            return '';
+        }
+
+        $first = strtolower(array_shift($words));
+        $rest = array_map(fn($w): string => ucfirst(strtolower($w)), $words);
+
+        return $first . implode('', $rest);
+    }
+
+    private function normalizeDefaultValue(string $value, string $type): mixed
+    {
+        return match ($type) {
+            'integer', 'int' => (int)$value,
+            'float' => (float)$value,
+            'boolean', 'bool' => filter_var($value, FILTER_VALIDATE_BOOLEAN),
+            default => $value,
+        };
+    }
+
+    private function askForViewHelperName(SymfonyStyle $io): string
+    {
+        $defaultName = null;
+        do {
+            $name = (string)$io->ask(
+                'Please provide the name of your ViewHelper',
+                $defaultName,
+            );
+
+            if (preg_match('/^\d/', $name)) {
+                $io->error('ViewHelper name should not start with a number.');
+                $defaultName = $this->tryToCorrectClassName($name, '');
+                $validValidatorName = false;
+            } elseif (preg_match('/[^a-zA-Z0-9]/', $name)) {
+                $io->error('ViewHelper name contains invalid chars. Please provide just letters and numbers.');
+                $defaultName = $this->tryToCorrectClassName($name, '');
+                $validValidatorName = false;
+            } elseif (preg_match('/^[a-z0-9]+$/', $name)) {
+                $io->error('ViewHelper must be written in UpperCamelCase like BlogExampleValidator.');
+                $defaultName = $this->tryToCorrectClassName($name, '');
+                $validValidatorName = false;
+            } else {
+                $validValidatorName = true;
+            }
+        } while (!$validValidatorName);
+
+        return $name;
+    }
+}