qr_generator-1.0.1/src/Form/OfflineQRCodeExportForm.php

<?php

declare(strict_types=1);

namespace Drupal\qr_generator\Form;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;
use Endroid\QrCode\Builder\Builder;
use Symfony\Component\HttpFoundation\Response;
use Endroid\QrCode\Writer\PngWriter;
use Endroid\QrCode\Writer\SvgWriter;
use Endroid\QrCode\Writer\PdfWriter;

/**
 * Form controller for generating and exporting stand-alone (offline) QR codes.
 *
 * This form lets a user enter a target URL and generate a downloadable QR code
 * without relying on any host system or online service at scan time.
 *
 * Key features:
 * - Accepts a full URL from the user.
 * - Allows customization of QR code size (in pixels) and margin.
 * - Supports multiple output formats (PNG, SVG, PDF).
 * - Uses the Endroid\QrCode library to create the QR code image.
 * - Streams the generated QR code directly to the browser as a file download.
 *
 * Workflow:
 * 1. User enters a valid URL and selects output parameters.
 * 2. Form validates the URL format, size, margin, and output format.
 * 3. Based on the chosen format, the corresponding writer (PngWriter, SvgWriter, PdfWriter) is instantiated.
 * 4. The QR code is generated using Endroid\QrCode\Builder with the given parameters.
 * 5. A binary response is returned to the browser with the proper MIME type and
 *    a filename based on the current timestamp.
 *
 * Example use cases:
 * - Creating QR codes for printed materials that point to static online resources.
 * - Providing direct access to a configuration URL for devices in offline-friendly contexts.
 * - Generating QR codes for physical product labels or event passes.
 *
 * @package Drupal\qr_generator\Form
 */
final class OfflineQRCodeExportForm extends FormBase
{

  /**
   * {@inheritdoc}
   */
  public function getFormId(): string
  {
    return 'qr_generator_offline_q_r_code_export';
  }

  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state): array
  {
    $form['link'] = [
      '#type' => 'url',
      '#title' => $this->t('URL'),
      '#description' => $this->t('Enter a full URL, including http:// or https://'),
      '#required' => TRUE,
    ];
    $form['size'] = [
      '#type' => 'number',
      '#title' => $this->t('Size (px)'),
      '#default_value' => 300,
      '#min' => 100,
      '#max' => 1000,
    ];
    $form['margin'] = [
      '#type' => 'number',
      '#title' => $this->t('Margin'),
      '#default_value' => 10,
      '#min' => 0,
      '#max' => 50,
    ];

    $form['format'] = [
      '#type' => 'select',
      '#title' => $this->t('Output format'),
      '#options' => [
        'png' => 'PNG',
        'svg' => 'SVG',
        'pdf' => 'PDF',
      ],
      '#default_value' => 'png',
    ];

    $form['submit'] = [
      '#type' => 'submit',
      '#value' => $this->t('Generate QR Code'),
    ];

    return $form;
  }

  /**
   * {@inheritdoc}
   */
  public function validateForm(array &$form, FormStateInterface $form_state): void
  {
    $url = $form_state->getValue('link');
    if (!filter_var($url, FILTER_VALIDATE_URL)) {
      $form_state->setErrorByName('link', $this->t('Please enter a valid URL.'));
    }
    $size = (int) $form_state->getValue('size');
    $margin = (int) $form_state->getValue('margin');
    $format = $form_state->getValue('format');

    // Validate size
    if ($size <= 0) {
      $form_state->setErrorByName('size', $this->t('Size must be a positive number.'));
    }

    // Validate margin
    if ($margin < 0) {
      $form_state->setErrorByName('margin', $this->t('Margin cannot be negative.'));
    }

    // Validate format
    $allowed_formats = ['png', 'pdf', 'svg']; // Example allowed values
    if (!in_array($format, $allowed_formats)) {
      $form_state->setErrorByName('format', $this->t('Invalid format selected. Allowed formats: @formats', [
        '@formats' => implode(', ', $allowed_formats),
      ]));
    }
  }

  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state): void
  {
    $url = $form_state->getValue('link');
    $size = (int) $form_state->getValue('size');
    $margin = (int) $form_state->getValue('margin');
    $format = $form_state->getValue('format');
    

    // Determine writer
    $writer = match ($format) {
      'svg' => new SvgWriter(),
      'pdf' => new PdfWriter(),
      default => new PngWriter(),
    };

    $builder = new Builder();
    $result = $builder->build($writer, null, false, $url, null, null, $size, $margin);
    $filename = \Drupal::time()->getCurrentTime() . '.' . $format;
    $response = new Response($result->getString());
    $response->headers->set('Content-Type', $result->getMimeType());
    $response->headers->set('Content-Disposition', 'attachment; filename="'.$filename.'"');
    $response->send();
    exit;
  }
}